Monomeric thorium chalcogenolates with bipyridine and terpyridine ligandsDedicated to R. A. Andersen on the occasion of his 75th birthday.Electronic supplementary information (ESI) available: X-Ray crystallographic files in CIF format for the crystal structures of 1-5; calculated and observed PXRD profiles for 1-5. CCDC 1841858 ((bipy)2Th(SPh)4, 1); 1841859 ((bipy)2Th(SePh)4·py, 2); 1841860 ((bipy)2Th(SC6F5)4·2THF, 3); 1841861 ((bipy)2Th(SeC6F5)4·2THF, 4); 1841862 ((py)(terpy)Th(SPh)4·2py, 5). F

• Main Authors: Ringgold, Marissa, Wu, Wen, Stuber, Matthew, Kornienko, Anna Y, Emge, Thomas J, Brennan, John G
• Format: Article
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c8dt02543f

Thorium chalcogenolates Th(ER) 4 react with 2,2′-bipyridine (bipy) to form complexes with the stoichiometry (bipy) 2 Th(ER) 4 (E = S, Se; R = Ph, C 6 F 5 ). All four compounds have been isolated and characterized by spectroscopic methods and low-temperature single crystal X-ray diffraction. Two of the products, (bipy) 2 Th(SC 6 F 5 ) 4 and (bipy) 2 Th(SeC 6 F 5 ) 4 , crystallize with lattice solvent, (bipy) 2 Th(SPh) 4 crystallizes with no lattice solvent, and the selenolate (bipy) 2 Th(SePh) 4 crystallizes in two phases, with and without lattice solvent. In all four compounds the available volume for coordination bounded by the two bipy ligands is large enough to allow significant conformational flexibility of thiolate or selenolate ligands. 77 Se NMR confirms that the structures of the selenolate products are the same in pyridine solution and in the solid state. Attempts to prepare analogous derivatives with 2,2′,6′,2′′-terpyridine (terpy) were successful only in the isolation of (terpy)(py)Th(SPh) 4 , the first terpy compound of thorium. These materials are thermochromic, with color attributed to ligand-to-ligand charge transfer excitations. Thorium chalcogenolates react with bipyridine or terpyridine to form a series of chelate stabilized Th(ER) 4 compounds (E = S, Se; R = Ph, C 6 F 5 ). 77 Se NMR shows that the eight coordinate structures are maintained in solution. These compounds are thermochromic, with color originating from a visible ligand to ligand charge transfer excitation.