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Hydrotalcite (HT) intercalated tryptophan (trpH) and phenylalanine (pheH) hybrid materials have been prepared by the reconstruction method. Based on elemental analysis results, such materials were found to be prepared with the general formulas [Mg6Al2(OH)16](trp)1.42(OH + anions)0.58·4H2O and [Mg6Al2(OH)16](phe)1.26(OH + anions)0.74·4H2O, respectively. After characterization by powder X-ray diffraction and Fourier Transform Infrared Spectroscopy, the amino acid intercalated clays were used directly in Matrix Assisted Laser Desorption Ionization Mass Spectrometry experiments, where the clay was used as the matrix. The guests were detected in negative mode as [trpH–H]− at m/z 203 and as [pheH–H]− at m/z 164. From the mass spectrometry experiments no interference of ions from the clay was detected, meaning that such inorganic material is stable under the laser radiation and more important that it is adequate for use in such experiments. For the experiments using this particular approach we propose an alternative term—HALDI—standing for Host Assisted Laser Desorption Ionization mass spectrometry.

The crystal structure of 4-phenyl-benzaldehyde reveals the presence of a dimer linked by the C=O and C9-H groups of adjacent molecules. In the liquid phase, the presence of C-H...O bonded forms is revealed by both vibrational and NMR spectroscopy. A DeltaH value of -8.2 +/- 0.5 kJ mol(-1) for the dimerisation equilibrium is established from the temperature-dependent intensities of the bands assigned to the carbonyl-stretching modes. The NMR data suggest the preferential engagement of the C(2,6)-H and C(10/12)/C(11)-H groups as hydrogen bond donors, instead of the C(9)-H group. While ab initio calculations for the isolated dimers are unable to corroborate these NMR results, the radial distribution functions obtained from molecular dynamics simulations show a preference for C(2,6)-H and C(10/12)/C(11)-H...O contacts relative to the C(9)-H...O ones.