Quantification of cation–anion interactions in crystalline monopotassium and monosodium glutamate salts

Abstract

Crystalline salt compounds composed of metal cations and organic anions are becoming increasingly popular in a number of fields, including the pharmaceutical and food industries, where such formulations can lead to increased product solubility. The origins of these effects are often in the interactions between the individual components in the crystals, and understanding these forces is paramount for the design and utilisation of such materials. Monosodium glutamate monohydrate and monopotassium glutamate monohydrate are two solids that form significantly different structures with correspondingly dissimilar dynamics, while their chemistry only differs in cation identity. Crystals of each were characterised experimentally with single-crystal X-ray diffraction and terahertz time-domain spectroscopy and theoretically using solid-state density functional theory simulations, in order to explain the observed differences in their bulk properties. Specifically, crystal orbital overlap and Hamiltonian population analyses were performed to examine the role that the individual interactions between the cation and anion played in the solid-state structures and the overall energetic profiles of these materials.

Rapid Determination of Thiabendazole Pesticides in Rape by Surface Enhanced Raman Spectroscopy

“…Besides, the performance of Becke three-parameter Lee–Yang–Parr functional (B3LYP) functional in combination with various basis sets has been extensively tested for molecular geometries, vibrational frequencies, ionization energies and electron affinities, dipole and quadrupole moments, atomic charges, infrared intensities and magnetic properties [ 31 ]. Among the various of functions and basis sets in DFT, the hybrid functional B3LYP with the 6-31G (d,p) basis set has been commonly used in the Raman spectroscopic calculation of biological molecules [ 32 , 33 ]. In this paper, B3LYP/6-31G (d,p) was used for the theoretical simulation and calculation of thiabendazole molecules.…”

Methyl-rotation dynamics in metal–organic frameworks probed with terahertz spectroscopy

“…31 By combining the experimental data with quantum mechanical simulations, it is possible to fully characterize the atomic-level structure, dynamics, and forces that are present within the solid. [32][33][34][35] Because of the inherent dependence on a rigorous description of the weak forces, the accurate simulation of the low-frequency vibrational spectra provides a benchmark of the theoretical approach. 30,36 A good match between the experimental vibrational spectrum and the simulated spectra can be considered a validation method for the ab initio simulations, enabling additional data that would be difficult to obtain experimentally (e.g.…”

Chemical bonding in Uranium‐based materials: A local vibrational mode case study of Cs 2UO 2Cl 4 and UCl 4 crystals

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“…46 These two techniques are almost identical in their formulation and they work similarly to conventional density of states (DOS) calculation, but instead of considering the contributions from all orbitals in a molecular or periodic system, they enable the study of specific interaction pairs between two sets of orbitals. 47 COOP and COHP schemes allows for quantifying the orbital overlap and the strength of interatomic bonds. 48 These methods offer valuable insights into the bonding characteristics in periodic systems, providing a detailed analysis of specific orbital interactions.…”