Tetranuclear Titanium Nitride Cluster: Dinitrogen Cleavage Under Mild Conditions and Its Reactivity

Abstract

Abstract Heating the readily available trinuclear Ti dinitrogen complex [{TiCp*( µ ‐Cl)} 3 ( µ 3 ‐ η 1 :  η 2 :  η 2 ‐N 2 )] 1 (Cp* = η 5 ‐C 5 Me 5 ), originally reported by C. Yélamos and J. Jover, in benzene at 80 °C leads to the cleavage of N≡N bond, forming a tetranuclear titanium nitride cluster [{TiCp*} 4 Cl( µ ‐Cl) 3 ( µ 3 ‐N) 2 ] 2 . The structure of 2 was confirmed by single‐crystal X‐ray diffraction analysis. Kinetics study and density functional theory (DFT) calculations indicate that the energy barrier for the NN bond cleavage in the transformation from 1 to 2 is about 26 kcal mol −1 . Complex 2 exhibits reactivity toward various electrophiles, producing a range of nitrogen‐containing compounds in the presence of air, while concurrently regenerating Ti(IV) salts. Furthermore, complex 2 reacts with pinacolborane, leading to the formation of N‐B bond derivatives [{TiCp*( µ ‐NBPin)Cl} 2 ] 3 . When complex 2 – 15 N is treated with pyridine or 4‐dimethylaminopyridine (DMAP), it dissociates to form a bent trinuclear Ti nitrido complex [{TiCp*} 3 Cl 3 (L) 2 ( µ ‐ 15 N) 2 ] 4‐L (L = py or DMAP).