A novel three-dimensional coordination polymer constructed with mixed-valence dimeric copper(i,ii) unitsElectronic supplementary information (ESI) available: synthesis and data for 1. See http://www.rsc.org/suppdata/cc/b2/b210914j/

A novel three-dimensional coordination polymer with a mixed-valence localized copper(I,II) dimeric unit, [Cu2(4-pya)3]n (4-pya = 4-pyridinecarboxylate), was hydrothermally synthesized via a simultaneous in-situa redox and hydrolysis reaction of Cu(II) and 4-cyanopyridine and crystallographically characterized to be a twofold interpenetrated three-dimensional coordination network with a cubic [Cu16(4-pya)12] building unit.