Hydrogen bonding in solids correlation of spectroscopic and crystallographic data

CrystalExplorer is a native cross-platform program supported on Windows, MacOS and Linux with the primary function of visualization and investigation of molecular crystal structures, especially through the decorated Hirshfeld surface and its corresponding two-dimensional fingerprint, and through the visualization of void spaces in the crystal via isosurfaces of the promolecule electron density. Over the past decade, significant changes and enhancements have been incorporated into the program, such as the capacity to accurately and quickly calculate and visualize quantitative intermolecular interactions and, perhaps most importantly, the ability to interface with the Gaussian and NWChem programs to calculate quantum-mechanical properties of molecules. The current version, CrystalExplorer21, incorporates these and other changes, and the software can be downloaded and used free of charge for academic research.

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CrystalExplorer: a program for Hirshfeld surface analysis, visualization and quantitative analysis of molecular crystals

An empirical potential based on permanent atomic multipoles and atomic induced dipoles is reported for alkanes, alcohols, amines, sulfides, aldehydes, carboxylic acids, amides, aromatics, and other small organic molecules. Permanent atomic multipole moments through quadrupole moments have been derived from gas phase ab initio molecular orbital calculations. The van der Waals parameters are obtained by fitting to gas phase homodimer QM energies and structures, as well as experimental densities and heats of vaporization of neat liquids. As a validation, the hydrogen bonding energies and structures of gas phase heterodimers with water are evaluated using the resulting potential. For 32 homo- and heterodimers, the association energy agrees with ab initio results to within 0.4 kcal/mol. The RMS deviation of the hydrogen bond distance from QM optimized geometry is less than 0.06 A. In addition, liquid self-diffusion and static dielectric constants computed from a molecular dynamics simulation are consistent wit...

Polarizable Atomic Multipole-based Molecular Mechanics for Organic Molecules

A structural investigation of the marine algal polysaccharide poly-α-L-guluronic acid is described. The molecular chains consist of 1 4 diaxially linked L-guluronic acid residues in the 1C chair conformation and are stabilized in a twofold helix conformation by an intra-molecular O(2)H … O(6)D hydrogen-bond. The X-ray fiber diffraction photograph has been indexed to an orthorhombic unit cell in which a = 8.6 A, b (fiber axis) = 8.7 A, c = 10.7 A.



A structure corresponding to the space group P212121 is proposed, in which all intermolecular hydrogen bonds interact with water molecules and in which all oxygen atoms except for the inaccessible bridge oxygens are involed. The relationship between the shape and structure of the polyguluronic acid molecule and its biological function is discussed.

Structural components of alginic acid. II. The crystalline structure of poly-alpha-L-guluronic acid. Results of x-ray diffraction and polarized infrared studies.

A history of cocrystals reported in the literature prior to the year 2000 is presented. Concentration is on cocrystals that contain only organic components, not including species commonly referred to as solvates and clathrates. However, brief mention is made of some cocrystals containing both organic and inorganic components. The discovery and early history of cocrystals are discussed, with emphasis on centers of activity. Numerous examples are then utilized to illustrate the structural variety and utility of cocrystals described in the literature.

A Survey of Cocrystals Reported Prior to 2000

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Hydrogen Bond Studies. 39. Reinvestigation of the Crystal Structure of Acetic Acid (at +5 degrees C and -190 degrees C).

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Hydrogen Bond Studies. 35. The Crystal Structure of the 1:1 Addition Compound of Ammonium Acetate and Acetic Acid.

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Hydrogen Bond Studies. 38. The Crystal Structure of Hydrazinium Acetate.

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Inger Nahringbauer

Papers

Hydrogen Bond Studies. 39. Reinvestigation of the Crystal Structure of Acetic Acid (at +5 degrees C and -190 degrees C).

Hydrogen Bond Studies. 35. The Crystal Structure of the 1:1 Addition Compound of Ammonium Acetate and Acetic Acid.

Hydrogen Bond Studies. 38. The Crystal Structure of Hydrazinium Acetate.

Hydrogen Bond Studies. 26. The Crystal Structure of Ammonium Acetate Monammine, CH3COONH4.NH3 (at -40 and -190 degrees C).