Reactivity of dioxoosmium(VI) porphyrins toward arylhydrazine. Isolation of hydrazidoosmium and amidoosmium porphyrins.
Reactions of dioxoosmium(VI) porphyrins [Os(VI)(Por)O(2)] with excess 1,1-diphenylhydrazine in tetrahydrofuran at ca. 55 degrees C for 15 min afforded bis(hydrazido(1-))osmium(IV) porphyrins [Os(IV)(Por)(NHNPh(2))(2)] (1a, Por = TPP (meso-tetraphenylporphyrinato dianion); 1b, Por = TTP (meso-tetrakis(p-tolyl)porphyrinato dianion)), hydroxo(amido)osmium(IV) porphyrins [Os(IV)(Por)(NPh(2))(OH)] (2a, Por = TPP; 2b, Por = TTP), and bis(hydrazido(2-))osmium(VI) porphyrin [Os(VI)(Por)(NNPh(2))(2)] (3c, Por = TMP (meso-tetramesitylporphyrinato dianion)). The same reaction under harsher conditions (in refluxing tetrahydrofuran for ca. 1 h) gave a nitridoosmium(VI) porphyrin, [Os(VI)(Por)(N)(OH)] (4b, Por = TTP). Oxidation of 1a,b with bromine in dichloromethane afforded bis(hydrazido(2-)) complexes [Os(VI)(TPP)(NNPh(2))(2)] (3a) and [Os(VI)(TTP)(NNPh(2))(2)] (3b), respectively. All the new osmium porphyrins were identified by (1)H NMR, IR, and UV-vis spectroscopy and mass spectrometry; the structure of 2b was determined by X-ray crystallography (Os-NPh(2) = 1.944(6) A, Os-OH = 1.952(5) A).
Leung
Sarana Ka-Yan
SK
Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong Kong, Pokfulam Road, Hong Kong.
Huang
Jie-Sheng
JS
Zhu
Nianyong
N
Che
Chi-Ming
CM