Versatile Reactivity of Half-Sandwich Ir and Rh Complexes toward Carboranylamidinates and Their Derivatives: Synthesis, Structure, and Catalytic Activity for Norbornene Polymerization

Authors

  • Dr. Zi-Jian Yao,

    1. Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200433 (P.R. China), Fax: (+86) 21-65643776
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  • Ge Su,

    1. Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200433 (P.R. China), Fax: (+86) 21-65643776
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  • Prof. Dr. Guo-Xin Jin

    Corresponding author
    1. Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200433 (P.R. China), Fax: (+86) 21-65643776
    2. State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032 (P.R. China)
    • Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200433 (P.R. China), Fax: (+86) 21-65643776
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Abstract

Synthesis, structure, and reactivity of carboranylamidinate-based half-sandwich iridium and rhodium complexes are reported for the first time. Treatment of dimeric metal complexes [{Cp*M(μ-Cl)Cl}2] (M=Ir, Rh; Cp*=η5-C5Me5) with a solution of one equivalent of nBuLi and a carboranylamidine produces 18-electron complexes [Cp*IrCl(CabN-DIC)] (1 a; CabN-DIC=[iPrN[DOUBLE BOND]C(closo-1,2-C2B10H10)(NHiPr)]), [Cp*RhCl(CabN-DIC)] (1 b), and [Cp*RhCl(CabN-DCC)] (1 c; CabN-DCC=[CyN[DOUBLE BOND]C(closo-1,2-C2B10H10)(NHCy)]). A series of 16-electron half-sandwich Ir and Rh complexes [Cp*Ir(CabN′-DIC)] (2 a; CabN′-DIC=[iPrN[DOUBLE BOND]C(closo-1,2-C2B10H10)(NiPr)]), [Cp*Ir(CabN′-DCC)] (2 b, CabN′-DCC=[CyN[DOUBLE BOND]C(closo-1,2-C2B10H10)(NCy)]), and [Cp*Rh(CabN′-DIC)] (2 c) is also obtained when an excess of nBuLi is used. The unexpected products [Cp*M(CabN,S-DIC)], [Cp*M(CabN,S-DCC)] (M=Ir 3 a, 3 b; Rh 3 c, 3 d), formed through BH activation, are obtained by reaction of [{Cp*MCl2}2] with carboranylamidinate sulfides [RN[DOUBLE BOND]C(closo-1,2-C2B10H10)(NHR)]S (R=iPr, Cy), which can be prepared by inserting sulfur into the C[BOND]Li bond of lithium carboranylamidinates. Iridium complex 1 a shows catalytic activities of up to 2.69×106 gPNBequation image h−1 for the polymerization of norbornene in the presence of methylaluminoxane (MAO) as cocatalyst. Catalytic activities and the molecular weight of polynorbornene (PNB) were investigated under various reaction conditions. All complexes were fully characterized by elemental analysis and IR and NMR spectroscopy; the structures of 1 ac, 2 a, b; and 3 a, b, d were further confirmed by single crystal X-ray diffraction.

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