C4-Ferrocenylsilyl-bridged and -substituted N-heterocyclic carbenes: complexation of germanium chloride.

While the 1 : 1 reaction of C4-trichlorosilyl-functionalized N-heterocyclic carbene (NHC) (2) with [(η ⁵ -C ₅ H ₄ Li) ₂ Fe] ₃ [TMEDA] ₂ (3) gives C4-sila[1]ferrocenophane-substituted NHC (4), C4-ferrocenylsilyl-bridged bis-NHC (6) is synthesized by combining 3 with C4-chlorodimethylsilyl-functionalized NHC (5) in a 1 : 2 ratio, (compound 5 is prepared by reaction of the anionic N-heterocyclic dicarbene (NHDC) [:C{[N(2,6-Pr ⁱ ₂ C ₆ H ₃ )] ₂ CHCLi}] _n (1) with Me ₂ SiCl ₂ ). In addition, ligand 4- and 6-based GeCl ₂ complexes (7 and 8) are also synthesized. Compounds 4-8 have been characterized by ¹ H, ¹³ C, and ²⁹ Si NMR spectroscopy and single crystal X-ray diffraction.