High-Field EPR and Magnetic Susceptibility Studies on Binuclear and Tetranuclear Copper Trifluoroacetate Complexes. X-ray Structure Determination of Three Tetranuclear Quinoline Adducts of Copper(II) Trifluoroacetate

2009 ◽  
Vol 131 (29) ◽  
pp. 10279-10292 ◽  
Author(s):  
Andrew Ozarowski ◽  
Iwona B. Szymańska ◽  
Tadeusz Muzioł ◽  
Julia Jezierska
Keyword(s):  
Magnetic Susceptibility ◽  
Structure Determination ◽  
High Field ◽  
X Ray

Studies of Australian soft corals. XXXII. The structure determination of degraded xenicin-type diterpenes from several Efflatounaria species

1983 ◽  
Vol 36 (11) ◽  
pp. 2279 ◽  
Author(s):  
BF Bowden ◽  
JC Coll ◽  
VA Patrick ◽  
DM Tapiolas
Keyword(s):  
Single Crystal ◽  
Chemical Transformation ◽  
Structure Determination ◽  
High Field ◽  
Soft Corals ◽  
X Ray ◽  
The Third

Three new diterpenes have been isolated from soft corals of the genus Efflatounaria (Coelenterata, Octocorallia, Alcyonacea, Xeniidae). The structure of the first compound (4) was elucidated on the basis of high-field 1H n.m.r. spectroscopy while that of the second metabolite (5) was determined by single-crystal X-ray analysis. The third diterpene (6) was structurally related to (5), and its structure was confirmed by chemical transformation. All three diterpenes can be derived from xenicin-type precursors, by cleavage and recyclization.

Tropical Marine Algae. V. The Structure Determination of Two Novel Sesquiterpenes From the Red Alga Laurencia tenera (Rhodophyceae, Ceramiales, Rhodomelaceae)

1989 ◽  
Vol 42 (10) ◽  
pp. 1695 ◽  
Author(s):  
JC Coll ◽  
BW Skelton ◽  
AH White ◽  
AD Wright
Keyword(s):  
Single Crystal ◽  
Structure Determination ◽  
High Field ◽  
Marine Algae ◽  
Red Alga ◽  
X Ray Diffraction ◽  
X Ray

Laurencia tenera has been shown to contain two novel sesquiterpenes. The structure of the less abundant metabolite (3) was determined by single-crystal X-ray diffraction as (1S,2R,4S,5R,6R,8S,9R)-4,8-dibromo-2,5,6,9-tetramethyltricyclo[7.2.0.01.6] undecane-3-one.‡ The more abundant, but less stable metabolite (4) was investigated by extensive high-field N.M.R. spectroscopy. Its structure is proposed as (1S*,2R*,4R*,5R*,6R*,8R*)-4-bromo-2,5,6-trimethyl-11-methylenetricyclo[6.2.1.01.6]undecan-3-one.§ The sesquiterpene (3) is isomeric with the known metabolite perforatone (5).

The protonation of the ethylenediphosphinetetraacetate anion and the crystal structure of the bis (hydrogen bromide) of ethylenediphosphinetetraacetic acid

1981 ◽  
Vol 46 (12) ◽  
pp. 3063-3073 ◽  
Author(s):  
Jana Podlahová ◽  
Bohumil Kratochvíl ◽  
Vratislav Langer ◽  
Josef Šilha ◽  
Jaroslav Podlaha
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Structure Determination ◽  
Free Acid ◽  
Hydrogen Bromide ◽  
Carboxyl Groups ◽  
Spectroscopic Methods ◽  
X Ray ◽  
Partial Formation

The equilibria and mechanism of addition of protons to the ethylenediphosphinetetraacetate anion (L4-) were studied in solution by the UV, IR, 1H and 31P NMR spectroscopic methods. A total of six protons can be bonded to the anion. They are added stepwise, first with partial formation of zwitterions containing P-H bonds, which then dissociate with formation of the free acid, H4L, where all four protons are bonded in carboxyl groups. The formation of zwitterions is strongly dependent on the concentration. In the final stage, the acid bonds two additional protons to form the bis-phosphonium cation, H6L2+. A number of isostructural salts containing this cation, H4L.2 HX (X = Cl, Br, I), have been prepared. The X-ray crystal structure determination of the bromide confirmed the expected arrangement. The bromide crystals are monoclinic, a = 578.2, b = 1 425.0, c = 1 046.7 pm, β = 103.07° with a space group of P21/c, Z = 2. The final R factor was 0.059 based on 1 109 observed reflections. The structure consists of H6L2+ cations containing protons bonded to phosphorus atoms (P-H distance 134 pm) and of bromide anions, located in gaps which are also sufficiently large for I- anions in the isostructural iodide. The interbonding of phosphonium cations proceeds through hydrogen bonds, C-OH...O=C, in which the O...O distance is 275.3 pm.

scholarly journals Radical Ion Salts and Complexes, Part XVII. TCNQ Salts of 1,4-Dimethylpyridine and 2,3-Bis(1-methyl-4-pyridinio)butane

1999 ◽  
Vol 23 (3) ◽  
pp. 196-197
Author(s):  
Timothy J. Houghton ◽  
Stephen C. Wallwork
Keyword(s):  
Structure Determination ◽  
X Ray ◽  
Electrical Conductivities ◽  
Complex Salts ◽  
Radical Ion Salts

X-Ray structure determination of the complex salts [MeNC5H4Me]+[TCNQ2]- [1,4-dimethylpyridinium 2(7,7,8,8-tetracyanoquinodimethane) (1-); I] and [Me(NC5H4)(Me)CH-CH(Me)(C5H4N)Me]2+[TCNQ4]2- [ meso-2,3-bis( N-methyl-4-pyridyl)butane(2+) 4(7,7,8,8-tetracyanoquinodimethane) (2-); II], where TCNQ=(CN)2C(C6H4)C(CN)2, shows that, although in both salts the TCNQ moieties are stacked in columns, lateral shifts break these columns into diads for I and tetrads for II causing their electrical conductivities to be only moderate (Σ = 2–4 × 10−3 ohm−1 cm−1).

Syntheses, X-ray, MSn, NMR and CD structure determination of nickel(II) complexes of Schiff bases of (S)-N-(2-benzoylphenyl)-1-benzylpyrrolidine-2-carboxamide and aromatic α-amino acids

Polyhedron ◽  
2008 ◽  
Vol 27 (17) ◽  
pp. 3477-3483 ◽  
Author(s):  
Milan Nádvorník ◽  
Vratislav Langer ◽  
Robert Jirásko ◽  
Michal Holčapek ◽  
Tomáš Weidlich ◽  
...  
Keyword(s):  
Amino Acids ◽  
Schiff Bases ◽  
Structure Determination ◽  
X Ray ◽  
Determination Of Nickel
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