Metal chelates of N-benzothiazol-2-yl-, N-benzoxazol-2-yl- and N-(1H-benzimidazol-2-yl)-benzamide
Introduction
Previous investigations of synthesis and characterization of metal complexes with guanidine and isourea structural elements [1], [2], [3] are followed now by studies of metal complexes from title ligands N-benzothiazol-2-yl-benzamide (1), N-benzoxazol-2-yl-benzamide (2), and N-(1H-benzimidazol-2-yl)-benzamide (3) (Scheme 1).
Metal complexes (mainly Zn(II)) with guanidinium structure and from benzimidazoles and related compounds are known as protease inhibitors [4] or are used in structure investigation of metallo proteins [5]. They are also of interest with respect to their connection to purin bases [6].
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Experimental
All chemicals and solvents were dried and purified by the usual methods. Melting points are corrected and were measured using a Boetius melting-point apparatus. Mass spectra were recorded on a Masslab VG 12-250 device and for the ESI-spectrum of 3e on a LC-MS Platform 1 spectrometer, Fa. Micromass (1:1 H2O/acetonitrile). NMR spectra were recorded on a Unity 400 spectrometer, 1H: σ (ppm), 399.95 MHz, solvent DMSO-d6; 13C: σ (ppm), 100.58 MHz, solvent DMSO-d6. The XPS spectra were recorded on a
Synthesis and spectroscopic characterization of ligands and metal complexes
Synthesis of ligands 1–3 was performed easily by reaction of N-(ethoxyethylsulfanylmethylene)-benzamide [7] and ortho-substituted aniline derivatives XC6H4NH2 (X=SH; OH; NH2) in boiling ethanol (Scheme 3). Compounds 1–3 were obtained as crystals in very good yields (90%) and are pure after one recrystallization. Compound 1 furnished suitable single crystals for X-ray analysis.
Under the same conditions educts (3,4-diaminophenyl)phenylmethanone and 2-amino-4-methylphenol, respectively, gave
Supplementary material
Crystallographic data for the structures in this paper have been deposited with the Cambridge Crystallographic Data Center as supplementary publication Nos. CCDC-140164, -140165, and -140166 for 1, 1a, and 2b, respectively. Copies of the data can be obtained free of charge, on application to CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK (fax: +44-1223-336-033; e-mail: [email protected] or www: http://www.ccdc.cam.ac.uk).
Acknowledgements
The authors (J.A-C., M.L-P.) wish to acknowledge the financial support given by DAAD Bonn.
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2008, Acta Crystallographica Section C: Crystal Structure Communications
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