Solvothermal Synthesis, Structure Of Deuterated Olefin-Copper(I) Coordination Polymers

The studies of ferroelectric and dielectric materials are mainly based on inorganiccompounds while few studies focus on hybrid metal-organic compounds. Prophaseresearch of our group indicated that deuteration makes great influence on the physicalproperties of as-synthesized compounds. In order to obtain materials with good dielectricproperty, we synthesized a series of deuterated and undeuderated pyridine derivatives,and selected four ligands, including 4-(2-allyl-2H-tetrazol-5-yl)pyridine (L⁵),3-(2-allyl-2H-tetrazol-5-yl)pyridine (L^e), 4-(2-allyl-2H-tetrazol-5-yl)-2,6-d₂-pyridine(L⁶), and 3-(2-allyl-2H-tetrazol-5-yl)-2,6-d₂-pyridine (L^f), to react with CuBr or CuClunder methanothermal and anaerobic conditions at 70-75℃. Eight crystalline compoundsof olefin-copper(â… ) were obtained and all of them were determined structurely usingsingle crystal X-ray diffraction. In the olefin-copper(â… ) complexes of L⁵ and L⁶, two Cu(â… )centers, which coordinate to vinyl group in one ligang and pyridine N atom from anotherone, are bridged through twoμ₂-halogen anions to form a dimmer node and result in theformation 1-dimensional double chain. The structures of olefin-copper(â… ) complexes ofL^e and L^f show a trigon plane coordination geometry of Cu(â… ) center, which is fulfilled byN from pyridine ring, double bond of olefin ligand and terminal halogen atom. A novel1-dimensional straight line chain with alternating Cu atoms and ligands is formed.Interestingly, all coordinated olefinic bonds in olefin-copper(â… ) complexes are longer thanfree ethylene, indicating that the coordination of copper(â… ) could potentially activate theolefinic bond. The structure characteristics enable all complexes to form strongface-to-face offsetÏ€-Ï€stacking interactions and various kinds of weak hydrogen bondsthus helping it to assemble networks.