Spectral and structural studies of dimethylphenyl betaine hydrate.
Hydrates of betaines can be divided into four groups depending on the interactions of their water molecules with the carboxylate group. Dimethylphenyl betaine crystallizes as monohydrate (1), in which water molecules mediate in hydrogen bonds between the carboxylate groups. The water molecules are H-bonded only to one oxygen atom of the dimethylphenyl betaine molecules and link them into a chain via two O(1W)-H⋯O hydrogen bonds of the lengths 2.779(2) and 2.846(2)Å. The structures of monomer (2) and dimer (4) hydrates in vacuum, and the structure of monomer (3) in an aqueous environment have been optimized by the B3LYP/6-311++G(d,p) approach and the geometrical results have been compared with the X-ray diffraction data of 1. The calculated IR frequencies for the optimized structure have been used for the assignments of FTIR bands, the broad absorption band in the range 3415-3230 cm(-1) has been assigned to the O(1w)-H⋯O hydrogen bonds. The correlations between the experimental (1)H and (13)C NMR chemical shifts (δexp) of 1 in D2O and the magnetic isotropic shielding constants (σcalc) calculated by the GIAO/B3LYP/6-311G++(d,p) approach, using the screening solvation model (COSMO), δexp =a+b σcalc, for optimized molecule 3 in water solution are linear and well reproduce the experimental chemical shifts.
Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60780 Poznań, Poland. Electronic address: szafran@amu.edu.pl.
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Szafran
Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60780 Poznań, Poland.
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Ostrowska
Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60780 Poznań, Poland.
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Katrusiak
Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60780 Poznań, Poland.
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Dega-Szafran
D001622:Betaine / Q000031:analogs & derivatives* / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D014961:X-Ray Diffraction / Q000379:methods
D001622:Betaine
DFT calculations; Dimethylphenyl betaine hydrate; FTIR and NMR spectra; Hydrogen bonds; X-ray diffraction