Binuclear Sulfide Niobium Clusters Coordinated by Diimine Ligands: Synthesis, Structure, Photocatalytic Activity and Optical Limiting Properties

• Published in: European journal of inorganic chemistry Vol. 2015; no. 17; pp. 2865 - 2874
• Main Authors: Rogachev, Alexander V., Gushchin, Artem L., Abramov, Pavel A., Kozlova, Ekaterina A., Vicent, Cristian, Piryazev, Dmitry, Barlow, Adam, Samoc, Marek, Humphrey, Mark G., Llusar, Rosa, Fedin, Vladimir P., Sokolov, Maxim N.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.06.2015; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: Chalcogens; Clusters; Clusters compounds; Ligands; Nanoparticles; Niobium; Optical limiters; Optical properties; Photocatalysis; Structure elucidation; Titanium dioxide
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201500319

Substitution reactions of binuclear niobium cluster anion [Nb2S4(NCS)8]4– with different types of pyridine‐based diimine ligands have been carried out. In the case of 2,2′‐bipyridine (bipy) and its derivatives, only monosubstituted complexes [Nb2S4(NCS)6L]2– have been isolated. In the case of 1,10‐phenanthroline and 2‐(2‐pyridyl)benzimidazole (Hpbz), both mono‐ and disubstituted complexes, [Nb2S4(NCS)6L]2– and [Nb2S4(NCS)4L2], respectively, have been obtained. Crystal structures of (Et4N)2[Nb2S4(NCS)6(bipy)]·0.5bipy·0.7CH3CN and [Nb2S4(pbmz)2(NCS)4]·5DMF·0.8H2O have been determined. All compounds have been characterized by NMR, ESI mass spectrometry, IR, UV/Vis spectroscopy, and CV. TiO2 nanoparticles modified with (Et4N)2[Nb2S4(NCS)6(bipy)] show moderate photocatalytic activity in the reaction of H2 generation from water in the presence of Na2S/Na2SO3 as a sacrificial electron donor system. The linear and nonlinear optical properties of the complexes with bipyridine ligands have been studied; the complexes function as broad‐band optical limiters. A series of complexes, [Nb2S4(NCS)6L]2– and [Nb2S4(NCS)4L2], where L is a bipyridine, phenanthroline or 2‐(2‐pyridyl)benzimidazole has been prepared. TiO2 nanoparticles modified with (Et4N)2[Nb2S4(NCS)6(bipy)] exhibit photocatalytic activity for H2 generation from water in the presence of a sacrificial electron‐donor system. The complexes function as optical limiters.