N‐Heterocyclic Carbene–Phosphinidene Complexes of the Coinage Metals |
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| Authors: | Dr Adinarayana Doddi Dirk Bockfeld Dr Alexandre Nasr Dr Thomas Bannenberg Prof?Dr Peter G Jones Prof?Dr Matthias Tamm |
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| Affiliation: | Institut für Anorganische und Analytische Chemie, Technische Universit?t Braunschweig, Hagenring?30, 38106 Braunschweig (Germany) http://www.tu‐braunschweig.de/iaac |
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| Abstract: | Coinage metal complexes of the N‐heterocyclic carbene–phosphinidene adduct IPr ? PPh (IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene) were prepared by its reaction with CuCl, AgCl, and (Me2S)AuCl], which afforded the monometallic complexes (IPr ? PPh)MCl] (M=Cu, Ag, Au). The reaction with two equivalents of the metal halides gave bimetallic (IPr ? PPh)(MCl)2] (M=Cu, Au); the corresponding disilver complex could not be isolated. (IPr ? PPh)(CuOTf)2] was prepared by reaction with copper(I) trifluoromethanesulfonate. Treatment of (IPr ? PPh)(MCl)2] (M=Cu, Au) with Na(BArF) or AgSbF6 afforded the tetranuclear complexes (IPr ? PPh)2M4Cl2]X2 (X=BArF or SbF6), which contain unusual eight‐membered M4Cl2P2 rings with short cuprophilic or aurophilic contacts along the chlorine‐bridged M???M axes. Complete chloride abstraction from (IPr ? PPh)(AuCl)2] was achieved with two equivalents of AgSbF6 in the presence of tetrahydrothiophene (THT) to form (IPr ? PPh){Au(THT)}2]SbF6]2. The cationic tetra‐ and dinuclear complexes were used as catalysts for enyne cyclization and carbene transfer reactions. |
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| Keywords: | carbene ligands coinage metals copper gold phosphinidene |
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