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DFT study of vanadyl (IV) complexes with low molecular mass ligands: Picolinate, oxalate, malonate, and maltolate

Authors

  • Guilherme Dos Santos Rodrigues,

    1. Grupo de Pesquisa em Química Inorgânica Teórica—(GPQIT), Departamento de Química–ICEx, Universidade Federal de Minas Gerais–UFMG, 31.270-901-Belo Horizonte-MG, Brasil
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  • Ivan da Silva Cunha,

    1. Grupo de Pesquisa em Química Inorgânica Teórica—(GPQIT), Departamento de Química–ICEx, Universidade Federal de Minas Gerais–UFMG, 31.270-901-Belo Horizonte-MG, Brasil
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  • Guilherme Gomes Silva,

    1. Grupo de Pesquisa em Química Inorgânica Teórica—(GPQIT), Departamento de Química–ICEx, Universidade Federal de Minas Gerais–UFMG, 31.270-901-Belo Horizonte-MG, Brasil
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  • Antonio Luiz Oliveira de Noronha,

    1. Grupo de Pesquisa em Química Inorgânica Teórica—(GPQIT), Departamento de Química–ICEx, Universidade Federal de Minas Gerais–UFMG, 31.270-901-Belo Horizonte-MG, Brasil
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  • Heitor Avelino de Abreu,

    1. Grupo de Pesquisa em Química Inorgânica Teórica—(GPQIT), Departamento de Química–ICEx, Universidade Federal de Minas Gerais–UFMG, 31.270-901-Belo Horizonte-MG, Brasil
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  • Hélio Anderson Duarte

    Corresponding author
    1. Grupo de Pesquisa em Química Inorgânica Teórica—(GPQIT), Departamento de Química–ICEx, Universidade Federal de Minas Gerais–UFMG, 31.270-901-Belo Horizonte-MG, Brasil
    • Grupo de Pesquisa em Química Inorgânica Teórica—GPQIT, Departamento de Química—ICEx, Universidade Federal de Minas Gerais—UFMG, 31.270-901-Belo Horizonte-MG, Brasil
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Abstract

The insulin-mimetic activity of the VO2+ complexes are much related to its chemical speciation in the blood serum. Low molecular mass ligands must have an important role in the mechanism of the VO2+ biological activity affecting directly its absorption efficacy. In the present work, the chemical speciation of vanadyl (VO2+) with malonate, maltolate, oxalate and picolinate ligands has been investigated by means of DFT/PCM calculations. Metal/Ligand 1:1 and 1:2 complexes have been calculated. All tautomers, conformations and the presence of water molecules acting as ligand fulfilling the coordination sphere of the metal center have been studied. The results showed that the 1:1 species prefer to have square pyramidal structure with two water molecules in the equatorial axis. The 1:2 species prefer the hexacoordinated structure with one water molecule in the available coordination site in the cis position with respect to the oxo group. The 6-membered ring malonate complex prefers to keep the square pyramidal structure without water molecule in the coordination sphere. The Gibbs free reaction energy for the formation of the 1:2 complexes from the interaction of the 1:1 complexes and the ligand was estimated. The error of the estimated values compared to the experimental data is not larger than 5 kcal mol−1 at the PBE/TZVP level of theory using the UAHF-PCM for estimating the solvation free energy. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010

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