Dinitrogen Functionalization with Carbon Dioxide and Carbon Disulfide Giving Symmetric and Unsymmetric Hydrazido Complexes

Abstract

Here we show that a tridentate bis(aryloxide)anilide-ligated titanium/potassium scaffold promotes functionalization of coordinated N 2 with CO 2 and CS 2 through formation of NÀ C bonds. Treatment of a naphthalene complex with N 2 gave an end-on bridging dinitrogen complex featuring a [Ti 2 K 2 N 2 ] core. The dinitrogen complex underwent insertion of CO 2 into each TiÀ NN bond to afford an N,N'-dicarboxylated hydrazido complex. Stepwise nitrogen-carbon bond formation at coordinated N 2 proceeded to afford an unsymmetric hydrazido complex upon sequentially treating the dinitrogen complex with CS 2 and CO 2 . Addition of Me 3 SiCl to the dicarboxylated hydrazido complex resulted in partial silylation of the carboxylate groups but did not lead to removal of the functionalized N 2 unit from the metal centers. However, reduction of the dicarboxylated hydrazido complex with potassium naphthalenide afforded an oxo-bridged dinuclear complex along with release of free potassium cyanate.

Aza-Michael Addition of Dinitrogen to α,β-Unsaturated Carbonyl Compounds in a Dititanium Framework

“…In principle, the addition of an activated N 2 unit to unsaturated organic substrates could offer an atom-efficient route for the synthesis of organonitrogen compounds. However, studies toward this goal remained limited despite great interest and recent advances. − The nucleophilic addition of N 2 or N 2 -derived nitrido and imido species to unsaturated carbon-heteroatom bonds such as CO, − CO 2 , ,,− aldehydes/ketones, − acid halides, − nitriles, , and heteroallenes ,,,,− has been reported. However, the addition reaction of N 2 with unsaturated C–C bonds has remained almost unexplored to date. , In particular, the addition of an N 2 unit to an α,β-unsaturated carbonyl compound through the C–N bond formation to produce an NN-functionalized organic compound has not been reported previously.…”

Hydrazido complexes prepared by methylation of an anionic end-on bridging dinitrogen dititanium complex

“…Nevertheless, N–C bond formation from linear end-on bridging dinitrogen is rare. 16,17 We previously reported the titanium dinitrogen complex [K(THF) 6 ][{(O 3 C)Ti} 2 (μ-N 2 ){K 3 (THF) 3 }] ( 1 ) ([O 3 C] 4− = [(3,5- t Bu 2 -2-OC 6 H 2 ) 3 C] 4− ), which displays a strongly activated N 2 ligand coordinated by two titanium metals in a linear end-on fashion as well as three potassium metals in a side-on fashion. Initial reactivity studies of 1 showed that the nucleophilic character of its dinitrogen unit can promote N–C bond formation with carbon-based reagents.…”