The reactions of 18 crown 6 with each of K 2(M=Zn, Hg; mnt=1,2 dicyanoethene 1,2 dithiolate, C 2S 2(CN) 2- 2) were studied and novel complexes [K(18 C 6)] 2[Zn(mnt) 2](1) and [K(18 C 6)] 2[Hg(mnt)...The reactions of 18 crown 6 with each of K 2(M=Zn, Hg; mnt=1,2 dicyanoethene 1,2 dithiolate, C 2S 2(CN) 2- 2) were studied and novel complexes [K(18 C 6)] 2[Zn(mnt) 2](1) and [K(18 C 6)] 2[Hg(mnt) 2](2) were characterized by elemental analysis, IR spectrum and X ray diffraction analysis. Complex 1 displays a one dimensional chain of [K(18 C 6)] 2[Zn(mnt) 2] bridged by K O interactions between adjacent [K(18 C 6)] + units. Complex 2 is also a one dimensional chain of [K(18 C 6)] 2[Hg(mnt) 2] bridged by K...S weak interactions between adjacent [K(18 C 6)] + and [Hg(mnt) 2] 2- .展开更多
Developing new birefringent materials with large optical anisotropy is extremely urgent due to the fantastic progress of laser science and technology.Here,two tin(Ⅱ)-based oxalates,K_(2)Sn(C_(2)O_(4))_(2)·H_(2)O...Developing new birefringent materials with large optical anisotropy is extremely urgent due to the fantastic progress of laser science and technology.Here,two tin(Ⅱ)-based oxalates,K_(2)Sn(C_(2)O_(4))_(2)·H_(2)O and K_(2)Sn_(2)(C_(2)O_(4))_(2)F_(2)·H_(2)O,were successfully synthesized by simultaneously introducingπ-conjugated[C_(2)O_(4)]^(2)-groups and distorted Sn^(2+)-polyhedra with stereochemically active lone pairs.展开更多
Reactions of DyCl_(3)·6H_(2)O or Dy_(2)O_(3) with 2-quinolinecarboxylic acid(H-QLC)yielded two compounds,namely,[Dy_(4)(QLC)_(12)(H_(2)O)_(6)]·4H_(2)O(1)and[Dy(QLC)_(3)(H_(2)O)_(2)]_(n)(2).Compound 1 is a li...Reactions of DyCl_(3)·6H_(2)O or Dy_(2)O_(3) with 2-quinolinecarboxylic acid(H-QLC)yielded two compounds,namely,[Dy_(4)(QLC)_(12)(H_(2)O)_(6)]·4H_(2)O(1)and[Dy(QLC)_(3)(H_(2)O)_(2)]_(n)(2).Compound 1 is a linear tetranuclear structure with one central[Dy_(2)(QLC)_(4)(H_(2)O)_(4)]subunit and two terminal[Dy(QLC)_(3)(H_(2)O)]subunits linked by bridging QLC^(-)ligands.Compound 2 has a one-dimensional(1D)chain wherein the[Dy(QLC)_(2)]unit formed by two QLC^(-)ligands chelating a Dy(Ⅲ)ion is connected by the bridging QLC^(-)ligands.Compounds 1 and 2 exhibit slow magnetic relaxation behaviour in the absence of a static magnetic field,which is rarely observed in lanthanide-carboxylate compounds.During the structural evolution from a linear Dy_(4) cluster of 1 into a 1D chain of 2,the anisotropy energy barrier(U_(eff))is enhanced from 45.4(2)to 144.2(1)K.Though the Dy(Ⅲ)centers in 1 and 2 all are eight-coordinated with square antiprismatic coordination environments,the higher energy barrier observed for 2 could be the result of a more favorable crystal field for the Dy(Ⅲ)ions in 2.展开更多
A new 1D coordination polymer,[Fe_(3)(μ_(2)-bntrz)_(6)(bntrz)_(2)(μ_(2)-tcnsme)_(2)](tcnsme)_(4)·4H_(2)O(1·4H_(2)O),based on[Fe_(3)(μ_(2)-bntrz)_(6)]trinuclear units covalently linked by symmetric double ...A new 1D coordination polymer,[Fe_(3)(μ_(2)-bntrz)_(6)(bntrz)_(2)(μ_(2)-tcnsme)_(2)](tcnsme)_(4)·4H_(2)O(1·4H_(2)O),based on[Fe_(3)(μ_(2)-bntrz)_(6)]trinuclear units covalently linked by symmetric double cyanocarbanion coligands involving 12-membered metallacycles has been prepared and characterised.The crystal structure of 1·4H_(2)O revealed a trinuclear fragment,[Fe_(3)(μ_(2)-bntrz)_(6)(bntrz)_(2)(μ_(2)-tcnsme)_(2)]^(4+),composed of a central Fe^(Ⅱ)ion(Fe1)and two external metal ions(Fe2),similar to that described for the discrete trinuclear complex[Fe_(3)(μ_(2)-bntrz)_(6)(tcnset)_(6)](2)previously reported.Magnetic studies of 1·4H_(2)O showed a continuous gradual decrease of the magnetic signal,characteristic of the presence of a complete one-step gradual HS to LS transition(T_(1/2)=281 K)different from the abrupt one described for 2.This difference has been attributed to the presence of competing ferro-and anti-ferroelastic interactions,induced,respectively,by the intra-(μ_(2)-bntrz)and inter-trimer(μ_(2)-tcnsme)covalent links in 1·4H_(2)O.TGA and powder X-ray diffraction analyses revealed that 1·4H_(2)O shows a complete and reversible“dehydration(1)/hydration(1·4H_(2)O)”process that occurs,respectively,by heating 1·4H_(2)O at 370 K and by soaking in water the dehydrated sample(1).The magnetic behaviour of 1 exhibits a two-step SCO transition at ca.245 K.Thanks to the combined magnetic and vibrational infrared data allowing correct extraction of the contribution of the two Fe^(Ⅱ)active centres(one central Fe1 and two external Fe2 ions),the first step(370-245 K)was attributed to a concomitant HS/LS switching of the central Fe1 and a half of the Fe2 ions and the second one,occurring below 245 K,was attributed to the HS/LS transition of the remaining HS state among the randomly distributed Fe2 external ions.Photomagnetic experiments have been performed for both hydrated(1·4H_(2)O)and dehydrated(1)phases.As expected from their thermal transition temperatures,no photomagnetic response was observed for 1·4H_(2)O at 638 nm nor at 450 nm,while the dehydrated phase(1)shows an increase of the magnetic moment,reaching a maximum of 1.4 cm^(3)K mol^(−1)at 22 K,followed by the thermallyinduced HS to LS relaxation with TLIESST=41 K.展开更多
A viologen derivative-and a carboxylic acid-based one-dimensional(1D)cocrystal Zn(Ⅱ)coordination polymer,{[Zn(bcbpy)_(2)][Zn(sip)Cl]·4H_(2)O}_(n)(1,bcbpy=1,1’-bis(3-carboxybenzyl)-4,4’-bipyridinium,sip=5-sulfo...A viologen derivative-and a carboxylic acid-based one-dimensional(1D)cocrystal Zn(Ⅱ)coordination polymer,{[Zn(bcbpy)_(2)][Zn(sip)Cl]·4H_(2)O}_(n)(1,bcbpy=1,1’-bis(3-carboxybenzyl)-4,4’-bipyridinium,sip=5-sulfoisophthalate),has been produced solvothermally and structurally characterized.Complex 1 comprises two cationic chains(Chain-1)and one anionic chain(Chain-2)that cross each other and grow into a 3D supramolecular structure through hydrogen bonding interactions.Notably,under UV 365 nm irradiation,1 showed a noteworthy photochromic transition between colorless and deep blue,which should be attributed to the generation of viologen radicals.Interestingly,it exhibited a two-step coloring phenomenon when heated,with the color changing to yellow and brown at 230℃and 250℃,respectively.Furthermore,1 demonstrated selective gas-chromic behavior toward ethylamine(EA),and it is recoverable by washing with MeCN.Furthermore,1 can be deposited on filter paper and demonstrates a potential application as an inkless print material.Interestingly,when complex 1 is removed from liquid nitrogen,as the temperature rises from 80 to 290 K,it exhibits a yellow green afterglow.In addition,the production of polyvinyl alcohol(PVA)film,1-PVA,has made the photochromism of 1 practical in ink-free printing,UV detection,and information anti-counterfeiting,and it is confirmed that the photochromic properties of viologen complex can be improved in PVA medium.展开更多
The electronic[Xe]4f^(13) configurations of Yb(Ⅲ)ions generate a variety of electronic energy levels,resulting in the fantastic optical and magnetic multifunctional properties of Yb(Ⅲ)complexes.Here,2-hydroxy-3-meth...The electronic[Xe]4f^(13) configurations of Yb(Ⅲ)ions generate a variety of electronic energy levels,resulting in the fantastic optical and magnetic multifunctional properties of Yb(Ⅲ)complexes.Here,2-hydroxy-3-methoxy benzoic acid(H_(2)MBA)was used to construct two dinuclear and one-dimensional Yb(Ⅲ)complexes namely[Yb_(2)(HMBA)_(2)(MBA)_(2)(DMF)_(2)(H_(2)O)_(2)]·6H_(2)O(1,DMF=N,N-dimethylformamide)and[NH_(4)][Yb(HMBA)_(4)](2).Fluorescence measurements reveal that H_(2)MBA can sensitize the characteristic near-infrared luminescence of Yb(Ⅲ).Magnetic susceptibility measurements show that the two Yb(Ⅲ)complexes are field-induced single-molecule magnets(SMMs)with anisotropy barriers of 18(1)cm^(-1) and 20(1)cm^(-1) for 1 and 2,respectively.The magnetism-luminescence-structure correlations as well as relaxation pathways are investigated by ab initio calculations and fluorescence spectrometry.展开更多
In the process of generating assembly dimension chain automatically, there are many problems such as complex assembly relationship, variety of constraints of components and complex dimension and tolerance relations of...In the process of generating assembly dimension chain automatically, there are many problems such as complex assembly relationship, variety of constraints of components and complex dimension and tolerance relations of components. These problems lead to many difficulties in search process and need lots of man-machine interaction. Because of these difficulties, this paper presents a method of automatic generation of assembly dimension chain based on tolerance cell. This method is realized through obtaining assembly tolerance cell and part tolerance cell first. These two types of tolerance cell are extracted and expressed in the form of linked list structure in computer further. Then assembly dimension chain is searched automatically based on obtained tolerance cell, and the correct assembly dimension chain is extracted finally. A system of generating assembly dimension chain automatically has been developed based on DELMIA and successfully deployed in aircraft assembly simulation in the engineerine practice.展开更多
Non-centrosymmetric(NCS)metal chalcogenides are candidates for promising nonlinear optical(NLO)crystals in infrared(IR)bands.However,most research has been focused on sulfides and selenides,with few studies focused on...Non-centrosymmetric(NCS)metal chalcogenides are candidates for promising nonlinear optical(NLO)crystals in infrared(IR)bands.However,most research has been focused on sulfides and selenides,with few studies focused on tellurides.For the first time,we systematically investigated the linear-optical and NLO properties of a ternary NLO-active telluride,Ba_(2)Ge_(2)Te_(5),at the experimental and theoretical levels.It adopts the NCS space group of Pna2_(1)(no.33)and features an unusual one-dimensional helical chain of[Ge_(2)Te_(5)]^(4−)separated by Ba^(2+).Ba_(2)Ge_(2)Te_(5)exhibits a suitable birefringence(Δn)of 0.07,and a giant NLO coefficient d33 of 286.8 pm V^(−1)at a wavelength of 2050 nm(∼0.61 eV),much larger than that of the reference AgGaS2(18.2 pm V^(−1)).This work indicates that ethane-like[Ge_(2)Te_(6)]is an instructive NLO-active functional group that can be used to design novel and promising IR-NLO materials.展开更多
The normal contact force determines the behavior of a particle system.To investigate the normal contact force in a one‐dimensional sphere chain subjected to impact load,by comparing the simulation results of the exis...The normal contact force determines the behavior of a particle system.To investigate the normal contact force in a one‐dimensional sphere chain subjected to impact load,by comparing the simulation results of the existing typical normal contact force models embedded in the discrete element program,an improved normal contact force model was proposed in this paper.The improved model con-sists of two parts:the Cundall model for loading and the Daniel model for unloading.Moreover,a systematic test was designed to verify the accuracy and applicability of the improved model.The results showed that the calculated contact force curves agree well with the experimental results.Furthermore,the improved model is implemented in the solution algorithm without need for complex numerical methods and parameters fitting,leading to more efficient simulations.展开更多
文摘The reactions of 18 crown 6 with each of K 2(M=Zn, Hg; mnt=1,2 dicyanoethene 1,2 dithiolate, C 2S 2(CN) 2- 2) were studied and novel complexes [K(18 C 6)] 2[Zn(mnt) 2](1) and [K(18 C 6)] 2[Hg(mnt) 2](2) were characterized by elemental analysis, IR spectrum and X ray diffraction analysis. Complex 1 displays a one dimensional chain of [K(18 C 6)] 2[Zn(mnt) 2] bridged by K O interactions between adjacent [K(18 C 6)] + units. Complex 2 is also a one dimensional chain of [K(18 C 6)] 2[Hg(mnt) 2] bridged by K...S weak interactions between adjacent [K(18 C 6)] + and [Hg(mnt) 2] 2- .
基金supported by the National Natural Science Foundation of China(Grant No.22201195,22122106,22071158,and 21971171)Natural Science Foundation of Sichuan Province(2023NSFSC1066)the Fundamental Research Funds from Sichuan University(2021SCUNL101).
文摘Developing new birefringent materials with large optical anisotropy is extremely urgent due to the fantastic progress of laser science and technology.Here,two tin(Ⅱ)-based oxalates,K_(2)Sn(C_(2)O_(4))_(2)·H_(2)O and K_(2)Sn_(2)(C_(2)O_(4))_(2)F_(2)·H_(2)O,were successfully synthesized by simultaneously introducingπ-conjugated[C_(2)O_(4)]^(2)-groups and distorted Sn^(2+)-polyhedra with stereochemically active lone pairs.
基金supported by the NNSF of China(Grants,21561015,21361011,and 21661014)the Young Scientist Training Project of Jiangxi Province(Grant 20153BCB23017)the NSF of Jiangxi(Grant 20151BAB203002).
文摘Reactions of DyCl_(3)·6H_(2)O or Dy_(2)O_(3) with 2-quinolinecarboxylic acid(H-QLC)yielded two compounds,namely,[Dy_(4)(QLC)_(12)(H_(2)O)_(6)]·4H_(2)O(1)and[Dy(QLC)_(3)(H_(2)O)_(2)]_(n)(2).Compound 1 is a linear tetranuclear structure with one central[Dy_(2)(QLC)_(4)(H_(2)O)_(4)]subunit and two terminal[Dy(QLC)_(3)(H_(2)O)]subunits linked by bridging QLC^(-)ligands.Compound 2 has a one-dimensional(1D)chain wherein the[Dy(QLC)_(2)]unit formed by two QLC^(-)ligands chelating a Dy(Ⅲ)ion is connected by the bridging QLC^(-)ligands.Compounds 1 and 2 exhibit slow magnetic relaxation behaviour in the absence of a static magnetic field,which is rarely observed in lanthanide-carboxylate compounds.During the structural evolution from a linear Dy_(4) cluster of 1 into a 1D chain of 2,the anisotropy energy barrier(U_(eff))is enhanced from 45.4(2)to 144.2(1)K.Though the Dy(Ⅲ)centers in 1 and 2 all are eight-coordinated with square antiprismatic coordination environments,the higher energy barrier observed for 2 could be the result of a more favorable crystal field for the Dy(Ⅲ)ions in 2.
基金funded by the French CNRS(MITI Project),Mol-CoSM ANR Project No.ANR-20-CE07-0028-01financial support from“Région de Bretagne and Universitéde Brest”financial support of the Polish National Science Centre within the Opus project no.2020/39/B/ST5/02815.
文摘A new 1D coordination polymer,[Fe_(3)(μ_(2)-bntrz)_(6)(bntrz)_(2)(μ_(2)-tcnsme)_(2)](tcnsme)_(4)·4H_(2)O(1·4H_(2)O),based on[Fe_(3)(μ_(2)-bntrz)_(6)]trinuclear units covalently linked by symmetric double cyanocarbanion coligands involving 12-membered metallacycles has been prepared and characterised.The crystal structure of 1·4H_(2)O revealed a trinuclear fragment,[Fe_(3)(μ_(2)-bntrz)_(6)(bntrz)_(2)(μ_(2)-tcnsme)_(2)]^(4+),composed of a central Fe^(Ⅱ)ion(Fe1)and two external metal ions(Fe2),similar to that described for the discrete trinuclear complex[Fe_(3)(μ_(2)-bntrz)_(6)(tcnset)_(6)](2)previously reported.Magnetic studies of 1·4H_(2)O showed a continuous gradual decrease of the magnetic signal,characteristic of the presence of a complete one-step gradual HS to LS transition(T_(1/2)=281 K)different from the abrupt one described for 2.This difference has been attributed to the presence of competing ferro-and anti-ferroelastic interactions,induced,respectively,by the intra-(μ_(2)-bntrz)and inter-trimer(μ_(2)-tcnsme)covalent links in 1·4H_(2)O.TGA and powder X-ray diffraction analyses revealed that 1·4H_(2)O shows a complete and reversible“dehydration(1)/hydration(1·4H_(2)O)”process that occurs,respectively,by heating 1·4H_(2)O at 370 K and by soaking in water the dehydrated sample(1).The magnetic behaviour of 1 exhibits a two-step SCO transition at ca.245 K.Thanks to the combined magnetic and vibrational infrared data allowing correct extraction of the contribution of the two Fe^(Ⅱ)active centres(one central Fe1 and two external Fe2 ions),the first step(370-245 K)was attributed to a concomitant HS/LS switching of the central Fe1 and a half of the Fe2 ions and the second one,occurring below 245 K,was attributed to the HS/LS transition of the remaining HS state among the randomly distributed Fe2 external ions.Photomagnetic experiments have been performed for both hydrated(1·4H_(2)O)and dehydrated(1)phases.As expected from their thermal transition temperatures,no photomagnetic response was observed for 1·4H_(2)O at 638 nm nor at 450 nm,while the dehydrated phase(1)shows an increase of the magnetic moment,reaching a maximum of 1.4 cm^(3)K mol^(−1)at 22 K,followed by the thermallyinduced HS to LS relaxation with TLIESST=41 K.
基金National Natural Science Foundation of China for financial support(21671022).
文摘A viologen derivative-and a carboxylic acid-based one-dimensional(1D)cocrystal Zn(Ⅱ)coordination polymer,{[Zn(bcbpy)_(2)][Zn(sip)Cl]·4H_(2)O}_(n)(1,bcbpy=1,1’-bis(3-carboxybenzyl)-4,4’-bipyridinium,sip=5-sulfoisophthalate),has been produced solvothermally and structurally characterized.Complex 1 comprises two cationic chains(Chain-1)and one anionic chain(Chain-2)that cross each other and grow into a 3D supramolecular structure through hydrogen bonding interactions.Notably,under UV 365 nm irradiation,1 showed a noteworthy photochromic transition between colorless and deep blue,which should be attributed to the generation of viologen radicals.Interestingly,it exhibited a two-step coloring phenomenon when heated,with the color changing to yellow and brown at 230℃and 250℃,respectively.Furthermore,1 demonstrated selective gas-chromic behavior toward ethylamine(EA),and it is recoverable by washing with MeCN.Furthermore,1 can be deposited on filter paper and demonstrates a potential application as an inkless print material.Interestingly,when complex 1 is removed from liquid nitrogen,as the temperature rises from 80 to 290 K,it exhibits a yellow green afterglow.In addition,the production of polyvinyl alcohol(PVA)film,1-PVA,has made the photochromism of 1 practical in ink-free printing,UV detection,and information anti-counterfeiting,and it is confirmed that the photochromic properties of viologen complex can be improved in PVA medium.
基金supported by the National Natural Science Foundation of China(No.21271052 and 21905062)the Science and Technology Program Foundation of Guangdong Province(No.2015A030313502)the First talent cultivation program of Guangzhou University(RP2020084).
文摘The electronic[Xe]4f^(13) configurations of Yb(Ⅲ)ions generate a variety of electronic energy levels,resulting in the fantastic optical and magnetic multifunctional properties of Yb(Ⅲ)complexes.Here,2-hydroxy-3-methoxy benzoic acid(H_(2)MBA)was used to construct two dinuclear and one-dimensional Yb(Ⅲ)complexes namely[Yb_(2)(HMBA)_(2)(MBA)_(2)(DMF)_(2)(H_(2)O)_(2)]·6H_(2)O(1,DMF=N,N-dimethylformamide)and[NH_(4)][Yb(HMBA)_(4)](2).Fluorescence measurements reveal that H_(2)MBA can sensitize the characteristic near-infrared luminescence of Yb(Ⅲ).Magnetic susceptibility measurements show that the two Yb(Ⅲ)complexes are field-induced single-molecule magnets(SMMs)with anisotropy barriers of 18(1)cm^(-1) and 20(1)cm^(-1) for 1 and 2,respectively.The magnetism-luminescence-structure correlations as well as relaxation pathways are investigated by ab initio calculations and fluorescence spectrometry.
文摘In the process of generating assembly dimension chain automatically, there are many problems such as complex assembly relationship, variety of constraints of components and complex dimension and tolerance relations of components. These problems lead to many difficulties in search process and need lots of man-machine interaction. Because of these difficulties, this paper presents a method of automatic generation of assembly dimension chain based on tolerance cell. This method is realized through obtaining assembly tolerance cell and part tolerance cell first. These two types of tolerance cell are extracted and expressed in the form of linked list structure in computer further. Then assembly dimension chain is searched automatically based on obtained tolerance cell, and the correct assembly dimension chain is extracted finally. A system of generating assembly dimension chain automatically has been developed based on DELMIA and successfully deployed in aircraft assembly simulation in the engineerine practice.
基金supported by the National Natural Science Foundation of China(21771179,21771182 and 22175175)the Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZR118)the Natural Science Foundation of Fujian Province(2019J01133).
文摘Non-centrosymmetric(NCS)metal chalcogenides are candidates for promising nonlinear optical(NLO)crystals in infrared(IR)bands.However,most research has been focused on sulfides and selenides,with few studies focused on tellurides.For the first time,we systematically investigated the linear-optical and NLO properties of a ternary NLO-active telluride,Ba_(2)Ge_(2)Te_(5),at the experimental and theoretical levels.It adopts the NCS space group of Pna2_(1)(no.33)and features an unusual one-dimensional helical chain of[Ge_(2)Te_(5)]^(4−)separated by Ba^(2+).Ba_(2)Ge_(2)Te_(5)exhibits a suitable birefringence(Δn)of 0.07,and a giant NLO coefficient d33 of 286.8 pm V^(−1)at a wavelength of 2050 nm(∼0.61 eV),much larger than that of the reference AgGaS2(18.2 pm V^(−1)).This work indicates that ethane-like[Ge_(2)Te_(6)]is an instructive NLO-active functional group that can be used to design novel and promising IR-NLO materials.
基金National Natural Science Foundation of China,Grant/Award Numbers:51874118,51778211supported by the National Natural Science Foundation of China(Nos.51874118,51778211).
文摘The normal contact force determines the behavior of a particle system.To investigate the normal contact force in a one‐dimensional sphere chain subjected to impact load,by comparing the simulation results of the existing typical normal contact force models embedded in the discrete element program,an improved normal contact force model was proposed in this paper.The improved model con-sists of two parts:the Cundall model for loading and the Daniel model for unloading.Moreover,a systematic test was designed to verify the accuracy and applicability of the improved model.The results showed that the calculated contact force curves agree well with the experimental results.Furthermore,the improved model is implemented in the solution algorithm without need for complex numerical methods and parameters fitting,leading to more efficient simulations.
