Synthesis of distibiranes and azadistibiranes by cycloaddition reactions of distibenes with diazomethanes and azides.

Cycloaddition reactions of distibene [L(Me 2 N)GaSb] 2 (L = HC[C(Me)NDipp] 2 ; Dipp = 2,6- i -Pr 2 C 6 H 3 )[double bond, length as m-dash] with a series of organoazides RN 3 (R = Ph, p -CF 3 Ph, 1-adamantyl (ada)) yielded azadistibiranes [L(Me 2 N)GaSb] 2 NR (R = Ph 1, p -CF 3 Ph 2, ada 3), whereas Me 3 SiN 3 reacted with insertion into one Ga-Sb bond and formation of L(Me 2 N)GaSbSb(NSiMe 3 )Ga(NMe 2 )L (4). Analogous compounds 5 and 6 formed after heating of 1 and 2 above 60 °C. Prolonged heating of 5 resulted in a [2 + 2] cycloaddition accompanied by elimination of LGa(NMe 2 ) 2 and formation of tetrastibacyclobutane 7, while the reaction of 5 with a second equivalent of PhN 3 gave heteroleptic azadistibirane 9, which isomerized at elevated temperature to distibene 10. Cycloaddition also occurred in reactions of [L(X)GaSb] 2 (X = NMe 2 , OEt, Cl) with Me 3 Si(H)CN 2 , yielding distibiranes [L(X)GaSb] 2 C(H)SiMe 3 (X = NMe 2 11, OEt 12, Cl 13). Compounds 1-13 were characterized by IR, UV-Vis and NMR spectroscopy and sc-XRD. The mechanism of the reaction of [L(Me 2 N)GaSb] 2 with PhN 3 and Me 3 SiN 3 and the electronic nature of the resulting compounds were studied by DFT calculations.