Synthesis, Structures And Characterization Of Transition Metal Complexes Of N-heterocycle-containing Ligands And Clusters Induced By Rare Earth Metal Ions

N-heterocyclic compounds and their transition metal complexes and rare earth clusters have become one of the hot research topics in inorganic chemistry and material chemistry due to their attractive potential applications in the fields of life science,photochemistry, electrochemistry,magnetism as well as catalysis.With these in mind,a series of metal complexes have been designed and synthesized using general solution synthesis and hydrothermal synthesis.X-Ray single crystal diffraction has been performed on fifteen synthesized complexes and the single crystal structure determinations show that,among the fifteen complexes,ten are N-heterocyclic transition metal complexes and five are rare earth clusters.Based on NMR technique,the structures of two N-heterocyclic compounds and three N-heterocyclic metal complexes in solution have been investigated.In addition, the structures of the two N-heterocyclic compounds in solution,have been proved by quantum chemical calculations.The electrochemical properties and thermal properties of some of the synthesized metal complexes have also been studied.Reaction of isoniazid with CuCN,CuI,PtI₄ and FeSO₄ gave four complexes.X-Ray single crystal structure determinations carried out on these four complexes show that one is a two-dimensional(2D) coordination polymer,one is a one-dimensional(1D) coordination polymer,the third one is a dinuclear complex and the fourth one is a mononuclear complex.The influence of anions and central metal ions on crystal structures of the complexes has been studied and compared.Based on NMR technique,the structure of the complex of CuCN with isonicotinly hydrazide in solution has been investigated.In addition,the thermal stability of the complexes of CuCN,CuI,PtI₄ with isonicotinly hydrazide has been investigated and the possible thermal decomposition modes have been proposed.Reaction of nicotine with CuI,CuBr,HgI₂ and HgBr₂ yielded four complexes.X-Ray single crystal structure analysis carried out on these four complexes indicates that two of them are tetranuclear clusters and the other two are 1D chain-like coordination polymers. The coordination modes of CuI and CuBr with nicotine have been studied and compared with each other.In the cases of Cu⁺ and Hg²⁺ complexes,although Cu⁺ and Hg²⁺ ions have the same electronic configuration,d¹⁰,they belong to different rows and have different atomic charges and radius.These factors clearly influence the structures of their complexes with nicotine.The structures of CuI and HgI₂ with nicotine in solution have also been studied.For the complexes of CuI,HgI₂ and HgBr₂ with nicotine,their thermal stability has been analysed and the possible decomposition modes have also been proposed.Although isoniazid and nicotine have some similarities,for example,both ligands have a pyridine ring,there are significant differences between them:isoniazid has a bulky substituent(-CONHNH₂) atγposition but nicotine has a different bulky substituent (N-methylpyrrolidine) atβposition.These differences could have influence on the molecular strucutres of the complexes.X-Ray crystal structure determinations carried out on the complexes have clearly confirmed this.In fact,under the same reaction conditions, different molecular structures could be obtained by reacting CuI with isoniazid or nicotine. To summarize,the two ligands have different sizes,different conformations as well as different stereo hindrance,which make them adopt different coordination modes and different arrangements when forming the complexes with the ligands.Using hydrothermal syntheis,two complexes,2,2'-bipyridine-Cd²⁺ and isonicotinic acid-Co²⁺,have been obtained and their structures characterized by X-ray single crystal diffraction.Based on 2D NMR technique,the structures of other two N-heterocyclic compounds, chlorpromazine hydrochloride and promethazine hydrochloride,in solution have been investigated.All the ¹H-NMR and ¹³C-NMR peaks of chlorpromazine hydrochloride in DMSO-d₆,CD₃COCD₃ and CDCl₃ those of promethazine hydrochloride in DMSO-d₆ and CDCl₃ have been fully assigned.The differences between the peaks of side chains of the two N-heterocyclic compounds in different solvents have also been analyzed.The data showed that both compounds in CDCl₃ solution have folded conformations,which is probably due to the interactions between the cations andÏ€system in the molecules.This is also consistent with the results obtained from the quantum chemical calculations carried out on these compounds.The roles of pr³⁺and Dy³⁺ ions have been discussed when they induced[MS4]^2-(M＝Mo,W) and Ag⁺ to form the three clusters with 1D helical anion-chain.The influence of the different solvated ions and the building blocks,[MoS₄]²⁺ and[WS₄]²⁺,on the conformations of the anion skeletons and the size of the unit cells has also been discussed.The self-assembly of AgI induced by the solvated rare earth ions has been studied and a new type of cluster was obtained.Comparison of the crystal structure of this cluster with the reported related structurally characterized clusters shows that the versatility of coordination modes of I^- anion can result in the versatility of structures of the clusters.Using[W^V(CN)₈]^3- as the building block,a 1D chain-like cluster has been synthesized by the induction of a solvated rare earth cation.The crystal strucutre of the cluster shows that in the presence of CN^- as a strong bridging ligand,the versatility of the coordination modes of rare earth cations has important influence on the formation of the clusters of this type.