REACTIONS OF CYCLIC BIS(AMINO)GERMYLENES AND BIS(AMINO)STANNYLENES WITH [CPFE(CO)2]2 AND CPFE(CO)2ME (CP=ETA(5)-C5H5) - SYNTHESES AND SINGLE-CRYSTAL X-RAY STRUCTURES OF 4 NEW INSERTION COMPOUNDS

The interaction of El(NtBu)2SiMe2, El = Ge, Sn with CpFe(CO)2Me in tol uene has yielded CpFe(CO)2[El(NtBu)2SiMe2]Me, El = Ge (2) and El = Sn (3), respectively. Both compounds have been characterized by NMR, IR, MS, elemental analysis, and single crystal X-ray methods. Compound 2 c rystallizes in the monoclinic system, space group P2(1)/m, Z = 2, a = 9.330(6) angstrom, b = 12.552(9) angstrom, c = 9.939(7) angstrom, beta = 105.01(2)-degrees, V = 1124(1) angstrom3. The isostructural 3 forms orthorhombic crystals of space group Pnma, Z = 4, a = 17.871(9) angst rom, b = 12.998(7) angstrom, c = 9.838(5) angstrom, V = 2285(2) angstr om3. The refinement of 2 with 1431 unique, observed (I > 2sigma(I)) re flections led to final agreement indices of R = 0.043, R(W) = 0.048. T he structure of 3 was refined to R = 0.027 (R(W) = 0.027) by using 139 7 unique and observed (I > 2sigma(I)) reflections. Treatment of [CpFe( CO)2]2 with 2 equiv. of El(NtBu)2SiMe2 under identical reaction condit ions afforded [CpFe(CO)2]2Ge(NtBu)2SiMe2,4, for the cyclic germylene, whereas in the case of the tin homolog the tetranuclear complex {[CpFe (CO)2Sn(NtBu)2SiMe2]2.C7H8}, 5, was isolated. Complete characterizatio ns (NMR, IR, MS, EA, single crystal X-ray determination) were carried out on both compounds. The solid state structure of 5 contains one of the longest (2.992(2) angstrom) unbridged tin-tin bonds known to date. The trinuclear compound 4 is triclinic, space group Pl, Z = 2. Its la ttice parameters are: a = 9.549(5) angstrom, b = 10.102(5) angstrom, c = 16.438(8) angstrom, alpha = 81.98(4)-degrees, beta = 74.00(3)-degre es, gamma = 62.80(3)-degrees, V = 1355(1) angstrom3. Refinement of thi s structure using 3100 unique, observed (I > 2sigma(I)) data led to ag reement indices of R = 0.023 and R(W) = 0.023. The tetranuclear 5 crys tallizes as a toluene solvate. Crystal data: monoclinic, space group P 2(1)/n, Z = 2, a = 10.547(7) angstrom, b = 19.944(11) angstrom, c = 11 .366(7) angstrom, beta = 92.36(5)-degrees. Of 3024 collected data 2724 were considered unique and observed (I > 3sigma(I)) and used in the r efinement. Final agreement indices are R = 0.031, R(W) = 0.033.