Di-μ3-chlorido-1:2:3κ3Cl;2:3:4κ3Cl-di-μ2-chlorido-1:2κ2Cl;3:4κ2Cl-tetrakis[(4-amino-1,5-dimethyl-2-phenyl-2,3-dihydro-1H-pyrazol-3-one-κ2N4,O)chloridocadmium(II)] 1.7-hydrate: a new six-coordinate geometry index, τ6

• Published in: Acta crystallographica. Section E, Crystallographic communications Vol. 81; no. 5; pp. 393 - 400
• Main Authors: Helen Stoeckli-Evans, M. G. Shankar, R. Kumaravel, A. Subashini, T. Sabari Girisun, K. Ramamurthi, Monika Kučeráková, Michal Dušek, Aurélien Crochet
• Format: Journal Article
• Language: English
• Published: International Union of Crystallography 01.05.2025
• Subjects: 4-aminoantipyrine; cadmium(ii); crystal structure; hydrogen bonding; six-coordinate geometry index; tetranuclear
• ISSN: 2056-9890
• DOI: 10.1107/S2056989025003123

The title centrosymmetric tetranuclear cadmium(II) complex of 4-aminoantipyrine and chloride ions, [Cd4Cl8(C11H13N3O)4]·1.7H2O, was synthesized using methanol as solvent. The two independent Cd2+ ions in the asymmetric unit have different geometries; the outer Cd atoms have fivefold CdONCl3 coordination spheres, while the inner Cd atoms have sixfold CdONCl4 coordination spheres. The complex is consolidated by intramolecular N—H...O and N—H...Cl hydrogen bonds. In the crystal, a combination of N—H...Cl and Ow—H...Cl (w = water) hydrogen bonds link the components to form chains propagating along the a-axis direction. The chains are crosslinked by C—H...Cl and C—H...O hydrogen bonds to form a three-dimensional structure. A new geometry index, τ6, is proposed to quantitatively estimate the geometry of a sixfold coordinated atom.