Structural Chemistry And Spectrum Research Of Organic-inorganic Hybrid Lead Iodide Templated By Transition Metal Complex

The research on organic—inorganic hybrid lead iodide templated by organic groups is an appealing field for their great potential practical applications in many fields, such as, optical conductor, electroluminescence, third—order nonlinear optical material, ferroelectric materials, ferroelastic materials and so on. The organic groups can control and modify the structure of inorganic framework, for its rigidity in conjunct mode, flexibility in stereochemistry and strong capability of coordination. So far, the organic-inorganic hybrid lead iodides with transition metal complex as counter-cation are very rare. It is significant to synthesize this kind of novel compound, and study the rule of assemble, structure and the relation between structure and property. We carried out the following research work based on summary of literature search systematically. We have made achievements on such aspect: 1. Devising and synthesizing four novel organic-inorganic hybrid lead iodides and a iodide with Zn—alkylamine coordinated polymer as cation, employing X-ray single crystal diffractometer technology to determine their structures: [Zn(C₈H₂₃N₅)]₂(Pb₃I₁₀) (1); [Zn(C₃H₁₂N₃)₂](Pb₂I₆) (2) ;[Ni(C₈H₂₃N₅)](Pb₂I₆) (3) ;[Pb(C₆H₁₈N₄)](Pb₂I₆) (4) ;[Zn(C₄H₂₆N₃)₂]I₂ (5) , of which compounds 1 is one-dimensional chain-like hybrid, compounds 2 possesses one-dimensional pillar-liked inorganic structure, compounds 3,4 belong to lead iodide hybrid with 1D double chains ladder-liked inorganic structures, and compound 5 is iodide. In compound 3, there exist Ni —I coordination bonds between counter-cation and inorganic framework, which makes compound 3 different from other title compounds. 2. The effects of reaction conditions on productions are considered and studied, and we found a feasible method of synthesizing the organic-inorganic hybrid lead iodides with transition metal complex as counter-cation. 3. The character of Pb-I polyhedral structure and the mode of Pb-I bond are classified and discussed based on summary of literature about lead iodide. The relationship between the framework structure and the connecting manner of Pb-I polyhedra is researched. 4. The IR and Raman spectra of the four compounds have been characterized. DSR spectra of the 4 novel compounds have been characterized. The DSR spectra show the compounds possess absorbed peaks of d—d transition and LMCT. Fluorescences of all the compounds are vanished. 5. The TGA was employed to characterize the thermostability of compound 1,2,3. We found that they have conformable regularities: at the first stage(about 300⁴00 ℃),the organic molecules are lost; at the second stage(about 400⁵50or 600℃), the iodine is lost. 6. DFT/BLYP calculation was carried out to study the nature of bonds and the electronic structure of compound 1,2,3,4. Some conclusions can be drawn from the results, Pb atom offers 6p orbit to form molecular orbit with iodine and the 6s electrons of Pb atom exist as lone-pair electron.