Syntheses and Characterizations of Hetero-Bimetallic Chromium-Dinitrogen Transition-Metal Complexes
Xueli Wang, Yixi Wang, Yue Wu, Gao-Xiang Wang, Junnian Wei*, Zhenfeng Xi
Inorg. Chem., 2023. DOI: 10.1021/acs.inorgchem.3c02944.
In the domain of N2 activation, hetero-bimetallic dinitrogen complexes are garnering substantial interest due to their potential to induce polarization in nonpolar N2 gas. Herein, we present the syntheses and characterizations of three novel hetero-multimetallic dinitrogen complexes: Cp*Cr(depe)N2V(depe)Me[O,P,O] 5, Cp*Cr(depe)N2V(depe)Tipp[O,P,O] 6, and [Cp*Cr(depe)N2]2TiTipp[O,P,O] 7. These complexes were synthesized via a transmetalation process involving the treatment of [Cr0–N2]− 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 N2 ligands concurrently coordinated to two chromium and one titanium atoms. Raman spectroscopic data show that the N–N stretching vibration of the N2 moiety is clearly downshifted relative to free N2 and to mononuclear [Cr0–N2]− complex 4.
