Crystallographic Study of the Reaction of Zinc Vapor with Fully Cd2+-Exchanged Zeolite X. Complete Reduction of Cd2+by Zn, Extraction of SiO44-and AlO45-from the Zeolite Framework, and Reduction of Si4+to Si

2000 ◽  
Vol 104 (42) ◽  
pp. 9811-9816 ◽  
Author(s):  
Shenyan Zhen ◽  
Karl Seff
Keyword(s):  
Zinc Vapor ◽  
Zeolite X ◽  
Zeolite Framework ◽  
Complete Reduction ◽  
Crystallographic Study

Polymorphic phase transition of a membrane protein - analysis of continuous diffuse electron diffraction intensity

1986 ◽  
Vol 44 ◽  
pp. 166-167
Author(s):  
Douglas L. Dorset ◽  
Andrew K. Massalski
Keyword(s):  
Molecular Sieve ◽  
Three Dimensional ◽  
Pore Geometry ◽  
Two Dimensional ◽  
Diffraction Intensity ◽  
Polymorphic Phase Transition ◽  
E Coli ◽  
Crystallographic Study ◽  
Hexagonal Form ◽  
Polymorphic Forms

Matrix porin, the ompF gene product of E. coli, has been the object of a electron crystallographic study of its pore geometry in an attempt to understand its function as a membrane molecular sieve. Three polymorphic forms have been found for two-dimensional crystals reconstituted in phospholipid, two hexagonal forms with different lipid content and an orthorhombic form coexisting with and similar to the hexagonal form found after lipid loss. In projection these have been shown to retain the same three-fold pore triplet geometry and analyses of three-dimensional data reveal that the small hexagonal and orthorhombic polymorphs have similar structure as well as unit cell spacings.

Effect of Chemical and Radiochemical Impurities from Eluants on 99mTc-Labeling Efficiency

1977 ◽  
Vol 16 (06) ◽  
pp. 241-246
Author(s):  
W. Earl Barnes ◽  
L. G. Colombetti
Keyword(s):  
Large Concentration ◽  
Complete Reduction ◽  
99Mtc Labeling ◽  
Spontaneous Oxidation

SummaryOccasionally, radiopharmaceuticals prepared from the eluates of 99Mo-99m T c generators that have not been eluted for several days contain large amounts of free pertechnetate, as tested by radiochromatography and biologically by administration to patients. We find the most probable causes of poor 99mTc-labeling in these cases to be:a) the presence of a large concentration of 99TcO4 – in eluants;b) insufficient stannous ions available for the complete reduction of Tc due to spontaneous oxidation of Sn in the vial and also due to oxidation of stannous ions by the presence of larger than expected concentrations of H2O2 and HO2 radicals in the eluant.

A Crystallographic Study of Bis[S-benzyl-5-bromo-2-oxoindolin-3-ylidenemethanehydrazonthioate] Disulfide Solvated with Dimethylsulfoxide

2012 ◽  
Vol 9 (2) ◽  
pp. 87
Author(s):  
Mohd Abdul Fatah Abdul Manan ◽  
M. Ibrahim M. Tahir ◽  
Karen A. Crouse ◽  
Fiona N.-F. How ◽  
David J. Watkin
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Solvent Molecule ◽  
Site Occupancy ◽  
Unit Cell Parameters ◽  
Intermolecular Hydrogen Bonds ◽  
Triclinic Space Group ◽  
Cell Parameters ◽  
Crystallographic Study ◽  
Thiol Form

The crystal structure of the title compound has been determined. The compound crystallized in the triclinic space group P -1, Z = 2, V = 1839 .42( 18) A3 and unit cell parameters a= 11. 0460( 6) A, b = 13 .3180(7) A, c=13. 7321 (8) A, a = 80.659(3 )0, b = 69 .800(3 )0 and g = 77 .007 (2)0 with one disordered dimethylsulfoxide solvent molecule with the sulfur and oxygen atoms are distributed over two sites; S101/S102 [site occupancy factors: 0.6035/0.3965] and 0130/0131 [site occupancy factor 0.3965/0.6035]. The C22-S2 l and C 19-S20 bond distances of 1. 779(7) A and 1. 788(8) A indicate that both of the molecules are connected by the disulfide bond [S20-S21 2.055(2) A] in its thiol form. The crystal structure reveals that both of the 5-bromoisatin moieties are trans with respect to the [S21-S20 and CI 9-Nl 8] and [S20-S21 and C22-N23] bonds whereas the benzyl group from the dithiocarbazate are in the cis configuration with respect to [S21-S20 and C19-S44] and [S20-S21 and C22-S36] bonds. The crystal structure is further stabilized by intermolecular hydrogen bonds of N9-H35···O16 formed between the two molecules and N28-H281 ···O130, N28-H281 ···O131 and C4 l-H4 l l ···O 131 with the solvent molecule.

Building a Picture of Heteroborane Isomerisation: Synthesis and Characterisation of the 10-(Dialkyl- sulfane)-7,8-diphenyl-7,8-dicarba-nido-undecaboranes 7,8-Ph2-10-L-7,8-nido-C2B9H10 (L = SMe2, SMeEt, SEt2) and of Intermediate and Isomerised Products Arising from Metallation of the First of These

1999 ◽  
Vol 64 (6) ◽  
pp. 1013-1027 ◽  
Author(s):  
Shirley Dunn ◽  
Rhona M. Garrioch ◽  
Georgina M. Rosair ◽  
Lorraine Smith ◽  
Alan J. Welch
Keyword(s):  
Boron Atom ◽  
Experimental Information ◽  
Crystallographic Study

Three new, substituted, nido carboranes, 7,8-Ph2-10-(SMe2)-7,8-nido-C2B9H10 (1a), 7,8-Ph2-10- (SMeEt)-7,8-nido-C2B9H10 (1b) and 7,8-Ph2-10-(SEt2)-7,8-nido-C2B9H10 (1c) have been synthesised and characterised, including a crystallographic study of the first. Deprotonation of 1a followed by treatment with (MeCN)2(CO)2MoBr(η-C3H5) at 0 °C affords the non-icosahedral 1,2-Ph2-4-(SMe2)-5-(η-C3H5)-5,5-(CO)2-5,1,2-closo-MoC2B9H8 (2a), which on subsequent warming transforms into icosahedral 2,8-Ph2-5-(SMe2)-1-(η-C3H5)-1,1-(CO)2-1,2,8-closo- MoC2B9H8 (3a). It is argued that under the conditions of these rearrangements the B-S bond is likely to remain intact, and consequently that the identity of the SMe2-labelled boron atom in 3a affords useful experimental information on the course of the isomerisation.

Study of Coke Distribution in HZSM-5 by 129-Xe NMR

1992 ◽  
Vol 57 (4) ◽  
pp. 733-738 ◽  
Author(s):  
Jean L. Bonardet ◽  
M. C. Barrage ◽  
Jack P. Fraissard ◽  
Ludmila Kubelková ◽  
Jana Nováková ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Zeolite Framework

The location of coke formed during conversion of methanol or acetone on HZSM-5 zeolites has been examined using 129-Xe NMR spectroscopy. The results show that the type of reaction and the method of regeneration have great importance for the location of carbonaceous residues inside or outside the zeolite framework.

X-ray Crystallographic Study of Alkylammonium Anthracene-9-carboxylates as a Model for Fibrous Structure of Binary Anthracene Salt Gels

2004 ◽  
Vol 69 (6) ◽  
pp. 1292-1300 ◽  
Author(s):  
Tahahiro Tani ◽  
Kazuki Sada ◽  
Masatsugu Ayabe ◽  
Yuya Iwashita ◽  
Takanori Kishida ◽  
...  
Keyword(s):  
Alkyl Chain ◽  
Columnar Structure ◽  
Hydrogen Bond Network ◽  
One Dimensional ◽  
X Ray ◽  
Crystallographic Study ◽  
Alkylammonium Salts ◽  
Bond Network ◽  
Fibrous Assemblies ◽  
Long Alkyl Chain

Crystal structure of hexylammonium anthracene-9-carboxylate was investigated. The salt was arranged by a one-dimensional hydrogen bond network to form a columnar structure in the crystalline state. This columnar structure should be the model of fibrous assemblies in the organogels of anthracene-9-carboxylate alkylammonium salts having a long alkyl chain.

A preliminary crystallographic study of CDCP2 fromArabidopsis thaliana

2008 ◽  
Vol 64 (a1) ◽  
pp. C245-C246
Author(s):  
B.-C. Jeong ◽  
K.S. Yoo ◽  
J.S. Shin ◽  
H.K. Song
Keyword(s):  
Crystallographic Study
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