Publication detail

Structural, magnetic, redox and theoretical characterization of seven-coordinate first-row transition metal complexes with a macrocyclic ligand containing two benzimidazolyl N-pendant arms

DRAHOŠ, B. CÍSAŘOVÁ, I. LAGUTA, O. SANTANA, V. NEUGEBAUER, P. HERCHEL, R.

Original Title

Structural, magnetic, redox and theoretical characterization of seven-coordinate first-row transition metal complexes with a macrocyclic ligand containing two benzimidazolyl N-pendant arms

Type

journal article in Web of Science

Language

English

Original Abstract

A structurally new heptadentate derivative of a 15-membered pyridine-based macrocycle containing two benzimidazol-2-yl-methyl N-pendant arms (L = 3,12-bis((1H-benzimidazol-2-yl)methyl)-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]octadeca-1(18),14,16-triene) was synthesized and its complexes with the general formula [M(L)](ClO4)(2)center dot 1.5CH(3)NO(2) (M = Mn-II (1), Fe-II (2), Co-II (3) and Ni-II (4)) were thoroughly investigated. X-ray crystal structures confirmed that all complexes are seven-coordinate with axially compressed pentagonal bipyramidal geometry having the largest distortion for Ni-II complex 4. Fe-II, Co-II and Ni-II complexes 2, 3 and 4 show rather large magnetic anisotropy manifested by moderate to high obtained values of the axial zero-field splitting parameter D (7.9, 40.3, and -17.2 cm(-1), respectively). Magneto-structural correlation of the Fe-II, Co-II and Ni-II complexes with L and with previously studied structurally similar ligands revealed a significant impact of the functional group in pendant arms on the magnetic anisotropy especially that of the Co-II and Ni-II complexes and some recommendations concerning the ligand-field design important for anisotropy tuning in future. Furthermore, complex 3 showed field-induced single-molecule magnet behavior described with the Raman (C = 507 K-n s(-1) for n = 2.58) relaxation process. The magnetic properties of the studied complexes were supported by theoretical calculations, which very well correspond with the experimental data of magnetic anisotropy. Electrochemical measurements revealed high positive redox potentials for M3+/2+ couples and high negative redox potentials for M2+/+ couples, which indicate the stabilization of the oxidation state +II expected for the sigma-donor/pi-acceptor ability of benzimidazole functional groups.

Keywords

SINGLE-ION-MAGNET; STATE PERTURBATION-THEORY; BASIS-SETS; CHAIN MAGNET; ANISOTROPY; VALENCE; RELAXATION; BEHAVIOR; IMPLEMENTATION; VISUALIZATION

Authors

DRAHOŠ, B.; CÍSAŘOVÁ, I.; LAGUTA, O.; SANTANA, V.; NEUGEBAUER, P.; HERCHEL, R.

Released

14. 4. 2020

Publisher

Royal Society of Chemistry

Location

CAMBRIDGE

ISBN

1477-9234

Periodical

Dalton Transactions

Year of study

49

Number

14

State

United Kingdom of Great Britain and Northern Ireland

Pages from

4425

Pages to

4440

Pages count

16

URL

https://pubs.rsc.org/en/content/articlelanding/2020/DT/D0DT00166J#!divAbstract

Full text in the Digital Library

http://hdl.handle.net/11012/187017

BibTex

@article{BUT163834,
  author="Bohuslav {Drahoš} and Ivana {Císařová} and Oleksii {Laguta} and Vinicius Tadeu {Santana} and Petr {Neugebauer} and Radovan {Herchel}",
  title="Structural, magnetic, redox and theoretical characterization of seven-coordinate first-row transition metal complexes with a macrocyclic ligand containing two benzimidazolyl N-pendant arms",
  journal="Dalton Transactions",
  year="2020",
  volume="49",
  number="14",
  pages="4425--4440",
  doi="10.1039/d0dt00166j",
  issn="1477-9234",
  url="https://pubs.rsc.org/en/content/articlelanding/2020/DT/D0DT00166J#!divAbstract"
}