In the pursuit of high-performance single-molecule magnets(SMMs),incorporating intramolecular magnetic coupling emerges as a pivotal strategy.Among these,d-f SMMs have garnered significant attention due to their remar...In the pursuit of high-performance single-molecule magnets(SMMs),incorporating intramolecular magnetic coupling emerges as a pivotal strategy.Among these,d-f SMMs have garnered significant attention due to their remarkable versatility,which lies in their ability to tune coordination environments and facilely substitute metal centers.However,achieving performance-centric d-f SMMs through the synergistic interplay between highly anisotropic f ions and d-f magnetic interactions remains a formidable challenge.While mononuclear hexagonal bipyramidal(D_(6h))Dy^(Ⅲ)SMMs have been successfully isolated,the exploration of d-f SMMs featuring D_(6h)-lanthanide metal centers remains uncharted territory.In this study,we employed planar bipodal ligands in conjunction with“staple-like”axial phenoxide ligands to synthesize the first hexagonal bipyramidal d-f SMM.Remarkably,this compound exhibits alternating-current magnetic susceptibilities peaking up to 68 K with an energy barrier surpassing 1,200 K,thus establishing a new benchmark within the heterometallic d-f SMM landscape inclusive of complexes with diamagnetic d metals and paramagnetic f ions.Notably,the ferromagnetic interaction at the d-f sites engenders oscillating relaxation times contingent on the magnetic field—a characteristic distinct from mononuclear SMMs.These findings shed light on a deliberate design approach for d-f SMMs,emphasizing the cooperative utilization of high-barrier lanthanide modules alongside d ions through magnetic interactions.This synergy significantly enhances and diversifies the magnetic dynamics of these intriguing molecular systems.展开更多
We report here a new Dy^(Ⅲ)-SIM[Dy(OPCy_(3))_(2)(H_(2)O)_(5)](CF_(3)SO_(3))_(3)·_(2)OPCy_(3)(OPCy_(3)=tricyclohexylphosphine oxide)with a pentagonal bipyramidal geometry,which exhibits a blocking temperature T_(...We report here a new Dy^(Ⅲ)-SIM[Dy(OPCy_(3))_(2)(H_(2)O)_(5)](CF_(3)SO_(3))_(3)·_(2)OPCy_(3)(OPCy_(3)=tricyclohexylphosphine oxide)with a pentagonal bipyramidal geometry,which exhibits a blocking temperature T_(B)=8.5 K and an anisotropy barrier U_(eff)=562 K.Ab initio calculations show that this complex exhibits the largest U_(calc)=732 K among the Dy^(Ⅲ)-SIM complexes containing the[Dy(L)_(2)(H_(2)O)_(5)]^(3+)(L=phosphine oxide derivative)cationic unit.展开更多
A range of pyrazolate-based ligands have been used to balance the multidentate-chelating feature and the magnetic axiality in“destroyed”pentagonal-bipyramidal(DPB)dysprosium(III)single-molecule magnets(SMMs).This fa...A range of pyrazolate-based ligands have been used to balance the multidentate-chelating feature and the magnetic axiality in“destroyed”pentagonal-bipyramidal(DPB)dysprosium(III)single-molecule magnets(SMMs).This family of complexes are air-stable and share the general formulae of[DyX^(1)X^(2)(L_(eq))_(5)][BPh_(4)],where X^(1)and X^(2)are the anionic axial ligands,including pyrazolate-based ligands and chloride;L_(eq)is the equatorial solvent molecule such as tetrahydrofuran(THF),pyridine(py)and thiazole(NS).展开更多
The fabrication of electronic devices utilizing single-molecule magnets(SMMs)requires deposition on conducting surfaces,which usually consist of thiophilic elements such as gold,silver and copper.Thus,SMMs possessing ...The fabrication of electronic devices utilizing single-molecule magnets(SMMs)requires deposition on conducting surfaces,which usually consist of thiophilic elements such as gold,silver and copper.Thus,SMMs possessing sulphur-containing ligands that are capable of attaching on such surfaces through chemical bonding are fascinating.Here,we designed and successfully isolated a series of pentagonalbipyramidal dysprosium(Ⅲ)compounds with a sulfur-containing macrocycle PYNS ligand,[Dy(L_(A))_(2)(PYNS)][BPh_(4)](PYNS=2,6-bis(4-(pyridin-2-yl)thiazol-2-yl)pyridine);L_(A)^(−)=^(t)BuO^(−)for 1Dy;(S)-PhEtO^(−)for 2Dy;CF_(3)PhMeO^(−)for 3Dy;Ph_(3)SiO^(−)for 4Dy;(^(t)BuO)_(3)SiO^(−)for 5Dy).They exhibit zero-field SMM behaviour with effective energy barriers U_(eff) between 679 and 807 K,and the magnetic blocking temperatures T_(B)^(IRREV) for 3Dy and 5Dy were determined to be 2.5 K while,that of 4Dy is 3 K.The sulfur atoms at the peripheral position of PYNS are expected to act as linkers to adsorb the molecules onto gold surfaces.展开更多
Pentagonal bipyramidal(PBP)complexes with a first-order spin–orbit coupling contribution can be readily obtained,mainly through chemical design optimization ensuring minimum structural distortion and a more symmetric...Pentagonal bipyramidal(PBP)complexes with a first-order spin–orbit coupling contribution can be readily obtained,mainly through chemical design optimization ensuring minimum structural distortion and a more symmetrical ligand field.This conclusion follows from the investigation of a series of five Fe(II)complexes:[FeL^(N5)(H_(2)O)Cl]Cl·4.5H_(2)O,1;[FeL^(N5)Cl_(2)]·3H_(2)O,2;[FeL^(N5)Br_(2)],3;[FeL^(N5)I_(2)],4;and[Fe_(0.12)Zn_(0.88)L^(N5)I_(2)],5(L^(N5) stands for the pentadentate macrocyclic ligand formed by the condensation of 2,6-diacetylpyridine and 2,9-di(α-methylhydrazino)-1,10-phenanthroline).Theoretical calculations revealed quasi-degeneracy of the dxz and dyz orbitals for the complexes with halide ligands at the apical positions(ΔE=91,134,and 142 cm^(−1),respectively,for 2–4).This small energy gap leads to SO states with very strong mixing of the ground and first excited quintet states.Therefore,the ZFS Hamiltonian is not suitable for modelling the magnetic properties of complexes 2–5.This does not apply for 1 withΔE=412 cm^(−1).The recorded magnetic behaviors indicated strong magnetic anisotropy;for 1 D=−24 cm^(−1) was obtained.The Br and I derivatives were found to behave as SMMs(with a U/k_(B) of about 90 K),the latter even in the absence of a static field.展开更多
Low-symmetry metal-organic cages(MOCs)have received increasing attention due to their complex structures and more advanced functions.Here,we report a new MOC cage with a unique trigonal bipyramidal configuration,[M_(5...Low-symmetry metal-organic cages(MOCs)have received increasing attention due to their complex structures and more advanced functions.Here,we report a new MOC cage with a unique trigonal bipyramidal configuration,[M_(5)L_(6)],constructed via the combination effects of coordination bonds and π…π interactions.A series of structures(BIF-136 to BIF-141)based on this[M_(5)L_(6)]cage were synthesized by the self-assembly of BH(bim)_(3)-ligands and Ni(II)ions under various solvothermal conditions.Each[M_(5)L_(6)]consists of two[M_(4)L_(3)]defective cubic cages sharing three metal nodes,which include two geometric types of flexible Ni(Ⅱ)centers(tetrahedral and octahedral).Benefiting from these modifiable metal centers,these cage-based crystals realized abundant coordination environments and a dimension transition from a 0D cage to a 1D cage-based chain,accompanied by modulations of conjugation degrees,electronic push-pull effects and band gaps.Due to their diverse structural features,we have systematically investigated their third-order nonlinear optical(NLO)properties.To our surprise,these structures show a typical reverse saturated absorption(RSA)response.In particular,BIF-141 achieves excellent optical limiting(OL)performance with a low minimum normalized transmittance(T_(min))of 0.20.This study not only provides a new strategy for constructing low-symmetry cages but also contributes to the understanding of the mechanism of their optical applications.展开更多
A Ni(Ⅱ)complex harnessed in a pentagonal bipyramidal environment by a rigid N_(5)-macrocyclic ligand(i.e.1,3,10,12-tetramethyl-1,2,11,12-tetraaza[3](2,6)-pyridino[3](2,9)-1,10-phenanthrolinophane-2,10-diene)is shown ...A Ni(Ⅱ)complex harnessed in a pentagonal bipyramidal environment by a rigid N_(5)-macrocyclic ligand(i.e.1,3,10,12-tetramethyl-1,2,11,12-tetraaza[3](2,6)-pyridino[3](2,9)-1,10-phenanthrolinophane-2,10-diene)is shown to exhibit axial anisotropy with a ZFS D parameter in the order of−10 to−15 cm^(-1),and this anisotropy is not significantly changed by apical ligand substitution.Using the latter complex as a building unit,a ferromagnetic 1-D CN-bridged Ni-Cr coordination polymer with SCM behavior characterized by a barrier of magnetization reversal U_(eff)/k_(B)=54 K(37 cm^(-1))withτ0=2.28×10^(−11)s was obtained.The Cr(Ⅲ)complex involved in the design was chosen to favor parallel organization of the anisotropy axes of the Ni units along the 1-D array,and thus maximize the magnetic anisotropy of the supramolecular system.A related chain compound prepared with diamagnetic[Ni(CN)_(4)]^(2−)units,and a trinuclear CN-bridged[NiCr_(2)]complex enabled assessing respectively the magnetic anisotropy of Ni(Ⅱ)in this coordination sphere and its exchange interaction with Cr(Ⅲ)found to be ferromagnetic and of the order of 10 cm^(-1).The crystal structures and magnetic behaviors of all compounds are reported.展开更多
By allowing H_(2)SeO_(4),Cy_(2)NH,CyNH_(2) or Bz2NH to react respectively with SnPh_(3)Cl(in methanol),SnPh_(2)Cl_(2)(in water+methanol)and MgCl_(2)·6H_(2)O(in methanol)in specific ratios,the studied complexes ar...By allowing H_(2)SeO_(4),Cy_(2)NH,CyNH_(2) or Bz2NH to react respectively with SnPh_(3)Cl(in methanol),SnPh_(2)Cl_(2)(in water+methanol)and MgCl_(2)·6H_(2)O(in methanol)in specific ratios,the studied complexes are obtained.The suggested structures are discrete and polymer,the environment of the tin center being trans trigonal bipyramidal(compound 1),tetrahedral(compound 2)and octahedral(compound 3),the anions behaving as a bidentate selenate.展开更多
One new hydrogenosuccinate and two succinate adduct and complex have been synthesized and studied by infrared,UV-Visible and NMR(Nuclear Magnetic Resonance Spectroscopy)^(119)Sn spectroscopies.The suggested structure ...One new hydrogenosuccinate and two succinate adduct and complex have been synthesized and studied by infrared,UV-Visible and NMR(Nuclear Magnetic Resonance Spectroscopy)^(119)Sn spectroscopies.The suggested structure is discrete,the hydrogenosuccinate behaving as a monodentate ligand or only involved in hydrogen bonding,the environment around the magnesium centre being triangular(compound 3).The succiate anion is a monochelating ligand(compound 1 and 2).In all the suggested structures,when extra hydrogen bonds are considered,supramolecular architectures are obtained(compound 2 and 3).展开更多
Herein,we have presented a novel and easy to operate seed-mediated system for fabricating gold bipyramids(AuBPs)with 85%yields without any separation/purification processes.The used gold seeds are reduced by tannin an...Herein,we have presented a novel and easy to operate seed-mediated system for fabricating gold bipyramids(AuBPs)with 85%yields without any separation/purification processes.The used gold seeds are reduced by tannin and citrate,two kinds of air stable ligands,and conventio nally employed unstable NaBH4 are thoroughly cast off.In addition,the as-proposed gold seeds can also be employed for AuNRs fabrication with rather larger diameters(22.2-60.3 nm),which is difficult to be achieved by conve ntional seed mediated fabrication system.展开更多
The complex Fe(aapo)2Cl3 with chemical formula C14H16Cl3FeN4O4 was obtained by the reaction of FeCl36H2O with apoHCl (apo = 2璦mino pyridine N璷xide) in acetonitrile. The result shows that CH3CN has been hydrolysised ...The complex Fe(aapo)2Cl3 with chemical formula C14H16Cl3FeN4O4 was obtained by the reaction of FeCl36H2O with apoHCl (apo = 2璦mino pyridine N璷xide) in acetonitrile. The result shows that CH3CN has been hydrolysised with the water from FeCl36H2O dissolving, and then the hydrolysised product condenses with apo to give aapo. A single-crystal X璻ay study of Fe(aapo)2Cl3 shows it belongs to the monoclinic system, space group C2/c with a = 15.873(3), b = 10.322(2), c = 11.987(2) ? b = 106.35(1), V = 1884.5(6) 3, Z = 4, Mr = 466.51, Dc = 1.644 g/cm3, m(MoKa) = 1.253 mm-1, F(000) = 948, R = 0.0377 and wR = 0.0749 for 1262 observed reflections with I > 2(I). Fe (Ⅲ) is coordinated by a trigonal bipyramidal geometry with three chlorine atoms lying on the equatorial plane and two oxygen atoms connected with the nitrogen atoms of pyridine rings occupying the axial positions, while the iron and Cl(1) atoms lie on the crystallographic 2-fold axis. The dihedral angle of two pyridine rings is 71.74(9). There exist N(2)H(2)…O(1)?hydrogen bonds in the crystal structure.展开更多
The title crystal of 2-germatranylmethyl-N- (4'-methylphenyl)succinimide (C18H24GeN2O5) was determined by single crystal X-ray diffraction- The crystalbelongs to the orthorhombic system, space group P212121 with M...The title crystal of 2-germatranylmethyl-N- (4'-methylphenyl)succinimide (C18H24GeN2O5) was determined by single crystal X-ray diffraction- The crystalbelongs to the orthorhombic system, space group P212121 with Mr = 420. 99, a= 6. 716(1), b=22- 860(8), c= 11. 891 (3) A, V= 1826(1) A3, Z=4,Dx= 1. 53 Mg. m-3,A= 0. 71073A, μ= 1. 684 mm-l, and F(000) =872. The structure was solved by direct methods. The final refinement is converged with unweighted and weighted agreement factors of 0. 047 and 0. 064 for 1610 observed reflections with I≥3δ(I). The results of structure analysis indicate that the framework of this five-coordinated germanium compound is a distorted trigonal bipyramid(TBP).展开更多
Two novel complexes {[Zn（IM4py）2（tp）（H2O）]2H2O}. 1 and {[Cd（IM4py）2（tp）- （H2O）]1.25H2O},, 2 （IM4py = 2-（4＇-pyridinyl）-4,4,5,5-tetramethylimidazoline-l-oxyl and tp = terephthalate dianion） have been sy...Two novel complexes {[Zn（IM4py）2（tp）（H2O）]2H2O}. 1 and {[Cd（IM4py）2（tp）- （H2O）]1.25H2O},, 2 （IM4py = 2-（4＇-pyridinyl）-4,4,5,5-tetramethylimidazoline-l-oxyl and tp = terephthalate dianion） have been synthesized and characterized by elemental analyses, IR spectrum and single-crystal X-ray diffraction. Crystal data for complex I： monoclinic, space group C2/c, a = 20.648（7）, b = 12.130（4）, c = 14.036（4） A, β = 106.351（5）°, C32H42N6O9Zn, Mr = 720.09, V = 3373.3（2） A3, Z= 4, Dc = 1.418 g/cm^3μt（MoKα） = 0.790 mm^-1, F（000） = 1512, the final R = 0.0407 and wR = 0.0894 for 3480 independent reflections with Rint = 0.0432. Crystal data for complex 2： monoclinic, space group C2/c, a = 21.332（6）, b = 12.063（3）, c = 14.246（4） A, β = 106.704（4）°, C32H40.50N6O8.25Cd, Mr = 753.60, V= 3511.2（2） A^3, Z = 4, Dc = 1.426 g/cm^3,μ（MoKα） = 0.679 mm^--1, F（000） = 1554, the final R = 0.0419 and wR = 0.0961 for 3627 independent reflections with Rint = 0.0440. The framework structures of complexes 1 and 2 are 3-D networks via the hydrogen bonds among 1-D chains. The notable characteristics of the two complexes are that the coordination polyhedron of Zn（Ⅱ） adopts a rare distorted five-coordinate square pyramidal geometry in 1, and the Cd（Ⅱ） complex exhibits an unusual distorted seven-coordinate pentagonal bipyramid in 2.展开更多
Novel coordinatively saturated platinum(II)compounds bearing C-linked carbohydrates were synthesized and characterized.The complexes exhibit bipyramidal trigonal geometry with a bidentate nitrogen ligand and ethylene ...Novel coordinatively saturated platinum(II)compounds bearing C-linked carbohydrates were synthesized and characterized.The complexes exhibit bipyramidal trigonal geometry with a bidentate nitrogen ligand and ethylene in the equatorial plane.The axial positions are occupied by a halide ligand X and a D-galactose or D-glucose derivative,linked either via C1 or C6.The compounds were designed for evaluation of the biological activity because they combine the steady coordinative saturation,the beneficial action of the modular sugar moiety and the organometallic nature of the Pt-sugar linkage,which is expected to be stable in the biological media,until the target is reached.The newly synthesized molecules were stable in mixed DMSO/aqueous solvents,able to bind DNA in vitro and exhibited a selective cytotoxic activity on cancer cells through apoptosis activation.展开更多
Using the[1+1]condensation approach for the preparation of new macrocyclic scaffolds(L^(N6)_(phen)and L^(N4O2)_(phen))with the rigid phenanthroline-based‘head’unit produces the air-stable mononuclear compounds[Dy(L^...Using the[1+1]condensation approach for the preparation of new macrocyclic scaffolds(L^(N6)_(phen)and L^(N4O2)_(phen))with the rigid phenanthroline-based‘head’unit produces the air-stable mononuclear compounds[Dy(L^(N6)_(phen))(Ph_(3)SiO)_(2)](PF_(6))(1-L^(N6)_(phen))and[Dy(L^(N4O2)_(phen))(Ph_(3)SiO)_(2)](PF_(6))(1-L^(N4O2)_(phen))through a stepwise metal-ion templated synthesis.Both compounds exhibit pseudo-D_(6h)symmetry with different degrees of distortion from the ideal hexagonal bipyramidal geometry,depending on the planarity of the equatorial macrocycles and the intramolecularπ-πstacking interactions between the phenyl groups of the apical siloxide ligand and the equatorial macrocycle.Both compounds are single-molecule magnets(SMMs)with large energy barriers for the magnetization reversal,exhibiting out-of-phase AC susceptibility signals up to 75 K or 90 K.The closer-to-ideal D_(6h)complex 1-L^(N4O2)_(phen)possesses a U_(eff)of 1360 K,which is the highest reported barrier among all mononuclear Dy^(Ⅲ)SMMs synthesized using the[1+1]Schiff-base macrocycle approach.The experimental results are supported by ab initio calculations,which indicate relaxation of the magnetization via the first-or second-excited state for 1-L^(N6)_(phen)and 1-L^(N4O2)_(phen),respectively.The results demonstrate the ability of Schiff-base macrocycles to facilitate the synthesis of high-performance and air-stable SMMs through a chemical modulation of the individual carbonyl‘head’and amine subunits,deciphering the factors which affect the magnetic dynamics of SMMs.展开更多
Four compounds with the formula[M_(2)(dmphen)4(μ-C_(2)O_(4))](ClO_(4))_(2)·2dmso[M=Fe(1),Co(2)and Zn(4);dmphen=2,9-dimethyl-1,10-phenanthroline]and[Ni2(dmphen)_(4)(μ-C_(2)O_(4))]_(3)[NbO(C_(2)O_(4))_(3)]2·...Four compounds with the formula[M_(2)(dmphen)4(μ-C_(2)O_(4))](ClO_(4))_(2)·2dmso[M=Fe(1),Co(2)and Zn(4);dmphen=2,9-dimethyl-1,10-phenanthroline]and[Ni2(dmphen)_(4)(μ-C_(2)O_(4))]_(3)[NbO(C_(2)O_(4))_(3)]2·_(16)H_(2)O(3)have been synthesized using the tris(oxalato)oxoniobate(V)complex anion as the oxalate source,and their structures have been determined by single crystal X-ray diffraction.X-ray quality crystals of highly insoluble oxalate-bridged species were obtained by taking advantage of the slow release of oxalate by the tris(oxalato)oxoniobate(V)complex anion.The structures of 1-4 all contain oxalate-bridged dimetal(Ⅱ)units with didentate dmphen molecules acting as end-cap ligands;electroneutrality is achieved by perchlorate(1-4)and oxotris(oxalato)niobate(V)(3)anions.Each divalent metal ion in 1-4 is tris-chelated in a six-coordinate distorted octahedral environment.The niobium(V)ion in 3 is seven-coordinate in a distorted pentagonal bipyramidal geometry built from one oxo group and six oxygen atoms from three didentate oxalate ligands.The values of the metal-metal separation across the bis-chelating oxalate are 5.626(1)(1),5.575(1)(2),5.434(1)to 5.447(1)(3)and 5.603(1)Å(4).The cryomagnetic measurements in the temperature range of 2.0 to 300 K for compounds 1-3 show the occurrence of antiferromagnetic interactions between the divalent metal ions across the oxalate bridge.The nature and amplitude of these magnetic interactions are rationalized by simple symmetry considerations and compared with those previously reported for related oxalate-bridged systems.展开更多
We herein report the syntheses,crystal structures,and magnetic properties of two complexes based on the anisotropic pentagonal bipyramidal Fe^(Ⅱ) starting material[Fe(L_(N_(3)O_(2)))]^(2+),namely[Fe(L_(N_(3)O_(2)))(H...We herein report the syntheses,crystal structures,and magnetic properties of two complexes based on the anisotropic pentagonal bipyramidal Fe^(Ⅱ) starting material[Fe(L_(N_(3)O_(2)))]^(2+),namely[Fe(L_(N_(3)O_(2)))(H_(2)O)_(2)]-[MQ]2·H_(2)O(1)and[Fe(L_(N_(3)O_(2)))(CN)][ABSA]·3H_(2)O(2)(L_(N_(3)O_(2))=2,13-dimethyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene;MQ^(−)=methyl orange anion;ABSA^(−)=4-aminoazobenzene-4’-sulfonic anion).Compound 1 is a mononuclear material where the[Fe(L_(N_(3)O_(2)))(H_(2)O)_(2)]^(2+)cations form a one-dimensional(1D)chain by the hydrogen bonds between the bulky MQ^(−)anions and the coordinated water molecules.With a slightly different anion,ABSA^(−),a cyano-bridged Fe^(Ⅱ) chain is formed for compound 2.This chain has a similar structure as that in our recently reported compound[Fe(L_(N_(5)))(CN)][BF4](Chem.Commun.,2015,51,4360).However,compared with the reported result where the chains interact with each other through theπ⋯πinteractions,the chains in 2 are well isolated by the bulky ABSA^(−)anions with the shortest interchain Fe⋯Fe distances around 12.0Å.Magnetic investigation on 1 reveals the easyaxis magnetic anisotropy of the mononuclear Fe^(Ⅱ) centre(zero-field splitting parameter D=−3.7 cm^(−1)),which leads to the field-induced slow magnetic relaxation.For compound 2,the Fe^(2+)spins are antiferromagnetically coupled through the cyano bridges with a coupling constant of J=−4.13(2)cm^(−1) with the Hamiltonian H=−JΣS_(i)·S_(i+1).AC magnetic measurements revealed the pure single-chain magnetic(SCM)behaviour of these isolated chains with an effective energy barrier of 26.1(5)K.This system represents a good example showing that the structures and magnetic properties,such as field-induced single-ion magnets,SCMs,and SCM-based magnets,can be selectively prepared by anion modification.展开更多
The mononuclear complex[Yb(H_(3)L^(1,1,4))]·2MeOH(1·2MeOH),with a new heptadentate N4O3 ligand,was isolated and structurally characterised.The opto-magnetic properties of 1·2MeOH were investigated,showi...The mononuclear complex[Yb(H_(3)L^(1,1,4))]·2MeOH(1·2MeOH),with a new heptadentate N4O3 ligand,was isolated and structurally characterised.The opto-magnetic properties of 1·2MeOH were investigated,showing that this complex is a bifunctional compound.Accordingly,1·2MeOH reveals two coexisting functionalities:field-induced single molecule magnet behaviour,and Yb^(3+)-centred NIR fluorescence dependent on temperature(25-300 K).The magnetic relaxation in this pentagonal bipyramidal complex does not seem to be of the Orbach type,and this is supported by the discrepancy between the anisotropic energy barrier found by fitting the magnetic data to an Orbach model and by spectroscopic studies.Ab initio calculations further validate the magnetic relaxation mechanisms and spectroscopic results.展开更多
Crystalline borates are a rich source of diverse optical materials.Here,a rare earth borate fluoride,Sc_(2)F_(2)(B_(2)O_(5)),has been obtained by a conventional hydrothermal reaction.It is unlike other rare earth bora...Crystalline borates are a rich source of diverse optical materials.Here,a rare earth borate fluoride,Sc_(2)F_(2)(B_(2)O_(5)),has been obtained by a conventional hydrothermal reaction.It is unlike other rare earth borate fluorides synthesized under harsh conditions.In the layered structure of Sc_(2)F_(2)(B_(2)O_(5)),ScO_(4)F_(2) octahedra and ScO_(5)F_(2) pentagonal bipyramids connect to each other to form[Sc_(4)O_(10)F_(4)]_(∞) frameworks,which are further linked by B_(2)O_(5)^(4−)anion groups.Specifically,Sc_(2)F_(2)(B_(2)O_(5))does not belong to any types of reported rare earth borate fluoride.More attractively,this compound displays a deep ultraviolet cutoff edge(<200 nm)and very large birefringence(0.19)at 1064 nm based on theoretical calculations.The outstanding birefringence can be seen to originate from the synergistic effect of B_(2)O_(5) and ScO_(n)F_(2) groups when analysed for their polarizability anisotropy-weighted electron density(PAWED).展开更多
基金supported by the National Natural Science Foundation of China(22073115,22131011,21821003)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(24xkjc003)。
文摘In the pursuit of high-performance single-molecule magnets(SMMs),incorporating intramolecular magnetic coupling emerges as a pivotal strategy.Among these,d-f SMMs have garnered significant attention due to their remarkable versatility,which lies in their ability to tune coordination environments and facilely substitute metal centers.However,achieving performance-centric d-f SMMs through the synergistic interplay between highly anisotropic f ions and d-f magnetic interactions remains a formidable challenge.While mononuclear hexagonal bipyramidal(D_(6h))Dy^(Ⅲ)SMMs have been successfully isolated,the exploration of d-f SMMs featuring D_(6h)-lanthanide metal centers remains uncharted territory.In this study,we employed planar bipodal ligands in conjunction with“staple-like”axial phenoxide ligands to synthesize the first hexagonal bipyramidal d-f SMM.Remarkably,this compound exhibits alternating-current magnetic susceptibilities peaking up to 68 K with an energy barrier surpassing 1,200 K,thus establishing a new benchmark within the heterometallic d-f SMM landscape inclusive of complexes with diamagnetic d metals and paramagnetic f ions.Notably,the ferromagnetic interaction at the d-f sites engenders oscillating relaxation times contingent on the magnetic field—a characteristic distinct from mononuclear SMMs.These findings shed light on a deliberate design approach for d-f SMMs,emphasizing the cooperative utilization of high-barrier lanthanide modules alongside d ions through magnetic interactions.This synergy significantly enhances and diversifies the magnetic dynamics of these intriguing molecular systems.
基金support from Ministerio de Economía y Competitividad(MINECO)for Projects CTQ2014-56312-P and PGC2018-102052-B-C21,the Junta de Andalucía(FQM-195)FEDER project A-FQM-172-UGR18 and the University of Granada is gratefully acknowledged+1 种基金A part of this work was carried out at HFLSM,IMR,Tohoku UniversityI.F.D.O.also acknowledges support by COLABS.GR would like to thank the SERB(CRG/2018/000430)for financial support.S.D.thanks the UGC for a Senior Research Fellowship.
文摘We report here a new Dy^(Ⅲ)-SIM[Dy(OPCy_(3))_(2)(H_(2)O)_(5)](CF_(3)SO_(3))_(3)·_(2)OPCy_(3)(OPCy_(3)=tricyclohexylphosphine oxide)with a pentagonal bipyramidal geometry,which exhibits a blocking temperature T_(B)=8.5 K and an anisotropy barrier U_(eff)=562 K.Ab initio calculations show that this complex exhibits the largest U_(calc)=732 K among the Dy^(Ⅲ)-SIM complexes containing the[Dy(L)_(2)(H_(2)O)_(5)]^(3+)(L=phosphine oxide derivative)cationic unit.
基金supported by the NSFC(21773130)the Key Laboratory Construction Program of Xi’an Municipal Bureau of Science and Technology(201805056ZD7CG40)+3 种基金the China Postdoctoral Science Foundation(2019T120892 and 2018M631138)the Shaanxi Postdoctoral Science Foundation,the Natural Science Basic Research Plan in Shaanxi Province of China(Program No.2019JQ-292)the Shenzhen Science and Technology Program(JCYJ20180306170859634)the Cyrus Chung Ying Tang Foundation and the Fundamental Research Funds for Central Universities.
文摘A range of pyrazolate-based ligands have been used to balance the multidentate-chelating feature and the magnetic axiality in“destroyed”pentagonal-bipyramidal(DPB)dysprosium(III)single-molecule magnets(SMMs).This family of complexes are air-stable and share the general formulae of[DyX^(1)X^(2)(L_(eq))_(5)][BPh_(4)],where X^(1)and X^(2)are the anionic axial ligands,including pyrazolate-based ligands and chloride;L_(eq)is the equatorial solvent molecule such as tetrahydrofuran(THF),pyridine(py)and thiazole(NS).
基金supported by the National Natural Science Foundation of China(No.22375157)the Fundamental Research Funds for Central Universities(No.xtr052023002)+1 种基金the Special Support Plan of Shaanxi Province for Young Topnotch Talent,the Medical-Engineering Cross Project of the First Affiliated Hospital of XJTU(No.QYJC02)Programme of Introducing Talents of Discipline to Universities(B23025).
文摘The fabrication of electronic devices utilizing single-molecule magnets(SMMs)requires deposition on conducting surfaces,which usually consist of thiophilic elements such as gold,silver and copper.Thus,SMMs possessing sulphur-containing ligands that are capable of attaching on such surfaces through chemical bonding are fascinating.Here,we designed and successfully isolated a series of pentagonalbipyramidal dysprosium(Ⅲ)compounds with a sulfur-containing macrocycle PYNS ligand,[Dy(L_(A))_(2)(PYNS)][BPh_(4)](PYNS=2,6-bis(4-(pyridin-2-yl)thiazol-2-yl)pyridine);L_(A)^(−)=^(t)BuO^(−)for 1Dy;(S)-PhEtO^(−)for 2Dy;CF_(3)PhMeO^(−)for 3Dy;Ph_(3)SiO^(−)for 4Dy;(^(t)BuO)_(3)SiO^(−)for 5Dy).They exhibit zero-field SMM behaviour with effective energy barriers U_(eff) between 679 and 807 K,and the magnetic blocking temperatures T_(B)^(IRREV) for 3Dy and 5Dy were determined to be 2.5 K while,that of 4Dy is 3 K.The sulfur atoms at the peripheral position of PYNS are expected to act as linkers to adsorb the molecules onto gold surfaces.
文摘Pentagonal bipyramidal(PBP)complexes with a first-order spin–orbit coupling contribution can be readily obtained,mainly through chemical design optimization ensuring minimum structural distortion and a more symmetrical ligand field.This conclusion follows from the investigation of a series of five Fe(II)complexes:[FeL^(N5)(H_(2)O)Cl]Cl·4.5H_(2)O,1;[FeL^(N5)Cl_(2)]·3H_(2)O,2;[FeL^(N5)Br_(2)],3;[FeL^(N5)I_(2)],4;and[Fe_(0.12)Zn_(0.88)L^(N5)I_(2)],5(L^(N5) stands for the pentadentate macrocyclic ligand formed by the condensation of 2,6-diacetylpyridine and 2,9-di(α-methylhydrazino)-1,10-phenanthroline).Theoretical calculations revealed quasi-degeneracy of the dxz and dyz orbitals for the complexes with halide ligands at the apical positions(ΔE=91,134,and 142 cm^(−1),respectively,for 2–4).This small energy gap leads to SO states with very strong mixing of the ground and first excited quintet states.Therefore,the ZFS Hamiltonian is not suitable for modelling the magnetic properties of complexes 2–5.This does not apply for 1 withΔE=412 cm^(−1).The recorded magnetic behaviors indicated strong magnetic anisotropy;for 1 D=−24 cm^(−1) was obtained.The Br and I derivatives were found to behave as SMMs(with a U/k_(B) of about 90 K),the latter even in the absence of a static field.
基金supported by the National Natural Science Foundation of China(22275192).
文摘Low-symmetry metal-organic cages(MOCs)have received increasing attention due to their complex structures and more advanced functions.Here,we report a new MOC cage with a unique trigonal bipyramidal configuration,[M_(5)L_(6)],constructed via the combination effects of coordination bonds and π…π interactions.A series of structures(BIF-136 to BIF-141)based on this[M_(5)L_(6)]cage were synthesized by the self-assembly of BH(bim)_(3)-ligands and Ni(II)ions under various solvothermal conditions.Each[M_(5)L_(6)]consists of two[M_(4)L_(3)]defective cubic cages sharing three metal nodes,which include two geometric types of flexible Ni(Ⅱ)centers(tetrahedral and octahedral).Benefiting from these modifiable metal centers,these cage-based crystals realized abundant coordination environments and a dimension transition from a 0D cage to a 1D cage-based chain,accompanied by modulations of conjugation degrees,electronic push-pull effects and band gaps.Due to their diverse structural features,we have systematically investigated their third-order nonlinear optical(NLO)properties.To our surprise,these structures show a typical reverse saturated absorption(RSA)response.In particular,BIF-141 achieves excellent optical limiting(OL)performance with a low minimum normalized transmittance(T_(min))of 0.20.This study not only provides a new strategy for constructing low-symmetry cages but also contributes to the understanding of the mechanism of their optical applications.
文摘A Ni(Ⅱ)complex harnessed in a pentagonal bipyramidal environment by a rigid N_(5)-macrocyclic ligand(i.e.1,3,10,12-tetramethyl-1,2,11,12-tetraaza[3](2,6)-pyridino[3](2,9)-1,10-phenanthrolinophane-2,10-diene)is shown to exhibit axial anisotropy with a ZFS D parameter in the order of−10 to−15 cm^(-1),and this anisotropy is not significantly changed by apical ligand substitution.Using the latter complex as a building unit,a ferromagnetic 1-D CN-bridged Ni-Cr coordination polymer with SCM behavior characterized by a barrier of magnetization reversal U_(eff)/k_(B)=54 K(37 cm^(-1))withτ0=2.28×10^(−11)s was obtained.The Cr(Ⅲ)complex involved in the design was chosen to favor parallel organization of the anisotropy axes of the Ni units along the 1-D array,and thus maximize the magnetic anisotropy of the supramolecular system.A related chain compound prepared with diamagnetic[Ni(CN)_(4)]^(2−)units,and a trinuclear CN-bridged[NiCr_(2)]complex enabled assessing respectively the magnetic anisotropy of Ni(Ⅱ)in this coordination sphere and its exchange interaction with Cr(Ⅲ)found to be ferromagnetic and of the order of 10 cm^(-1).The crystal structures and magnetic behaviors of all compounds are reported.
文摘By allowing H_(2)SeO_(4),Cy_(2)NH,CyNH_(2) or Bz2NH to react respectively with SnPh_(3)Cl(in methanol),SnPh_(2)Cl_(2)(in water+methanol)and MgCl_(2)·6H_(2)O(in methanol)in specific ratios,the studied complexes are obtained.The suggested structures are discrete and polymer,the environment of the tin center being trans trigonal bipyramidal(compound 1),tetrahedral(compound 2)and octahedral(compound 3),the anions behaving as a bidentate selenate.
基金Plasseraud,ICMUB UMR CNRS 6302,University of Burgundy,Faculty of Sciences,Dijon,France.
文摘One new hydrogenosuccinate and two succinate adduct and complex have been synthesized and studied by infrared,UV-Visible and NMR(Nuclear Magnetic Resonance Spectroscopy)^(119)Sn spectroscopies.The suggested structure is discrete,the hydrogenosuccinate behaving as a monodentate ligand or only involved in hydrogen bonding,the environment around the magnesium centre being triangular(compound 3).The succiate anion is a monochelating ligand(compound 1 and 2).In all the suggested structures,when extra hydrogen bonds are considered,supramolecular architectures are obtained(compound 2 and 3).
基金the National Natural Science Foundation of China(No.21775004)Wanjiang Scholar Program。
文摘Herein,we have presented a novel and easy to operate seed-mediated system for fabricating gold bipyramids(AuBPs)with 85%yields without any separation/purification processes.The used gold seeds are reduced by tannin and citrate,two kinds of air stable ligands,and conventio nally employed unstable NaBH4 are thoroughly cast off.In addition,the as-proposed gold seeds can also be employed for AuNRs fabrication with rather larger diameters(22.2-60.3 nm),which is difficult to be achieved by conve ntional seed mediated fabrication system.
基金the Natural Science Foundation of Xuzhou Normal University (01BXL009)
文摘The complex Fe(aapo)2Cl3 with chemical formula C14H16Cl3FeN4O4 was obtained by the reaction of FeCl36H2O with apoHCl (apo = 2璦mino pyridine N璷xide) in acetonitrile. The result shows that CH3CN has been hydrolysised with the water from FeCl36H2O dissolving, and then the hydrolysised product condenses with apo to give aapo. A single-crystal X璻ay study of Fe(aapo)2Cl3 shows it belongs to the monoclinic system, space group C2/c with a = 15.873(3), b = 10.322(2), c = 11.987(2) ? b = 106.35(1), V = 1884.5(6) 3, Z = 4, Mr = 466.51, Dc = 1.644 g/cm3, m(MoKa) = 1.253 mm-1, F(000) = 948, R = 0.0377 and wR = 0.0749 for 1262 observed reflections with I > 2(I). Fe (Ⅲ) is coordinated by a trigonal bipyramidal geometry with three chlorine atoms lying on the equatorial plane and two oxygen atoms connected with the nitrogen atoms of pyridine rings occupying the axial positions, while the iron and Cl(1) atoms lie on the crystallographic 2-fold axis. The dihedral angle of two pyridine rings is 71.74(9). There exist N(2)H(2)…O(1)?hydrogen bonds in the crystal structure.
文摘The title crystal of 2-germatranylmethyl-N- (4'-methylphenyl)succinimide (C18H24GeN2O5) was determined by single crystal X-ray diffraction- The crystalbelongs to the orthorhombic system, space group P212121 with Mr = 420. 99, a= 6. 716(1), b=22- 860(8), c= 11. 891 (3) A, V= 1826(1) A3, Z=4,Dx= 1. 53 Mg. m-3,A= 0. 71073A, μ= 1. 684 mm-l, and F(000) =872. The structure was solved by direct methods. The final refinement is converged with unweighted and weighted agreement factors of 0. 047 and 0. 064 for 1610 observed reflections with I≥3δ(I). The results of structure analysis indicate that the framework of this five-coordinated germanium compound is a distorted trigonal bipyramid(TBP).
基金This work was supported by the National Natural Science Foundation of China (No. 20331010 and 20571045) Natural Science Foundation of Tianjin (No. 043602211)
文摘Two novel complexes {[Zn（IM4py）2（tp）（H2O）]2H2O}. 1 and {[Cd（IM4py）2（tp）- （H2O）]1.25H2O},, 2 （IM4py = 2-（4＇-pyridinyl）-4,4,5,5-tetramethylimidazoline-l-oxyl and tp = terephthalate dianion） have been synthesized and characterized by elemental analyses, IR spectrum and single-crystal X-ray diffraction. Crystal data for complex I： monoclinic, space group C2/c, a = 20.648（7）, b = 12.130（4）, c = 14.036（4） A, β = 106.351（5）°, C32H42N6O9Zn, Mr = 720.09, V = 3373.3（2） A3, Z= 4, Dc = 1.418 g/cm^3μt（MoKα） = 0.790 mm^-1, F（000） = 1512, the final R = 0.0407 and wR = 0.0894 for 3480 independent reflections with Rint = 0.0432. Crystal data for complex 2： monoclinic, space group C2/c, a = 21.332（6）, b = 12.063（3）, c = 14.246（4） A, β = 106.704（4）°, C32H40.50N6O8.25Cd, Mr = 753.60, V= 3511.2（2） A^3, Z = 4, Dc = 1.426 g/cm^3,μ（MoKα） = 0.679 mm^--1, F（000） = 1554, the final R = 0.0419 and wR = 0.0961 for 3627 independent reflections with Rint = 0.0440. The framework structures of complexes 1 and 2 are 3-D networks via the hydrogen bonds among 1-D chains. The notable characteristics of the two complexes are that the coordination polyhedron of Zn（Ⅱ） adopts a rare distorted five-coordinate square pyramidal geometry in 1, and the Cd（Ⅱ） complex exhibits an unusual distorted seven-coordinate pentagonal bipyramid in 2.
基金This work was supported by the National Basic Research Program of China (973 Project,No.2013CB932901),and the National Natural Science Foundation of China (Nos.11274066,51172047,51102050,amd U1330118).This project was sponsored by Shanghai Pujiang Program and 'Shu Guang' project of Shanghai Municipal Education Commission and Shanghai Education Development Foundation (No.09SG01).
基金the MIUR for the financial support(PRIN2015–Prot.20154X9ATP).
文摘Novel coordinatively saturated platinum(II)compounds bearing C-linked carbohydrates were synthesized and characterized.The complexes exhibit bipyramidal trigonal geometry with a bidentate nitrogen ligand and ethylene in the equatorial plane.The axial positions are occupied by a halide ligand X and a D-galactose or D-glucose derivative,linked either via C1 or C6.The compounds were designed for evaluation of the biological activity because they combine the steady coordinative saturation,the beneficial action of the modular sugar moiety and the organometallic nature of the Pt-sugar linkage,which is expected to be stable in the biological media,until the target is reached.The newly synthesized molecules were stable in mixed DMSO/aqueous solvents,able to bind DNA in vitro and exhibited a selective cytotoxic activity on cancer cells through apoptosis activation.
基金the UK EPSRC(grants EP/V003089/1,EP/X036626/1)for financial supportthe National Natural Science Foundation of China(grant 92261103).
文摘Using the[1+1]condensation approach for the preparation of new macrocyclic scaffolds(L^(N6)_(phen)and L^(N4O2)_(phen))with the rigid phenanthroline-based‘head’unit produces the air-stable mononuclear compounds[Dy(L^(N6)_(phen))(Ph_(3)SiO)_(2)](PF_(6))(1-L^(N6)_(phen))and[Dy(L^(N4O2)_(phen))(Ph_(3)SiO)_(2)](PF_(6))(1-L^(N4O2)_(phen))through a stepwise metal-ion templated synthesis.Both compounds exhibit pseudo-D_(6h)symmetry with different degrees of distortion from the ideal hexagonal bipyramidal geometry,depending on the planarity of the equatorial macrocycles and the intramolecularπ-πstacking interactions between the phenyl groups of the apical siloxide ligand and the equatorial macrocycle.Both compounds are single-molecule magnets(SMMs)with large energy barriers for the magnetization reversal,exhibiting out-of-phase AC susceptibility signals up to 75 K or 90 K.The closer-to-ideal D_(6h)complex 1-L^(N4O2)_(phen)possesses a U_(eff)of 1360 K,which is the highest reported barrier among all mononuclear Dy^(Ⅲ)SMMs synthesized using the[1+1]Schiff-base macrocycle approach.The experimental results are supported by ab initio calculations,which indicate relaxation of the magnetization via the first-or second-excited state for 1-L^(N6)_(phen)and 1-L^(N4O2)_(phen),respectively.The results demonstrate the ability of Schiff-base macrocycles to facilitate the synthesis of high-performance and air-stable SMMs through a chemical modulation of the individual carbonyl‘head’and amine subunits,deciphering the factors which affect the magnetic dynamics of SMMs.
基金supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq),Fundação de AmparoàPesquisa do Estado de Minas Gerais(Project PPM 00508-16)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior(CAPES)Ministerio Español de Economía y Competitividad(MINECO)(Project CTQ2016-75068P and Unidad de Excelencia María de Maetzu MDM-2015-0538).
文摘Four compounds with the formula[M_(2)(dmphen)4(μ-C_(2)O_(4))](ClO_(4))_(2)·2dmso[M=Fe(1),Co(2)and Zn(4);dmphen=2,9-dimethyl-1,10-phenanthroline]and[Ni2(dmphen)_(4)(μ-C_(2)O_(4))]_(3)[NbO(C_(2)O_(4))_(3)]2·_(16)H_(2)O(3)have been synthesized using the tris(oxalato)oxoniobate(V)complex anion as the oxalate source,and their structures have been determined by single crystal X-ray diffraction.X-ray quality crystals of highly insoluble oxalate-bridged species were obtained by taking advantage of the slow release of oxalate by the tris(oxalato)oxoniobate(V)complex anion.The structures of 1-4 all contain oxalate-bridged dimetal(Ⅱ)units with didentate dmphen molecules acting as end-cap ligands;electroneutrality is achieved by perchlorate(1-4)and oxotris(oxalato)niobate(V)(3)anions.Each divalent metal ion in 1-4 is tris-chelated in a six-coordinate distorted octahedral environment.The niobium(V)ion in 3 is seven-coordinate in a distorted pentagonal bipyramidal geometry built from one oxo group and six oxygen atoms from three didentate oxalate ligands.The values of the metal-metal separation across the bis-chelating oxalate are 5.626(1)(1),5.575(1)(2),5.434(1)to 5.447(1)(3)and 5.603(1)Å(4).The cryomagnetic measurements in the temperature range of 2.0 to 300 K for compounds 1-3 show the occurrence of antiferromagnetic interactions between the divalent metal ions across the oxalate bridge.The nature and amplitude of these magnetic interactions are rationalized by simple symmetry considerations and compared with those previously reported for related oxalate-bridged systems.
基金the Major State Basic Research Development Program(2013CB922102),NSFC(91022031,21101093,21471077)supported by a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions and the Fundamental Research Funds for the Central Universities(020514380006).
文摘We herein report the syntheses,crystal structures,and magnetic properties of two complexes based on the anisotropic pentagonal bipyramidal Fe^(Ⅱ) starting material[Fe(L_(N_(3)O_(2)))]^(2+),namely[Fe(L_(N_(3)O_(2)))(H_(2)O)_(2)]-[MQ]2·H_(2)O(1)and[Fe(L_(N_(3)O_(2)))(CN)][ABSA]·3H_(2)O(2)(L_(N_(3)O_(2))=2,13-dimethyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene;MQ^(−)=methyl orange anion;ABSA^(−)=4-aminoazobenzene-4’-sulfonic anion).Compound 1 is a mononuclear material where the[Fe(L_(N_(3)O_(2)))(H_(2)O)_(2)]^(2+)cations form a one-dimensional(1D)chain by the hydrogen bonds between the bulky MQ^(−)anions and the coordinated water molecules.With a slightly different anion,ABSA^(−),a cyano-bridged Fe^(Ⅱ) chain is formed for compound 2.This chain has a similar structure as that in our recently reported compound[Fe(L_(N_(5)))(CN)][BF4](Chem.Commun.,2015,51,4360).However,compared with the reported result where the chains interact with each other through theπ⋯πinteractions,the chains in 2 are well isolated by the bulky ABSA^(−)anions with the shortest interchain Fe⋯Fe distances around 12.0Å.Magnetic investigation on 1 reveals the easyaxis magnetic anisotropy of the mononuclear Fe^(Ⅱ) centre(zero-field splitting parameter D=−3.7 cm^(−1)),which leads to the field-induced slow magnetic relaxation.For compound 2,the Fe^(2+)spins are antiferromagnetically coupled through the cyano bridges with a coupling constant of J=−4.13(2)cm^(−1) with the Hamiltonian H=−JΣS_(i)·S_(i+1).AC magnetic measurements revealed the pure single-chain magnetic(SCM)behaviour of these isolated chains with an effective energy barrier of 26.1(5)K.This system represents a good example showing that the structures and magnetic properties,such as field-induced single-ion magnets,SCMs,and SCM-based magnets,can be selectively prepared by anion modification.
基金the Spanish Ministerio de Innovación,Ciencia y Universidades(PGC2018102052-B-C21)the Portuguese Foundation for Science and Technology/MCTES(UIDB/50011/2020&UIDP/50011/20)for financial supportXunta de Galicia for his Ph.D.fellowship(ED481A-2018/136).
文摘The mononuclear complex[Yb(H_(3)L^(1,1,4))]·2MeOH(1·2MeOH),with a new heptadentate N4O3 ligand,was isolated and structurally characterised.The opto-magnetic properties of 1·2MeOH were investigated,showing that this complex is a bifunctional compound.Accordingly,1·2MeOH reveals two coexisting functionalities:field-induced single molecule magnet behaviour,and Yb^(3+)-centred NIR fluorescence dependent on temperature(25-300 K).The magnetic relaxation in this pentagonal bipyramidal complex does not seem to be of the Orbach type,and this is supported by the discrepancy between the anisotropic energy barrier found by fitting the magnetic data to an Orbach model and by spectroscopic studies.Ab initio calculations further validate the magnetic relaxation mechanisms and spectroscopic results.
基金support from the National Natural Science Foundation of China(22101248)the National Key Laboratory Development Fund(20210002)the Lvyangjinfeng Talent Program of Yangzhou(YZLYJFJH2021YXBS083).
文摘Crystalline borates are a rich source of diverse optical materials.Here,a rare earth borate fluoride,Sc_(2)F_(2)(B_(2)O_(5)),has been obtained by a conventional hydrothermal reaction.It is unlike other rare earth borate fluorides synthesized under harsh conditions.In the layered structure of Sc_(2)F_(2)(B_(2)O_(5)),ScO_(4)F_(2) octahedra and ScO_(5)F_(2) pentagonal bipyramids connect to each other to form[Sc_(4)O_(10)F_(4)]_(∞) frameworks,which are further linked by B_(2)O_(5)^(4−)anion groups.Specifically,Sc_(2)F_(2)(B_(2)O_(5))does not belong to any types of reported rare earth borate fluoride.More attractively,this compound displays a deep ultraviolet cutoff edge(<200 nm)and very large birefringence(0.19)at 1064 nm based on theoretical calculations.The outstanding birefringence can be seen to originate from the synergistic effect of B_(2)O_(5) and ScO_(n)F_(2) groups when analysed for their polarizability anisotropy-weighted electron density(PAWED).
