Synthesis and Characterization of para‐Nitrophenoxides of Zirconium(IV)

Abstract

Compounds of the composition ZrCl₃(OC₆H₄NO₂‐p) and ZrCl₂(OC₆H₄NO₂‐p)₂ have been synthesized from the reaction of ZrCl₄ with equimolar and bimolar amounts of the trimethylsilyl derivative of p‐nitrophenol in benzene under reflux. Attempts to isolate the tetrakis derivative, Zr(OC₆H₄NO₂‐p)₄, even by heating the components in high‐boiling solvents were unsuccessful. Based upon analytical data, conductance, cryoscopic, IR and ¹H NMR studies, dimeric structures with bridging through phenoxo groups have been proposed for these compounds. The thermal decomposition of these complexes is a combination of both exothermic and endothermic processes, as is inferred from TG/DT studies. Reactions of these compounds with nitrogen bases viz., pyridine, 1,10‐phenanthroline and 2,2′‐bipyridyl results in breakdown of the bridged structure and formation of simple addition compounds, which have been assigned octahedral structures.

Keywords:

• para‐Nitrophenoxides
• Exothermic process
• Thermal decomposition
• Dimeric structures