Biomedical subjects
Publications and source records attributed to M M R R Costa.
In the 1:1 adduct formed between L-phenylalanine and 4-nitrophenol [alternative IUPAC name: (2S)-2-ammonio-3-phenylpropanoate-4-nitrophenol (1/1)], C9H11NO2.C6H5NO3, the L-phenylalanine molecule is in the zwitterionic state. The overall structure is stabilized via strong hydrogen bonding between polar zones and van der Waals interactions between non-polar zones, which alternate with the polar zones.
The title compound, tetraaquabis(hydrogen L-malato)strontium(II) dihydrate, [Sr(C4H5O5)2(H2O)4].2H2O, is a new non-linear optical semi-organic material with a second harmonic generation efficiency approximately 3.5 times greater than that of potassium dihydrogen phosphate. The malate anions are interconnected through directional O-H...O hydrogen bonding, in a head-to-tail arrangement, creating extended anionic chains along [001]. Neighbouring parallel chains are crosslinked by water molecules, resulting in a three-dimensional architecture. The Sr2+ ion is coordinated by eight O atoms. This material is a new candidate for non-linear optical applications since the crystals are stable and easy to grow.
The title compound, C2H6NO2+.C2Cl3O2-, crystallizes in the P4(1) space group with two glycinium cations and two trichloroacetate anions in the asymmetric unit. The glycinium cations have nearly Cs point-group symmetry which is only broken by the H atoms of the amine group. The trichloroacetate anions show typical bond lengths and angles, one of the trichloromethyl groups being disordered. Chains of alternating anions and cations run along the c axis. Within these chains, consecutive anion-cation pairs are bound via strong hydrogen bonds involving the carboxylate anions and the carboxyl or amine groups of the cations. Weaker hydrogen bonds bind neighbouring chains together.
In the title compound, C(2)H(6)NO(2)(+).C(2)F(3)O(2)(-), the main N-C-COOH skeleton of the glycinium cation is almost perfectly planar. The trifluoroacetate anion has a staggered conformation with typical bond distances and angles. The CF(3) group is slightly disordered. The structure is stabilized by an extensive network of strong O-H.O hydrogen bonds and weaker N-H.O bonds.