Toward Multifunctional Mo(VI-IV) Complexes: cis-Dioxomolybdenum(VI) Complexes Containing Hydrogen-Bond Acceptors or Donors
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- 作者：Lyndal M. R. Hill ; Michelle K. Taylor ; Victor Wee Lin Ng ; Charles G. Young
- 刊名：Inorganic Chemistry
- 出版年：2008
- 出版时间：February 4, 2008
- 年：2008
- 卷：47
- 期：3
- 页码：1044 - 1052
- 全文大小：263K
- 年卷期：v.47,no.3(February 4, 2008)
- ISSN：1520-510X
文摘
The complexes cis-TpiPrMoVIO2(OAr-R) (TpiPr = hydrotris(3-isopropylpyrazol-1-yl)borate, -OAr-R = hydrogen-bondingphenolate derivative) are formed upon reaction of TpiPrMoO2Cl, HOAr-R, and NEt3 in dichloromethane. The orange,diamagnetic, dioxo-Mo(VI) complexes exhibit strong 
(MoO2) IR bands at ca. 935 and 900 cm-1 and NMR spectraindicative of Cs symmetry. They undergo electrochemically reversible, one-electron reductions at potentials in therange -0.836 to -0.598 V vs SCE; the only exception is the 2-CO2Ph derivative, which exhibits an irreversiblereduction at -0.924 V. The complexes display distorted octahedral geometries, with a cis arrangement of terminaloxo ligands and with d(Mo=O)av = 1.695 Å and 
ng.gif">(MoO2)av = 103.2
. The R groups of the 2-CHO and 2-NHCOMederivatives are directed away from the oxo groups and into a cleft in the TpiPr ligand; these derivatives arecharacterized by Mo-O-Cipso angles of ca. 131 (conformation 1). The R group(s) in the 2-CO2Me and 2,3-(OMe)2derivatives lie above the face of the three O-donor atoms (directed away from the TpiPr ligand) and the complexesdisplay Mo-O-Cipso angles of 153.1(2) and 149.7(2), respectively (conformation 2). Conformations 1 and 2 areboth 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 projectaway from the TpiPr ligand and Mo-O-Cipso angles of 134.2(2) and 147.7(2), respectively. Many of the complexesexhibit fluxional behavior on the NMR time scale, consistent with the rapid interconversion of two conformers insolution.
(MoO2) IR bands at ca. 935 and 900 cm-1 and NMR spectraindicative of Cs symmetry. They undergo electrochemically reversible, one-electron reductions at potentials in therange -0.836 to -0.598 V vs SCE; the only exception is the 2-CO2Ph derivative, which exhibits an irreversiblereduction at -0.924 V. The complexes display distorted octahedral geometries, with a cis arrangement of terminaloxo ligands and with d(Mo=O)av = 1.695 Å and ng.gif">(MoO2)av = 103.2. The R groups of the 2-CHO and 2-NHCOMederivatives are directed away from the oxo groups and into a cleft in the TpiPr ligand; these derivatives arecharacterized by Mo-O-Cipso angles of ca. 131 (conformation 1). The R group(s) in the 2-CO2Me and 2,3-(OMe)2derivatives lie above the face of the three O-donor atoms (directed away from the TpiPr ligand) and the complexesdisplay Mo-O-Cipso angles of 153.1(2) and 149.7(2), respectively (conformation 2). Conformations 1 and 2 areboth 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 projectaway from the TpiPr ligand and Mo-O-Cipso angles of 134.2(2) and 147.7(2), respectively. Many of the complexesexhibit fluxional behavior on the NMR time scale, consistent with the rapid interconversion of two conformers insolution.