Ruthenium-Benzothiadiazole Building Block Derived Dynamic Heterometallic Ru-Ag Coordination Polymer and Its Enhanced Water-Splitting Feature.

This article deals with the development of the unprecedented redox-mediated heterometallic coordination polymer {[Ru(acac)(μ-bis-η-,η-NBTD)Ag(ClO)]ClO} () via the oxidation of the monomeric building block -[Ru(acac)(η-N-BTD)] () by AgClO (BTD = exodentate 2,1,3-benzothiadiazole, acac = acetylacetonate). Monomeric -[Ru(acac)(η-N-BTD)] () and [Ru(acac)(η--BTD)(CHCN)] () were simultaneously obtained from the electron-deficient BTD heterocycle and the electron-rich metal precursor Ru(acac)(CHCN) in refluxing CHCN. Molecular identities of - were authenticated by their single-crystal X-ray structures as well as by solution spectral features. These results also reflected the elusive trigonal-planar geometry of the Ag ion in Ru-Ag-derived polymeric . Ru(III) ( = 1/2)-derived displayed metal-based anisotropic EPR with ⟨⟩/Δ = 2.12/0.56 and paramagnetically shifted H NMR. Spectroelectrochemistry in combination with DFT/TD-DFT calculations of and ( = 1+, 0, 1-) determined a metal-based (Ru/Ru) oxidation and BTD-based reduction (BTD/BTD). The drastic decrease in the emission intensity and quantum yield but insignificant change in the lifetime of with respect to could be addressed in terms of static quenching and/or a paramagnetism-induced phenomenon. A homogeneously dispersed dumbbell-shaped morphology and the particle diameter of were established by microscopic (TEM-EDX/SEM) and DLS analysis, respectively. Moreover, the dynamic nature of polymeric was highlighted by its degradation to the η--BTD coordinated monomeric fragment , which could also be followed spectrophotometrically in polar protic EtOH. Interestingly, both monomeric and polymeric exhibited efficient electrocatalytic activity toward water oxidation processes (OER, HER) on immobilization on an FTO support, which also divulged the better intrinsic water oxidation activity of in comparison to .