The physical and electronic properties of Metal-Organic Frameworks containing dipyridylthiazolo[5,4-d]thiazole

Five Metal-Organic Frameworks ({[M-2(tdc)(2)(L)(2)]<middle dot>2DMF}, tdc = 2,5-thiophenedicarboxylate, M = Zn-II (1-Zn), Cu-II (1-Cu), Mn-II (1-Mn), {[Zn(oba)(L)]<middle dot>DMF<middle dot>H2O} (2-Zn), oba = 4,4 '-oxybisbenzoate, and {[Zn-2(bpdc)(2)(L)(2)]<middle dot>L}, (3-Zn) bpdc = 4,4 '-biphenyldicarboxylate) that incorporate the redox-active 2,5-dipyridylthiazolo[5,4-d]thiazole (DPTzTz) ligand (L) have been synthesised and their electronic properties elucidated. The ligand-based organic radicals were generated using in situ techniques and monitored using a suite of solid-state spectroelectrochemistry techniques. The absence of a near infra-red band (NIR), indicating through-space intervalence charge transfer (IVCT), in all analysed materials suggests that both the inter-ligand distance between cofacial TzTz moieties and the flexibility of the TzTz moiety affect the through-space IVCT.