Six-coordinate molybdenum nitrosyls with a single ene-1,2-dithiolate ligand

Abstract The synthesis and molecular structures of the (Tp*)Mo(NO)(SS) family of compounds (where (Tp*) is hydrotris(3,5-dimethyl-1-pyrazolyl)borate; (SS) is an ene-1,2-dithiolate) are reported. The compounds; (Tp*)Mo(NO)(bdt) ( 1 ), (Tp*)Mo(NO)(tdt) ( 2 ), and (Tp*)Mo(NO)(bdtCl 2 ) ( 3 ) (bdt, 1,2-benzenedithiolate; tdt, 3,4-toluenedithiolate; bdtCl 2 , 3,6-dichlorobenzenedithiolate), are the first such structurally characterized {MoNO} 4 compounds that contain a [(Tp*)Mo(NO)] 2+ fragment ligated to an ene-1,2-dithiolate. The compounds crystallize in the space groups P 2 1 / c ( 1 ) ( a =11.115(2) A, b =13.667(3) A, c =16.410(3) A; β =98.36(3)°, Volume=2466.4(8) A 3 , Z =4); P 2 1 / n ( 2 ) ( a =15.579(3) A, b =9.942(2) A, c =16.527(3) A; β =95.79(3)°, Volume=2546.7(9) A 3 , Z =4); and Pnma ( 3 ) ( a =17.9879(9) A, b =13.2277(7) A, c =11.2505(6) A; Volume=2676.9(2) A 3 , Z =4). The molecular structures show that the inner coordination sphere remains invariant within this family. A remarkable feature is the fold angle ( θ ) between the MoS 2 plane and S 2 C 2 plane of the ene-1, 2-dithiolate chelate ring. The fold angles ( θ ) of 42.1° in 1 , 41.1° in 2 and 44.4° in 3 are substantially larger than in analogous compounds with a terminal oxo group. Additional insight into the chemistry and properties of complexes 1 – 3 has been obtained by cyclic voltammetry, IR, NMR, electronic absorption and He I photoelectron (PES) spectroscopies.