ISSN:
0009-2940
Keywords:
Alkynes
;
Nickel complexes
;
Stannenes
;
Metallacycloalkenes
;
Kinetic and thermodynamic reaction control
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Synthesis, Structure, and Reactivity of a Stanna(II)-nickela(III)-cyclobutene KomplexesThe (ethyne)nickel(0) complex (iPr2PC2H4PiPr2)Ni(C2H2) (1) reacts with the stannene Sn[CH(SiMe3)2]2 below -30°C to yield the stanna(II)-nickela(II)-cyclobutene complex (iPr2PC2H4PiPr2)YYNiCH=YYCHSn[CH(SiMe3)2]2 (2; 83%) as the kinetically controlled product; 2 has been characterized by IR and NMR spectroscopy and an X-ray crystal-structure determination. The latter shows the central four-membered ring to be planar with a long Ni - Sn bond [2.626(1) Å]. According to the temperature-dependent NMR spectra, 2 dissociates reversibly in solution to the starting components. The synthesis reaction thus represents an equilibrium as long as the temperature is below 20°C. These observations indicate that the structural lability of the stanna(II)-nickela(II)-cyclobutene moiety is associated with the weakness of the Ni - Sn bond. The bonding situation in 2 is best described as an “inner complex” in which a stannyl anion is coordinated to a nickel(II) cation. An ethereal solution of 2 undergoes an oxidative addition of one ethyne C - H bond to the stannene at 20°C to give the Ni(0)/Sn(IV) complex iPr2PC2H4PiPr2)Ni({η2-HC≡CSn(H)[CH(SiMe3)2]2} (3) as the thermodynamically controlled product. Reaction of 3 with CO liberates the new alkyne ligand.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19921250117
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