Crystal structure, solid state and solution characterisation of copper(II) coordination compounds of ethyl 5-methyl-4-imidazolecarboxylate (emizco)
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- 作者：Josefina Montes-Ayala ; Concepció ; n Escartí ; n-Guzmá ; n ; Silvia E. Castillo-Blum ; Edgar O. Rodrí ; guez-Herná ; ndez ; Sylvain Bernè ; s ; Ma. Jesú ; s Rosales-Hoz and Norá ; h Barba-
- 关键词：Emizco ; Cu(II) ; Coordination compounds ; Ester hydrolysis ; Crystal structures
- 刊名：Journal of Inorganic Biochemistry
- 出版年：2005
- 出版时间：2005
- 年：2005
- 卷：99
- 期：8
- 页码：1676-1684
- 全文大小：278 K
文摘
The synthesis and characterisation of the following compounds derived from the biological relevant compound ethyl 5-methyl-4-imidazolecarboxylate (emizco) (1): [Cu(emizco)Cl2] (2), [Cu(emizco)2Cl2] (3), [Cu(emizco)2Br2] (4), [Cu(emizco)2(H2O)2](NO3)2 (5) and [Cu(emizco)4](NO3)2 (6), is presented. These compounds were characterised by IR and UV spectroscopic techniques, in addition the crystal structures of compounds 1–5 were determined. For complexes 2–5, emizco is coordinated as a bidentate ligand, through the oxygen atom of the carboxylate moiety and the nitrogen atom of the imidazolic ring. Different geometries are stabilised: compound 2 includes a pentacoordinated square pyramidal metal centre, while 3–5 are derived from octahedral geometry. Halide compounds 3 and 4 show a cis-octahedral arrangement, which is not very common on [CuN2O2X2] systems, while 5 stabilises the trans-octahedral isomer. Compound 6 displays a square planar geometry. Finally, hydrolysis of emizco to its corresponding carboxylic acid (mizco), allowed the preparation of another square planar complex 7, identified as [Cu(mizco)2] 0.5H2O. Solution studies of these compounds indicate that emizco is not substituted from the coordination sphere, remaining as a bidentate ligand. Halides are substituted by water molecules, changing from cis octahedral to the trans-[Cu(emizco)2(H2O)2]2+ isomer.