Wydział Chemii

Archana Yadav

Prem Lama

Alina Bieńko

Dariusz Bieńko

Kafeel Ahmad Siddiqui

2018

Polyhedron

141

247-261

10.1016/j.poly.2017.11.047

Naukowa

Angielski

Artykuł

Hydrothermal self-assembly of orotic acid (C5H4N2O4double bond; length as m-dashOrH3) with metal salt Cu(Ac)2·H2O yielded a new OrH based hydrogen bonded coordination network of formula [Cu(OrH)(2NH3)(H2O)]·H2O (1) and [Cu(OrH) (2NH3)]2 (2). Single crystal X–ray study on 1 confirms that +2 charges on the metal ions (Cu2+) are balanced by OrH anion. N–H⋯O and O–H⋯O hydrogen bonding synthons are the only artifact for the resulting hydrogen bonded copper-OrH architecture. Temperature dependent measurements of magnetic susceptibility reveals the occurrence of competitive exchange interactions with a net ferromagnetic character in 1 (J = +0.48 cm−1) and strong antiferromagnetic interaction in 2 (J = −4.93 cm−1). Magnetic superexchange interaction transmitted through equatorial–axial hydrogen bridge system promotes weak ferromagnetic interactions in 1 while in 2 it is in basal-basal position, in which two dx2-y2orbitals is involved in exchange mechanism reveals the coexistence of two antiferromagnetic exchange pathways, intramolecular much stronger than intermolecular. The natural bond orbital (NBO) analysis applied separately to α and β spin density matrices clearly shows two important magnetic superexchange pathway with shorter Cu⋯Cu contact 5.542(4) Å and 4.845(4) Å or 5.755(1) Å in (1) and inter dimer 6.665(1) Å and 4.6744(9) Å for (2).

Hydrogen bonding, Metal-OrH coordination network, Ferromagnetic and antiferromagnetic interactions, DFT calculation

https://doi.org/10.1016/j.poly.2017.11.047

http://www.elsevier.com