186494-13-3Relevant academic research and scientific papers
Titanocene complexes of ring-opened dibenzothiophene and related dimercaptobiaryl ligands
Stafford, Philip R.,Rauchfuss, Thomas B.,Verma, Atul K.,Wilson, Scott R.
, p. 203 - 214 (2007/10/03)
This paper describes organotitanium derivatives resulting from the reactions of titanocene dichloride with derivatives of dibenzothiophene (DBT). Lithium cleavage of DBT gives 2,2′-Li(LiS)C12H8 which reacts with (C5H5)2TiCl2 to give the metallacyclic complex (C5H5)2TiSC12H8 (1). Two side products were isolated in smaller amounts, the thiolates (C5H5)2Ti(SC6H4-2-Ph)2 (2) and (C5H5)2Ti(SC6H4-2-Ph)Cl. DNMR studies showed that 1 and its MeC5H4 analog 3 are stereochemically non-rigid as a result of the folding of the organosulfur chelate. The structure of (MeC5H4)2TiSC12H8 was verified by single crystal X-ray diffraction; the complex consists of the expected (MeC5H4)2Ti moiety coordinated to the carbon and sulfur of the ring-cleaved DBT. An attempt to generate 2,2′-Li(LiS)C12H8 via the double metalation of 2-phenylbenzenethiol with two equivalents of BuLi in the presence of TMEDA, followed by treatment with (C5H5)2TiCl2, gave the deep green complex (C5H5)2TiS2C24H16 (4), Single crystal X-ray diffraction indicated that 4 is a complex of the 2,2-dimercapto-3,3′-diphenylbiphenyl ligand (2,2′-(LiS)2-3,3′-Ph2C12H6), resulting from the coupling of two molecules of 1-Ph-2-LiS-3-LiC6H3. DNMR studies showed that this complex is stereochemically rigid. The free dithiol was liberated by treatment of 4 with anhydrous HCl. The complex of the unsubstituted 2,2′-dimercaptobiphenyl was prepared by treatment of 2,2′-Li(LiS)C12H8 with one equivalent of sulfur followed by quenching the reaction with titanocene dichloride to give (C5H5)2TiS2C12H8 (6). Electrochemical studies show that the TiIV/III couple is reversible for all new compounds; the reduction potentials are lower for the chelating dithiolates and highest for the C-S chelate complexes 1 and 3.
