Sánchez-Férez F, Rius-Bartra JM, Calvet T, Font-Bardia M, Pons J. Steric and Electronic Effects on the Structure and Photophysical Properties of Hg(II) Complexes.
Inorg Chem 2021;
60:3851-3870. [PMID:
33629838 PMCID:
PMC8483444 DOI:
10.1021/acs.inorgchem.0c03640]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Since many factors influence the
coordination around a metal center,
steric and electronic effects of the ligands mainly determine the
connectivity and, thus, the final arrangement. This is emphasized
on Hg(II) centers, which have a zero point stabilization energy and,
thus, a flexible coordination environment. Therefore, the unrestricted
Hg(II) geometry facilitates the predominance of the ligands during
the structural inception. Herein, we synthesized and characterized
a series of six Hg(II) complexes with general formula (Hg(Pip)2(dPy)) (Pip = piperonylate, dPy = 3-phenylpyridine (3-phpy)
(1), 4-phenylpyridine (4-phpy) (2), 2,2′-bipyridine
(2,2′-bipy) (3), 1,10-phenanthroline (1,10-phen)
(4), 2,2′:6′,2′-terpyridine (terpy)
(5), or di(2-picolyl)amine (dpa) (6)). The
elucidation of their crystal structures revealed the arrangement of
three monomers (3, 5, and 6), one dimer (4), and two coordination polymers (1 and 2) depending on the steric requirements
of the dPy and predominance of the ligands. Besides, the study of
their photophysical properties in solution supported by TD-DFT calculations
enabled us to understand their electronic effects and the influence
of the structural arrangement on them.
Six Hg(II)
complexes containing 1,3-benzodioxole-5-carboxylic
acid and pyridine derivatives bearing N-, N^N′-, and N^N^N-donor sites have been characterized
and their crystal structure elucidated. Steric crowding defined the
predominance of the linkers in the structural arrangement, varying
from monomers to coordination polymers. Their photophysical properties
were analyzed through experimental and TD-DFT calculations, identifying
the character and regions involved on each electronic transition.
In addition, seclusion of the HOMO from the LUMO defined them as appropriate
to selective band gap tuning.
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