Vol.:(0123456789) 1 3
Monatshefte für Chemie - Chemical Monthly (2019) 150:219–231
https://doi.org/10.1007/s00706-018-2330-8
ORIGINAL PAPER
Synthesis, X‑ray structure, and DFT modeling of a new polymeric
zinc(II) complex of 2‑mercaptonicotinic acid (MntH), {[Zn(Mnt–Mnt)
(en)]·H
2
O}
n
Muhammad Akhtar
1
· Ivelina Georgieva
2
· Tsvetan Zahariev
2
· Natasha Trendaflova
2
· Tayyaba Ahmad
3
·
Aqeela Noor
3
· Muhammad Nawaz Tahir
4
· Muhammad Mazhar
5
· Anvarhusein A. Isab
6
· Saeed Ahmad
7
Received: 5 June 2018 / Accepted: 6 November 2018 / Published online: 16 January 2019
© Springer-Verlag GmbH Austria, part of Springer Nature 2019
Abstract
Two zinc(II) complexes of 2-mercaptonicotinic acid (MntH), {[Zn(Mnt–Mnt)(en)]·H
2
O}
n
and [Zn(Mnt–Mnt)(H
2
O)], were
prepared by the reaction of ZnCl
2
and MntH in the presence of ethylenediamine (en). They were characterized by elemen-
tal analysis, and IR,
1
H,
13
C NMR and UV–Vis spectroscopic studies. In the presence of en, the sulfur atoms of the MntH
ligands were connected and formed a disulfde linkage in the Mnt–Mnt dimer. The single crystal X-ray difraction analysis
of {[Zn(Mnt–Mnt)(en)]·H
2
O}
n
complex revealed the polymer structure organization. Each zinc atom is fve coordinated in
distorted trigonal bipyramidal polyhedron by three oxygen atoms of two bridging Mnt–Mnt ligands and two nitrogen atoms
of an en molecule. The vibrational modes, which characterized the carboxylic oxygen coordination of the Mnt–Mnt ligand
to Zn(II), were determined by periodic DFT/PAW/PW91 calculations. Molecular structure modeling, vibrational spectra
calculations, and natural bond orbital analysis of the monomer and dimer ligands as well as of the Zn(II) complexes were
performed at the DFT/TDDFT/mPW1PW91 level to explain the available IR, NMR and UV–Vis spectroscopic data and to
confrm the ligand coordination to the metal ion. The formation of disulfde Mnt–Mnt ligand in [Zn(Mnt–Mnt)(H
2
O)] was
confrmed by the absence of the absorption band at 377 nm in the UV–Vis spectrum. The molecular modeling fragment of
[Zn(Mnt–MntH)
2
(H
2
O)] suggested that the most probable structure is that consisting of fve coordinated Zn(II) with one
aqueous oxygen and four carboxylic oxygens of two bidentate bound Mnt–Mnt ligands in a polymeric structure.
Graphical abstract
Keywords Zinc(II) Complexes · 2-Mercaptonicotinic acid · X-ray structure · DFT Calculations
Introduction
Zinc plays an active role in the structural functions of pro-
teins and as a biochemical catalyst. Zinc(II) ions are known
to take part in information transfer and cellular control
[1–3]. In several enzymes, zinc is attached to the protein
by a combination of histidine and cysteine residues, and
bears a labile (oxygen donor) ligand [3–6]. The enzymes
Electronic supplementary material The online version of this
article (https://doi.org/10.1007/s00706-018-2330-8) contains
supplementary material, which is available to authorized users.
* Ivelina Georgieva
ivelina@svr.igic.bas.bg
* Saeed Ahmad
saeed_a786@hotmail.com
Extended author information available on the last page of the article