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Title: | Toward Multifunctional Mo(VI−IV) Complexes: cis-Dioxomolybdenum(VI) Complexes Containing Hydrogen-Bond Acceptors or Donors | Contributor(s): | Hill, LMR (author); Taylor, Michelle K (author); Ng, VWL (author); Young, CG (author) | Publication Date: | 2008 | DOI: | 10.1021/ic701957b | Handle Link: | https://hdl.handle.net/1959.11/8139 | Abstract: | The complexes cis-TpiPrMoVIO2(OAr-R) (TpiPr = hydrotris(3-isopropylpyrazol-1-yl)borate, -OAr-R = hydrogen-bonding phenolate derivative) are formed upon reaction of TpiPrMoO2Cl, HOAr-R, and NEt3 in dichloromethane. The orange, diamagnetic, dioxo−Mo(VI) complexes exhibit strong ν(MoO2) IR bands at ca. 935 and 900 cm-1 and NMR spectra indicative of Cs symmetry. They undergo electrochemically reversible, one-electron reductions at potentials in the range −0.836 to −0.598 V vs SCE; the only exception is the 2-CO2Ph derivative, which exhibits an irreversible reduction at −0.924 V. The complexes display distorted octahedral geometries, with a cis arrangement of terminal oxo ligands and with d(Mo=O)av = 1.695 Å and (MoO2)av = 103.2°. The R groups of the 2-CHO and 2-NHCOMe derivatives are directed away from the oxo groups and into a cleft in the TpiPr ligand; these derivatives are characterized by Mo−O−Cipso angles of ca. 131° (conformation 1). The R group(s) in the 2-CO2Me and 2,3-(OMe)2 derivatives lie above the face of the three O-donor atoms (directed away from the TpiPr ligand) and the complexes display Mo−O−Cipso angles of 153.1(2) and 149.7(2)°, respectively (conformation 2). Conformations 1 and 2 are both observed in the positionally disordered 2-COMe and 2-COEt derivatives, the two conformers having Mo−O−Cipso angles of 130−140 and >150°, respectively. The 3-COMe and 3-NEt2 derivatives have substituents that project away from the TpiPr ligand and Mo−O−Cipso angles of 134.2(2) and 147.7(2)°, respectively. Many of the complexes exhibit fluxional behavior on the NMR time scale, consistent with the rapid interconversion of two conformers in solution. | Publication Type: | Journal Article | Source of Publication: | Inorganic Chemistry, 47(3), p. 1044-1052 | Publisher: | American Chemical Society | Place of Publication: | United States of America | ISSN: | 1520-510X 0020-1669 |
Fields of Research (FoR) 2008: | 030207 Transition Metal Chemistry 030201 Bioinorganic Chemistry |
Socio-Economic Objective (SEO) 2008: | 970103 Expanding Knowledge in the Chemical Sciences | Peer Reviewed: | Yes | HERDC Category Description: | C1 Refereed Article in a Scholarly Journal |
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Appears in Collections: | Journal Article |
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