Two novel 3-D coordination polymers with 5-methoxyisophthalate and flexible N-donor co-ligands showing pentanuclear or alternate mono/binuclear Cu(ii) units

Abstract

Two novel 3-D coordination polymers with different Cu(II) subunits as nodes and mixed bridging ligands as linkers, namely [Cu₅(μ₃-OH)₂(1,3-bip)₂(CH₃O-ip)₄]_n (1) and {[Cu₄(1,3-btp)₂(CH₃O-p)₄(H₂O)₂]·2H₂O}_n (2) (CH₃O-H₂ip = 5-methoxyisophthalate, 1,3-bip = 1,3-bis(imidazol)propane, 1,3-btp = 1,3-bis(1,2,4-triazol-1-yl)propane), were prepared under hydrothermal conditions. Complex 1 exhibits a CsCl-type network with [Cu₅(μ₃-OH)₂]⁸⁺ clusters acting as nodes, which represents the first 3-D network based on pentanuclear Cu(II) clusters. Complex 2 features a 3-D pillared-layer network with (4,6)-connected (4⁴.6²)(4⁴.6⁸.8³)-fsc topology, which is a rare example of homometallic coordination polymers constructed by alternate binuclear metal clusters and single metal centres. Variable-temperature magnetic susceptibility measurements show dominant ferromagnetic interactions in the pentanuclear clusters of 1 and strong antiferromagnetic interactions in the dinuclear paddle-wheel units of 2.