Cyclic voltammetry of ferrocene-containing β-diketones as a tool to obtain group electronegativities. The structure of 3-ferrocenoyl-1,1,1-trifluoro-2-hydroxyprop-2-ene

1999 ◽  
Vol 77 (3) ◽  
pp. 378-386 ◽  
Author(s):  
WC (Ina) du Plessis ◽  
Johannes JC Erasmus ◽  
Gert J Lamprecht ◽  
Jeanet Conradie ◽  
T Stanley Cameron ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Structure Determination ◽  
Methyl Esters ◽  
Enol Form ◽  
X Ray ◽  
Reduction Potentials ◽  
Group Electronegativity ◽  
Ferrocenyl Group ◽  
Group A

Formal reduction potentials (E°' values vs. Ag/Ag+ given in parentheses) in acetonitrile of 1-ferrocenyl-4,4,4-trifluorobutane-1,3-dione (ferrocenoyltrifluoroacetone, Hfctfa, 0.394 V), 1-ferrocenyl-4,4,4-trichlorobutane-1,3-dione (ferrocenoyltrichloroacetone, Hfctca, 0.370 V), 1-ferrocenylbutane-1,3-dione (ferrocenoylacetone, Hfca, 0.313 V), 1-ferrocenyl-3-phenylpropane-1,3-dione (benzoylferrocenoylmethane, Hbfcm, 0.306 V), and 1,3-diferrocenylpropane-1,3-dione (diferrocenoylmethane, Hdfcm, 0.265 and 0.374 V for the two electrochemically nonequivalent ferrocenyl groups) were determined. A linear relationship between observed group electronegativity, χ, and E°' as well as observed infrared carbonyl stretching frequencies of methyl esters of the type RCOOMe resulted in average χ-values, on the Gordy scale, of 1.87 for the ferrocenyl group and 2.82 for the ferrocenium group. A single crystal X-ray structure determination of Hfctfa (monoclinic, P21/n, Z = 4, R = 0.029) showed that this β-diketone crystallizes in the enol form. Asymmetric enolization in a direction furthest from the aromatic ferrocenyl group was observed.Key words: ferrocene, β-diketone, group electronegativity, cyclic voltammetry.

Structure determination of fatty acid ester biofuels via in situ cryocrystallisation and single crystal X-ray diffraction

CrystEngComm ◽  
2019 ◽  
Vol 21 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Siriyara Jagannatha Prathapa ◽  
Cara Slabbert ◽  
Manuel A. Fernandes ◽  
Andreas Lemmerer
Keyword(s):  
Crystal Structure ◽  
Fatty Acid ◽  
Fatty Acid Ester ◽  
Structure Determination ◽  
Homologous Series ◽  
Methyl Esters ◽  
X Ray Diffraction ◽  
X Ray

In situ cryocrystallisation enabled the crystal structure determination of a homologous series of low-melting n-alkyl methyl esters Cn−1H2n+1CO2CH3.

Conformation of Methylsulfonyl Group: A Comparison of the Data for 2-Chlorophenyl Methyl Sulfone in Solution and in Crystal

1996 ◽  
Vol 61 (5) ◽  
pp. 733-741
Author(s):  
Václav Všetečka ◽  
Ivana Císařová ◽  
Jaroslav Podlaha
Keyword(s):  
Crystal Structure ◽  
Dipole Moment ◽  
Dihedral Angle ◽  
Structure Determination ◽  
Title Compound ◽  
Methyl Carbon ◽  
Moment Measurement ◽  
X Ray ◽  
Group A

The conformation of methylsulfonyl group attached to 2-substituted benzene ring was studied in the crystal and in solution. X-Ray crystal structure determination of the title compound demonstrates single conformation with the dihedral angle of 66.9(2)° between the planes defined by the aromatic ring and by the pivot atom of the ring, sulfur and the methyl carbon. In solution, dipole moment measurement leads to the conclusion that the compound also adopts a similar single conformation with slightly different dihedral angle of 53(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

Theoretical Study and X-ray Structure Determination of Dimethyldihydropyrene

1998 ◽  
Vol 63 (9) ◽  
pp. 3125-3127 ◽  
Author(s):  
Richard Vaughan Williams ◽  
W. Daniel Edwards ◽  
Ashwani Vij ◽  
Robert W. Tolbert ◽  
Reginald H. Mitchell
Keyword(s):  
Structure Determination ◽  
Theoretical Study ◽  
X Ray
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