Elemental Carbon Chain Bridging Two Iron Centers:  Syntheses and Spectroscopic Properties of Donor−Acceptor [Fe]−C4−[Fe] Complexes Isolated in Two Different Oxidation States. X-ray Crystal Structure of [Cp*(dppe)Fe−C4−Fe(CO)2Cp*]

1997 ◽  
Vol 16 (26) ◽  
pp. 5988-5998 ◽  
Author(s):  
Françoise Coat ◽  
Marie-Andrée Guillevic ◽  
Loic Toupet ◽  
Frédéric Paul ◽  
Claude Lapinte
2011 ◽  
Vol 396-398 ◽  
pp. 2338-2341
Author(s):  
Xing Chuan Wei ◽  
Zhi Li Liu ◽  
Kun Zhang ◽  
Zhi Yun Du ◽  
Xi Zheng

In this paper, (2E,6E)-2,6-Bis(2,3,4-tri-methoxy -benzylidene)cyclohexanone (omitted as tmbcho) (1) was obtained by the reaction of acetic acid, tetrahydrofuran, cyclohexanone and 2,3,4-tri-methoxy-benzaldehyde. Three non-classic hydrogen bonds were observed in the compound. X-ray crystallography shows that the crystal structure is stabilized by intermolecular C-H•••π interactions and it contains plenty of conjugated double bonds. The title compound was characterized by UV-vis and fluorescent spectral studies.


1995 ◽  
Vol 50 (9) ◽  
pp. 1335-1339 ◽  
Author(s):  
Marietta S. Schriewer-Pöttgen ◽  
Wolfgang Jeitschko

AbstractThe previously reported mercury perrhenate Hg5Re2O10, prepared hydrothermally, has now been obtained by reaction of HgO with the mercury(II) metaperrhenate Hg(ReO4)2 in sealed silica tubes. A second modification of this compound can be obtained by reaction of elemental mercury with Hg(ReO 4)2 also in sealed silica tubes. Its crystal structure has been determined from single-crystal X-ray data: P21/c, a - 861.5(1), b = 1200.9(2), c = 1203.9(2) pm, β = 97.15(1)°, Z = 4, R = 0.024 for 1733 structure factors and 105 variables. Both modifications may be represented by the formula Hg2+-2Hg2O - 2ReO4-, indicating that mercury occurs in oxidation states I and II. In both modifications the mercury and some oxygen atoms form two-dimensionally infinte, puckered, cationic nets of the composition (Hg2+-2Hg2O)n , which are separated by the ReO4- tetrahedra. In the modification reported earlier the mercury oxygen nets consist of condensed 16-membered rings, while the nets of the present modification contain 10- and 22-membered rings.


Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 269 ◽  
Author(s):  
Rosita Diana ◽  
Ugo Caruso ◽  
Luigi Di Costanzo ◽  
Gelsomina Bakayoko ◽  
Barbara Panunzi

We developed a new benzodifuran derivative as the condensation product between 2,6-diamino-4-(4-nitrophenyl)benzo[1,2-b:4,5-b’]difuran-3,7-dicarboxylate and 3-hydroxy-2-naphthaldehyde. The intramolecular hydrogen-bond interactions in the terminal half-salen moieties produce a sterically encumbered highly conjugated main plane and a D-A-D (donor-acceptor-donor) T-shaped structure. The novel AIEgen (aggregation-induced enhanced emission generator) fulfils the requirement of RIR (restriction of intramolecular rotation) molecules. DR/NIR (deep red/near infrared) emission was recorded in solution and in the solid state, with a noteworthy photoluminescence quantum yield recorded on the neat crystals which undergo some mechanochromism. The crystal structure study of the probe from data collected at a synchrotron X-ray source shows a main aromatic plane π-stacked in a columnar arrangement.


1988 ◽  
Vol 43 (10) ◽  
pp. 1256-1262 ◽  
Author(s):  
Hans-Friedrich Klein ◽  
Goetz Lull ◽  
Birgit Rodenhäuser ◽  
Gerhard Cordier ◽  
Helmut Paulus

Mononuclear cobalt(o) complexes containing olefin and trimethylphosphane ligands Co(olefin)(PMe3)3 (olefin = C2H4 (1), C3H6 (2), cyclopentene (3), trans-1,2-diphenylethene (4), tetrafluorobenzo-bicyclo-(2.2.2)-octadiene (5)), are obtained from CoCl2 by reaction with magnesium in the presence of the ligands or by substitution of 3 with olefin. X-ray crystal structure determinations of 4 and 5 show a distorted tetrahedral arrangement of ligands around the cobalt atom. Chemical and spectroscopic properties are consistent with a paramagnetic valence state of the compounds in solution. By reaction with carbon monoxide a dicobalt complex is formed, while azobenzene gives paramagnetic Co(N2Ph2)(PMe3)2.


1984 ◽  
Vol 39 (5) ◽  
pp. 643-648 ◽  
Author(s):  
Hans-Friedrich Klein ◽  
Joachim Groß ◽  
Hubert Witty ◽  
Dietmar Neugebauer

Mononuclear cobalt(0) complexes containing diolefin and trimethylphosphane ligands Co(cycloocta-1,5-diene)(PMe3)2 and Co[(CH2=CHMe2Si)2O](PMe3)2 are obtained from CoCl2 by reaction with magnesium in the presence of the ligands or by substitution of cobalt(olefin)tris- (trimethylphosphane) with diolefin. Chemical and spectroscopic properties confirm the para- magnetic valence state of the compounds in solution. An X-Ray crystal structure determination of Co[(CH2=CHMe2Si)2O](PMe3)2 shows a tetrahedral arrangement of ligand functions around the cobalt atom. With butadiene a diamagnetic dinuclear complex [Co(C4H6)(PMe3)3]2 is obtained containing π-allyl co-ordination of two Co(PMe3)3 units to a linear dimer of butadiene


1992 ◽  
Vol 47 (6) ◽  
pp. 755-759 ◽  
Author(s):  
Thomas Kaukorat ◽  
Peter G. Jones ◽  
Reinhard Schmutzler

The 1H NMR spectrum of the spirophosphorane 3 at room temperature indicates dynamic behaviour of the cation. The low-temperature 1H NMR spectra of 3 exhibit two sets of doublets for the protons of the diastereotopic N(CH3)2 groups. The free enthalpy of activation for the dynamic process was determined (58.6 KJ/mole). In the reaction of 3 with sodium tetraphenylborate the crystalline compound, 4, involving the non-coordinating anion, [B(C6H5)4]-, was obtained. The X-ray crystal structure analysis of 4 reveals the presence of a five-membered ring, formally as a result of intramolecular donor-acceptor interaction between the nitrogen atom of the N(CH3)2 group and phosphorus. The geometry at phosphorus deviates somewhat from ideal trigonal bipyramidal.


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