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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" }