Synthesis and characterization of TpiPrMoO(S2PR2) (R = Pri, Ph, OEt, OPri, (-)-mentholate) and {HB(OMe)(Pripz)2}MoO(S2PPri2), including isomers of known 1,2-borotropically-shifted complexes

• Published in: Inorganic chemistry 2009-03, Vol.48 (5), p.1960-1966
• Main Authors: Young, Charles G, Malarek, Michael S, Evans, David J, Doonan, Christian J, Ng, Victor Wee Lin, White, Jonathan M
• Format: Article
• Language: English
• Subjects: Boron - chemistry; Crystallography, X-Ray; Isomerism; Methanol - chemistry; Molybdenum - chemistry; Organometallic Compounds - chemical synthesis; Organometallic Compounds - chemistry; Spectrum Analysis
• ISSN: 1520-510X
• DOI: 10.1021/ic8015518

Green/blue TpiPrMoO(S2PR2) (TpiPr = hydrotris(3-isopropylpyrazolyl)borate; R = Pri, Ph, OEt, OPri, (-)-mentholate) complexes were synthesized and characterized by elemental analysis, mass spectrometry, IR and NMR spectroscopy, and X-ray crystallography. The diamagnetic, six-coordinate, oxo-Mo(IV) complexes possess distorted octahedral geometries defined by terminal oxo, bidentate dithio acid, and tridentate TpiPr ligands. The R = Pri and Ph derivatives are isomers of previously reported 1,2-borotropically shifted complexes, TpiPr*MoO(S2PR2) (TpiPr* = hydrobis(3-isopropylpyrazolyl)(5-isopropylpyrazolyl)borate; ref: Inorg. Chem. 1996, 35, 5368). Conversion of TpiPrMoO(S2PPh2) into TpiPr*MoO(S2PPh2) at elevated temperatures (>80 degrees C) showed that the borotropically shifted isomer was thermodynamically more stable than the unshifted species. Reaction with methanol converts TpiPrMoO(S2PPri2) into {HB(OMe)(Pripz)2}MoO(S2PPri2) (Pripz = 3-isopropylpyrazolyl), which was characterized by spectroscopic and crystallographic methods.