Intramolecularly coordinated heteroleptic organostannylene tungsten pentacarbonyl complexes 4-tBu-2,6-[P(O)(OiPr)(2)](2)C6H2Sn(X)W(CO)(5) (X = Cl, F, PPh2, PPh2[W(CO)(5)]). Syntheses and reactivity

The synthesis of the intramolecularly coordinated heteroleptic organostannylene tungsten pentacarbonyl complexes 4-tBu-2,6-[P(O)(OiPr)(2)](2)C6H2Sn(X)W(CO)(5) (1, X = Cl; 2, X = F; 3, X = PPh2) and of 4-tBu-2,6-[P(O)(OiPr)(2)](2)C6H2Sn[W(CO)(5)]PPh2[W(CO)(5)], 4, are reported. UV-irradiation of compound 4 in tetrahydrofurane serendipitously gave the bis(organostannylene) tungsten tetracarbonyl complex cyclo-O2W[OSn(R)](2)W(CO)(4) (R = 4-tBu-2,6-[P(O)(OiPr)(2)](2)C6H2), 5, that contains an unprecedented W(0)-Sn-O-W(VI) bond sequence. The compounds 1-5 were characterized by means of single crystal X-ray diffraction analysis, H-1, C-13, F-19, P-31, Sn-119 NMR, and IR spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and elemental analysis. Compound 4 features a hindered rotation about the Sn-P bond.