Insertion Reactivity of CO₂, PhNCO, Me₃CCN, and Me₃CNC with the Uranium−Alkynyl Bonds in (C₅Me₅)₂U(CCPh)₂

The insertion reactivity of (C5Me5)2U(CCPh)2, 1, has been studied with CO2, PhNCO, Me3CCN, and Me3CNC. Insertion into both U−CCPh bonds of 1 occurs with the first three substrates to form (C5Me5)2U(O2CCCPh)2, 2, (C5Me5)2U[PhNC(CCPh)O-κ2N,O]2, 3, and (C5Me5)2U[NC(CMe3)(CCPh)]2, 4, respectively. Only 1 equiv of Me3CNC reacts with 1 to form (C5Me5)2[(PhCC)CN(CMe3)-η2C,N]U(CCPh), 5, a result similar to the iPrNCNiPr insertion that forms (C5Me5)2[iPrNC(CCPh)NiPr-κ2N,N′]U(CCPh), 6.本研究针对配合物二(五甲基环戊二烯基)二(苯乙炔基)铀((C5Me5)2U(C≡CPh)2，记为1)的插入反应活性展开了系统探究，所选用的反应底物包括二氧化碳(CO2)、异氰酸苯酯(PhNCO)、叔丁基氰(Me3CC≡N)以及叔丁基异氰(Me3CN≡C)。对于前三种底物，配合物1的两条铀-苯乙炔基(U−C≡CPh)键均发生插入反应，分别生成配合物二(五甲基环戊二烯基)二(苯丙炔酸根)铀((C5Me5)2U(O2CC≡CPh)2，2)、二(五甲基环戊二烯基)二{[PhNC(C≡CPh)O]-κ2N,O}铀((C5Me5)2U[PhNC(C≡CPh)O-κ2N,O]2，3)以及二(五甲基环戊二烯基)二{[N=C(CMe3)(C≡CPh)]}铀((C5Me5)2U[N=C(CMe3)(C≡CPh)]2，4)。仅1当量的叔丁基异氰与配合物1发生反应，生成配合物二(五甲基环戊二烯基)[(PhC≡C)C=N(CMe3)-η2C,N](苯乙炔基)铀((C5Me5)2[(PhC≡C)C=N(CMe3)-η2C,N]U(C≡CPh)，5)；该反应结果与二异丙基碳二亚胺(iPrN=C=NiPr)的插入反应类似，后者可生成配合物二(五甲基环戊二烯基){[iPrNC(C≡CPh)NiPr]-κ2N,N′}(苯乙炔基)铀((C5Me5)2[iPrNC(C≡CPh)NiPr-κ2N,N′]U(C≡CPh)，6)。