The reactions of [Pd2Cl2(μ-PP)2] (PP = dppm, dmpm) with Et2NC≡CNEt2 in methylene chloride solution: X-ray crystal structures of [Pd2Cl2(μ-CH2)(μ-dppm)2] and hexakis(diethylamino)benzene, C6(NEt2)6

The binuciear palladium(I) complex, [Pd2Cl2(μ-dppm)2] (dppm = bis(diphenylphosphino)methane), has been shown to react with bis(diethylamino)acetylene, Et2NC≡CNEt2, in methylene chloride solution to yield two isolable products, the known methylene-bridged complex, [Pd2Cl2(μ-CH2)(μ-dppm)2], and hexakis(diethylamino)benzene, C6(NEt2)6, both of which have been characterized crystallographically. The source of the bridging methylene group in [Pd2Cl2(μ-CH2)(μ-dppm)2] has been shown to be the methylene chloride solvent. A mechanism that accounts for the formation of the two isolable products is proposed. The complex, [Pd2Cl2(μdmpm)2] (dmpm = bis(dimethylphosphino)methane), was similarly found to react with Et2NC≡NEt2 in methylene chloride solution to yield [Pd2Cl2(μ-CH2)(μ-dmpm)2], which was identified spectroscopically. Key words: acetylene, palladium, cyclooligomerization, aminoacetylene, hexakis(diethylamino)benzene.

Download Full-text

Synthesen und Kristallstrukturen von Tris(di-n-propylamino)-p-brombenzylphosphonium-bromiden: [(C3H7)2N]3PCH2C6H4Br+Br- und [(C3H7)2N]3PCH2C6H4Br+Br3-/Syntheses and Crystal Structures of Tris(di-n-propylamino)-p-bromobenzyl-phosphonium Bromides: [(C3H7)2N]3PCH2C6H4Br+Br- and [(C3H7)2N]3PCH2C6H4Br+Br3-

Zeitschrift für Naturforschung B ◽

10.1515/znb-1999-0121 ◽

1999 ◽

Vol 54 (1) ◽

pp. 113-116 ◽

Cited By ~ 2

Author(s):

J. Nolte ◽

P. Neubauer ◽

H. Vogt ◽

M. Meisel

Keyword(s):

Crystal Structures ◽

Chloride Solution ◽

Methylene Chloride ◽

Monoclinic Space Group ◽

Triclinic Space Group ◽

Space Group ◽

Methylene Chloride Solution

Tris(di-n-propylamino)-p-bromobenzylphosphonium bromide [(C3H7)2N]3PCH2C6H4Br+- Br- (1) has been prepared by the reaction of tris(di-n-propylamino)phosphine with p-bromobenzylbromide in methylene chloride. The colorless crystals are monoclinic, space group P21, Z = 2, a = 930.2(3), b = 1501.2(3), c = 1093.5(2) pm, β = 105,97(4)°. The lattice contains Br- anions and [(C3H7)2N]3PCH2C6H4Br+ cations. [(C3H7)2N]3PCH2C6H4Br+Br- (2) has been obtained by treating 1 with equimolar quantities of elemental bromine in methylene chloride solution. The yellow-red crystals of 2 are triclinic, space group P1̄, Z = 2, a = 1069.5(3), b = 1267.7(7), c = 1273.7(3) pm, α= 87.27(3), β = 82,67, γ = 67.15°, and consist of [(C3H7)2N]3PCH2C6H4Br+ cations and linear Br3- anions. The three N atoms in the cations of 2 are planar.

Download Full-text

Synthese und Kristallstruktur der Benzyltriphenylphosphonium-bromide: [C6H5-CH2P(C6H5)3]+Br-CH2Cl2 und [C6H5-CH2P(C6H5)3]+Br3- / Synthesis and Crystal Structures of (Benzyl)triphenylphosphonium Bromides, [C6H5-CH2P(C6H5)3]+Br-CH2Cl2 and [C6H5-CH2P(C6H5)3]+Br3-

Zeitschrift für Naturforschung B ◽

10.1515/znb-1997-1107 ◽

1997 ◽

Vol 52 (11) ◽

pp. 1321-1324 ◽

Cited By ~ 5

Author(s):

J. Hübner ◽

D. Wulff-Molder ◽

H. Vogt ◽

M. Meisel

Keyword(s):

Crystal Structures ◽

Chloride Solution ◽

Methylene Chloride ◽

Monoclinic Space Group ◽

Triclinic Space Group ◽

Space Group ◽

Methylene Chloride Solution ◽

Triphenylphosphonium Bromide

(Benzyl)triphenylphosphonium bromide, [C6H5-CH2P(C6H5)3]+Br- (CH2Cl2) (1) has been prepared by the reaction of triphenylphosphine with benzylbromide and its structure determined. The colorless crystals are triclinic, space group P1̄, Z = 2, a = 976.0(3), b = 1069.0(3), c = 1226.1(4) pm, α = 94.13(3), β = 104.70(3), γ = 100.14(3)°. The lattice contains Br- anions and [C6H5-CH2P(C6H5)3]+ cations. [C6H5-CH2P(C6H5)3]Br3 (2) has been obtained by treating compound 1 with equimolar quantities of elemental bromine in methylene chloride solution. The red crystals of 2 are monoclinic, space group P21/c, Z = 4, a = 917.9(2), b = 1022.6(2), c = 2573.6(5) pm, β = 99.11(2)°, and comprise[C6H5-CH2P(C6H5)3]+ cations and linear, slightly asymmetrical Br3- anions with bromine-bromine distances of 246.19(11) and 263.69(11) pm.

Download Full-text

Synthese und Kristallstruktur des Bromdifluormethyl-triphenyl- phosphoniumbromids, [(C6H5)3PCF2Br]+ Br- / Synthesis and Crystal Structure of Bromodifluoromethyl-triphenylphosphonium Bromide, [(C6H5)3PCF2Br]+ Br-

Zeitschrift für Naturforschung B ◽

10.1515/znb-2000-0206 ◽

2000 ◽

Vol 55 (2) ◽

pp. 167-170 ◽

Cited By ~ 6

Author(s):

C. Bender ◽

D. Wulff-Molder ◽

H. Vogt ◽

F. Ritschl ◽

M. Meisel

Keyword(s):

Crystal Structure ◽

Chloride Solution ◽

Methylene Chloride ◽

Monoclinic Space Group ◽

Synthesis And Crystal Structure ◽

X Ray ◽

Methylene Chloride Solution ◽

Mndo Calculations ◽

Triphenylphosphonium Bromide ◽

Good Agreement

Abstract Difluorobromomethyl-triphenylphosphonium bromide [(C6H5)3PCF2Br]+ Br- (1) has been prepared by the reaction of triphenylphosphine with dibromodifluoro-methane in acetonitrile or methylene chloride. The colorless crystals are monoclinic, space group P 21/n, Z=4, a = 1067.1(2), b = 1488,5(2), c = 1178,2(2) pm, β = 95,67(3)°. The lattice contains Br- anions and [(C6H5)3PCF2Br]+ cations with a Br-Br distance of 322,33(11) pm.. For the title compound the results of AM 1, PM 3 ,and MNDO calculations are in good agreement with corresponding values determined by the X-ray analysis only in the case of PM 3.The yellow-red [(C6H5)3PCF2Br]+ Br3- (2) has been obtained by treating 1 with equimolar quantities of elemental bromine in methylene chloride solution.

Download Full-text

The addition of 2,4-dinitrobenzenesulphenyl chloride to 1,3-disubstituted allenes: a reexamination

Canadian Journal of Chemistry ◽

10.1139/v79-019 ◽

1979 ◽

Vol 57 (1) ◽

pp. 119-127 ◽

Cited By ~ 6

Author(s):

Dennis G. Garratt ◽

Pierre Beaulieu

Keyword(s):

Double Bond ◽

Chloride Solution ◽

Methylene Chloride ◽

Effective Mechanism ◽

Substituent Group ◽

Methylene Chloride Solution ◽

Inductive Effects ◽

Allene System

The reaction of 2,4-dinitrobenzenesulphenyl chloride with eight alkyl 1,3-disubstituted allenes in methylene chloride solution has been investigated. In contrast to earlier reports, attack by sulphur is found to occur exclusively at the central allenic carbon. The direction of approach of sulphenyl chloride leads preferentially to the formation of the E isomers in accord with the concept of steric approach control. The ratio of E to Z alkene is found to increase as the bulk of the substituent group cis to the arylthio group increases. We observe, however, very little regioselectivity with respect to which of the mutually perpendicular π bonds of the allene system is attacked, suggesting the presence of an effective mechanism for transmission of inductive effects to the more distant double bond.

Download Full-text

Crystal structures of highly stabilized ylides: methyl(3-methoxy,2-methoxycarbonylbenzoyl) triphenyl- phosphoranylideneacetate and methyl(2-methoxycarb-6-nitrobenzoyl)triphenyl phos phoranyl ideneacetate and the salt methyl(triphenylphosphoranylidene)acetate tetrafluoroborate

Canadian Journal of Chemistry ◽

10.1139/v98-211 ◽

1998 ◽

Vol 76 (12) ◽

pp. 1844-1852

Author(s):

Fernande D Rochon ◽

Robert Melanson ◽

Margaret M Kayser

Keyword(s):

Key Words ◽

Crystal Structures ◽

Nitro Derivative ◽

Transient Species ◽

X Ray Diffraction ◽

X Ray ◽

Ionic Salt ◽

Higher Temperature ◽

Cyclic Anhydrides ◽

Wittig Reactions

At lower temperatures stabilized ylides react with unsymmetrically substituted phthalic anhydrides to give two acyclic adducts. When the reactions are allowed to proceed at higher temperature enol lactones are formed. Identification of the acyclic intermediates was necessary to understand the mechanism of these Wittig reactions. The transient species trapped in the reaction with trimethyloxonium tetrafluoroborate were unambiguously identified by crystallographic methods. The crystal structures of the tetrafluoroborate salt of methyl(triphenylphosphoranyl idene)- acetate (8), methyl(3-methoxy,2-methoxycarbonylbenzoyl)triphenylphosphoranylideneacetate (6β), and methyl(2-methoxycarbonyl,6-nitrobenzoyl)triphenylphosphoranylideneacetate (7α) were studied by X-ray diffraction. The ionic salt (8) is monoclinic, P21c,a= 12.640(5), b = 13.945(9), c = 14.825(6) Å, β = 125.32(3)°, Z = 4, and R = 0.065 (F >5.4 σ(F)). Crystal 6 β is monoclinic, P21c,a = 16.391(16), b = 9.029(6), c = 19.835(19) Å, β = 116.60(6)°, Z = 4, and R = 0.070 (F > 4.6 σ(F)), while crystal 7α is also monoclinic, P21c,a = 9.513(5), b = 9.361(3), c = 30.908(13) Å, β = 98.42(3)°, Z = 4, and R = 0.057 (F >5 σ(F)). In the BF 4- salt (12), the four P-C distances are equal (1.791(5)-1.801(7) Å) with identical tetrahedral angles. For the two triphenylphosphoranylideneacetate compounds, the fourth P-C(1) bond is shorter (1.762(6)-1.734(5) Å) than the three P-C(Ph) bonds (avg. 1.809(5) Å). The angles C(1)-P-C(Ph) are also larger (avg. 112.9(2)° for 6β and 111.9(2)° for 7α) than the C(Ph)-P-C(Ph) angles (avg. 105.8(2)° for 6 β and 106.9(2)° for 7α). These values suggest a multiple nature for the P-C(1) bond. In the nitro derivative, the nitro and the ester groups are disordered equally in positions 2 and 6. Key words: Wittig reactions, cyclic anhydrides, stabilized ylide, phosphoranylidenes, crystal structures.

Download Full-text

Synthesis and aldol cyclotrimerization of 4,7-di-tert-butylacenaphthenone

Canadian Journal of Chemistry ◽

10.1139/v06-062 ◽

2006 ◽

Vol 84 (10) ◽

pp. 1268-1272 ◽

Cited By ~ 5

Author(s):

Aaron W Amick ◽

Keith S Griswold ◽

Lawrence T Scott

Keyword(s):

Key Words ◽

Crystal Structures ◽

Silica Gel ◽

Room Temperature ◽

Titanium Tetrachloride ◽

X Ray ◽

Synthetic Intermediates

An efficient gram scale synthesis of the previously unknown 4,7-di-tert-butylacenaphthenone (3b) is reported. The facile isomerization of epoxide 9b to ketone 3b occurs simply on stirring a solution of 9b with silica gel at room temperature. Aldol cyclotrimerization of 3b with titanium tetrachloride gives 2,5,8,11,14,17-hexa-tert-butylde cacyclene (1b) in 58% isolated yield. X-ray crystal structures have been obtained for the synthetic intermediates 4,7-di-tert-butylacenaphthene (2b) and 4,7-di-tert-butylacenaphthylene (8b).Key words: aromatic, decacyclene, hydrocarbon, nonalternant, polycyclic.

Download Full-text

A 13C Spin-Lattice Relaxation Study of the Effect of Substituents on Rigid-Body Rotational Diffusion in Methylene Chloride Solution and in the Solid State

The Journal of Physical Chemistry ◽

10.1021/j100062a019 ◽

1994 ◽

Vol 98 (11) ◽

pp. 2844-2847 ◽

Cited By ~ 4

Author(s):

Xiaorong Tang ◽

Alan J. Benesi

Keyword(s):

Solid State ◽

Rigid Body ◽

Chloride Solution ◽

Methylene Chloride ◽

Rotational Diffusion ◽

Lattice Relaxation ◽

Spin Lattice Relaxation ◽

Spin Lattice ◽

Methylene Chloride Solution ◽

Relaxation Study

Download Full-text

Nuclear magnetic resonance studies of ketone.BF3 complexes. I. Exchange reactions in methylene chloride solution

Canadian Journal of Chemistry ◽

10.1139/v68-350 ◽

1968 ◽

Vol 46 (12) ◽

pp. 2147-2157 ◽

Cited By ~ 25

Author(s):

R. J. Gillespie ◽

J. S. Hartman

Keyword(s):

Chloride Solution ◽

Methylene Chloride ◽

Chemical Exchange ◽

Exchange Process ◽

Exchange Reactions ◽

Methylene Chloride Solution ◽

Donor Acceptor ◽

Group 3 ◽

Proton Resonances ◽

Increasing Temperature

1H and 19F n.m.r. studies of BF3 adducts of some simple methyl ketones in methylene chloride solution have led to the following conclusions. (1) Only 1:1 adducts are formed which are not appreciably dissociated. (2) The down-field shifts of the proton resonances caused by complexation with BF3 are essentially independent of the ketone and depend only on the distance of the proton from the carbonyl group. (3) BF3 exchange is rapid on the n.m.r. time scale at room temperature, but the exchange process can be slowed sufficiently by lowering the temperature that separate signals due to free and complexed species can be observed. (4) Collapse of the 10B−11B isotope shift with increasing temperature showed that a second chemical exchange process, which exchanges fluorine among boron atoms, occurs in addition to the process of rapid breaking and re-forming of donor–acceptor bonds. A possible mechanism for this fluorine scrambling reaction is discussed.

Download Full-text

The reaction of some propargyl alcohols with benzeneselenenyl chloride

Canadian Journal of Chemistry ◽

10.1139/v81-134 ◽

1981 ◽

Vol 59 (6) ◽

pp. 927-934 ◽

Cited By ~ 12

Author(s):

Dennis G. Garratt ◽

Pierre L. Beaulieu ◽

Veronique M. Morisset

Keyword(s):

Chloride Solution ◽

Methylene Chloride ◽

Kinetic Control ◽

Methylene Chloride Solution ◽

Propargyl Alcohols

The reaction of benzeneselenenyl chloride with twenty-two propargyl alcohols in methylene chloride solution is reported. Products of both Markownikoff and anti-Markownikoff regiochemistry are formed in an anti stereospecific manner. The regioselectivity or specificity is found to be very dependent upon the nature of the substituents geminal to the alcoholic moiety. In general the presence of bulky substituents geminal to the alcoholic moiety tend to favour formation of the anti-Markownikoff adduct under conditions of kinetic control. The Markownikoff adducts are found to be favoured thermodynamically.

Download Full-text