The use of [Fe(dithiooxalate)2(NO)]2− as a tecton in crystal engineering

Abstract

A series of crystalline salts based on the complex dianion [Fe(dto)₂(NO)]²⁻ (dto = 1,2-dithiooxalate) with hydrogen-bond donor cations have been synthesised. The preparation and structural characterisation of the new crystalline phases [4,4′-H₂bipy][Fe(dto)₂(NO)]·H₂O (1), [3,3′-H₂bipy][Fe(dto)₂(NO)] (2) and [H₂Me₄bipyz][Fe(dto)₂(NO)]·2H₂O (3) (Me₄bipyz = 3,3′,5,5'-tetramethyl-4,4′-bipyrazole) are reported, and show that a charge-assisted NH⋯dto synthon is formed in each of compounds 1–3. In compound 1 the anion forms a dimer in the solid-state, and variable temperature magnetic susceptibility measurements reveal a weak antiferromagnetic interaction with a best fit superexchange parameter J = –3.18 (2) cm⁻¹, where H = –2JS₁S₂.