Synthesis, characterization, solid-state molecular structures, and deprotonation reactions of cationic alcohol complexes of osmium nitrosyl porphyrins.
New alkoxide (OEP)Os(NO)(OR) (OEP = 2,3,7,8,12,13,17,18-octaethylporphyrinato dianion; R = ethyl, isopropyl, hexyl, cyclohexyl) compounds and alcohol [(OEP)Os(NO)(HOR)]+ complexes (R = methyl, ethyl, isopropyl, hexyl, cyclohexyl) have been prepared in high yields and have been fully characterized by IR, 1H NMR, and UV-vis spectroscopy, and by elemental analyses. The (OEP)Os(NO)(OEt) compound was characterized by single-crystal X-ray crystallography. The cationic aqua and alcohol [(OEP)Os(NO)(HOR)]+ complexes (R = ethyl, isopropyl, hexyl) complexes were also characterized by single-crystal X-ray crystallography, and the latter represent the first osmium alcohol structures to be reported. The electrophilic [(OEP)Os(NO)]+ cation in the [(OEP)Os(NO)(HOR)]+ complexes renders the coordinated alcohol ligands susceptible to deprotonation by pyridine to produce the corresponding alkoxide (OEP)Os(NO)(OR) derivatives. A one-pot reaction sequence for the preparation of new (OEP)Os(NO)(OR) complexes from (OEP)Os(NO)(OEt) was developed, which was based on (i) initial protonation of the ethoxide compound to give [(OEP)Os(NO)(HOEt)]+, (ii) alcohol substitution by ROH to give [(OEP)Os(NO)(HOR)]+, and (iii) deprotonation of the latter by pyridine to give (OEP)Os(NO)(OR).
Cheng
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Department of Chemistry and Biochemistry, University of Oklahoma, 620 Parrington Oval, Norman, Oklahoma 73019, USA.
Powell
D R
DR
Khan
M A
MA
Richter-Addo
G B
GB
D000438:Alcohols / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D008024:Ligands; D008665:Metalloporphyrins / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D009992:Osmium; D013329:Structure-Activity Relationship
D000438:Alcohols; D008024:Ligands; D008665:Metalloporphyrins; D009992:Osmium