Structures, Energetics and Vibrational Frequency Shifts of Hydrated Pyrimidine

Author

J. Coleman Howard
Nathan I. Hammer
Gregory S. Tschumper, Missouri University of Science and TechnologyFollow

Abstract

More than 70 unique micro-hydrated structures of pyrimidine, ranging in size from 1 to 7 water molecules, have been characterized with the B3LYP density functional and the 6-311++G(2df,2pd) triple-ζ split-valence basis set. Explicitly correlated MP2-F12 single-point computations were performed on each structure with a correlation consistent triple-ζ basis set to estimate the relative and dissociation energies at the MP2 complete basis set (CBS) limit. Many of these new structures have significantly lower energies than those previously reported (by as much as 12.66 kcal mol-1). For clusters with 1 and 2 water molecules, the MP2-F12 relative and dissociation energies are virtually identical to the corresponding CCSD(T)-F12 values. As the number of hydrating waters increases, the structures in which the water molecules are clustered together at one of the N atoms have lower energies than those where the water molecules are more distributed around the pyrimidine ring. Micro-hydrated structures that effectively extend the low energy hydrogen-bonding motifs to both sides of the ring, as would be expected in the bulk phase, reproduce the experimentally observed vibrational frequency shifts of v₁ and v_8b in very dilute aqueous pyrimidine solutions to within 1 cm^-1. Micro-hydrated structures of pyrimidine in which water molecules are clustered together have lower energies than structures in which the water molecules are more evenly spread around the pyrimidine ring.© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recommended Citation

J. C. Howard et al., "Structures, Energetics and Vibrational Frequency Shifts of Hydrated Pyrimidine," ChemPhysChem, vol. 12, no. 17, pp. 3262 - 3273, Wiley, Dec 2011.

The definitive version is available at https://doi.org/10.1002/cphc.201100457

Department(s)

Chemistry

Publication Status

Full Access

Comments

National Science Foundation, Grant 0955550

Keywords and Phrases

computational chemistry; hydrophobic effect; solvation; vibrational spectroscopy; water clusters

International Standard Serial Number (ISSN)

1439-7641; 1439-4235

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Wiley, All rights reserved.

Publication Date

09 Dec 2011