Experimental and theoretical investigation of hydrogen bonded complexes between glycolic acid and water

Theoretical MP2 and B3LYPD3 calculations, as well as experimental matrix isolation infrared spectroscopy studies, were used to investigate the 1:1 complexes formed between glycolic acid and water. Out of five computationally predicted forms of GA⋯H2O complex the most stable one was detected experimentally in solid argon. This structure is characterized by two intermolecular OH⋯O hydrogen bonds depicting a six-member ring in which water acts both as a proton acceptor and as a proton donor. Two other structures with the alcoholic OH group acting as a proton donor are also tentatively suggested to be present in solid argon.

Energy decomposition analysis based on broken symmetry unrestricted density functional theory

In this paper, the generalized Kohn-Sham energy decomposition analysis (GKS-EDA) scheme is extended to molecular interactions in open shell singlet states, which is a challenge for many popular EDA methods due to the multireference character. Based on broken symmetry (BS) unrestricted density functional theory with a spin projection approximation, the extension scheme, named GKS-EDA(BS) in this paper, divides the total interaction energy into electrostatic, exchange-repulsion, polarization, correlation, and dispersion terms. Test examples include the pancake bond in the phenalenyl dimer, the ligand interactions in the Fe(ii)-porphyrin complexes, and the radical interactions in dehydrogenated guanine-cytosine base pairs and show that GKS-EDA(BS) is a practical EDA tool for open shell singlet systems.

Infrared spectroscopy of gas phase alpha hydroxy carboxylic acid homo and hetero dimers

New gas phase infrared spectroscopy is reported for an aromatic alpha hydroxy carboxylic acid homo dimer of 9-hydroxy-9-fluorene carboxylic acid (9HFCA)₂, and the hetero dimer of 9HFCA with glycolic acid.

Quantitative probing of subtle interactions among H-bonds in alpha hydroxy carboxylic acid complexes

The alpha OH stretching frequency may be affected upon complexing with water and formic acid.