Synthesis and characterization of para-nitrophenoxides of zirconium(IV)

Article abstract of DOI:10.1081/SIM-120037525

Compounds of the composition ZrCl₃(OC₆H ₄NO₂-p) and ZrCl₂(OC₆H₄ NO₂-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.