The complexes cis-[Pt(C6F5)2(RC≡CR)2] (R = Et 1a or Ph 1b) have been prepared by treating cis-[Pt(C6F5)2(thf)2] (thf = tetrahydrofuran) with the appropriate alkyne. They undergo facile ligand exchange with either cis-[Pt(C6F5)2(thf)2] or [NBun4]2[Pt(C6F5) 4] giving rise respectively to neutral cis-[Pt(C6F5)2(thf)(RC≡CR)] 2 or anionic [NBun4][Pt(C6F5) 3(PhC≡CPh)] 7b mono(η2-alkyne) derivatives. A series of mono(η2-alkyne) complexes of formulae cis-[Pt(C6F5)2L(RC≡CR)] (L = pyridine 3a, 3b; PPh3 4a; SbPh3 5b; or CO 6a, 6b) and [N(PPh3)2][Pt(C6F5) 3(EtC≡CEt)] 7a has also been prepared. None of these complexes except 7b shows ν(C≡C) absorptions in their IR spectra. The molecular structures of complexes 1b and 7b have been established by X-ray diffraction studies: 1b, monoclinic, space group C2/c, a = 19.177(4), b = 8.4971(4), c = 19.790(3) Å, β = 103.297(14)° and Z = 4 (C2 symmetry imposed); 7b, monoclinic, space group P21/c, a = 10.5179(9), b = 17.5834(20), c = 25.369(5) Å, β = 99.376(11)° and Z = 4. Parameters within the acetylene moiety of 1b suggest that the platinum→alkyne π-back bonding is minimal.
|Number of pages||6|
|Journal||Journal of the Chemical Society, Dalton Transactions|
|Publication status||Published - 1993|
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