A novel tridentate ligand N-（6-（diphenylphosphoryl）pyridin-2-yl）-2,2,2-trifluoroacetamide （DPPOPFA） was designed and synthesized. Crystal structure of the ligand revealed the ＂keto＂ form of ligand in solid sta...A novel tridentate ligand N-（6-（diphenylphosphoryl）pyridin-2-yl）-2,2,2-trifluoroacetamide （DPPOPFA） was designed and synthesized. Crystal structure of the ligand revealed the ＂keto＂ form of ligand in solid state other than the ＂enor＇ one, and it was also found that two kinds of molecules with different conformations were connected by hydrogen bonding between amide N-H and phos- phoryl P=O. This ionic ligand was used to coordinate a variety of lanthanide ions, forming neutral 3：1 complexes. Absolute overall quantum yields of these complexes in solid states were 36% for Eu（III）, 29% for Tb（III） and 3% for Dy（III） with lifetimes of 1.1, 1.1 and 0.087 ms, respectively. The complexes had excellent thermal stability and did not decompose till 370 ℃. And they could subli- mate in vacuum （1 ×10^-4 Pa） at 330℃ due to the weak molecular interaction.展开更多
Three stable 4-substituted pyridine-based ruthenium（II）complexes[RuCl2（PPh3）L]（L=4-R-2,6-bis （diethylaminomethylene）pyridine,R=Br,H or allyloxy）were synthesized.The catalytic activities of the complexes toward...Three stable 4-substituted pyridine-based ruthenium（II）complexes[RuCl2（PPh3）L]（L=4-R-2,6-bis （diethylaminomethylene）pyridine,R=Br,H or allyloxy）were synthesized.The catalytic activities of the complexes toward transfer hydrogenation from alcohols to ketones were investigated.The electronic effects of the para-substituent in the pyridyl ring were probed and we found that the electron-donating group increased the catalytic activity.The result suggests that an electron-donating group is probably preferential for linking the catalytic ruthenium complex and the chemically inert supporting molecules such as a carbosilane dendrimer.展开更多
A series of half-sandwich group IV metal complexes with tridentate monoanionic phenoxy-imine arylsulfide [O-NS] ligand [2-Bu^t4-Me-6-（（2-（SC6H5）C6H4N = CHC6H2O）]- （La） and dianionic phenoxy-amine arylsulfide [O...A series of half-sandwich group IV metal complexes with tridentate monoanionic phenoxy-imine arylsulfide [O-NS] ligand [2-Bu^t4-Me-6-（（2-（SC6H5）C6H4N = CHC6H2O）]- （La） and dianionic phenoxy-amine arylsulfide [O-N-S] ligand [2-Bu^t4-Me-6-（（2-（SC6H5）C6H4N-CH2C6H2O）]2- （Lb） have been synthesized and characterized. Lb was obtained easily in high yield by reduction of ligand La with excess LiAlH4 in cool diethyl ether. Half-sandwich Group Ⅳ metal complexes CpTi[O-NS]Cl2 （1a）, CpZr[O-NS]Cl2 （1b）, CpTi[O-N-S]Cl （2a）, CpZr[O-N-S]Cl （2b） and CpZr[O-N-S]Cl （2c） were synthesized by the reactions of La and Lb with CpTiCl3, CpZrCl3 and Cp ZrCl3, and characterized by IR, ^1H-NMR, ^13C-NMR and elemental analysis. In addition, an X-ray structure analysis was performed on ligand Lb. The title Group IV half-sandwich bearing tridentate [O,N,S] ligands show good catalytic activities for ethylene polymerization in the presence of methylaluminoxane （MAO） as co-catalyst up to 1.58 × 10^7 g-PE.mol-Zr-1.h-1. The good catalytic activities can be maintained even at high temperatures such as 100 ℃ exhibiting the excellent thermal stability for these half-sandwich metal pre-catalysts.展开更多
Solvent extraction of base metals using bis((1-decylbenzimidazol-2-yl)methyl)amine (BDNNN) showed a lack of pH-metric separation of the metals. The extraction system was described quantitatively using the equilibria i...Solvent extraction of base metals using bis((1-decylbenzimidazol-2-yl)methyl)amine (BDNNN) showed a lack of pH-metric separation of the metals. The extraction system was described quantitatively using the equilibria involved to derive the mathematical explanation for the two linear log D vs pHe plots for each metal ion extraction curve, and coordination numbers could also be extracted from the two slopes. The lack of separation was attributed to the absence of stereochemical “tailor making” since the complexes isolated from the reaction of the ligand, bis((1H-benzimidazol- 2-yl)methyl)amine (NNN), with base metals suggested the formation of similar octahedral complex species from spectral and crystal structure evidence. The bis tridentate coordination observed was in agreement with information extracted from the extraction data. This investigation opens up an opportunity and an approach for the evaluation of amines as extractants but cautions against tridentate ligands.展开更多
Here,we report two europium(III)complexes(Eu1 and Eu2)with high photoluminescence quantum yield,based on tridentate isoquinoline derivatives(HL1 and HL2).The single crystal structures of Eu1 and Eu2 show that three li...Here,we report two europium(III)complexes(Eu1 and Eu2)with high photoluminescence quantum yield,based on tridentate isoquinoline derivatives(HL1 and HL2).The single crystal structures of Eu1 and Eu2 show that three ligands coordinate with an Eu(III)ion through diphenylphosphoryl oxygen,pyridyl nitrogen and carboxyl oxygen atoms(O^N^O)with no solvent in the first coordination sphere.展开更多
Fac-[MnBr(L^(1,2)-κ^(2)N^(1),N^(2))(CO)_(3)]and fac-[MnBr(L^(3))(CO)_(3)](1–3)(2,6-bis(benzimidazole-2’-yl)pyridine(L^(1)),2,6-bis(1-ethyl-benzimidazol-2’-yl)pyridine(L^(2))and 2-(2-pyridyl)benzimidazole(L^(3))),c...Fac-[MnBr(L^(1,2)-κ^(2)N^(1),N^(2))(CO)_(3)]and fac-[MnBr(L^(3))(CO)_(3)](1–3)(2,6-bis(benzimidazole-2’-yl)pyridine(L^(1)),2,6-bis(1-ethyl-benzimidazol-2’-yl)pyridine(L^(2))and 2-(2-pyridyl)benzimidazole(L^(3))),capable of CO release upon illumination at 468 nm,were synthesized and fully characterized,including the single crystal X-ray analysis of 1 and 2.展开更多
A novel tetranuclear complex[Pb_(4)L_(4)(CO_(3))_(2)]·4H_(2)O(1·4H_(2)O)is reported,which was obtained through the electrochemical oxidation of a lead anode under an ambient atmosphere in a CH_(3)CN:MeOH sol...A novel tetranuclear complex[Pb_(4)L_(4)(CO_(3))_(2)]·4H_(2)O(1·4H_(2)O)is reported,which was obtained through the electrochemical oxidation of a lead anode under an ambient atmosphere in a CH_(3)CN:MeOH solution of N’-isonicotinoylpicolinohydrazonamide(HL).CO_(3)^(2−) anions were formed through the conversion of aerial CO_(2) via the Pb^(2+)–L complex system under electrochemical conditions.The ligand L links two Pb^(2+) cations through the carbonyl oxygen atom,while the CO_(3)^(2−) anion links two Pb^(2+) cations through two monodentate and one bidentate oxygen atoms.The molecular structure of 1 is stabilized by a pair of Pb⋯O tetrel bonds formed with the bidentate oxygen atom of the CO_(3)^(2−) anion,while molecules of 1 are interlinked through reciprocalπ(chelate ring)⋯π(chelate ring),π(chelate ring)⋯π(noncovalent ring)and Pb⋯π(noncovalent ring)interactions,yielding a 1D supramolecular chain.The same reaction but under a nitrogen atmosphere yielded a novel mononuclear complex[PbL2]·MeOH·2H_(2)O(2·MeOH·2H_(2)O).In the structure of 2,each ligand L exhibits a tridentate coordination mode.Molecules of 2 are also interlinked through reciprocalπ(chelate ring)⋯π(chelate ring),π(chelate ring)⋯π(noncovalent ring)and Pb⋯π(noncovalent ring)interactions,similar to 1,yielding a 1D supramolecular chain.The energetic features of these assemblies were studied using DFT calculations.Additionally,QTAIM analysis was employed to characterize noncovalent contacts,including intermolecular Pb⋯N tetrel bonds.These tetrel bonds were further analyzed using the ELF and Laplacian of electron density 2D maps,which confirmed their noncovalent nature.The optical properties of the complexes were revealed using UV–vis and diffuse reflectance spectroscopy and spectrofluorometry.Both complexes were found to be emissive in a solution of MeOH.CIE-1931 chromaticity coordinates of(0.38,0.37)and(0.31,0.32)for 1·4H_(2)O and 2·MeOH·2H_(2)O,respectively,fall within the white gamut of the chromaticity diagram.展开更多
Lanthanides have relatively recently been recognized as ideal candidates for the construction of advanced magnetic materials that would allow for their future applications in spintronics and high-density data storage....Lanthanides have relatively recently been recognized as ideal candidates for the construction of advanced magnetic materials that would allow for their future applications in spintronics and high-density data storage.Despite enormous progress that deals with the control of magnetic anisotropy and slow relaxation of magnetization in Single Molecule Magnets(SMMs),further improvements are still indispensable to go beyond the ultra-low temperature regime.We have thus prepared four lanthanide complexes([ErL_(2)(OTf)(MeOH)_(2)](OTf)_(2)(1),[YbL_(2)(OTf)_(2)](OTf)(2),[ErL(NO_(3))_(3)(H_(2)O)](3)and[YbL(NO_(3))_(3)(MeOH)]·MeCN(4))with a tridentate Schiff-base ligand L,to unravel magneto-structural correlations in this new family of field-induced Single Ion Magnets(SIMs).Interestingly,as revealed by the single crystal X-ray diffraction,their structures are synthetically tuned by the choice of the applied counterion.The static and dynamic magnetic properties of 1–4 were investigated revealing that all compounds behave as field-induced Single Ion Magnets(SIMs).Their energy barriers Ueff decrease in the sequence:4,2,3,1,with an order of magnitude difference between the highest and the lowest value.To correlate the observed magnetic properties with spectroscopic data,low-temperature absorption spectroscopy was performed.This has allowed the determination of the energy levels of the Ln(Ⅲ)ions and the exact composition of the state vectors for the Ln(Ⅲ)ground multiplets via crystal-field analysis(CFA)and semiempirical superposition model(SPM)approach.Theoretical and magneto-structural correlation studies indicate that one can modulate the heterotopic coordination spheres around the prolate Er(Ⅲ)and Yb(Ⅲ)solely with the counterions.This leads to rarely observed high-coordinate SIM species with the LnNxOy first coordination sphere(where Ln–Er or Yb,x=3 or 6,y=2,3 or 6).Their performance can be related to the intricate interactions between the electron density on the Ln ion and the crystal field created by the surroundings.展开更多
A new dimeric Ni(II)complex,[Ni_(2)L^(1)_(2)(CH_(3)CN)_(4)](ClO_(4))_(2)·2CH_(3)CN(1),was synthesized using an N_(2)O donor reduced Schiff base[(HL1)=2-[(3-methylamino-propylamino)-methyl]-4-phenol].Surprisingly,...A new dimeric Ni(II)complex,[Ni_(2)L^(1)_(2)(CH_(3)CN)_(4)](ClO_(4))_(2)·2CH_(3)CN(1),was synthesized using an N_(2)O donor reduced Schiff base[(HL1)=2-[(3-methylamino-propylamino)-methyl]-4-phenol].Surprisingly,during an attempt to replace its ClO_(4)-ion with SCN-,the N_(2)O donor ligand in situ converted to a tetradentate N_(2)O_(2)donor ligand and formed a metal complex,[Ni(HL^(2))(NCS)(CH_(3)CN)](2).A probable mechanism via deaminative coupling for this conversion is proposed.Using 2 as a metalloligand under basic conditions,a trinuclear metal complex,[Ni3(L^(2))2(NCS)2(H_(2)O)4]·H_(2)O(3),was prepared.Single crystal structural characterization revealed that in all three metal complexes,the Ni(II)atoms were in an octahedral environment with coordinated solvent molecules(CH_(3)CN in 1 and 2 and H_(2)O in 3).Among the three metal complexes,1 and 3 showed catecholase-like biomimicking activity.The calculation of the turnover numbers(K_(cat)=7.9 for 1,14.5 for 3)reveals that 3 is a better catalyst than 1.Mechanistic cycles are proposed for this biomimicking activity on the basis of ESI-MS spectrometry and iodometric measurements.Temperaturedependent magnetic susceptibility measurements suggest that the Ni(II)ions in metal complexes 1 and 3 are antiferromagnetically coupled(J=-32.22 cm^(-1) for 1,J=-10.4 cm^(-1) for 3),consistent with their geometries and bridging angles.Theoretically calculated J values(J=-40.15 cm^(-1) for 1,J=-14.53 cm^(-1) for 3)by the DFT method corroborate well with the experimental values.展开更多
Asymmetric direct hydrogenation(ADH)is a straightforward and atom-economic methodology to achieve optically active compounds.The synthesis of chiral compounds bearing stereogenic centers has been well established.In c...Asymmetric direct hydrogenation(ADH)is a straightforward and atom-economic methodology to achieve optically active compounds.The synthesis of chiral compounds bearing stereogenic centers has been well established.In contrast,the construction of atropisomers,especially atropisomers bearing multiple chiral elements,has sporadically been explored.Herein,we report an innovative atroposelective iridium-catalyzed hydrogenation of N-arylindole ketones and heterobiaryl ketones via dynamic kinetic resolution(DKR)based on a Lewis acid-base interaction between the nitrogen atom and the carbonyl group of ketones,providing C-N and C-C atropisomers bearing multiple chiral elements with excellent enantioselectivities,diastereoselectivities and yields.The lynchpin of the DKR-ADH process stands in the newly developed planar-chiral tridentate PNO ligand,which ensures the excellent control of enantioselectivity and diastereoselectivity simultaneously.The synthetic utilization of this protocol is proved through stereospecific transformation to a tridentate PNN ligand bearing axial and central chirality,which shows promising potential in iridium-catalyzed asymmetric hydrogenation of simple ketones.展开更多
The reaction of NiCl2 and 3-hydrazine-4-amino-1,2,4-triazole （Hatr） in the mixed solvent of EtOH and H2O yielded a dimer compound （[Ni2（Hatr）2（H2O）2（EtOH）2Cl2]ClzoEtOH） with water and EtOH molecules coordina...The reaction of NiCl2 and 3-hydrazine-4-amino-1,2,4-triazole （Hatr） in the mixed solvent of EtOH and H2O yielded a dimer compound （[Ni2（Hatr）2（H2O）2（EtOH）2Cl2]ClzoEtOH） with water and EtOH molecules coordinated to nickle ions. It crystallized in trigonal space group R-3, a=b=29.67（1） A, c=8.95（7） A, β= 120（1）°, as determined by single-crystal X-ray diffraction. Then, they were fully characterized by the IR spectroscopy, differential scanning calorimetry （DSC）, thermogravimetry （TG）, and elemental analysis.展开更多
Reaction of a new type of bidentate ligand PhPQu [ PhPQu = 2-diphenylphosphino-4-methylquinoline] with Fe(CO)5 in bu-tanol gave trans-Fe(PhPQu-P)(CO)3 (1).Compound 1,which can act as a neutral tridentate organometalli...Reaction of a new type of bidentate ligand PhPQu [ PhPQu = 2-diphenylphosphino-4-methylquinoline] with Fe(CO)5 in bu-tanol gave trans-Fe(PhPQu-P)(CO)3 (1).Compound 1,which can act as a neutral tridentate organometallic ligand,was reacted with I B,II B metal compounds and a rhodium complex to give six binuclear complexes with Fe-M bonds,Fe(CO)3(u-Ph2PQu)MXn(2-7) [M=Zn(Ⅰ),Cd(Ⅱ),Hg(Ⅱ),Cu(Ⅰ),Ag(Ⅰ),Rh(Ⅰ)],and an ion-pair complex [Fe(CO)3(n-Ph2PQu)2HgI][HgI3]- (8).The structure of 8 was determined by X-ray crystallography.Complex 8 crystallizes in the space group P-1 with a=1.0758(3),b= 1.6210(4),c = 1.7155(4) nm; a = 75.60(2)β=71.81(2),Y = 81.78(2) and Z = 2 and its structure was refined to give agreement factors of R =0.050 and Rw = 0.057.The Fe-Hg bond distance is 0.2536 nm.展开更多
The mononuclear vanadium（V） complex with 2-hydroxyl-l-naphthaldehyde isonicotinoyl hydrazone was synthesized and characterized by single-crystal X-ray diffraction. The crystal is of monocfinic, space group P2 1/n wi...The mononuclear vanadium（V） complex with 2-hydroxyl-l-naphthaldehyde isonicotinoyl hydrazone was synthesized and characterized by single-crystal X-ray diffraction. The crystal is of monocfinic, space group P2 1/n with α = 10.3153（15）, b = 7.4024（11 ）, c = 24.413（4） A, β = 101.911（2）°, V= 1824.0（5） A^3, Z= 4, Mr = 427.28, Dc = 1.556 g/cm^3, F（000） = 880,μ（MoKα） = 0.591, the final R = 0.0372 and wR = 0.0926. The vanadium（V） atom adopts a distorted square-pyramidal geometry coordinated by the tridentate ligand and two oxygen atoms. The hydrogen bonds and strong π-π stacking interactions link the complex molecules into a 3-D network structure.展开更多
Schiff base metal complexes are of great importance in pharmaceutical science owing to their unique chemical properties, which enable them to exhibit diverse biological activities such as anti-bacterial,anti-oxidant, ...Schiff base metal complexes are of great importance in pharmaceutical science owing to their unique chemical properties, which enable them to exhibit diverse biological activities such as anti-bacterial,anti-oxidant, anti-inflammatory, and anti-tumor properties. Furthermore, Schiff base metal complexes can serve as reagents and catalysts in chemical reactions. This review aims to provide an overview of our recently published studies on Cu(Ⅱ) and Pd(Ⅱ) complexes derived from proline Schiff base ligands. We also discuss the potential applications of these metal complexes in the fields of antibacterial and chiral resolution.展开更多
基金Project supported by the National Key Basic Research Program of China(2014CB643802)the National Natural Science Foundation of China(21371012,21321001)
文摘A novel tridentate ligand N-（6-（diphenylphosphoryl）pyridin-2-yl）-2,2,2-trifluoroacetamide （DPPOPFA） was designed and synthesized. Crystal structure of the ligand revealed the ＂keto＂ form of ligand in solid state other than the ＂enor＇ one, and it was also found that two kinds of molecules with different conformations were connected by hydrogen bonding between amide N-H and phos- phoryl P=O. This ionic ligand was used to coordinate a variety of lanthanide ions, forming neutral 3：1 complexes. Absolute overall quantum yields of these complexes in solid states were 36% for Eu（III）, 29% for Tb（III） and 3% for Dy（III） with lifetimes of 1.1, 1.1 and 0.087 ms, respectively. The complexes had excellent thermal stability and did not decompose till 370 ℃. And they could subli- mate in vacuum （1 ×10^-4 Pa） at 330℃ due to the weak molecular interaction.
基金Supported by the National Natural Science Foundation of China（20576052） the Joint Innovation Fund of Jiangsu Province（BY2009107） the National Basic Research Program of China（2003CB615707）
文摘Three stable 4-substituted pyridine-based ruthenium（II）complexes[RuCl2（PPh3）L]（L=4-R-2,6-bis （diethylaminomethylene）pyridine,R=Br,H or allyloxy）were synthesized.The catalytic activities of the complexes toward transfer hydrogenation from alcohols to ketones were investigated.The electronic effects of the para-substituent in the pyridyl ring were probed and we found that the electron-donating group increased the catalytic activity.The result suggests that an electron-donating group is probably preferential for linking the catalytic ruthenium complex and the chemically inert supporting molecules such as a carbosilane dendrimer.
基金financially supported by the Shanghai Science and Technology Committee(08DZ2270500,08DJ1400103)Shanghai Leading Academic Discipline Project(B108)the National Basic Research Program of China(2009CB825300,2010DFA41160)
文摘A series of half-sandwich group IV metal complexes with tridentate monoanionic phenoxy-imine arylsulfide [O-NS] ligand [2-Bu^t4-Me-6-（（2-（SC6H5）C6H4N = CHC6H2O）]- （La） and dianionic phenoxy-amine arylsulfide [O-N-S] ligand [2-Bu^t4-Me-6-（（2-（SC6H5）C6H4N-CH2C6H2O）]2- （Lb） have been synthesized and characterized. Lb was obtained easily in high yield by reduction of ligand La with excess LiAlH4 in cool diethyl ether. Half-sandwich Group Ⅳ metal complexes CpTi[O-NS]Cl2 （1a）, CpZr[O-NS]Cl2 （1b）, CpTi[O-N-S]Cl （2a）, CpZr[O-N-S]Cl （2b） and CpZr[O-N-S]Cl （2c） were synthesized by the reactions of La and Lb with CpTiCl3, CpZrCl3 and Cp ZrCl3, and characterized by IR, ^1H-NMR, ^13C-NMR and elemental analysis. In addition, an X-ray structure analysis was performed on ligand Lb. The title Group IV half-sandwich bearing tridentate [O,N,S] ligands show good catalytic activities for ethylene polymerization in the presence of methylaluminoxane （MAO） as co-catalyst up to 1.58 × 10^7 g-PE.mol-Zr-1.h-1. The good catalytic activities can be maintained even at high temperatures such as 100 ℃ exhibiting the excellent thermal stability for these half-sandwich metal pre-catalysts.
文摘Solvent extraction of base metals using bis((1-decylbenzimidazol-2-yl)methyl)amine (BDNNN) showed a lack of pH-metric separation of the metals. The extraction system was described quantitatively using the equilibria involved to derive the mathematical explanation for the two linear log D vs pHe plots for each metal ion extraction curve, and coordination numbers could also be extracted from the two slopes. The lack of separation was attributed to the absence of stereochemical “tailor making” since the complexes isolated from the reaction of the ligand, bis((1H-benzimidazol- 2-yl)methyl)amine (NNN), with base metals suggested the formation of similar octahedral complex species from spectral and crystal structure evidence. The bis tridentate coordination observed was in agreement with information extracted from the extraction data. This investigation opens up an opportunity and an approach for the evaluation of amines as extractants but cautions against tridentate ligands.
基金supported through grants from the National Key R&D Program of China(Grant 2017YFA0205100)National Natural Science Foundation of China(Grant 21621061)+1 种基金Key Project of Science and Technology Plan of Beijing Education Commission(Grant KZ201910028038)Natural Science Foundation of Beijing Municipality(Grant 2172017).
文摘Here,we report two europium(III)complexes(Eu1 and Eu2)with high photoluminescence quantum yield,based on tridentate isoquinoline derivatives(HL1 and HL2).The single crystal structures of Eu1 and Eu2 show that three ligands coordinate with an Eu(III)ion through diphenylphosphoryl oxygen,pyridyl nitrogen and carboxyl oxygen atoms(O^N^O)with no solvent in the first coordination sphere.
文摘Fac-[MnBr(L^(1,2)-κ^(2)N^(1),N^(2))(CO)_(3)]and fac-[MnBr(L^(3))(CO)_(3)](1–3)(2,6-bis(benzimidazole-2’-yl)pyridine(L^(1)),2,6-bis(1-ethyl-benzimidazol-2’-yl)pyridine(L^(2))and 2-(2-pyridyl)benzimidazole(L^(3))),capable of CO release upon illumination at 468 nm,were synthesized and fully characterized,including the single crystal X-ray analysis of 1 and 2.
基金supported by the grant from the Russian Science Foundation(No.24-23-00118)MICIU/AEI of Spain(PID2020-115637GB-I00,FEDER funds)for financial supportthe CTI(UIB)for computational facilities.
文摘A novel tetranuclear complex[Pb_(4)L_(4)(CO_(3))_(2)]·4H_(2)O(1·4H_(2)O)is reported,which was obtained through the electrochemical oxidation of a lead anode under an ambient atmosphere in a CH_(3)CN:MeOH solution of N’-isonicotinoylpicolinohydrazonamide(HL).CO_(3)^(2−) anions were formed through the conversion of aerial CO_(2) via the Pb^(2+)–L complex system under electrochemical conditions.The ligand L links two Pb^(2+) cations through the carbonyl oxygen atom,while the CO_(3)^(2−) anion links two Pb^(2+) cations through two monodentate and one bidentate oxygen atoms.The molecular structure of 1 is stabilized by a pair of Pb⋯O tetrel bonds formed with the bidentate oxygen atom of the CO_(3)^(2−) anion,while molecules of 1 are interlinked through reciprocalπ(chelate ring)⋯π(chelate ring),π(chelate ring)⋯π(noncovalent ring)and Pb⋯π(noncovalent ring)interactions,yielding a 1D supramolecular chain.The same reaction but under a nitrogen atmosphere yielded a novel mononuclear complex[PbL2]·MeOH·2H_(2)O(2·MeOH·2H_(2)O).In the structure of 2,each ligand L exhibits a tridentate coordination mode.Molecules of 2 are also interlinked through reciprocalπ(chelate ring)⋯π(chelate ring),π(chelate ring)⋯π(noncovalent ring)and Pb⋯π(noncovalent ring)interactions,similar to 1,yielding a 1D supramolecular chain.The energetic features of these assemblies were studied using DFT calculations.Additionally,QTAIM analysis was employed to characterize noncovalent contacts,including intermolecular Pb⋯N tetrel bonds.These tetrel bonds were further analyzed using the ELF and Laplacian of electron density 2D maps,which confirmed their noncovalent nature.The optical properties of the complexes were revealed using UV–vis and diffuse reflectance spectroscopy and spectrofluorometry.Both complexes were found to be emissive in a solution of MeOH.CIE-1931 chromaticity coordinates of(0.38,0.37)and(0.31,0.32)for 1·4H_(2)O and 2·MeOH·2H_(2)O,respectively,fall within the white gamut of the chromaticity diagram.
基金supported by the research grant#UMO-2016/21/B/ST4/02064 from the Polish National Science Center.
文摘Lanthanides have relatively recently been recognized as ideal candidates for the construction of advanced magnetic materials that would allow for their future applications in spintronics and high-density data storage.Despite enormous progress that deals with the control of magnetic anisotropy and slow relaxation of magnetization in Single Molecule Magnets(SMMs),further improvements are still indispensable to go beyond the ultra-low temperature regime.We have thus prepared four lanthanide complexes([ErL_(2)(OTf)(MeOH)_(2)](OTf)_(2)(1),[YbL_(2)(OTf)_(2)](OTf)(2),[ErL(NO_(3))_(3)(H_(2)O)](3)and[YbL(NO_(3))_(3)(MeOH)]·MeCN(4))with a tridentate Schiff-base ligand L,to unravel magneto-structural correlations in this new family of field-induced Single Ion Magnets(SIMs).Interestingly,as revealed by the single crystal X-ray diffraction,their structures are synthetically tuned by the choice of the applied counterion.The static and dynamic magnetic properties of 1–4 were investigated revealing that all compounds behave as field-induced Single Ion Magnets(SIMs).Their energy barriers Ueff decrease in the sequence:4,2,3,1,with an order of magnitude difference between the highest and the lowest value.To correlate the observed magnetic properties with spectroscopic data,low-temperature absorption spectroscopy was performed.This has allowed the determination of the energy levels of the Ln(Ⅲ)ions and the exact composition of the state vectors for the Ln(Ⅲ)ground multiplets via crystal-field analysis(CFA)and semiempirical superposition model(SPM)approach.Theoretical and magneto-structural correlation studies indicate that one can modulate the heterotopic coordination spheres around the prolate Er(Ⅲ)and Yb(Ⅲ)solely with the counterions.This leads to rarely observed high-coordinate SIM species with the LnNxOy first coordination sphere(where Ln–Er or Yb,x=3 or 6,y=2,3 or 6).Their performance can be related to the intricate interactions between the electron density on the Ln ion and the crystal field created by the surroundings.
基金the University Grants Commission(UGC),New Delhi,for the Senior Research Fellowship[Sr.No.2061510240,Ref No.–21/06/2015(i)EU-V].
文摘A new dimeric Ni(II)complex,[Ni_(2)L^(1)_(2)(CH_(3)CN)_(4)](ClO_(4))_(2)·2CH_(3)CN(1),was synthesized using an N_(2)O donor reduced Schiff base[(HL1)=2-[(3-methylamino-propylamino)-methyl]-4-phenol].Surprisingly,during an attempt to replace its ClO_(4)-ion with SCN-,the N_(2)O donor ligand in situ converted to a tetradentate N_(2)O_(2)donor ligand and formed a metal complex,[Ni(HL^(2))(NCS)(CH_(3)CN)](2).A probable mechanism via deaminative coupling for this conversion is proposed.Using 2 as a metalloligand under basic conditions,a trinuclear metal complex,[Ni3(L^(2))2(NCS)2(H_(2)O)4]·H_(2)O(3),was prepared.Single crystal structural characterization revealed that in all three metal complexes,the Ni(II)atoms were in an octahedral environment with coordinated solvent molecules(CH_(3)CN in 1 and 2 and H_(2)O in 3).Among the three metal complexes,1 and 3 showed catecholase-like biomimicking activity.The calculation of the turnover numbers(K_(cat)=7.9 for 1,14.5 for 3)reveals that 3 is a better catalyst than 1.Mechanistic cycles are proposed for this biomimicking activity on the basis of ESI-MS spectrometry and iodometric measurements.Temperaturedependent magnetic susceptibility measurements suggest that the Ni(II)ions in metal complexes 1 and 3 are antiferromagnetically coupled(J=-32.22 cm^(-1) for 1,J=-10.4 cm^(-1) for 3),consistent with their geometries and bridging angles.Theoretically calculated J values(J=-40.15 cm^(-1) for 1,J=-14.53 cm^(-1) for 3)by the DFT method corroborate well with the experimental values.
基金supported by the National Key Research and Development Program of China(2023YFA1507500)the National Natural Science Foundation of China(22171260,92356302)+1 种基金the Natural Science Foundation of Liaoning Province(2023-MS-009)the Dalian Institute of Chemical Physics(DICP I202442)。
文摘Asymmetric direct hydrogenation(ADH)is a straightforward and atom-economic methodology to achieve optically active compounds.The synthesis of chiral compounds bearing stereogenic centers has been well established.In contrast,the construction of atropisomers,especially atropisomers bearing multiple chiral elements,has sporadically been explored.Herein,we report an innovative atroposelective iridium-catalyzed hydrogenation of N-arylindole ketones and heterobiaryl ketones via dynamic kinetic resolution(DKR)based on a Lewis acid-base interaction between the nitrogen atom and the carbonyl group of ketones,providing C-N and C-C atropisomers bearing multiple chiral elements with excellent enantioselectivities,diastereoselectivities and yields.The lynchpin of the DKR-ADH process stands in the newly developed planar-chiral tridentate PNO ligand,which ensures the excellent control of enantioselectivity and diastereoselectivity simultaneously.The synthetic utilization of this protocol is proved through stereospecific transformation to a tridentate PNN ligand bearing axial and central chirality,which shows promising potential in iridium-catalyzed asymmetric hydrogenation of simple ketones.
文摘The reaction of NiCl2 and 3-hydrazine-4-amino-1,2,4-triazole （Hatr） in the mixed solvent of EtOH and H2O yielded a dimer compound （[Ni2（Hatr）2（H2O）2（EtOH）2Cl2]ClzoEtOH） with water and EtOH molecules coordinated to nickle ions. It crystallized in trigonal space group R-3, a=b=29.67（1） A, c=8.95（7） A, β= 120（1）°, as determined by single-crystal X-ray diffraction. Then, they were fully characterized by the IR spectroscopy, differential scanning calorimetry （DSC）, thermogravimetry （TG）, and elemental analysis.
基金Project supported by the National Natural Science Foundation of China (No. 29672078)
文摘Reaction of a new type of bidentate ligand PhPQu [ PhPQu = 2-diphenylphosphino-4-methylquinoline] with Fe(CO)5 in bu-tanol gave trans-Fe(PhPQu-P)(CO)3 (1).Compound 1,which can act as a neutral tridentate organometallic ligand,was reacted with I B,II B metal compounds and a rhodium complex to give six binuclear complexes with Fe-M bonds,Fe(CO)3(u-Ph2PQu)MXn(2-7) [M=Zn(Ⅰ),Cd(Ⅱ),Hg(Ⅱ),Cu(Ⅰ),Ag(Ⅰ),Rh(Ⅰ)],and an ion-pair complex [Fe(CO)3(n-Ph2PQu)2HgI][HgI3]- (8).The structure of 8 was determined by X-ray crystallography.Complex 8 crystallizes in the space group P-1 with a=1.0758(3),b= 1.6210(4),c = 1.7155(4) nm; a = 75.60(2)β=71.81(2),Y = 81.78(2) and Z = 2 and its structure was refined to give agreement factors of R =0.050 and Rw = 0.057.The Fe-Hg bond distance is 0.2536 nm.
基金Supported by the Science Foundation of Guangxi Province (No. 0342025), the Youth Science Foundation of Guangxi Province (No. 0542020) and the Teaching and Research Award Programme for Outstanding Young Teachers in Higher Education Institutions of MOE, China
文摘The mononuclear vanadium（V） complex with 2-hydroxyl-l-naphthaldehyde isonicotinoyl hydrazone was synthesized and characterized by single-crystal X-ray diffraction. The crystal is of monocfinic, space group P2 1/n with α = 10.3153（15）, b = 7.4024（11 ）, c = 24.413（4） A, β = 101.911（2）°, V= 1824.0（5） A^3, Z= 4, Mr = 427.28, Dc = 1.556 g/cm^3, F（000） = 880,μ（MoKα） = 0.591, the final R = 0.0372 and wR = 0.0926. The vanadium（V） atom adopts a distorted square-pyramidal geometry coordinated by the tridentate ligand and two oxygen atoms. The hydrogen bonds and strong π-π stacking interactions link the complex molecules into a 3-D network structure.
基金the National Key R&D Program of China(No.2022YFA1302900)the National Natural Science Foundation of China (Nos.82130105, 92253305, 82121005, and 22177124)supported by the Lingang Laboratory (Nos.LG-GG-202204–02 and LG202103–04–01)。
文摘Schiff base metal complexes are of great importance in pharmaceutical science owing to their unique chemical properties, which enable them to exhibit diverse biological activities such as anti-bacterial,anti-oxidant, anti-inflammatory, and anti-tumor properties. Furthermore, Schiff base metal complexes can serve as reagents and catalysts in chemical reactions. This review aims to provide an overview of our recently published studies on Cu(Ⅱ) and Pd(Ⅱ) complexes derived from proline Schiff base ligands. We also discuss the potential applications of these metal complexes in the fields of antibacterial and chiral resolution.
