Distortion of Crystal Structures of Some Co^III Ammine Complexes. I. Distortion of Crystal Structure of [Co(NH₃)₅NO₂]Cl(NO₃) on Cooling

Abstract

The anisotropy of the structural distortion of sNO2]CI(NO3), pentaamminenitrocobalt(III) chloride nitrate, on cooling from 290 to 150K was studied by variable-temperature single-crystal X-ray diffraction. The changes in lattice parameters were used to calculate the strain tensors and to scan linear distortion in various crystallographic directions. The changes of different intra-and intermolecular distances in the structure were followed. Lattice strain induced by low temperature was compared with lattice strain in the same structure under high hydrostatic pressure and with lattice strain induced by homogeneous nitro-nitrito linkage isomerization. distortion may throw some light on the nature of these interactions, especially if one compares the structural distortion of related structures or the structural distortions of the same structure resulting from different actions (changes in temperature, changes in pressure and isomorphous substitution of atoms). Studies of intermolecular interactions, in turn, are important for predicting crystal structures and the existence of polymorphs, the design of materials, controlling the course of chemical reactions in crystals and many other applications.Distortion of a crystal structure can be characterized by the overall change in molar volume or, in other terms, by a mean volume expansion (contraction) coefficient, calculated as

Monitoring selected hydrogen bonds in crystal hydrates of amino acid salts: combining variable-temperature single-crystal X-ray diffraction and polarized Raman spectroscopy

“…The problem of correlating the anisotropy of structural strain on cooling with the relative strength of intermolecular hydrogen bonds in the crystal has been discussed since the publications by Ubbelohde et al 14 (see also ref. 15 for a more recent discussion). In earlier times, when hydrogen atoms were difficult to locate in the structure based on the data from X-ray diffraction experiments, it was suggested to use the information on the directions of maximum and minimum thermal expansion, in order to find the orientation of the hydrogen bonds.…”

Low temperature/high pressure polymorphism in dl-cysteine

“…At the same time, examples are known, when the anisotropy of strain was very different, even though the volume change on cooling and on hydrostatic compression was small and practically the same. 61,62 N-H5/O2 contact decreases from 3.19(1) to 3.13(1) A, so that it approaches the limits which would be considered as a ''hydrogen bond''. One can consider this process, as if a bifurcation hydrogen bond were formed instead of a single shorter bond.…”

Compression and Thermal Expansion in Organic and Metal–Organic Crystals: The Pressure–Temperature Correspondence Rule

“…In fact, some previously obtained results on crystals of organic compounds and metal–organic frameworks do not support the rule. − The difference in the crystal response to each of the stimuli was discussed in terms of the correlation between the intermolecular interaction patterns and anisotropic behavior . It needs to be noted that former investigations on the comparison of the pressure and temperature effects in these types of crystals were mostly performed as individual study cases, ,− or for small groups of structurally related crystals, − and focused on discussing the anisotropic strain within a narrow set of samples. Nevertheless, thanks to these researches and the general development of experimental and data-processing techniques in the last decades, the population of crystals studied under nonambient conditions significantly increased, becoming more diverse and representative.…”