Metal–organic frameworks incorporating Cu3(μ3-OH) clusters

Abstract

Interaction of 4,4′-bi(1,2,4-triazole) (btr) with copper(II) chloride (bromide) in aqueous or aqueous alcohol media led to a series of coordination polymers featuring the formation of µ₃-hydroxotricopper(II) clusters and their integration into 3D frameworks. These unprecedented structures originate in the propagation of trigonal hydroxotricopper(II) clusters bridged by tri- or tetradentate organic ligands. Complex [{Cu₃(μ₃-OH)}{Cu₃(μ₃-O)}(µ₄-btr)₃(H₂O)₄(OH)₂Cl₆]Cl·0.5H₂O adopts a structure of SrSi₂ topology, with eight-fold interpenetration of the coordination frameworks. The structure of [{Cu₃(μ₃-OH)}₂(μ₃-btr)₆(μ₄-btr)(μ-X)X₄]X₅·nH₂O (X = Br, n = 6; X = Cl, n = 8) involves 2D coordination layers [{Cu₃(μ₃-OH)}(μ₃-btr)₃]_n with an exceptional (3,6)-net topology, which are cross-linked by tetradentate btr ligands and bridging chloride (bromide) ions.