Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Isonicotinate-Zn(ii)/Cd(ii) bridged dicobaloximes : synthesis, characterization and electrocatalytic proton reduction studies

Yadav, Jitendra Kumar ; Mishra, Anjali LU ; Mishra, Gaurav Kumar ; Pal, Sarvesh Kumar LU ; Narvekar, Kedar Umakant ; Rahaman, Ahibur LU ; Singh, Nanhai ; Lama, Prem and Kumar, Kamlesh LU (2023) In New Journal of Chemistry 47(44). p.20583-20593
Abstract

Herein, we present the synthesis of two new dicobaloxime complexes, [{ClCo(dmgH)2(4-PyCOO)}2Zn(DMF)2] (1) and [{ClCo(dmgH)2(4-PyCOO)}2Cd(H2O)3(DMF)].4H2O (2) bridged by isonicotinate-Zn(ii) and Cd(ii) moieties. These complexes were synthesized upon reaction of a monomeric chlorocobaloxime [ClCo(dmgH)2(4-PyCOOH)] with Zn(NO3)2·6H2O and Cd(OAc)2·2H2O in a methanol/DMF solvent mixture. Both complexes are fully characterized by UV-Visible, FT-IR, and NMR (1H and 13C{1H}) spectral studies. The solid-state structures are also determined by single-crystal... (More)

Herein, we present the synthesis of two new dicobaloxime complexes, [{ClCo(dmgH)2(4-PyCOO)}2Zn(DMF)2] (1) and [{ClCo(dmgH)2(4-PyCOO)}2Cd(H2O)3(DMF)].4H2O (2) bridged by isonicotinate-Zn(ii) and Cd(ii) moieties. These complexes were synthesized upon reaction of a monomeric chlorocobaloxime [ClCo(dmgH)2(4-PyCOOH)] with Zn(NO3)2·6H2O and Cd(OAc)2·2H2O in a methanol/DMF solvent mixture. Both complexes are fully characterized by UV-Visible, FT-IR, and NMR (1H and 13C{1H}) spectral studies. The solid-state structures are also determined by single-crystal X-ray crystallography. In complex 1, Zn (ii) metal ions reside within a four coordinated distorted tetrahedral geometry (ZnO4) formed by two oxygen atoms of isonicotinate connected to cobaloxime units and two oxygen atoms of DMF molecules. In complex 2, the Cd(ii) metal ion exhibited distorted octahedral geometry (CdO6), with two oxygen atoms of isonicotinate that connect to cobaloxime units, one DMF, and three water molecules. The Co(iii) metal center of cobaloxime units in both complexes 1 and 2 displayed distorted octahedral geometry with two dmgH units in the equatorial plane whereas chloride ion (Cl−) and the nitrogen atom of isonicotinate occupy the axial coordination sites. The redox behaviour of both complexes was studied by cyclic voltammetry at variable scan rates in deoxygenated DMF/H2O (95 : 5) solution using 0.1 M TBAPF6 as the supporting electrolyte and a glassy carbon (GC) electrode as the working electrode. Both complexes exhibited similar redox properties and two redox couples CoIII/II and CoII/CoI are observed in the reductive scan. Furthermore, complexes are investigated as electrocatalysts for proton reduction in the presence of acetic acid (AcOH) and complex 1 exhibited impressive electrocatalytic activity compared to complex 2 and monomer. The stability study indicated the retention of molecular structural integrity during HER electrocatalytic experiments.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
New Journal of Chemistry
volume
47
issue
44
pages
11 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:85175555632
ISSN
1144-0546
DOI
10.1039/d3nj04014c
language
English
LU publication?
yes
id
06876e22-2484-44c1-8fb9-da4748cedf04
date added to LUP
2023-12-04 12:21:45
date last changed
2023-12-04 12:23:14
@article{06876e22-2484-44c1-8fb9-da4748cedf04,
  abstract     = {{<p>Herein, we present the synthesis of two new dicobaloxime complexes, [{ClCo(dmgH)<sub>2</sub>(4-PyCOO)}<sub>2</sub>Zn(DMF)<sub>2</sub>] (1) and [{ClCo(dmgH)<sub>2</sub>(4-PyCOO)}<sub>2</sub>Cd(H<sub>2</sub>O)<sub>3</sub>(DMF)].4H<sub>2</sub>O (2) bridged by isonicotinate-Zn(ii) and Cd(ii) moieties. These complexes were synthesized upon reaction of a monomeric chlorocobaloxime [ClCo(dmgH)<sub>2</sub>(4-PyCOOH)] with Zn(NO<sub>3</sub>)<sub>2</sub>·6H<sub>2</sub>O and Cd(OAc)<sub>2</sub>·2H<sub>2</sub>O in a methanol/DMF solvent mixture. Both complexes are fully characterized by UV-Visible, FT-IR, and NMR (<sup>1</sup>H and <sup>13</sup>C{<sup>1</sup>H}) spectral studies. The solid-state structures are also determined by single-crystal X-ray crystallography. In complex 1, Zn (ii) metal ions reside within a four coordinated distorted tetrahedral geometry (ZnO<sub>4</sub>) formed by two oxygen atoms of isonicotinate connected to cobaloxime units and two oxygen atoms of DMF molecules. In complex 2, the Cd(ii) metal ion exhibited distorted octahedral geometry (CdO<sub>6</sub>), with two oxygen atoms of isonicotinate that connect to cobaloxime units, one DMF, and three water molecules. The Co(iii) metal center of cobaloxime units in both complexes 1 and 2 displayed distorted octahedral geometry with two dmgH units in the equatorial plane whereas chloride ion (Cl<sup>−</sup>) and the nitrogen atom of isonicotinate occupy the axial coordination sites. The redox behaviour of both complexes was studied by cyclic voltammetry at variable scan rates in deoxygenated DMF/H<sub>2</sub>O (95 : 5) solution using 0.1 M TBAPF<sub>6</sub> as the supporting electrolyte and a glassy carbon (GC) electrode as the working electrode. Both complexes exhibited similar redox properties and two redox couples Co<sup>III</sup>/<sup>II</sup> and Co<sup>II</sup>/Co<sup>I</sup> are observed in the reductive scan. Furthermore, complexes are investigated as electrocatalysts for proton reduction in the presence of acetic acid (AcOH) and complex 1 exhibited impressive electrocatalytic activity compared to complex 2 and monomer. The stability study indicated the retention of molecular structural integrity during HER electrocatalytic experiments.</p>}},
  author       = {{Yadav, Jitendra Kumar and Mishra, Anjali and Mishra, Gaurav Kumar and Pal, Sarvesh Kumar and Narvekar, Kedar Umakant and Rahaman, Ahibur and Singh, Nanhai and Lama, Prem and Kumar, Kamlesh}},
  issn         = {{1144-0546}},
  language     = {{eng}},
  number       = {{44}},
  pages        = {{20583--20593}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{New Journal of Chemistry}},
  title        = {{Isonicotinate-Zn(ii)/Cd(ii) bridged dicobaloximes : synthesis, characterization and electrocatalytic proton reduction studies}},
  url          = {{http://dx.doi.org/10.1039/d3nj04014c}},
  doi          = {{10.1039/d3nj04014c}},
  volume       = {{47}},
  year         = {{2023}},
}