Tukur Abubakar, M. A. Kurawa, S. Isyaku


Two synthetic routes were used to synthesized zinc (II) complexes of pyrazole mechanochemically.The first route involved direct reaction of the appropriate zinc (II) acetates with pyrazole and pyrazolium chloride to form bispyrazole zinc (II) salts, [(HPz)2ZnCl2]. This was ground further in the second route with a two equivalents of a base (KOH) to make polymeric zinc (II) pyrazolate [Zn(Pz)2]. In all the synthesis above the ratio of ligand to zinc (II) acetate was 2:1. All the zinc (II) complexes were found to be of different colours and were characterized using solubility test, which showed that the complexes have poor solubility in most of the solvents used except in dimethylsulfoxide where they were soluble and the molar conductivity measurements of the complexes indicated low values (ranging from 2.10-2.23Ω-1cm2mol-1) which showed that they are non-electrolytes. The decomposition temperature showed that all the complexes have relatively low decomposition temperatures (109°C-110°C). Characterization of the complexes via infrared analysis confirmed the coordination of metal with the ligand through pyridine-nitrogen and deprotonated-nitrogen in the range of 409.89cm-1Zn-N 435.93cm-1 Zn-N bonds (for the route A and B respectively). The magnetic susceptibility measurements were carried out at room temperature and the effective magnetic moment values for all the complexes further confirmed complexation of the metal (II) ions with the ligand and also indicates that the zinc (II) complexes were diamagnetic.


Keywords:  Mechanochemical, Pyrazole, Pyrazolium Chloride, Grinding, Mechanochemical Elimination.

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Adams C. J., Kurawa M. A. and Orpen A. G., (2010). Coordination chemistry in the solid state: synthesis and interconversion of pyrazolium salts, pyrazole complexes, and pyrazolate MOFs. J. Royal Society of Chemistry. Dalton Trans., 39:6974–6984.

Adams C. J., Kurawa M. A., Lusi M. and Orpen A. G.,(2008). Solid State synthesis of coordination compounds from basic metal salts. Cryst. Eng Comm., 10:1790–1795

Alan L. Balch, (2009). Solid state synthesis of coordination compounds from basic metal salt. J. Angew. Chem., Int. Ed., 48:2641–2644.

Angelici, R.J. (1971). “Synthesis and Techniques in Inorganic Chemistry”, W. B. Savders Company, Dalton Trans. 2nd Edition, pp 115-125.

Antesberger J., G. W. V. Cave, M. C. Ferrarelli, M. W. Heaven, C. L. Raston and J. L. Atwood, (2005). Solvent-free, direct synthesis of supramolecular nano-capsules. Chem. Commun., 892–894.

Bahl A. and Bahl B. S. (2007). Advanced Organic Chemistry, S. C and and Company Ltd, Ram Nagar, New Delhi, 20th edition, pp 490 – 497.

Balema V. P., J. W. Wiench, M. Pruski and V. K. Pecharsky,(2002). Mechanochemically induced solid state generation of phosphorus ylides and the solvent-free witting reaction. Chem. Commun. Cambridge, Pp 45-47.

Chen T., B. Liang and X. Xin, (1997). Studies on Solid-Solid Reactions between 4-Methylbenzenamine and Copper (II)Chloridedihydrate, Cobalt (II)Chloridehexahydrate and

Groeneveld W.L, Okkersen H., and Reedijk J., (1976). Pyrazolato and related anions, salt of 4-nitropyrazole. Rec. Trav. Chim., 92:947.

Halcrow M. A., (2009). Pyrazole and pyrazolides-flexible synthons in self. In Heterocyclic chemistry. J. Dalton Trans.,2059 – 2073.

Kumar N. Sharma and Pareek A. (2013), synthesis of new Schiff base complexes and their applications. International Journal of Applied Research and Studies II (2):307-315.

Kuroda R., Yoshida J., Nakamura A. and Nishikiori S.I., (2009). Annealing assisted mechanochemical synthesis of transition-metal coordination compounds and co-crystal formation. J. Cryst. Eng. Comm., 11:427 – 432.

Lancashire R.J., (2015), Coordination Chemistry. Kingston, Jamaica. Available on Mon.html.

Maurya R. C. and Rajput S., (2004), Oxovanadium (IV) complexes of bioinorganic and medicinal relevance: synthesis, characterization and 3D molecular modeling and analysis of some oxovanadium (IV) complexes involving O, O-donor environment, J. Mol. Struct . 687(1): 35–44.

Raman N., Jeyamurugan R., Rajkapoor, B. and Mitu, L. (2010). Novel metal- based pharmacologically dynamic agents of transition metal (II) complexes: Designing, synthesis, structural elucidation, DNA binding and photo-induced DNA cleavage: activity, Spectro

chim. Acta, Part A 75(1):88-97.

See1 F., and Sperber V., (1968). Interpretation of NMR chemical shifts and magnetic susceptibilities. J. Angew. Chem., 80:38.

Sindhu Y., Athira C.J., Sujamol M. S., Selwin R.J. and Mohanan K., (2013). Synthesis, characterization, DNA cleavage, and antimicrobial studies of some transition metal complexes with a novel Schiff base derived from 2-aminopyrimidine, Synth. React. Inorg. Met-Org. Nano-Met. Chem. 43(3):226-23


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