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First Dinuclear Copper/Gallium Complexes: Supporting Cu 0 and Cu I Centres by Low‐Valent Organogallium Ligands
Author(s) -
Bollermann Timo,
Prabusankar Ganesan,
Gemel Christian,
Seidel Rüdiger W.,
Winter Manuela,
Fischer Roland A.
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201000465
Subject(s) - copper , chemistry , gallium , crystallography , crystal structure , molecule , redox , stereochemistry , inorganic chemistry , organic chemistry
The synthesis and structural characterisation of low‐valent dinuclear copper(I) and copper(0) complexes supported by organogallium ligands has been accomplished for the first time by the reductive coordination reaction of [GaCp*] (Cp*=pentamethylcyclopentadienyl) and [Ga(ddp)] (ddp=HC(CMeNC 6 H 3 ‐2,6‐ i Pr 2 ) 2 2‐diisopropylphenylamino‐4‐diisopropylphenylimino‐2‐pentene) with readily available copper(II) and copper(I) precursors. The treatment of CuBr 2 and Cu(OTf) 2 (OTf=CF 3 SO 3 ) with [Ga(ddp)] under mild conditions resulted in elimination of [Ga(L) 2 (ddp)] (L=Br, OTf) and afforded the novel gallium(I)/copper(I) compounds [{(ddp)GaCu(L)} 2 ] (L=Br ( 1 ), OTf ( 2 )). The single‐crystal X‐ray structure determinations of 1 and 2 reveal that these molecules are composed of {(ddp)GaCu(L)} dimeric units, with planar Cu I Ga I four‐membered rings and short Cu I ⋅⋅⋅Cu I distances, with 2 exhibiting the shortest Cu I ⋅⋅⋅Cu I contact reported to date of 2.277(3) Å. The all‐gallium coordinated dinuclear [Cu 2 (GaCp*)(μ‐GaCp*) 3 Ga(OTf) 3 ] ( 3 ) is formed when Cu(OTf) 2 is combined with [GaCp*] instead of [Ga(ddp)]. Notably, in the course of this redox reaction Lewis acidic Ga(OTf) 3 is formed, which coordinates to one of the electron‐rich copper(0) centres. Compound 3 is suggested as the first case of a structurally characterised complex of copper(0). By changing the copper(II) to a copper(I) source, that is, [Cu(cod) 2 ][OTf] (cod=1,5‐cyclooctadiene), the salt [Cu 2 (GaCp*) 3 (μ‐GaCp*) 2 ][OTf] 2 ( 4 ) is formed, the cationic part of which is related to previously described isoelectronic dinuclear d 10 complexes of the type [M 2 (GaCp*) 5 ] (M=Pd, Pt).