We report here the synthesis of a ferrocene-functionalized {Ti22Fc4} cluster with a ‘dimer-of-clusters’ topology, which represents the largest Ti-oxo cluster (TOCs) modified with organometallic groups yet to be reported. The...

Cooperative assembly of the neutral cluster {Ti8O5(OEt)18L2} (L = pyrazine-2,3-dicarboxylic acid) with different metal units of Mn­(NO3)2, CuCl2, Zn­(OEt)2, Cd­(NO3)2, Ce­(NO3)3, Lu­(NO3)3, and Lu­(NO3)2(OEt), or the [Cu2I2] cluster, generates a family of titanium–oxygen cluster (TOC)-based coordination polymers. These one-dimensional (1D) linear structures contain the same {Ti8L2} cluster but with variable bridging metal units. The regulation of the heterometal not only affects the chain geometries of the {MTi8} but also affects the way the 1D chains are stacked in the crystal lattice. Investigation of the catalytic activities toward alcohol oxidation demonstrated the synergetic effect of combining the metal site and the photosensitive {Ti8L2} cluster in the tailored structure. Under light illumination, the {MTi8} with dual catalytic sites shows greatly enhanced catalytic activity in the selective oxidation of alcohols to aldehydes. Because the compositions and structures of {MTi8} are highly tunable, this work spotlights the potential of utilizing such metal-bridged multidimensional Ti-oxo materials for cooperative photoredox catalysis for organic transformation.

Here, we systematically studied the self-assembly behavior of chiral polyoxytitanium clusters for the first time. Through the cooperative assembly of ferrocenecarboxylic acid and ketoxime ligands, we successfully incorporated the planar chirality of ferrocene (Fc) into the layered {Ti5} building blocks. The resulting {Ti5Fc} clusters can be used as structural units to assemble into large ordered structures in various ways; either a pair of {Ti5Fc} enantiomers are bridged by organic adhesive to form sandwich structures or two homochiral {Ti5Fc} units participate in the assembly to form the large clusters. Depending on the assembly modes, the chirality of {Ti5Fc} can be transferred to large nanoclusters or disappear to form mesostructures. The difference of the assembly modes between the {Ti5Fc} units can also tune the photoelectric activity of the resulting clusters, which has been verified by using {Ti 10 Fc-6/7} as catalysts for photocatalytic selective sulfide oxidation. This work not only is an important breakthrough in the study of the self-assembly of chiral nanoclusters but also provides an important reference for understanding of chiral transfer on the nanoscale.

Incorporating heterometal into titanium−oxygen clusters (TOCs) is an effective way to improve its catalytic activity. Herein, we synthesize three novel heterometallic TOCs with the formula of [Ti 6 Cu 2 O 7 (Dmg) 2 (OAc) 4 ( i PrO) 6 ]-[H 2 Ti 6 Cu 2 O 7 (Dmg) 2 (OAc) 4 ( i PrO) 8 ] ({Ti 6 Cu 2 }), [Ti 8 Cu 2 O 9 (Dmg) 2 (OAc) 2 ( i PrO) 12 ] ({Ti 8 Cu 2 }), and [Ti 10 Co 2 O 6 (Dmg) 2 (Pdc) 4 ( i PrO) 18 Cl 3 ] ({Ti 10 Co 2 }, DmgH 2 = dimethylglyoxime; PdcH 2 = pyridine-2,3-dicarboxylic acid) using dimethylglyoxime and different carboxylates as the synergistic ligands. By depositing the clusters {Ti 6 Cu 2 } and {Ti 10 Co 2 } on carbon cloth as electrodes, we investigated the electrocatalytic performance of TOCs for full water splitting for the first time. To reach a 10 mA cm −2 current density in an alkaline solution, the {Ti 10 Co 2 }@CC electrode needs an overpotential as low as 120 and 400 mV for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), respectively. In addition, full water-splitting equipment with {Ti 10 Co 2 }@CC as a cathode and an anode need only 1.67 V to deliver a current density of 10 mA cm −2 . Our work confirmed the potential of noble metal-free TOCs as bifunctional cluster-based electrocatalysts for water splitting, and their activities can be tuned by doping with different metal ions.