Monovalent structures properties

J. Gu, J. Leszczynski, A theoretical study of thymine and uracil tetrads structures, properties, and interactions with the monovalent k+ cation. J. Phys. Chem. A 105, 10366-10371 (2001)... 

Our knowledge of the structural properties and enzymic function of a large number of copper proteins has accumulated during the last few decades. The main results have been comprehensively reviewed 1—4) or presented at symposia (5—54). This survey is devoted to erythro-cuprein, one of the most actively studied copper proteins. Erythrocu-prein is sometimes called haemocuprein, hepatocuprein, cerebrocuprein, cytocuprein, or erythro-cupro-zinc protein. Alternatively, the name superoxide dismutase has been suggested as descriptive of its activity the enzyme-catalyzed disproportionation of anionic monovalent superoxide radicals. However, whether or not the enzymic reaction is specific for Oi- still needs to be investigated1). Thus, the name erythrocuprein is used throughout this review. 

Antibodies have been raised in rabbits against di-JV-acetylchitobiose and purified in order to obtain cell-surface probes that are monovalent. " The biological and structural properties of these specific antibodies allow new approaches to the study of cell-surface carbohydrates. 

High-Valence Metal Clusters. Structural properties of selected hexanuclear high-valence cluster complexes are described in Table 2.5. A series of molybdenum and tantalum derivatives of type [(M6Y8)X6] and [(M6Ys)L8] (M = Mo or W X = halide or alkoxide Y = halide or other monovalent anion and L = neutral Lewis-base) are known. The structures of these species are like that of the anion [(Mo6Cl8)Cl6] illustrated in Fig. 2.19 in which the molybdenum atoms are in the vertex of an octahedron. Metal-metal distances of about... 

In Justus von Liebig s laboratory, Fleitmann and Henneberg found that there were several metaphosphates with different properties, all of which had the formula MePC>4 (Me = monovalent metal ion). The story then becomes complicated, and mistakes in nomenclature led to ambiguities in this class of compounds. As well as Graham s salt there is a Maddrell s and a Kurol s salt . All have the same formula, NanH2Pn03n+i, but differ in structure and chain length. 

Monophosphabutadienes, 33 281-283 Monophosphacarbodiimides, 33 322 preparation, 33 323 reactivity, 33 322-325 stereoselective reaction, 33 324 Monophosphahexadienes, 33 305, 307-310 Monoterpyridine complexes of copper, 45 288 Monovalent cations hydration shell properties, 34 203-204 structure, 34 202-205... 

Octahedral coordination of Tiiv is also present in the titanium silicates ETS-4 and ETS-10. The structure of these materials is reported to be similar to that of zorite, and they can be described as microporous crystals with uniform pores similar in dimensions to classical small- and large-pore zeolites. In ETS-4 and ETS-10, there are two monovalent cations or one divalent cation for each Tilv ion (Kuznicki, 1989, 1990 Kuznicki et al., 1991a, 1991b, 1991c, 1993 Deeba et al., 1994). A recent report of the synthesis of ETS-10 with tetramethyl-ammonium chloride indicates a ratio of monovalent cations to Tilv of 1.6 (Valtchev et al., 1994). The acidic properties of these materials have not been reported. A material modified by the addition of Al3+ has been obtained, ETAS-10, which, after exchange with NH4 salts, exhibits acidic properties but these are due to the presence of Al3+ and not to the Tilv (Deeba et al., 1994). 

Despite the tremendous success in the development of nanomaterials, the level of control of their structure and properties is still very limited. When AuNPs are used as building blocks, monovalent, divalent, or higher valency nanoparticles would be required when aiming at the controlled and well-organized construction of 3D nanonetworks from a simple linear topology. 

Recently, Schultes Spasic, Mohanty and Bartel studied in exquisite detail the effects of monovalent and divalent cations on the conformation order of random RNA sequences [115, 116]. These authors investigated the following questions Can arbitrary RNA sequences fold into a unique structure Is this is an evolutionary property of RNA sequences [115, 116] Schultes et al. utilized biochemical tools, such as lead ion induced cleavage, ultracentrifugation, and gel electrophoretic mobility, to probe the structure of evolved and random RNA sequences [115, 116]. 

Mikheikin et al. (11) have formulated an alternative approach where terminal valencies are saturated by monovalent atoms whose quantum-chemical parameters (the shape of AO, electronegativity, etc.) are specially adjusted for the better reproduction of given characteristics of the electron structure of the solid (the stoichiometry of the charge distribution, the band gap, the valence band structure, some experimental properties of the surface groups, etc.). Such atoms were termed pseudo-atoms and the procedure itself was called the method of a cluster with terminal pseudo-atoms (CTP). The corresponding scheme of quantum-chemical calculations was realized within the frames of CNDO/BW (77), MINDO/3 (13), and CNDO/2 (30) as well as within the scope of the nonempirical approach (16). 

The cation exchange of layer silicates significantly influences some structural and colloid chemical properties. Depending on the charge of the cation, the interlayer space contains water in different quantities (Chapter 2, Section 2.1.2). So, the basal spacing (the distance between similar faces of adjacent layers) is different for monovalent, bivalent, and trivalent cations. For example, in monovalent montmorillonite, it is about 1.2 nm, and in bivalent and trivalent montmorillonite, it is about 1.5—1.6 nm. 

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