X-RAY POWDER DIFFRACTION CHARACTERIZATION OF POLYMERIC METAL DIAZOLATES

ABSTRACT

Polymeric metal diazolates typically appear as insoluble and intractable powders, the structure of which could only be retrieved by the extensive use of ab-initio X-ray powder diffraction (XRPD) methods from conventional laboratory data. A number of selected examples from the metal pyrazolate, imidazolate, pyrimidin-2-olate and pyrimidin-4-olate classes are presented, highlighting the specific crystallochemical properties, material functionality and methodological aspects of the structure determination process. Linear and helical one-dimensional polymers, layered systems and three-dimensional networks are described, with particular emphasis on polymorphism and on the thermal, optical, magnetic and sorption properties. A brief outline of the method, as it has been tailored in our laboratories during the last decade, is also offered.

Keywords:

• powder diffraction
• coordination polymers
• metal diazolates
• polymorphism
• crystal structure

ACKNOWLEDGEMENTS

We thank all co-workers who have participated in this project for their continuous support and helpful discussions. The Italian MURST, CNR, University of Insubria (Progetto di Eccellenza Sistemi Poliazotati), the Fondazioni Provinciale Comasca and Cariplo are acknowledged for funding.