Preparation and Visible-Light Response of Salicylate-Stabilized Heterobimetallic Pb-Ti-Oxo Clusters Initiated via Auxiliary Quaternary Ammonium Salts and a Solvent Effect.

In this study, with the assistance of quaternary ammonium salts we have successfully prepared a new family of salicylate-stabilized heterobimetallic Pb-Ti-oxo clusters, including H(TEA)[Pb 2 Ti 6 (μ 2 -O) 2 (μ 3 -O) 2 (O i Pr) 4 (PA) 2 (Sal) 6 (NO 3 ) 2 ] ( PTC-321 ; TEA = tetraethylammonium; HO i Pr = isopropanol; H 2 PA = phenylphosphonic acid; H 2 Sal = salicylic acid), {PbTi 3 (μ 2 -O)(μ 3 -O)(O i Pr) 2 (PA)(Sal) 3 (DMF)·CH 3 CN} n ( PTC-322 ; DMF = dimethylformamide), {PbTi 5 (μ 3 -O) 6 (Sal) 3 (CH 3 COO) 2 (DMF)(O i Pr) 2 } n ( PTC-323 ), [Pb 2 Ti 4 (Sal) 6 (EtO) 2 (O i Pr) 6 (HO i Pr) 2 ]·CH 3 NH 2 ( PTC-324 ; EtOH = CH 3 CH 2 OH), H[Pb 4 Ti 9 (μ 2 -O) 2 (μ 3 -O)(μ 4 -O) 6 (Sal) 7 (O i Pr) 13 ] ( PTC-325 ), and Pb 2 Ti 12 (μ 2 -O) 3 (μ 3 -O) 3 (μ 4 -O) 4 (Sal) 4 (OEt) 24 ( PTC-326 ). Single-crystal X-ray diffraction studies demonstrate that the {Ti 3 Pb(Sal) 3 } unit acts as the building block to constitute the diverse assembly of PTC-321-PTC-323 . Thereinto, the clusters in PTC-322 and PTC-323 are connected into infinite one-dimensional chains. Furthermore, the solvent effects have facilitated the heterobimetallic Pb-Ti-oxo clusters into various configurations in PTC-323-PTC-326 . Solid-state ultraviolet-visible spectroscopy analysis indicates that the optical absorption bands of these compounds shift effectively toward the visible-light region, and they were also employed as electrode precursors to investigate their visible-light-driven photocurrent response.