Structural and theoretical investigations of the Rh(III) and Co(III) complexes containing symmetrical edta-type ligands with mixed carboxylate and diamine rings: Quantum-mechanical/NBO insight into stability of geometrical isomers
Jeremić MS, Radovanović MD, Heinemann FW, Vasojević MM, Matović ZD (2019)
Publication Type: Journal article
Publication year: 2019
Journal
Book Volume: 169
Pages Range: 89-101
DOI: 10.1016/j.poly.2019.04.053
Abstract
The trans(O
5
O
6
) isomer of the Na[Rh(eddadp)]·4H
2
O and the K[Co(eddadp)]·3H
2
O (eddadp = ethylenediamine-N,N′-diacetate-N,N′-di-3-propionate) were synthesized and Na[Rh(eddadp)]·4H
2
O structure was confirmed by X-ray diffraction analysis. The percentage of particular isomers found in reaction equilibrium mixtures of [M(eddadp)]
−
complex has been reported. Single crystal X-ray diffraction of the complex revealed an octahedral geometry of the Rh(III) centre. Improved structural distortion analysis of M(III) (M = Rh, Co) complexes with symmetric edta-type of ligands containing mixed carboxylate and diamine rings was made. Structural distortion analysis has determined high values of total deviation of the octahedral angles (Δ(O
h
)) for both existing trans(O
5
) (34°) and trans(O
5
O
6
) (41°) isomers of [Rh(eddadp)]
−
complex, while in the case of a similar Co(III) complex, relatively low value (31°) for trans(O
5
) has been established. Extensive QM/NBO calculations were made for both systems [M(eddadp)]
−
and [M(1,3-pddadp)]
−
using different DFT methods (B3LYP/SDD, M06/SDD, MP2/SDD). By correlating the structural parameters obtained from X-ray and DFT optimized 3D structures, the B3LYP/SDD method was used as the method of choice. Based on the correlation between the energies of the optimized systems and the strain parameters, the existence of the trans(O
6
) isomer of the [Rh(1,3-pddadp)]
−
complex was predicted. NRT (Natural Resonance Theory) analysis gave the best resonances for each isomer. Here the stability of particular isomer has been described in terms of 3-CHB bonds involving metal ions and Second Order Perturbation Theory analysis using Donor/Acceptor energies. Further, to explain the bonding nature of M-edta-type complexes the Natural Coulomb Electrostatics (NCE) analysis has been done as well. The pairwise steric exchange interaction E
I,J
pwx
results obtained for the best-ranked resonances of different isomers are in excellent agreement with favored isomers reported so far. For the energy limit of the possibility of forming geometric isomers, a value of about 6 kcal mol
−1
is proposed.
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How to cite
APA:
Jeremić, M.S., Radovanović, M.D., Heinemann, F.W., Vasojević, M.M., & Matović, Z.D. (2019). Structural and theoretical investigations of the Rh(III) and Co(III) complexes containing symmetrical edta-type ligands with mixed carboxylate and diamine rings: Quantum-mechanical/NBO insight into stability of geometrical isomers. Polyhedron, 169, 89-101. https://dx.doi.org/10.1016/j.poly.2019.04.053
MLA:
Jeremić, Marija S., et al. "Structural and theoretical investigations of the Rh(III) and Co(III) complexes containing symmetrical edta-type ligands with mixed carboxylate and diamine rings: Quantum-mechanical/NBO insight into stability of geometrical isomers." Polyhedron 169 (2019): 89-101.
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