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Substituent effects on weakly bound complexes of phenols and carbon monoxide in argon matrices: hydrogen bonding at cryogenic temperatures

Journal Article · · J. Am. Chem. Soc.; (United States)
DOI:https://doi.org/10.1021/ja00338a016· OSTI ID:5768221

Quenching at 20 K of gaseous mixtures consisting of argon, a monosubstituted phenol, and carbon monoxide (M:R:CO = 500:1:5) leads to complexes which have nu/sub OH/ and nu/sub CO/ stretching frequencies shifted 28-60 and 10-16.5 cm/sup -1/, respectively, from monomeric values. The magnitude and direction of shifts involving meta- and para-substituted phenols are consistent with a hydrogen-bound dimer (ArOH...CO) as proposed for the parent phenol. In argon matrices containing ortho-substituted phenols doped with CO, 1:1 complexes are also formed which most likely possess bifurcated hydrogen bonds. For para- and meta-substituted phenols the evidence indicates that the acidity of the phenol is a major factor in inducing shifts of nu/sub OH/ and nu/sub CO/. The shifts induced by ortho-substituted phenols do not correlate well with known aqueous acidities. Speculation thus centers about the role of intrinsic acidities in determining the properties of proton donors in rare-gas matrices. This work represents the first study devoted to substituent effects in gas matrices. 36 references, 7 figures, 2 tables.

Research Organization:
State Univ. of New York, Stony Brook
OSTI ID:
5768221
Journal Information:
J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 106:26; ISSN JACSA
Country of Publication:
United States
Language:
English