Structural characterization of protonated benzeneseleninic acid, the dihydroxyselenonium ion

2000 ◽  
Vol 56 (6) ◽  
pp. 1029-1034 ◽  
Author(s):  
Henning Osholm Sørensen ◽  
Nicolai Stuhr-Hansen ◽  
Lars Henriksen ◽  
Sine Larsen

The structure of the dihydroxyphenylselenonium ion (C_{6}H_{7}O_{2}Se^{+}) has been determined in its benzenesulfonate (C_{6}H_{5}O_{3}Se^{-}) and p-toluenesulfonate (C_{7}H_{7}O_{3}S ^{-}) salts. Whereas the former salt is disordered, the latter less dense salt is well defined. This difference in crystallization behaviour is attributed to a C—H...O hydrogen bond involving the methyl group of the p-toluenesulfonate ion. The two salts display very similar hydrogen-bond arrangements and differ only with respect to the stacking of the phenyl groups. The dihydroxyselenonium ion is a strong acid with a pK value of −0.9 determined from the variation of the 77Se chemical shift. A comparison with the two deprotonated species reveals a systematic increase in the Se—O bond lengths and the pyramidal configuration around Se with the number of protons attached.

1999 ◽  
Vol 121 (10) ◽  
pp. 2307-2308 ◽  
Author(s):  
T. Beringhelli ◽  
G. D'Alfonso ◽  
M. Panigati ◽  
F. Porta ◽  
P. Mercandelli ◽  
...  

2012 ◽  
Vol 10 (6) ◽  
pp. 1709-1759 ◽  
Author(s):  
Milan Melnik ◽  
Ondrej Sprusansky ◽  
Clive Holloway

AbstractThis review covers almost two hundred and twenty heterobinuclear platinum compounds in which Pt⋯M separation is over 3.0 Å. The M is a transition metal (Cu, Ag, Au, Ti, V, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni and Pd). There is an example of a lanthanide, Yb and a actinide, U. The Pt atom has oxidation numbers 0, +2 and +4. The Pt coordination geometries include trigonal planar Pt(0); square planar Pt(II); trigonal bipyramidal, and pseudo octahedral Pt(IV), with the most frequent being square planar. The most common ligands for Pt are P and C donor atoms, as well as a chlorine atom. The Pt — Ag distance of 3.002(1) Å is the shortest found in this series. There are examples which contain two crystallographically independent molecules, which differ mostly by degree of distortion and even one unique example, which contains eight such molecules. These are examples of distortion isomerism. Factors affecting bond lengths and angles are discussed and some ambiguities in coordination polyhedral are outlined.


RSC Advances ◽  
2015 ◽  
Vol 5 (72) ◽  
pp. 58246-58254 ◽  
Author(s):  
Bandana Singh ◽  
Ashok K. S. Chauhan ◽  
Ramesh C. Srivastava ◽  
Andrew Duthie ◽  
R. J. Butcher

Synthesis of tellurated acrylates, ArTeCHCHCOOR and their solid state structures have been explored. The 125Te chemical shift and 2J(1H–125Te) are useful indicators of their geometry in solution.


2008 ◽  
Vol 47 (34) ◽  
pp. 6430-6432 ◽  
Author(s):  
Prema G. Vasudev ◽  
Sunanda Chatterjee ◽  
Kuppanna Ananda ◽  
Narayanaswamy Shamala ◽  
Padmanabhan Balaram

1997 ◽  
Vol 53 (3) ◽  
pp. 504-512 ◽  
Author(s):  
A. Martin ◽  
A. A. Pinkerton ◽  
R. D. Gilardi ◽  
J. C. Bottaro

Three biguanidinium salts of the energetic dinitramide anion have been prepared and structurally characterized from room-temperature X-ray diffraction data. Biguanidinium mono-dinitramide, (BIGH)(DN), triclinic, P\overline 1, a = 4.3686 (4), b = 9.404 (2), c = 10.742 (1) Å, \alpha = 83.54 (1), \beta = 80.386 (9), \gamma = 79.93 (1)°, V = 426.8 (1) Å3, Z = 2, D x = 1.62 g cm−3. Biguanidinium bis-dinitramide, (BIGH2)(DN)2, monoclinic, C2/c, a = 11.892 (2), b = 8.131 (1), c = 13.038 (2) Å, \beta = 115.79 (1)°, V = 1135.1 (3) Å3, Z = 4, D x = 1.84 g cm−3. Biguanidinium bis-dinitramide monohydrate, (BIGH2)(DN)2.H2O, orthorhombic, P212121, a = 6.4201 (6), b = 13.408 (1), c = 14.584 (2) Å, V = 1255.4 (4) Å3, Z = 4, D x = 1.76 g cm−3. All three structures are characterized by extensive hydrogen bonding. Both the mono- and diprotontated cations consist of two planar halves twisted with respect to each other. The dinitramide anion has a surprisingly variable and asymmetric structure. The two halves of the anion are twisted with respect to each other; however, the twist varies from 5.1 to 28.9°. In addition, the two ends of the anion have significantly different geometries, e.g. the `equivalent' N—N bond lengths differ by up to 0.045 Å.


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