Some New Hexacoordinated Aluminium(III) Complexes of Sterically Hindered Heterocyclic β-Diketones and N-Protected Amino Acids : Preparation And Structural Considerations Based Upon Spectral [IR And NMR (1H, 13C and 27Al)] Studies

A number of new sterically hindered heterocyclic beta-diketones and N-protected amino acids -modified Al(OPri)(3) products of composition either Al[RCOC:C(O)N(C6H5)N:CCH3][O2CCH(R')NC(O)C6H4C(O)](2) where R= -C2H5 and R'= -CH2C6H5, -CH(CH3)(2), -CH(CH3)C2H5; R= -CH3 and R'= -CH(CH3)(2), -CH(CH3)C2H5; R= -C6H5 and R'= -CH2C6H5, -CH(CH3)(2), or Al[RCOC:C(O)N(C6H5)N: CH3](2)[O2CCH(R')NC(O)C6H4C(O)] where R= -C2H5 and R' = -CH(CH3)(2), -CH(CH3)C2H5; R= -CH3 and R'= -CH2C6H5, -CH(CH3)C2H5; R= -C6H5 and R'= -CH2C6H5, -CH(CH3)(2), -CH(CH3)C2H5, were prepared by the interaction of sterically hindered heterocyclic beta-diketones and N-protected amino acids in 1 : 1 : 2 and 1 : 2 : 1 molar ratios in anhydrous refluxing benzene. The structures of these newly synthesized sterically hindered heterocyclic beta-diketones and N-protected amino acids -modified Al(OPri)(3) products were suggested on the basis of analytical data, molecular weight measurements and spectral studies. The Al-27 NMR spectral study of some of these complexes revealed the presence of hexacoordinated aluminium centres in these products.