Bis(alkylzink)substituiertes Phosphan und Sulfan sowie deren schweren Homologen des Typs E[ZnC(SiMe 3) 3] 2 (E=PSi iPr 3, AsSi iPr 3, S, Se, Te)

Abstract

The reaction of lithium tri isopropylsilylphosphanide 1a and -arsanide 1b with tris(trimethylsilyl)methylzinc chloride 2 yields bis[tris(trimethylsilyl)methylzinc]tri isopropylsilylphosphandiide 3a and -arsandiide 3b, respectively. The pnictogen atoms are in a trigonal pyramidal surrounding, and the CZnP as well as the CZnAs moieties are bent. Due to the steric crowding, a bis(alkylzinc) substituted amine was not detected, but the metathesis reaction of lithium tri isopropylsilylamide with 2 gives tris(trimethylsilyl)methylzinc tri isopropylsilylamide 4. The reaction of the compounds 3a and 3b with elemental chalkogenes yields the substitution of the i Pr 3SiP and i Pr 3SiAs fragments by sulfur ( 5), selenium ( 6) and tellurium ( 7). Bis[tris(trimethylsilyl)methylzink] sulfide 5 crystallizes as a dimeric molecule with a folded Zn 2S 2 cycle in the syn/ anti configuration. The syn-(Me 3Si) 3CZn moiety shows weak Lewis acid–base interactions with the transannular sulfur atom. Crystallographic data of 3b: triclinic, P 1 ̄ , a=1198.68(8), b=1377.58(8), c=1628.8(2) pm, α=91.434(6)°, β=108.340(7)°, γ=113.767(4)°, Z=2, wR 2=0.1305 on F 2 values for 7787 reflections.