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

Abstract

From the reaction of Co(II) hydroxy-carbonates and N-p-(R)-phenethyliminodiacetic acids (H₂pheida, R = H and H₂MOpheida, R = CH₃O) two binary complexes have been obtained in aqueous media. The crystal pattern of [Co(pheida)(H₂O)₃]·1.5H₂O (1) (monoclinic, space group C2/c) differs from the related non-hydrated crystal of [Co(MOpheida)(H₂O)₃] (2) (monoclinic, space group P2₁/c). Both Co(II) complexes display distorted octahedral geometry imposed by 3d⁷ 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-NO₂ 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_g) 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 H₂MOpheida acid also reported herein.

Keywords:

• Cobalt(II) complexes
• iminodiacetate(2-)chelate
• crystal structure
• supramolecular chemistry
• DFT calculations
• optical band gap energy measurements

Supplementary material

Crystallographic data for the crystal structures reported in this paper have been deposited with the Cambridge Crystallographic Centre as Supplementary Publication No. CCDC 750074 for [Co(pheida)(H₂O)₃]·1.5H₂O (1) and CCDC 750075 for [Co(MOpheida)(H₂O)₃] (2). Copies of the data can be obtained free of charge on application to the Director, CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK (Fax: [phone]) or E-mail: [email protected] or http://www.ccdc.cam.ac.uk.

Author contributions

Dheerendra Kumar Patel: Writing original draft, Investigation and analysis, DFT calculations. Alicia Domínguez-Martín: Formal analysis. Duane Choquesillo-Lazarte: Single crystal data analysis. Josefa María González-Pérez: Project administration. Juan Niclós-Gutiérrez: Conceptualization, Supervision, Project administration, Resources, Review and editing.

Disclosure statement

We are presenting paper entitled, “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”. We declare that there are no competing financial interests or personal relationships that could have appeared to influence the work reported herein.

Acknowledgements

Dheerendra Kumar Patel thanks the University of Granada for his stay at Prof Juan Niclós-Gutiérrez research group.

Additional information

Funding

Financial support of Junta de Andalucía (FQM-283 Research Group) and Factoría de Cristalización are acknowledged. Dheerendra Kumar Patel thanks the Spanish Agency for International Cooperation and Development (AECID) for a research grant. This study was also supported by Agencia de Innovación y Desarrollo de Andalucía.