Syntheses, Crystal Structures, Weak Interactions, and Magnetic Properties of Two Bis(maleonitriledithiolate)copper(II) Salts with Substituted Benzyl 1-Methylimidazolium

Abstract

In two new bis(maleonitriledithiolate)copper(II) salts, [Bz-1-MeIm]₂[Cu(mnt)₂] (1) and [4-NO₂Bz-1-MeIm]₂[Cu(mnt)₂] (2) ([Bz-1-MeIm]⁺ = Bz-1-MeMz = 1-methyl-3-benzylimidazolium; [4-NO₂Bz-1-MeIm]⁺ = 1-methyl-3-(4′-nitrobenzyl)imidazolium), 1 crystallizes in the triclinic system with space group P-1, whereas 2 crystallizes in the monoclinic system with space group P2₁/c. The cations and anions stack alternately into a column by π···π and C‒H···π interactions, and the C‒H···N and C‒H···O hydrogen bonds consolidate the crystal packing and give further rise to a 3D network structure. Magnetic susceptibility measurements show that 1 displays strong antiferromagnetic interaction with θ = –255.98 K, whereas 2 shows weak ferromagnetic coupling with θ = 0.527 K.

Keywords:

• crystal structures
• magnetic properties
• substituted benzyl 1-methylimidazolium
• weak interactions

Acknowledgments

This work has been partially supported by the Science and Technology Project (No. 2010B080701002, 2011B080701026) from Guangdong Science and Technology Department, the Undergraduates’ Innovative Experimental Program in University from Department of Education of Guangdong province (No. 1056413047), and the key Academic Program of the 3rd phase “211 Project” of South China Agricultural University (No. 2009B010100001).