Pressure-induced H-transfers in the networks of hydrogen bonds

High-pressure diffraction studies of molecular organic solids. A personal view

“…Other hydrogen bonds in the structures of crystalline amino acids are more compressible than the short NHÁ Á ÁO bonds within the head-to-tail chains, the changes in the N-O distances usually being about AE0.02-0.05 Å GPa À1 . Similar values were measured for the compressibility of NHÁ Á ÁO and OHÁ Á ÁO hydrogen bonds in other organic crystals (Katrusiak, 1990a(Katrusiak, ,b, 1991a(Katrusiak, ,b,c, 1995(Katrusiak, , 1996(Katrusiak, , 2001(Katrusiak, , 2003(Katrusiak, , 2004aBoldyreva, 2003aBoldyreva, ,b, 2004aBoldyreva, ,b,c, 2006. For a comparison, recently measured typical values for proteins are about AE0.1-0.01 Å GPa À1 (Fourme et al, 2001Girard et al, 2005Girard et al, , 2007Colloc'h et al, 2006;Li & Akasaka, 2006).…”

“…At the same time, they can find important applications in molecular electronics and in the pharmaceutical industry (Boldyreva & Boldyrev, 1999;Shakhtshneider et al, 1999;Hemley & Dera, 2000;Boldyreva, Shakhtshneider et al, 2000;Katrusiak, 2001;Boldyreva, 2003a,b;Fabbiani et al, 2003Fabbiani et al, , 2004Boldyreva, Drebushchak, Paukov et al, 2004;Boldyreva, Drebushchak, Shakhtshneider, Ahsbahs, Uchtmann et al, 2004;Fabbiani, Allan, Marshall et al, 2005Fabbiani et al, 2006Fabbiani et al, , 2007Boldyreva, 2006Boldyreva, , 2007a.…”

“…Linear strain in the crystal structure does not always correlate with the changes in the interatomic distances in the hydrogen bonds in the same directions due to the conformational changes and rotation of molecules (Boldyreva, 1994(Boldyreva, , 2001(Boldyreva, , 2003a(Boldyreva, ,b, 2004a(Boldyreva, ,b,c, 2006Boldyreva et al, 1997aBoldyreva et al, ,b, 1998Boldyreva, Shakhtshneider et al, 2000;Katrusiak, 1996Katrusiak, , 2001Katrusiak, , 2003Katrusiak, , 2004a. Hydrogen bonds can be compressed but the structure expands and, vice versa, the structure can be compressed despite the expansion of the intermolecular hydrogen bonds.…”

“…Systematic studies of the compressibility of various types of hydrogen bonds in organic crystals were initiated by Katrusiak (1990aKatrusiak ( ,b, 1991aKatrusiak ( ,b,c, 1995Katrusiak ( , 1996Katrusiak ( , 2001Katrusiak ( , 2003Katrusiak ( , 2004a. The compressibility of a bond was shown to depend on the type of intermolecular motif within the crystal structure.…”

“…Larger apertures of high-pressure cells provided by new anvil designs, more reliable and less distorted intensities of reflections, two-dimensional detectors, brighter laboratory sources of X-rays and easier access to synchrotron radiationall this has enabled in situ high-pressure studies also of relatively weakly diffracting crystals with low (monoclinic and even triclinic) symmetry. Some of these technical developments are summarized by Katrusiak (2008), who was one of the pioneers of systematic research of the effect of high pressure on organic crystals (see, e.g., his reviews: Katrusiak, 1990aKatrusiak, , 1991aKatrusiak, ,b,c, 1996Katrusiak, , 2001Katrusiak, , 2003Katrusiak, , 2004a. The aim of my contribution is to complete that by Katrusiak by providing a few examples of the results achieved in recent years using these advanced techniques, and to give my personal vision of the main trends and the prospects in the research of organic molecular crystals.…”