Crystal structure and thermodynamic stability of the [Hg(Pyridine)\u2084(NO\u2083)\u2082] \ub7 2(Pyridine) inclusion compound

The studied compound belongs to the family of [MPy\u2084X\u2082] c5 2Py isomorphous clathrates. Its crystal structure exhibits a van der Waals architecture formed by neutral [HgPy\u2084(NO\u2083)\u2082] host molecules, with the guest pyridine molecules included in the cavities of the host lattice. The host complex is formed by coordination of four pyridines, located near the equatorial plane, and two nitrates, located axially, to the Hg(II) cation. One of nitrates ligates as a monodentate ligand and another as a bidentate. The coordination polyhedron is 'HgN\u2084O\u2083', with average Hg-NPy and Hg-Onitrate distances of 2.38(5) and 2.68(1) \uc5, respectively. The crystal structure is complicated with a superlattice and the crystal symmetry reduced to monoclinic, as compared to the structure usually occurring in the [MPy\u2084X\u2082] c5 2Py clathrates. The pyridine vapor pressure over the clathrate was measured in the 293-369 K temperature range by the static tensimetric method. Thermodynamic parameters of the clathrate dissociation were calculated from these data. For the reaction 1/3[HgPy\u2084(NO\u2083)\u2082] c5 2Pysolid=1/3[HgPy\u2083(NO\u2083)\u2082] solid + Pygas the parameters are as follows: \u394H\ubaav = 49.4(2) kJ/mol, \u394S\ubaav = 127(2) J/(mol K) and \u394G\uba\u2082\u2089\u2088=11.4(3) kJ/mol. The results are compared with previously reported data on compounds of the [MPy\u2084(NO\u2083)\u2082] c5 2Py series.NRC publication: Ye

Translated from Zhurnal Vysshei Nervnoi Deyatel'nosti imeni I

There is a strongly held opinion that one of the most important functions of sleep is its involvement in the formation of memories The standard test for studies of learning and memory processes in animals is the Morris water test Effects of Sleep Deprivation on Consolidation of Spatial Memory in Rats after 1032 Translated from Zhurnal Vysshei Nervnoi Deyatel'nosti imeni I. P. Pavlova, Vol. 61, No. 3, pp. 322-331, May-June, 2011. Original article submitted December 24, 2009. Accepted October 18, 2010. The effects of sleep deprivation produced using a carousel method on the consolidation of spatial memory were studied in rats (male Wistar rats) after one-day training using the Frick et al. protocol (2000) in a Morris water maze. Data were obtained providing evidence that the memory trace after rapid 3-h training was retained for one day. Sleep deprivation for 24 h after training prevented reinforcement (consolidation) of spatial memory. The results led to the conclusion that a model based on one-day training can be used to study the neurophysiological and neurochemical mechanisms of the effects of sleep deprivation on consolidation of spatial memory