Synthesis of Arsenic(V) Octaethylporphyrins and X-ray Crystal Structure of [(OEP)As(Me)(OH)]ClO4

[(OEP)As(OH)2]ClO4 (4-ClO4) and [(OEP)As(Ph)(OH)]ClO4 (12-ClO4) are synthesized in good yields by oxidative conversion of (OEP)AsCl (2) and (OEP)AsPh (10), respectively, with pyridinium tribromide followed by hydrolysis and counteranion exchange. 4-Cl is converted to [(OEP)As(R)(OH)]ClO4 (6-ClO4, R = Me; 8-ClO4, R = Et) and [(OEP)As(R)2]X (7-ClO4, R = Me; 9-PF6, R = Et) by the reaction with (COBr)2 followed by treatment with trialkylaluminum (alkyl = Me, Et) and counteranion exchange. The reaction of 6-Cl with PCl3 gives the corresponding chloride [(OEP)As(Me)(Cl)]Cl (13-Cl), from which [(OEP)As(Me)(OR)]ClO4 (14-ClO4, R = Me; 15-ClO4, R = Et; 16-ClO4, R = i-Pr), [(OEP)As(Me)(NH-n-Bu)]ClO4 (17-ClO4), [(OEP)As(Me)(NH-p-CH3C6H4)]ClO4 (18-ClO4), and [(OEP)As(Me)(Et)]ClO4 (19-ClO4) are synthesized. These compounds are stable toward air and moisture. The OH protons of [(OEP)As(R)(OH)]Cl (6-Cl, R = Me; 8-Cl, R = Et, 12-Cl, R = Ph) are acidic enough to generate [(OEP)As(R)(O)] (20, R = Me; 21, R = Et, 22, R = Ph)...