Institut für Anorganische Chemie, Auf der Morgenstelle 18, 72076 Tübingen Germany.; Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1a, D-52074 Aachen Germany,
Abstract:
In a reaction of tantalocene trihydride with the low valent aryl tin cation Ar*Sn(C6H6)]Al(OC{CF3}3)4] (1a) the hydridostannylene complex Cp2TaH2–Sn(H)Ar*]Al(OC{CF3}3)4] (2) was synthesized. Hydride bridged adducts Cp2WH2EAr*]Al(OC{CF3}3)4] (E = Sn 3a, Pb 3b) were isolated as products of the reaction between Cp2WH2 and cations Ar*E(C6H6)]Al(OC{CF3}3)4] (E = Sn 1a, Pb 1b). The tin adduct 3a exhibits a proton migration to give the hydridostannylene complex Cp2W(H)Sn(H)Ar*]Al(OC{CF3}3)4] 4a. The cationic complex 4a is deprotonated at the tin atom in reaction with base MeNHC at 80 °C to give a hydrido-tungstenostannylene Cp2W(H)SnAr*] 5a. Reprotonation of metallostannylene 5a with acid H(Et2O)2]BArF] provides an alternative route to hydridotetrylene coordination. Complex 4a adds hydride to give the dihydrostannyl complex Cp2W(H)–SnH2Ar*] (7). With styrene 4a shows formation of a hydrostannylation product Cp2W(H)Sn(CH2CH2Ph)Ar*]Al(OC{CF3}3)4] (8). The lead adduct 3b was deprotonated with MeNHC to give plumbylene 5b Cp2W(H)PbAr*]. Protonation of 5b with H(Et2O)2]Al(OC{CF3}3)4] at −40 °C followed by low temperature NMR spectroscopy indicates a hydridoplumbylene intermediate Cp2W(H)Pb(H)Ar*]+ (4b). Hydrido-tungstenotetrylenes of elements Ge (5c), Sn (5a) and Pb (5b) were also synthesized reacting the salt Cp2W(H)Li]4 with organotetrylene halides. The metallogermylene Cp2W(H)GeAr*] (5c) shows an isomerization via 1,2-H-migration to give the hydridogermylene Cp2WGe(H)Ar*] (9), which is accelerated by addition of AIBN. 9 is at rt photochemically transferred back to 5c under light of a mercury vapor lamp. Zirconocene dihydride Cp2ZrH2]2 reacts with tin cation 1a to give the trinuclear hydridostannylene adduct 10 ({Cp2Zr}2{μ-H})(μ-H)2μ-Sn(H)Ar*]Al(OC{CF3}3)4]. Deprotonation of 10 was carried out using benzyl potassium to give neutral ({Cp2Zr}2{μ-H})(μ-H)μ-Sn(H)Ar*] (11). 11 was also obtained from the reaction of low valent tin hydride Ar*SnH]2 with two equivalents of Cp2ZrH2]2. The trihydride Ar*SnH3 reacts with half of an equivalent of Cp2ZrH2]2 under evolution of hydrogen and formation of a dihydrostannyl complex 13 Cp2Zr(μ-H)SnH2Ar*]2 and with further equivalents of Ar*SnH3 to give bis(hydridostannylene) complex Cp2Zr{Sn(H)Ar*}2].Low valent cations of tin and lead were used to form hydridotetrylene coordination compounds. The mobility of the hydrogen substituent was investigated in deprotonation equilibria as well as in 1,2-H-shift reactions.
