CRYSTAL STRUCTURE OF DOUBLE SODIUM–COPPER(II) PARATUNGSTATE B, Na2Cu4[W12O40(OH)2]·22H2O, AND MIXED COPPER (II) PARATUNGSTATE B–HYDROXIDE, Cu5[W12O40(OH)2]·2Cu(OH)2·30H2O

2021 ◽  
Vol 62 (3) ◽  
pp. 379-389
Author(s):  
E. S. Duvanova ◽  
A. Yu. Mariichak ◽  
V. N. Baumer ◽  
G. M. Rozantsev ◽  
S. V. Radio
2011 ◽  
Vol 52 (1) ◽  
pp. 111-117 ◽  
Author(s):  
S. V. Radio ◽  
G. M. Rozantsev ◽  
V. N. Baumer ◽  
O. V. Shishkin

2013 ◽  
Vol 54 (1) ◽  
pp. 97-103 ◽  
Author(s):  
S. V. Radio ◽  
N. I. Gumerova ◽  
V. N. Baumer

1999 ◽  
Vol 52 (10) ◽  
pp. 955 ◽  
Author(s):  
Annette L. Nolan ◽  
Eric N. Wilkes ◽  
Trevor W. Hambley ◽  
Christine C. Allen ◽  
Robert C. Burns ◽  
...  

Crystallization of a solid at pH 4.0 from an aqueous acidified Rh3+–[WO4]2− solution resulted in the isolation of Na9[H3W12O42]·24H 2 O, which contains the protonated paratungstate B anion and which is likely the species identified previously as ‘acid paratungstate’. The compound is triclinic, space group P1– , a 10.603(2), b 12.134(3), c 14.042(3) Å, α 114.78(1), β 101.84(1), γ 108.34(1)˚, V 1432.9(5) Å3 , Z 1, and the structure was solved to an R1 value of 0.0404 (wR 2 0.1108) for 5997 independent observed reflections. The anion exhibits essentially the same isopolytungstate framework as paratungstate B, [H2W12O42]10− , consisting of two W3O13 and two W3O14 structural subunits linked by shared vertices. Bond valence arguments place two of the hydrogen atoms unequivocally in the internal cavity of the anion, with the remaining hydrogen atom also likely located in this cavity, but disordered over several internal oxygen atoms. The protonation of [H2W12O42 ]10− is shown to lead to species that are electrochemically reducible. Extended-HÜckel molecular orbital calculations confirm that protonation of paratungstate B within the internal cavity leads to a change in composition of the LUMO, now based mainly on electrochemically reducible W3O13 as opposed to (essentially) non-reducible W3O14 structural subunits. This results in species that are considerably more electrochemically active than the unprotonated anion. The role of [H3W12O42]9− as an intermediate in the polymerization of [WO4]2− to give the solution form of ψ-metatungstate, [H7W11O40]7− , which crystallizes as [H4W11O38]6− , is also discussed.


2010 ◽  
Vol 63 (10) ◽  
pp. 1678-1689 ◽  
Author(s):  
Sergii V. Radio ◽  
Maksym A. Kryuchkov ◽  
Elena G. Zavialova ◽  
Vyacheslav N. Baumer ◽  
Oleg V. Shishkin ◽  
...  

Author(s):  
Bikshandarkoil R. Srinivasan ◽  
Savita A. Kundaikar ◽  
Sudesh M. Morajkar ◽  
Christian Näther ◽  
Wolfgang Bensch

ChemInform ◽  
2010 ◽  
Vol 31 (12) ◽  
pp. no-no
Author(s):  
Annette L. Nolan ◽  
Christine C. Allen ◽  
Robert C. Burns ◽  
Geoffrey A. Lawrance ◽  
Eric N. Wilkes ◽  
...  

2014 ◽  
Vol 55 (5) ◽  
pp. 879-886 ◽  
Author(s):  
S. V. Radio ◽  
N. A. Melnik ◽  
E. S. Ivantsova ◽  
V. N. Baumer

Author(s):  
Douglas L. Dorset ◽  
Anthony J. Hancock

Lipids containing long polymethylene chains were among the first compounds subjected to electron diffraction structure analysis. It was only recently realized, however, that various distortions of thin lipid microcrystal plates, e.g. bends, polar group and methyl end plane disorders, etc. (1-3), restrict coherent scattering to the methylene subcell alone, particularly if undistorted molecular layers have well-defined end planes. Thus, ab initio crystal structure determination on a given single uncharacterized natural lipid using electron diffraction data can only hope to identify the subcell packing and the chain axis orientation with respect to the crystal surface. In lipids based on glycerol, for example, conformations of long chains and polar groups about the C-C bonds of this moiety still would remain unknown.One possible means of surmounting this difficulty is to investigate structural analogs of the material of interest in conjunction with the natural compound itself. Suitable analogs to the glycerol lipids are compounds based on the three configurational isomers of cyclopentane-1,2,3-triol shown in Fig. 1, in which three rotameric forms of the natural glycerol derivatives are fixed by the ring structure (4-7).


Sign in / Sign up

Export Citation Format

Share Document