Syntheses and Characterizations of Hetero-Bimetallic Chromium-Dinitrogen Transition-Metal Complexes.

In the domain of N 2 activation, hetero-bimetallic dinitrogen complexes are garnering substantial interest due to their potential to induce polarization in nonpolar N 2 gas. Herein, we present the syntheses and characterizations of three novel hetero-multimetallic dinitrogen complexes: Cp*Cr(depe)N 2 V(depe) Me [O, P, O] 5 , Cp*Cr(depe)N 2 V(depe) Tipp [O, P, O] 6 , and [Cp*Cr(depe)N 2 ] 2 Ti Tipp [O, P, O] 7 . These complexes were synthesized via a transmetalation process involving the treatment of [Cr 0 -N 2 ] - complex 4 with vanadium and titanium chloride complexes bearing alkyl or aryl substituted bis( o -hydroxyphenyl)-phenyl phosphine R [O, P, O] ligand (alkyl = methyl, aryl = 2,4,6-tri-isopropylbenzene). X-ray analysis shows that complexes 5 and 6 exhibit heterodinuclear structures, while complex 7 exhibits a heterotrinuclear core with two N 2 ligands concurrently coordinated to two chromium and one titanium atoms. Raman spectroscopic data show that the N-N stretching vibration of the N 2 moiety is clearly downshifted relative to free N 2 and to mononuclear [Cr 0 -N 2 ] - complex 4 .