Phosphate cleavage by organoiodinane oxyanion analogues of o-iodosobenzoate: experimental and computational studies

✍ Scribed by Robert A. Moss; Susmita Bose; Karsten Krogh-Jespersen

• Book ID: 102659357
• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 515 KB
• Volume: 10
• Category: Article
• ISSN: 0894-3230
• DOI: 10.1002/(sici)1099-1395(199701)10:1<27::aid-poc853>3.0.co;2-d

✦ Synopsis

1,3-Dihydro-1-oxido-3-methyl-1,2,3-benziodoxaphosphole 3-oxide (4) and 1-H-1-oxido-5-methyl-1,2,3benziodoxathiole 3,3-dioxide (5) were used to cleave (p)-nitrophenyl diphenyl phosphate (PNPDPP) (2) in aqueous micellar cetyltrimethylammonium chloride (CTACI) in phosphate buffer at (\mathrm{pH} 8). The maximum pseudo-first-order cleavage rate constants (with (1.0 \times 10^{-4} \mathrm{M} 4) or 5 and (1.0 \times 10^{-5} \mathrm{M}) 2) were (0.0016 \mathrm{~s}^{-1}) for 4 (\left([C T A C 1]=0.01 \mathrm{M}\right.) ) and (0.0013 \mathrm{~s}^{-1}) for (5([\mathrm{CTAC1}]=0.001 \mathrm{M})). Reagents 4 and 5 were, respectively, 44 and 57 times less reactive toward PNPDPP than iodosobenzoate (1) under comparable conditions. (A b) initio electronic structure calculations were carried out on 1, 4 and 5 and their protonated forms. Calculated structural parameters were compared with crystallographic data where possible. The computed atomic net charge on the oxido oxygens of 1,4 and 5 was found to track the reactivity toward PNPDPP.