Structural study of molybdenum(VI) complexes containing bidentate ligands: Synthesis, characterization and DFT calculations

A series of molybdenum(VI) complexes containing bidentate ligands: toluene-3,4-dithiol (1), 2-mercaptophenol (2), 2-aminothiophenol (3), ethane-1,2-dithiol (4), dithiooxamide (5) and 2-thiopheno-carboxamide (6) are reported. The hexacoordinated molybdenum tris-chelates compounds: tris-(toluene-3,4-dithiolate)molybdenum(VI) (7), tris-(2-mercaptophenolate)molybdenum(VI) (8), tris-(2-aminothiophenolate)molybdenum(VI) (9), tris-(ethane-1,2-dithiolate)molybdenum(VI) (10), and the bis-chelates, which also contain coordinated oxo ligands: bis-(dithiooxamidate)dioxomolybdenum(VI) (11) and bis-(2-thiopheno-carboxamide)dioxomolybdenum(VI) (12), were characterized by 1H and 13C NMR and IR spectroscopies, as well as elemental analyses and mass spectrometry. The structures of minimum energy of the coordination compounds were calculated using DFT (B3LYP/def2-TZVPP). Solid state structures of analogous compounds, as well as calculations indicated that the minimum energy structures correspond to those of trigonal prismatic geometry.

Six molybdenum(VI) complexes containing with the bidentate ligands (S,O; S,N and S,S donor ligands) were synthesized and characterized by 1D and 2D 1H and 13C NMR, IR spectroscopies, and mass spectrometry. A structural analysis of the structures for the complexes was carried out using DFT calculations (B3LYP/def2-TZVPP), and compared with solid state structures of analogous compounds in the literatureFigure optionsDownload as PowerPoint slideHighlights
► Six molybdenum(VI) compounds were synthesized containing bidentate ligands.
► 2D NMR and Mass Spectrometry (TOF) were employed for the characterization.
► TP geometry is preferred in solid state, solution and gas-phase for tris-chelates.
► S–S interligand interactions may be of outmost importance in determining the geometry.
► Calculations indicate C3 and C2 symmetries for tris and bis-chelates.