Formation and Cleavage of a Sb-Sb Double Bond: From Carbene-Coordinated Distibenes to Stibinidenes

Reactions of L(Cl)Ga-substituted stibine [L(Cl)Ga](2)SbCl (L=HC[C(Me)NAr](2); Ar=2,6-i-Pr2C6H3) with N-heterocyclic carbenes (R)NHCMe ((R)NHCMe=[C(R)NMe](2)C:; R=Me, Et, iPr) gave NHC-coordinated stibinidenes L(Cl)GaSb-(R)NHCMe (R=Me 1 a, Et 1 b, iPr 1 c) and distibenes L(Cl)GaSbSb((R)NHCMe)Ga(Cl)L (R=Me 2 a, Et 2 b, iPr 2 c). Distibenes 2 a and 2 b react with a second equivalent of (R)NHCMe with cleavage of the Sb-Sb double bond and formation of stibinidenes 1 a and 1 b. 1 a-2 b were spectroscopically characterized and the solid-state structures determined by single crystal X-ray diffraction (sc-XRD). Quantum chemical calculations gave a deeper insight into the electronic nature and bonding situation of 1 a-2 c and the reaction energetics were investigated in detail.

Automated summary

This study reports the reactions of L(Cl)Ga-substituted stibine with N-heterocyclic carbenes, resulting in the formation of novel stibinidenes and distibenes. Spectroscopic characterization, solid-state structure determination, and quantum chemical calculations were carried out to gain insight into the electronic nature and reaction energetics of these compounds.