Synthetic and reaction chemistry of heteroatom stabilized boryl and cationic borylene complexes

摘要

The synthesis,spectroscopic and structural characterization of the aryloxy and amino functionalized chloroboryl complexes (eta~5-C_5R_5)Fe(CO)_2B(OMes)Cl (R = H,2a;R = Me,3a) and (eta~5-C_5H_5)Fe(CO)_2B(N~iPr_2)Cl (7a) are reported.Compound 2a is shown to be a versatile substrate for further boron-centred substitution chemistry leading to the asymmetric boryl complexes (eta~5-C_5H_5)Fe(CO)_2B(OMes)ER_n [ER_n = OC_6H_4~tBu-4,2c;ER_n = SPh,2d] with retention of the metal-boron bond.The reactivities of 2a,3a and 7a towards the halide abstraction agent Na[BAr~f_4] have also been examined,in order to investigate the potential for the generation of cationic heteroatom-stabilized terminal borylene complexes.The application of this methodology to the mesityloxy derivatives 2a and 3a gives rise to B-F containing products,presumably via fluoride abstraction from the [BAr~f_4]~- counter-ion.By contrast,amino-functionalized complex 7a is more amenable to this approach,and the thermally robust terminal aminoborylene complex [(eta~5-C_5H_5)Fe(CO)_2B(N~iPr_2)][BAr~f_4] (9) can be isolated in ca.50% yield.The reactivity of 9 towards a range of nucleophilic and/or unsaturated reagents has been examined,with examples of addition,protonolysis and metathesis chemistries having been established.