Übergangsmetall‐Stannyl‐Komplexe, 31) Metall, Wasserstoff, Zinn‐Dreizentrenbindung bei Hydrido‐Stannyl‐Komplexen der 6. Nebengruppe

Transition‐Metal Stannyl Complexes, 3. – Metal, Hydrogen, Tin Three‐Center Bonding in Group VI Hydrido Stannyl Complexes The hydrido stannyl complex (π‐1,3,5‐Me3C6H3)(CO)2Cr(H)‐SnPh3 (1) is prepared by photochemical reaction of (π‐1,3,5‐Me3C6H3)(CO)3Cr with HSnPh3. The 119SnHCr coupling constant (327.6 Hz) and an X‐ray structure analysis [Sn – H 202(4), Cr – H 159(4), Cr – Sn 270.16(6) pm] show that the Sn – H bond is coordinated in an η2 fashion. The complexes (CO)4(R3P)‐W(H)SnPh3 (R3PPh3P, MePh2P) (2) and (CO)3(dppe)M(H)‐SnR3 (MCr, SnR3=SnPh3; MMo, SnR3=SnMe3, SnPh3; MW, SnR3=SnMe3, SnPh2Me, SnPh3) (4 – 6) are obtained either by thermal reaction of (CO)4(R3P)W(THF) or (CO)3(dppe)ML (LTHF, acetone) with HSiR3, or by photochemical reaction of (CO)4(dppe)M with HSnPh3. Reaction of (CO)4(Ph3P)W(THF) with HSnMe3 yields (CO)4(Ph3P)W(Sn‐Me3)2 (3). The Sn,M,H coupling constants in the complexes 2 and (CO)3(dppe)M(H)SnR3 (MCr, Mo) are in the range of 250 – 315 Hz and therefore these complexes seem to contain an η2‐coordinated stannane. Contrary to this, the SnWH coupling constants in (CO)3(dppe)W(H)SnR3 are considerably lower (70 – 90 Hz), suggesting complete oxidative addition of the H – Sn bond. The complexes (CO)3(dppe)M(H)SnPh3 decompose in benzene solution at room temperature to give, inter alia, hexaphenyldistannane. Ph6Sn2 · 2 C6H6 crystallizes in the space group \documentclass{article}\pagestyle{empty}\begin{document}$ R\bar 3 $\end{document} (Z=1); in the crystal lattice the benzene molecules are perpendicular to the three‐fold axis of symmetry of the distannane molecule.