A ‘Butterfly’-Shaped Water Tetramer in a Cu4 Complex Supported by a Hydrazone Ligand: Synthesis, Crystal Structure, Magnetic Properties, and Quantum Chemical Study

Sambuddha Banerjee; Soma Sen; Joy Chakraborty; Ray J. Butcher; Carlos J. Gómez García; Ralph Puchta; Samiran Mitra

doi:10.1071/CH09192

RESEARCH ARTICLE

A ‘Butterfly’-Shaped Water Tetramer in a Cu₄ Complex Supported by a Hydrazone Ligand: Synthesis, Crystal Structure, Magnetic Properties, and Quantum Chemical Study

Sambuddha Banerjee ^A , Soma Sen ^A , Joy Chakraborty ^A , Ray J. Butcher ^B , Carlos J. Gómez García ^C , Ralph Puchta ^D ^E and Samiran Mitra ^A ^F

+ Author Affiliations

- Author Affiliations

^A Department of Chemistry, Jadavpur University, Kolkata-700 032, India.

^B Department of Chemistry, Howard University, 2400 Sixth Street, N.W., Washington, DC, 20059, USA.

^C Instituto de Ciencia Molecular (ICMol). Parque Científico. Universidad de Valencia, 46980 Paterna (Valencia) Spain.

^D Inorganic Chemistry, Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany.

^E Computer Chemistry Center, Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, Nägelsbachstr 25, 91052 Erlangen, Germany.

^F Corresponding author. Email: smitra_2002@yahoo.com

Australian Journal of Chemistry 62(12) 1614-1621 https://doi.org/10.1071/CH09192
Submitted: 6 April 2009 Accepted: 10 July 2009 Published: 10 December 2009

Abstract

A potentially tetradentate NOOO donor hydrazone ligand, LH₂ (condensation product of benzhydrazide with O-vanillin) generates a tetranuclear Cu^II complex [Cu₄(L)₄]·4H₂O (1), whose void spaces are occupied by water tetramers presenting a ‘butterfly’ conformation with the highest dihedral angle reported to date, as revealed by its X-ray crystal structure. 1 has also been characterized using various spectroscopic techniques, including IR, UV-vis, and elemental analysis. Variable temperature magnetic susceptibility measurements reveal the presence of moderate antiferromagnetic intra-tetramer coupling between the four Cu^II centres connected through simple oxo groups of the hydrazone ligand with two different coupling constants (J₁ = –61.7(3) cm^–1 and J₂ = –92(1) cm^–1) corresponding to the two different Cu^II tetramers identified in the X-ray structure. We also report a quantum chemical study (MP2(full)/6–311+G(3df,2p)//B3LYP/6–311+G(3df,2p)) to calculate the stability of the water tetramers.

Acknowledgement

The authors sincerely acknowledge DRDO and AICTE New Delhi, the European Union (MAGMANet network of excellence) and the Spanish Ministerio de Educación y Ciencia (Projects MAT2007–61584 and Consolider-Ingenio 2010 CSD 2007–00010 in Molecular Nanoscience) for funding this project. We also thank Professor Tim Clark, of University of Erlangen-Nürnberg, Germany, for hosting this work in the CCC and the Regionales Rechenzentrum Erlangen (RRZE) for a generous allotment of computer time. We also thank the Generalitat Valenciana (Project PROMETEO/2009/095).

References

A ‘Butterfly’-Shaped Water Tetramer in a Cu4 Complex Supported by a Hydrazone Ligand: Synthesis, Crystal Structure, Magnetic Properties, and Quantum Chemical Study

Abstract

Acknowledgement

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A ‘Butterfly’-Shaped Water Tetramer in a Cu₄ Complex Supported by a Hydrazone Ligand: Synthesis, Crystal Structure, Magnetic Properties, and Quantum Chemical Study