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ISSN 1998-9539

Complexes of Ca(II), Ni(II) and Zn(II) with Hemi- and Dicarbahemiporphyrazines: Molecular Structure and Features of Metal-Ligand Bonding

Alexey V. Eroshin, Arseniy A. Otlyotov, Yuriy A. Zhabanov,@ Vladimir V. Veretennikov, and Mikhail K. Islyaikin

Ivanovo State University of Chemistry and Technology, Research Institute of Chemistry of Macroheterocyclic Compounds, 153000 Ivanovo, Russian Federation

@Corresponding author E-mail: zhabanov@isuct.ru

 

DOI: 10.6060/mhc201026z

Macroheterocycles 2021 14(2) 119-129

 

Equilibrium geometry and electronic structures of Ca(II), Ni(II) and Zn(II) complexes with hemi- and dicarbahemiporphyrazines were determined by DFT calculations at PBE0/pcseg-2 level followed by natural bond orbital (NBO) analysis of the electron density distribution.  Electronic structures of  Ni(II) complexes in ground and low-lying excited electronic states were determined by complete active space (CASSCF) method with following accounting dynamic correlation by multiconfigurational quasidegenerate second-order perturbation theory (MCQDPT2). According to data obtained by MCQDPT2 method the complexes of hemi- and dicarbahemiporphyrazine possess the ground states 1A1 and 3B1, respectively, and wave functions of the ground states have the form of a single determinant in the case of Ni(II) complex with hemiporphyrazine  and the wave function for Ni(II) with dicarbahemiporphyrazine were found to possess a complex composition, therefore this complex could not be treated using single-reference DFT methods.  The covalent component of metal-ligand bonding was found to increase significantly in the series: Ca(II) → Zn(II) → Ni(II). Large covalent contribution into Ni–N bonding is explained by additional LP(Np) → 3dx2-y2(Ni) and LP(Ni) → 3dx2-y2(Ni) interactions. The presence of agostic interactions -C–H∙∙∙Zn in the dicarbahemiporphyrazine complex was also confirmed.

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