Quantum Computational Chemistry: Modeling and Calculation of S-Block Metal Ion Complexes

Abstract

The computational study of some s-block metal nitrophenolate complexes, [Ca(THEEN)(PIC)]+ (1), [Ca(THPEN)(H2O)2]2+ (2), Ba(THPEN)(PIC)2 (3) [Na(THPEN)]22+ (4), [Sr(THPEN)(H2O)2]22+ (5) and [Ba(THPEN)(H2O)2]22+ (6) (where THEEN (N,N,N′,N′-Tetrakis(2-hydroxyethyl)ethylenediamine) and THPEN (N,N,N′,N′-Tetrakis(2-hydroxypropyl)ethylenediamine) are tetrapodal ligands and PIC− is 2,4,6-trinitrophenolate anion), is presented here using density functional theory (DFT) in its hybrid form B3LYP. The geometries of the title complexes are described by the quantum-chemical approach using input coordinates obtained from the previously synthesized and X-ray characterized diffraction data of [Ca(THEEN)(PIC)](PIC), [Ca(THPEN)(H2O)2](PIC)2, Ba(THPEN)(PIC)2, [Na(THPEN)]2(PIC)2, [Sr(THPEN)(H2O)2]2(DNP)4 and [Ba(THPEN)(H2O)2]2(DNP)4 (where DNP is 3,5-dinitrophenolate). Only the primary coordination sphere of complexes (1–6) is optimized in the gaseous phase. Calculations of the energy gaps of frontier orbitals (HOMO-LUMO), 13C-NMR shifts and vibrational bands are carried out using B3LYP/6-31 g + (d,p)/LANL2DZ level of theory. The calculated geometric and spectral parameters reproduced the experimental data with a well agreement.