E4 Transfer (E=P, As) to Ni Complexes

The use of [Cp '' Zr-2(eta(1:1)-E-4)] (E=P (1 a), As (1 b), Cp ''=1,3-di-tert-butyl-cyclopentadienyl) as phosphorus or arsenic source, respectively, gives access to novel stable polypnictogen transition metal complexes at ambient temperatures. The reaction of 1 a/1 b with [Cp(R)NiBr](2) (Cp(R)=Cp-Bn (1,2,3,4,5-pentabenzyl-cyclopentadienyl), Cp ''' (1,2,4-tri-tert-butyl-cyclopentadienyl)) was studied, to yield novel complexes depending on steric effects and stoichiometric ratios. Besides the transfer of the complete E-n unit, a degradation as well as aggregation can be observed. Thus, the prismane derivatives [(Cp ''' Ni)(2)(mu,eta(3:3)-E-4)] (2 a (E=P); 2 b (E=As)) or the arsenic containing cubane [(Cp ''' Ni)(3)(mu(3)-As)(As-4)] (5) are formed. Furthermore, the bromine bridged cubanes of the type [(Cp(R)Ni)(3){Ni(mu-Br)}(mu(3)-E)(4)](2) (Cp(R)=Cp ''': 6 a (E=P), 6 b (E=As), Cp(R)=Cp-Bn: 8 a (E=P), 8 b (E=As)) can be isolated. Here, a stepwise transfer of E-n units is possible, with a cyclo-E-4(2-) ligand being introduced and unprecedented triple-decker compounds of the type [{(Cp(R)Ni)(3)Ni(mu(3)-E)(4)}(2)(mu,eta(4:4)-E '(4))] (Cp(R)=Cp-Bn, Cp '''; E/E '=P, As) are obtained.

Automated summary

The use of different phosphorus or arsenic sources resulted in the successful synthesis of novel stable polypnictogen transition metal complexes. The reactions were influenced by steric effects and stoichiometric ratios, leading to the formation of diverse complex structures.