On the governing of alkaline earth metal nitrate coordination spheres by hexamethylenetetramine

Abstract

Alkaline earth metal nitrate coordination compounds with hexamethylenetetramine, []], have been synthesized and characterized by elemental and thermal analysis, IR spectroscopy, and X-ray crystallography. Introduction of hmta to the outer coordination sphere allows changing of the inner coordination sphere giving the dinuclear coordination compounds of calcium and strontium nitrates. The compounds are air stable at room temperature and soluble in water. The ions and molecules are assembled via , and hydrogen bonds. Thermal analyses show crucial differences in decomposition processes (especially in the case of 3 that finally decomposes to the mixture of SrO and Sr(NO₃)₂). The IR spectrum of 3 shows lack of bending vibration (present in the spectra of the respective pure salts at 741–759 cm⁻¹), while in 2 this band is weakened and shifted to lower frequencies. Only the IR spectrum of 3 clearly exhibits bands originating from overtones and combination bands (in the spectral range 2073–2474 cm⁻¹).

Keywords:

• Magnesium
• Calcium
• Strontium
• Hexamethylenetetramine
• Thermal decomposition
• IR spectroscopy

Acknowledgments

This work was financed by funds allocated by the Ministry of Science and Higher Education to the Institute of General and Ecological Chemistry, Technical University of Lodz.