Silylene complexes from a stable silylene and metal carbonyls: synthesis and structure of [Ni{(Bu t N–CHCH–NBu t )Si} 2 (CO) 2 ], a donor-free bis-silylene complex

[Ni(LSi)2(CO)2]3; the first silylene complex of nickel, has been obtained from the stable silylene 1,3-di-tert-2,3-dihydro-1H-1,3,2-diazasilol-2-ylidene (LSi)1 and tetracarbonylnickel; complex 3 was characterized by single crystal X-ray diffraction and NMR spectroscopy (1H, 13C, 29Si).