Serendipitous formation of oxygen-bridged CuII6M (M = MnII, CoII) double cubanes showing electrocatalytic water oxidation.

Hydroxido-bridged CuII6M double-cubane clusters (M = MnII, CoII) supported by D-penicillaminedisulfide were unexpectedly formed by treating a D-penicillaminato CuII2PtII2 complex with MBr2 in water. The clusters displayed heterogeneous electrocatalytic activities for water oxidation dependent on the central M shared by two CuII cubane units.

A chromotropic PtIIPdIICoII coordination polymer with dual electrocatalytic activity for water reduction and oxidation.

Here, we present a heterometallic coordination polymer that exhibits heterogeneous electrocatalytic activities for both water reduction and water oxidation. Treatment of the PtII2PdII2 tetranuclear complex [Pd2{Pt(NH3)2(D-pen)2}2] ([1]; D-H2pen = D-penicillamine) with CoX2 (X = Cl, Br) provided (PtII2PdII2CoII2)n coordination polymers [Co2(H2O)6(1)]X4 ([2]X4), in which the PtII2PdII2 units of [1] are linked by [Co2(µ-H2O)(H2O)5]4+ moieties in a 3D network structure. [2]X4 showed a colour change from orange to dark green upon dehydration, reflecting the geometrical conversion of the CoII centres in [Co2(µ-H2O)(H2O)5]4+ from an octahedron to a tetrahedron by the removal of aqua ligands. While both [2]Cl4 and [2]Br4 electrochemically catalysed water reduction to H2 in the solid state due to the presence of PdII active centres, water oxidation to O2 was catalysed only by [2]Br4, which is ascribed to the presence of Br- ions that mediate the catalytic reactions that occurred at CoII active centres.

Dimensional Structures and Electrocatalytic Activities of Platinum(II)-Palladium(II)-Manganese(II) Coordination Polymers Controlled by Chloride versus Bromide.

Here we report the synthesis and structural characterization of heterotrimetallic (PtII2PdII2MnII2)n coordination polymers that show different dimensionalities and electrocatalytic activities depending on chloride and bromide employed in the system. The reaction of the PtII2PdII2 tetranuclear complex [Pd2Pt2(NH3)4(d-pen)4] (1), bearing free carboxylate groups, with Mn2+ in the presence of chloride produced the (PtII2PdII2MnII2)n coordination polymer [Mn2Cl2(H2O)6(1)]Cl2 (2Cl), in which the PtII2PdII2 units of 1 are linked by [MnCl(H2O)3]+ moieties in a 1:2 ratio to form a 2D sheetlike structure. The corresponding reaction in the presence of bromide also gave the (PtII2PdII2MnII2)n coordination polymer [Mn2(H2O)6(1)]Br4 (3Br), but 3Br adopted a 3D network structure via a 1:1 linkage of the PtII2PdII2 units with [Mn2(H2O)6]4+ moieties. These complexes showed appreciably different electrocatalytic activities for H2 evolution.