Three molecular metals containing bis(maleonitriledithiolate)nickel(III) anion and 2-substituted benzyl triphenylphosphonium: Syntheses, crystal structures and magnetic properties

摘要

Three new molecular metals, [2RBzTPP][Ni(mnt)_2] (mnt~(2-)=maleonitriledithiolate; [2RBzTPP]~+ = l-(2'-R-benzyl)triphenylphosphonium, R-F(l), Br(2), NO_2(3)) have been synthesized and characterized by elemental analyses, IR, UV, single crystal X-ray diffraction and magnetic measurements. The single-crystal structure analysis indicates that 1 crystallizes in the triclinic space group P -1, while both 2 and 3 crystallizes in the monoclinic space group P2_1. The Ni(III) ions of 1,2, and 3 form a ID non-uniform magnetic chain within a [Ni(mnt)_2]~- anions column through Ni???Ni, Ni???S or S???S interactions. The effect of weak intramolecular interactions such as C-H???N, C-H???F, C-H???Br, C-H???π or C-H???0 hydrogen bonds in these molecular solids 1,2 or 3 generate a 3 D network structure. Magnetic measurements have shown that 1 exhibits a characteristic of spin-gap (Δ/k_b- 249.5 K) around 128 K, while 2 and 3 showed a very strong antiferromagnetic coupling feature with J= -875.6 and -820.3 cm~(-1) when the temperature is lowered.