Reactivity of Cp*W(O)2(CH2SiMe3) toward p-tolyl isocyanate: cycloaddition reactions of tungsten-oxo and -imido linkages

Reactions of Aminobis(phenolate)‐Supported Dioxidotungsten(VI) and Dioxidomolybdenum(VI) Complexes

“…Legzdins et al have studied analogous reactivity of dioxidotungsten complex Cp*WO 2 (CH 2 SiMe 3 ) with p ‐tolyl isocyanate, and reported that the use of hexanes as a reaction medium yields mono‐ and bis(imido) complexes, whereas the reaction in toluene solution affords an imido ureate complex 18a. In our experiments, the reaction was conducted in a toluene solution, while the tungsten precursor dissolved slowly upon reaction.…”

[2 + 2] cycloaddition reactions at terminal imido uranium(IV) complexes to yield isolable cycloadducts

“…Instead, the products of [2 + 2] cycloaddition of the isocyanate N@C p-bond to the U@N bond were observed, yielding the j 2 -N,N 0 -ureato complexes, R = Mes (4), Dipp (5), in 53% yield (Scheme 1). The cycloaddition of isocyanates with M = NR bonds to yield isolable ureato-ligated metal complexes has been reported with multiple metals (Groups 3-5 [36][37][38][39], Group 6 [40][41][42][43], Groups 7-9 [44,45]) however, such reactivity on uranium has only been postulated as an intermediate in the imido exchange reaction that occurs when U(N t Bu) 2 I 2 (tppo) 2 is treated with PhNCO [46]. In fact, only one structurally characterized uranium ureato complex has been reported in the literature, and it was prepared by insertion of CO 2 into uranium imido bonds, followed by a complicated, binuclear rearrangement [7].…”

Synthesis and ROMP activity of aminophenol-substituted tungsten(VI) and molybdenum(VI) complexes

“…Transition metal oxido compounds are known to react with alkyl and aryl isocyanates to produce corresponding metal imido complexes [12]. When complex 3 was heated in toluene solution with one equivalent of phenyl isocyanate, the reaction proceeded efficiently to produce imido derivative 5.…”