Synthesis, characterization, and quantum chemical study of cobalt(II) chelates with N-phenethyl-iminodiacetate(2-)-like ligands. Influence of p-(R)-phenethyl group on crystal pattern

From the reaction of Co(II) hydroxy-carbonates and N-p-(R)-phenethyliminodiacetic acids (Hpheida, R = H and HMOpheida, R = CHO) two binary complexes have been obtained in aqueous media. The crystal pattern of [Co(pheida)(HO)]·1.5HO (1) (monoclinic, space group C2/c) differs from the related non-hydrated crystal of [Co(MOpheida)(HO)] (2) (monoclinic, space group P2/c). Both Co(II) complexes display distorted octahedral geometry imposed by 3d electronic configuration. Our crystallographic results reveal that the metal chelates have a molecular structure and the used methoxy-substituent on the pheida skeleton yield different structural features. The iminodiacetic acid-arms [IDA] of pheida-like ligands adopt fac-NO conformation. For both chelators 1 and 2, single-point energy was calculated using restricted and/or unrestricted Hartree–Fock/BP/B3LYP functional. The analytical frequency, electronic absorption, and HOMO–LUMO energy gap were calculated using B3LYP functional with orbital basis set def2-SVP or def2-TZVP (for 2) along with the auxiliary basis set def2/J. The quantum chemical calculated geometry parameters are compared with their corresponding X-ray crystallographic data. The optical band gap (E ) arises due to the electronic transitions. The direct and indirect band gap energy measured 3.26, 3.19 eV for 1 and 3.39, 3.35 eV for 2, respectively, reflecting their semi-conducting nature. Crystal structure for HMOpheida acid also reported herein.