Coordination polymers based on octacyanometalates(iv,v) (M = Mo, W) and aliphatic polyamine copper(ii) tectons with [N3] donor atom sets

Abstract

The cyano-bridged [Cu^II(tetrenH₂)]₂[W^IV(CN)₈]₂·5H₂O (tetren = tetraethylenepentaamine) (1), [Cu^II(tetrenH₂)][Cu^II(tetrenH)][W^V(CN)₈][W^IV(CN)₈]·2.5H₂O (2), [Cu^II(dien)]₂[W^IV(CN)₈]·4H₂O (dien = diethylenetriamine) (3) and its isomorphous molybdenum(IV) analogue (4) have been prepared and structurally characterised. 1 and 2 are built from the W₂Cu₂(μ-CN)₄ squares extended into 1-D structure by cyano-bridges. 2-D 3 and 4 form a square grid pattern with tungsten atoms in the corners and –CN–Cu(dien)–NC– linkages on the edges of the squares. The magnetic behaviour of 1 and 3 indicates the presence of two isolated Cu^II spins S = 1/2 with a very weak antiferromagnetic coupling through the diamagnetic NC–W^IV–CN bridges in the low temperatures. Assembly 2 exhibits a weak ferromagnetic interaction between Cu^II and W^V isolated by diamagnetic [W^IV(CN)₈]⁴⁻ spacer from another Cu^II centre within W^V–CN–Cu^II–NC–W^IV–CN–Cu^II unit and the antiferromagnetic interaction between the Cu^II₂W^VW^IV units.