Crystal structures, electronic spectra and magnetic properties of homoleptic and heteroleptic metal-dithiolate molecular solids. (1st June 2018) - Chen, Xuan-Rong
Graphical abstract: Two nickel-bis-1, 2-dithiolene molecular solids, (4-ClBzEt3 N)[Ni(dmit) x (mnt)2- x ] ( x = 0 (1 ) and 1 (2 )) were synthesized and characterized by the IR spectra, PXRD, UV–Vis absorption. The variable-temperature magnetic susceptibility analysis shows that1 follow the Curie–Weiss law below 50 K and a spin-gap between 50 and 205 K, and2 exhibits a weak antiferromagnetic exchange interaction. Abstract: Two nickel-bis-(1, 2-dithiolate) molecular solids, (4-ClBzEt3 N)[Ni(dmit) x (mnt)2− x ] ( x = 0 (1 ) and 1 (2 )) (where 4-ClBzEt3 N + = 4-chloro-benzyltriethylammonium; dmit 2− = 2-thioxo-1, 3-dithiole-4, 5-dithiolate; mnt 2− = maleonitriledithiolate) were synthesized and characterized structurally. The infrared (IR) spectra, powder X-ray diffraction (PXRD), UV–Vis absorption and magnetic properties have been investigated for1 and2 . The homoleptic metal-dithiolene complex1 crystallizes in monoclinic system with space group P 1 ¯ . The anions of1 are aligned into columnar stacks along a -axis direction. The neighboring anions are connected via lateral-to-lateral S…S contacts of mnt 2− ligands are observed between the cations and the anions. The powder X-ray diffraction patterns are in good agreement with the simulated patterns based on the crystal structures, indicating the purity of the as-grow crystals. FT-IR and UV–Vis absorption spectra were recorded and analyzed for1 and2 . The variable-temperature magnetic susceptibility analysis shows that1 follow the Curie–Weiss law below 50 K and a spin-gap between 50 and 205 K, and2 exhibits a weak antiferromagnetic exchange interaction as the temperature is lowered and the magnetic susceptibility data follows the S = 1 /2 Heisenberg alternating linear-chain model in the temperature range 109–400 K and a spin gap below 109 K for2 .