Molecular Structures of Di(9-anthryl)Methanol and Di(9-anthryl) Ketone

1989 ◽  
Vol 42 (4) ◽  
pp. 603 ◽  
Author(s):  
HD Becker ◽  
V Langer ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Carbon Atom ◽  
Dihedral Angle ◽  
Molecular Structures ◽  
Steric Interaction ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Intramolecular Cycloaddition ◽  
X Ray ◽  
Central Carbon ◽  
Photochemical Isomerization

The molecular structures of di(9-anthryl)methanol (1) and di(9-anthryl) ketone (2) have been established by X-ray diffraction. The asymmetric unit of di(anthryl)methanol consists of two molecules in which the dihedral angle between the anthracene moieties is 81.4 and 86.3 respectively; steric interaction between the anthracene moieties results in them subtending angles of 115.0(7) and 115.8(8)� at the central carbon atom, and with unsymmetrical exocyclic angles at their point of attachment. In di(9-anthryl) ketone the planes of the anthracene systems are twisted out of the plane of the carbonyl group by 48.8 and 52.2� respectively, so that the dihedral angle between the two aromatic ring systems is 87.3�. The structures of di(anthryl)methanol and di(anthryl) ketone are discussed with respect to their different modes of photochemical isomerization by intramolecular cycloaddition.

scholarly journals Relation between photochromic properties and molecular structures in salicylideneaniline crystals

2012 ◽  
Vol 68 (3) ◽  
pp. 297-304 ◽  
Author(s):  
Kohei Johmoto ◽  
Takashi Ishida ◽  
Akiko Sekine ◽  
Hidehiro Uekusa ◽  
Yuji Ohashi
Keyword(s):  
Dihedral Angle ◽  
Steric Hindrance ◽  
Molecular Structures ◽  
Dihedral Angles ◽  
Clear Correlation ◽  
X Ray Diffraction ◽  
Photochromic Properties ◽  
X Ray ◽  
Benzene Rings ◽  
The Relationship

The crystal structures of the salicylideneaniline derivatives N-salicylidene-4-tert-butyl-aniline (1), N-3,5-di-tert-butyl-salicylidene-3-methoxyaniline (2), N-3,5-di-tert-butyl-salicylidene-3-bromoaniline (3), N-3,5-di-tert-butyl-salicylidene-3-chloroaniline (4), N-3,5-di-tert-butyl-salicylidene-4-bromoaniline (5), N-3,5-di-tert-butyl-salicylidene-aniline (6), N-3,5-di-tert-butyl-salicylidene-4-carboxyaniline (7) and N-salicylidene-2-chloroaniline (8) were analyzed by X-ray diffraction analysis at ambient temperature to investigate the relationship between their photochromic properties and molecular structures. A clear correlation between photochromism and the dihedral angle of the two benzene rings in the salicylideneaniline derivatives was observed. Crystals with dihedral angles less than 20° were non-photochromic, whereas those with dihedral angles greater than 30° were photochromic. Crystals with dihedral angles between 20 and 30° could be either photochromic or non-photochromic. Inhibition of the pedal motion by intra- or intermolecular steric hindrance, however, can result in non-photochromic behaviour even if the dihedral angle is larger than 30°.

Molecular Topology of Linked Anthracenes: X-Ray Structure Analyses of Alkyl Di-9-anthryl-glycolates, 9-Anthryl 9-Anthrylmethyl Ethers and Their Photoisomers

1989 ◽  
Vol 42 (11) ◽  
pp. 1869 ◽  
Author(s):  
HD Becker ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Alder Reaction ◽  
Diels Alder ◽  
Molecular Structures ◽  
Molecular Topology ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diels Alder Reaction ◽  
Photochemical Isomerization ◽  
Spatial Demand

The molecular structures of ethyl di-9-anthrylglycolate (1) and methyl di-9-anthrylglycolate (2), as well as those of three isomerization products of (2), have been established by single-crystal X-ray diffraction studies. In both (1) and (2), the anthracenemoieties are characterized by marked deviations from planarity. The stereospecific course of the thermal and photochemical isomerization of (2) by Diels -Alder reaction is suggested to be governed by the spatial demand of the alkoxycarbonyl group. Base-catalysed isomerization of (2) by migration of 9-anthryl from carbon to oxygen is associated with steric relief.

scholarly journals Complexes of Dichlorogermylene with Phosphine/Sulfoxide-Supported Carbone as Ligand

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2005
Author(s):  
Ugo Authesserre ◽  
Sophie Hameury ◽  
Aymeric Dajnak ◽  
Nathalie Saffon-Merceron ◽  
Antoine Baceiredo ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Carbon Atom ◽  
Diffraction Analysis ◽  
Coordination Complexes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Central Carbon Atom ◽  
Lone Pairs ◽  
Central Carbon

Due to their remarkable electronic features, recent years have witnessed the emergence of carbones L2C, which consist in two donating L ligands coordinating a central carbon atom bearing two lone pairs. In this context, the phosphine/sulfoxide-supported carbone 4 exhibits a strong nucleophilic character, and here, we describe its ability to coordinate dichlorogermylene. Two original stable coordination complexes were obtained and fully characterized in solution and in the solid state by NMR spectroscopy and X-ray diffraction analysis, respectively. At 60 °C, in the presence of 4, the Ge(II)-complex 5 undergoes a slow isomerization that transforms the bis-ylide ligand into an yldiide.

Molecular and Crystal Structure, and EPR Studies of Tetraphenylarsonium [Bis-(1,3-dithia-2-one-4,5-dithiolato)-nickelate], (AsPh4)[Ni(dmid)2]

1988 ◽  
Vol 43 (9) ◽  
pp. 1137-1143 ◽  
Author(s):  
R. Vicente ◽  
J. Ribas ◽  
C. Zanchini ◽  
D. Gatteschi ◽  
J.-P. Legros ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Dihedral Angle ◽  
Unpaired Electron ◽  
Room Temperature ◽  
Monoclinic Space Group ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Variable Parameters ◽  
X Ray

AbstractThe crystal structure of (AsPh4)[Ni(dmid)2 (dmid2- = 1,3-dithia-2-one-4,5-dithiolato) has been determined by X-ray diffraction studies: crystals are monoclinic, space group P21/n a = 14.724(2), b = 14.305(5), c = 15.570(3) Å, β = 92.20(1)°, V = 3277 Å3 , ᵨx = 1.63 g cm-3 for Z = 4, final conventional agreement indices R = 0.038 and Rw = 0.049 for 2115 unique, observed reflections and 211 variable parameters. The asymmetric unit contains one (AsPh4)+ cation and one [Ni(dmid)2] anion, both in general positions. The anions are isolated from each other by the bulky cations. The [Ni(dmid)2]- ion deviates strongly from planarity: the dihedral angle between the two Ni(dmid) moieties is 10.7°; one of the dmid ligand is almost planar, while the second one is severely puckered. Polycristalline powder and single crystal EPR spectra have been recorded at room temperature. Only one signal was observed in all crystal orientations. The angular depend-ences of the linewidth and of the g values have been determined, as well as the principal g values and directions. These results have been compared to those previously obtained for the analogue (n-Bu4N)[Ni(dmit)2 ] (drnit2- = 1,3-dithia-2-thione-4,5-dithiolato), and discussed in terms of the localization of the unpaired electron on the ligands. leading to a formal (III) and actual (II) nickel oxidation state.

Molecular Topology of Di(9-Anthryl)Ethanedione (9,9'-Anthril) and Some Generically Related Cyclic 1,2-Diketones

1991 ◽  
Vol 44 (2) ◽  
pp. 181 ◽  
Author(s):  
HD Becker ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Dihedral Angle ◽  
Molecular Structures ◽  
Dihedral Angles ◽  
Molecular Topology ◽  
Single Bond ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intramolecular Cycloadditions ◽  
Crystal Modifications

The molecular structures of di (9-anthryl) ethanedione (9,9′-anthril) and those of four 1,2-diketones derived from 9,9′-anthril by way of intramolecular cycloadditions were investigated by single-crystal X-ray diffraction studies. Two crystal modifications of 9,9′-anthril were available and found to differ in the dihedral angles (43.9 and 178.3°) about the 1,2-dicarbonyl moiety. The 1,2-dicarbonyl group of the cyclobutanedione moiety in the anthril 4π+4π cyclomer is associated with a dihedral angle of 2.6°. In the anthril isomer derived by 4π+2π cycloaddition, an exceptionally long single bond is indicative of molecular strain. The molecular structures of a keto enol and of a novel 1,2-diketo substituted triptycene, both obtained from the 4π+2π cyclomer by acid-catalysed rearrangement and dehydrogenation, respectively, were established. The topological and spectroscopic differences between the keto en01 and its 1,2-diketo precursor are discussed.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

Effect of Hydrated Metal Salts on the Coordination Product of Cobalt(II) halide and PNP Type Ligand, 2,6-bis(di-tertbutylphosphinomethyl) pyridine

2018 ◽  
Author(s):  
Tasneem Siddiquee ◽  
Abdul Goni
Keyword(s):  
Metal Salts ◽  
Molar Ratio ◽  
Pincer Complexes ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Pincer Ligand ◽  
Tetrahedral Geometry ◽  
X Ray ◽  
Distorted Tetrahedral Geometry ◽  
Cobalt Center

Chemical treatment of CoX<sub>2</sub><b><sup>. </sup></b>6H<sub>2</sub>O (X = Cl, Br, I) with the potentially tridentate PNP pincer ligand 2,6-bis(di-<i>tert</i>-butylphosphinomethyl)pyridine in 1:1 molar ratio results in cobalt(II) halide-PNP pincer complexes. The effect of the hydrated metal source on molecular structure and geometry of the complexes was studied by single crystal X-ray diffraction analysis. The complexes are neutral and the cobalt center adopts a penta-coordinate system with potential atropisomerization. Within the unit cell there are two distinct molecules per asymmetric unit. One of the two phosphorus atoms in the PNP ligand was observed to be partially oxidized to phosphinoxide. Disorder in the structure reflects a mixture of square pyramidal and distorted tetrahedral geometry.

Crystal structure determination of the conformation of two bicyclo[3.3.1]nonan-ones

1985 ◽  
Vol 63 (6) ◽  
pp. 1166-1169 ◽  
Author(s):  
John F. Richardson ◽  
Ted S. Sorensen
Keyword(s):  
Crystal Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Molecular Structures ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Final Agreement

The molecular structures of exo-7-methylbicyclo[3.3.1]nonan-3-one, 3, and the endo-7-methyl isomer, 4, have been determined using X-ray-diffraction techniques. Compound 3 crystallizes in the space group [Formula: see text] with a = 15.115(1), c = 7.677(2) Å, and Z = 8 while 4 crystallizes in the space group P21 with a = 6.446(1), b = 7.831(1), c = 8.414(2) Å, β = 94.42(2)°, and Z = 2. The structures were solved by direct methods and refined to final agreement factors of R = 0.041 and R = 0.034 for 3 and 4 respectively. Compound 3 exists in a chair–chair conformation and there is no significant flattening of the chair rings. However, in 4, the non-ketone ring is forced into a boat conformation. These results are significant in interpreting what conformations may be present in the related sp2-hybridized carbocations.

Tris(dimethylphenylphosphine)ruthenium(0) Complexes of n4-Coordinated Polycyclic Aromatic Hydrocarbons

2000 ◽  
Vol 53 (6) ◽  
pp. 507 ◽  
Author(s):  
Martin A. Bennett ◽  
Mark Bown ◽  
David C. R. Hockless
Keyword(s):  
Coordination Geometry ◽  
Crystal Data ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Tertiary Phosphine ◽  
X Ray ◽  
Tertiary Phosphines ◽  
Polycyclic Aromatic ◽  
R Value ◽  
Axial Site

From the reaction of [Ru2Cl3(PMe2Ph)6] Cl with the appropriate radical anions, yellow complexes of general formula [Ru(PMe2Ph)3(η4-arene)] [arene = naphthalene (C10H8) (1), anthracene (C14H10) (2), and triphenylene (C18H12) (3)] have been isolated in poor yield and characterized by elemental analysis, n.m.r. (1H, 13C, 31P) spectroscopy and single-crystal X-ray diffraction. Crystal data: (1), monoclinic, C2/c, a 31.096(8), b 12.012(4), c 17.078(8) Å, β 104.41(3)˚, V 6178(4) Å3, ? 8, refined to final R value of 0.032 with use of 3641 reflections [I > 3σ(I)]; (2), monoclinic, C2/c, a 55.909(4), b 14.348(5), c 17.573(5) Å, β 105.41(1)˚, V 13590(6) Å3, Z 16 (two molecules per asymmetric unit), refined to final R value of 0.049 with use of 7770 reflections [I > 3σ(I)]; (3), mono-clinic, Pn, a 9.377(3), b 12.229(3), c 15.975(3) Å, β 103.51(2)˚, V 1781.2 (7) Å3, Z 2, refined to final R value of 0.026 with use of 2830 reflections [I > 3σ(I)]. In each case, coordination of the zerovalent metal fragment Ru(PMe2Ph)3 to the diene section of one of the terminal rings causes the aromatic molecule to be folded by c. 40˚ at the outer carbon atoms of the diene. The coordination geometry about ruthenium is approximately square pyramidal, with the diene and two tertiary phosphines in the equatorial plane and the remaining tertiary phosphine in the axial site.

Strukturuntersuchungen an Diaryldichalkogeniden: Die Molekülstrukturen von [2,4,6-(CF3)3C6H2S]2,[2,4,6-Me3C6H2Te]2 und [2-Me2N-4,6-(CF3)2C6H2Te]2 / Structural Investigations of Diaryl Dichalcogenides: The Molecular Structures of [2,4,6-(CF3)3C6H2S]2, [2,4,6-Me3C6H2Te]2 and [2-Me2N-4,6-(CF3)2C6H2Te]2

1992 ◽  
Vol 47 (3) ◽  
pp. 305-309 ◽  
Author(s):  
Anja Edelmann ◽  
Sally Brooker ◽  
Norbert Bertel ◽  
Mathias Noltemeyer ◽  
Herbert W. Roesky ◽  
...  
Keyword(s):  
Molecular Structures ◽  
Monoclinic Space Group ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Structural Investigations ◽  
Space Group ◽  
X Ray

Abstract The Molecular Structures of [2,4,6-(CF3)3C6H2S]2 (1) [2,4,6-Me3C6H2Te]2 and [2-Me2N-4,6-(CF3)2C6H2Te]2 (3) have been determined by X-ray diffraction. Crystal data: 1: orthorhombic, space group P212121, Z = 4, a = 822.3(2), b = 1029.2(2), c = 2526.6(5) pm (2343 observed independent reflexions, R = 0.042); 2: orthorhombic, space group Iba 2, Z = 8, a = 1546.5(2), b = 1578.4(2), c = 1483.9(1) pm (2051 observed independent reflexions, R = 0.030); 3: monoclinic, space group P 21/c, Z = 4, a = 1118.7(1), b = 1536.5(2), c = 1492.6(2) pm, β = 98.97(1)° (3033 observed independent reflexions, R = 0.025).

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