Cyclohexyneplatinum(0) Complexes Containing Di-t-butylphenylphosphine, t-butyldiphenylphosphine or Trimethylphosphine

1992 ◽  
Vol 45 (1) ◽  
pp. 135 ◽  
Author(s):  
MA Bennett ◽  
HG Fick ◽  
GF Warnock
Keyword(s):  
Pure State ◽  
Room Temperature ◽  
Main Product ◽  
Similar Reaction ◽  
Molar Proportion ◽  
Sodium Amalgam ◽  
Tertiary Phosphines

Cyclohexyneplatinum (0) complexes Pt(C6H8)L2 [L = PBut2Ph(4), PbutPh2(5)] analogous to the known complex (3) (L=PPh3) have been prepared by reaction of the two-coordinate complexes PtL2 with 1,2-dibromocyclohexene and 1% sodium amalgam. The corresponding tricyclohexylphosphine complex is formed by a similar reaction but it could not be isolated in a pure state. Attempts to prepare analogues of (4) and (5) containing cycloheptyne or cyclooctyne were unsuccessful, possibly because the bulky t-butyl groups of the tertiary phosphines hinder coordination of the larger rings. Bulky tertiary phosphines do not displace PPh3 from (3) but trimethylphosphine reacts with (3) to give successively Pt(C6H8)(PMe3)2(PPh3) (10) and Pt(C6H8)(PMe3)2 (11), as shown by 31P{1H) n.m.r. spectroscopy. The tertiary phosphines in these complexes equilibrate rapidly at room temperature in benzene and only (10) can be isolated as a solid from the reaction. Complexes (4) and (5) react with HCl (1 molar proportion) to give n1-cyclohexen-l-yl complexes trans- PtCl (C6H9)L2 [L= PBut2Ph(6), PButPh2 (7)]. In the absence of air, (4) reacts with methanol at 65°C to give the hydrido complex trans- PtH (C6H9)(PBut2Ph)2 (8). In the presence of oxygen from the air, however, the main product is the dioxygen complex Pt(O2)(Pbut2Ph)2 (9). This represents an unusual example of complete displacement of cyclohexyne from a platinum(0) complex by a π-acceptor ligand.

Die Reaktion des weißen Phosphors mit Tetrachlorkohlenstoff unter dem Einfluß von Y-Strahlung, Licht und Wärme

1962 ◽  
Vol 17 (11) ◽  
pp. 703-711 ◽  
Author(s):  
D. Perner ◽  
A. Henglein
Keyword(s):  
Activation Energy ◽  
Carbon Tetrachloride ◽  
Room Temperature ◽  
Main Product ◽  
Thermal Reaction ◽  
White Phosphorus ◽  
Low Molecular Weight ◽  
Red Phosphorus ◽  
Γ Radiation ◽  
A Chain

Red phosphorus, phosphorus trichloride, trichloromethylphosphorus dichloride, hexachloroethane and a polymer consisting of carbon and chlorine are formed when solutions of white phosphorus in carbon tetrachloride are exposed to γ-radiation. Red phosphorus is the main product at room temperature. However, its yield rapidly decreases at higher temperatures and the yields of the low molecular weight products strongly increases. Typical G-values:The formation of the products PCl3 and CCl3PCl2 occurs by a chain reaction between phosphorus and carbon tetrachloride. A mechanism is proposed in which free radicals from the radiolysis of carbon tetrachloride attach the dissolved white phosphorus. The propagation of the chain is caused by chlorine transfer from carbon tetrachloride to partly trichloroalkylated or chlorinated phosphorus chains or rings. The activation energy of this transfer is found to be equal to 8.2 kcal/mole. This reaction with carbon tetrachloride is favored at high temperature while the competing process of the combination of those intermediate phosphorus chains and rings to give red phosphorus prodominates at low temperature. The red phosphorus formed contains one CCl3 group per 7 atoms of phosphorus. It was possible to synthesize trichloromethylphosphorus dichloride, trichloromethylphosphorus tetrachloride and trichloromethylphosphorus dibromide by treating the red phosphorus with chlorine or bromine, respectively.The thermal reaction between phosphorus and carbon tetrachloride also leads to PCl3 and CCl3PCl2 (ratio 1:3). Small amounts of red phosphorus and C2Cl6 could be traced too. The activation energy of the thermal reaction amounts to 22.2 kcal/moles. The photo reaction (visible light) leads to the same products. However, red phosphorus still is the main product at 100°C.

Synthesis of new substituted dihydroheptalene derivatives: SiO2- and base-catalyzed rearrangement of dimethyl trans-3,8-dihydroheptalene-3,8-dicarboxylate

2001 ◽  
Vol 79 (1) ◽  
pp. 35-41
Author(s):  
Nurullah Saraçoglu ◽  
Abdullah Menzek ◽  
Armagan Kinal ◽  
Metin Balci
Keyword(s):  
Room Temperature ◽  
Heat Of Formation ◽  
Major Product ◽  
Similar Reaction ◽  
Am1 Calculations ◽  
Hydrogen Shift ◽  
Proton Shift ◽  
Major Isomer ◽  
Prolonged Reaction Time ◽  
Lower Heat

Dimethyl trans-3,8-dihydroheptalene-3,8-dicarboxylate (trans-3) isomerizes to dimethyl cis-3,8-dihydroheptalene-3,8-dicarboxylate (cis-3) upon treatment with SiO2. On the other hand, base-catalyzed reaction of trans-3 undergoes a direct 1,3-intramolecular proton shift to give 6 at room temperature in 5 min. Prolonged reaction time formed isomers 7 and 8 in a ratio of 4:1. AM1 calculations indicate that the isomer 8, which is formed as minor product, has a lower heat of formation (–99.34 kcal mol–1) than that of the major isomer 7 (–92.05 kcal mol–1). However, when a similar reaction was performed at 100°C, the thermodynamically more stable isomer 8 was formed as the major product. Furthermore, cycloaddition reactions of these new dihydroheptalene derivatives 6 and 7 with different dienophiles have been studied. The mechanism has been discussed.Key words: dihydroheptalene, cycloaddition, 1,3-hydrogen shift, cycloheptatriene–norcaradiene equilibrium.

THE MERCURY PHOTOSENSITIZED REACTIONS OF BENZENE AT HIGH TEMPERATURES

1951 ◽  
Vol 29 (3) ◽  
pp. 233-242 ◽  
Author(s):  
E. J. Y. Scott ◽  
E. W. R. Steacie
Keyword(s):  
High Temperatures ◽  
Room Temperature ◽  
Main Product ◽  
Main Reaction ◽  
Kcal Mole ◽  
Detailed Mechanism ◽  
Maximum Value ◽  
Secondary Reactions

An investigation has been made of the mercury photosensitized decomposition of benzene at high temperatures. Practically no reaction occurs at room temperature. At higher temperatures the main product is diphenyl although even at 400°C. the maximum value of [Formula: see text] is 0.1. Ediphenyl has been found to be 13 kcal. mole−1. There is evidence that an activated molecule mechanism occurs. The secondary reactions are complex and it is not possible to arrive at a detailed mechanism, but the probable main reaction steps have been pointed out.

Studies of the acylarylnitrosamine reaction. I. The use of nitrosylsulfuric acid in the preparation of unsymmetrical biaryls

1967 ◽  
Vol 45 (13) ◽  
pp. 1539-1542 ◽  
Author(s):  
Yusuf Ahmad ◽  
M. Ikram Qureshi ◽  
M. Ibrahim Baig
Keyword(s):  
Pure State ◽  
Room Temperature ◽  
Nitrosylsulfuric Acid

Nitrosylsulfuric acid, which is very easy to prepare in a pure state and is quite stable at room temperature, has been found to be a very suitable reagent for the nitrosation of acylarylamines. The nitroso derivatives can be isolated easily, and on decomposition in benzene have yielded unsymmetrical biaryls in improved yields. Some of the nitrosations that could not be achieved earlier have now been accomplished successfully by this method.

Déplacements homolytiques intramoléculaires. 2. Décomposition du perpentène-4 oate de tert-butyle dans les éthers

1984 ◽  
Vol 62 (11) ◽  
pp. 2385-2390 ◽  
Author(s):  
A. Kharrat ◽  
C. Gardrat ◽  
B. Maillard
Keyword(s):  
Double Bond ◽  
Main Product ◽  
Similar Reaction ◽  
Tert Butyl ◽  
Lower Temperature ◽  
Induced Decomposition

The thermolysis of tert-butyl perpent-4-enoate 1 in THF led to several compounds; the main product, 5-(2-tetrahydrofuryl)-4-pentanolide (yield 42%) comes from an induced decomposition of the perester occurring with the addition of 2-tetrahydrofuryl radical to the double bond. A similar reaction was performed at a lower temperature, using butyl perdicarbonate as initiator, but did not define the mechanism (concerted or two-step). The thermolysis of 1 in ethers (THP, oxepane, 1,4-dioxane, dipropyl ether) appears to be a useful synthetic tool: several new γ-lactones have been obtained in this way.

A Potential New RAFT - Click Reaction or a Cautionary Note on the Use of Diazomethane to Methylate RAFT-synthesized Polymers

2011 ◽  
Vol 64 (4) ◽  
pp. 433 ◽  
Author(s):  
Ming Chen ◽  
Graeme Moad ◽  
Ezio Rizzardo
Keyword(s):  
Molecular Weight ◽  
Methyl Methacrylate ◽  
Room Temperature ◽  
Click Reaction ◽  
Raft Polymerization ◽  
Dipolar Cycloaddition ◽  
Low Molecular Weight ◽  
Similar Reaction ◽  
Poly Methyl Methacrylate ◽  
End Groups

It has been found that diazomethane undergoes a facile 1,3‐dipolar cycloaddition with both dithiobenzoate RAFT agents and the dithiobenzoate end‐groups of polymers formed by RAFT polymerization. Thus, 2‐cyanoprop‐2‐yl dithiobenzoate on treatment with diazomethane at room temperature provided a mixture of stereoisomeric 1,3‐dithiolanes in near quantitative (>95%) yield. A low‐molecular‐weight RAFT‐synthesized poly(methyl methacrylate) with dithiobenzoate end‐groups underwent similar reaction as indicated by immediate decolourization and a quantitative doubling of molecular weight. Higher‐molecular‐weight poly(methyl methacrylate)s were also rapidly decolourized by diazomethane and provided a product with a bimodal molecular weight distribution. Under similar conditions, the trithiocarbonate group does not react with diazomethane.

Organothallium Compounds. XV. Thallation of Polyfluoroaromatic Compounds

1979 ◽  
Vol 32 (4) ◽  
pp. 737 ◽  
Author(s):  
GB Deacon ◽  
D Tunaley
Keyword(s):  
Trifluoroacetic Acid ◽  
Sodium Acetate ◽  
Room Temperature ◽  
Sodium Iodide ◽  
Trifluoromethanesulfonic Acid ◽  
Boiling Water ◽  
Similar Reaction ◽  
Aqueous Sodium ◽  
Organothallium Compounds

Thallic trifluoromethanesulfonate has been prepared by reaction of trifluoromethanesulfonic acid with either thallic oxide or solutions of thallic trifluoroacetate in trifluoroacetic acid, and has been isolated as the trihydrate on crystallization fromnitromethane. The polyfluoroarenes,p-CH3OC6F4H, p-CH3C6F4H, m-H2C6F4, o-H2C6F4, p-H2C6F4, C6F5H, 1,3,5-F3C6H3 or 1,2,4-F3C6H3, have been thallated by thallic trifluoromethanesulfonate in trifluoroacetic acid, giving the corresponding poly- fluorophenylthallium(III) bis(trifluoromethanesulfonates), which have been characterized spectroscopically and by conversion into the corresponding (polyfluoro)iodobenzenes on treatment with sodium iodide. Only slight thallation of m-BrC6F4H and m-O2NC6F4H was observed. By contrast with thallic trifluoromethanesulfonate, thallic trifluoroacetate in trifluoroacetic acid induced little thallation of the most reactive polyfluorobenzene, p-CH3OC6F4H. Thallic trifluoromethanesulfonate also thallated p-CH3OC6F4H in nitromethane, sulfolane, and with the substrate as solvent, but p-CH3C6F4H failed to react. Treatment of the polyfluorophenylthallium(III) bis(trifluoromethane- sulfonates) with boiling aqueous sodium acetate caused symmetrization into the corresponding acetatobis(polyfluorophenyl)thallium(III) compounds. A similar reaction between 2,4,6-trifluoro- phenylthallium(III) bis(trifluoromethanesulfonate) and sodium acetate at room temperature yielded 2,4,6-trifluorophenylthallium(III) diacetate. 2,3,4,6-Tetrafluorophenylthallium(III) bis(trifluor0- methanesulfonate) was converted by boiling water into bis(2,3,4,6-tetrafluorophenyl)thallium(III) trifluoromethanesulfonate.

The radiation chemistry of dihydromyrcene

1967 ◽  
Vol 45 (2) ◽  
pp. 101-108 ◽  
Author(s):  
John L. Brash ◽  
Morton A. Golub
Keyword(s):  
Hydrogen Evolution ◽  
Pure State ◽  
Room Temperature ◽  
Benzene Solution ◽  
Radiation Chemistry ◽  
Cross Linking ◽  
Double Bonds ◽  
Trans Isomerization ◽  
The Cross ◽  
G Value

Dihydromyrcene was irradiated with 1-MeV electrons at room temperature both in the pure state and in benzene solution. The main reactions observed, and their G-values for the pure diisoprene, were loss of unsaturation (~7.8–9.9), cross-linking (or dimerization) (2.4–2.6), evolution of hydrogen (0.81), and trans → cis isomerization (< 0.5). As with squalene, the loss of double bonds in dihydromyrcene occurred only in the cross-linked residue, obtained on distillation of the irradiated isoprenoid. Although the residue (mainly dimer, with some trimer) was considered to be partially cyclized, no cyclization of uncross-linked (monomeric) dihydromyrcene was observed. Dihydromyrcene in 10% benzene solution (by weight) showed trans → cis and cis → trans isomerization with G-values of 0.63 and 1.2, respectively, hydrogen evolution with a G-value of 0.08, and a higher rate of loss of original unsaturation than in the pure state.

scholarly journals Beiträge zur Chemie des Phosphors, 85 Synthese und Eigenschaften der Diphosphirane (t-BuP)2CMe2 und (t-BuP)2CH2 Contributions to the Chemistry of Phosphorus, 85 Synthesis and Properties of the Diphosphiranes (t-BuP)2CMe2 and (t-BuP)2CH2

1978 ◽  
Vol 33 (11) ◽  
pp. 1208-1213 ◽  
Author(s):  
Marianne Baudler ◽  
Franz Saykowski
Keyword(s):  
Ir Spectra ◽  
Elemental Analysis ◽  
Pure State ◽  
Vacuum Distillation ◽  
Room Temperature ◽  
Mass Determination ◽  
Tert Butyl ◽  
Dimeric Compound ◽  
Molecular Mass Determination ◽  
Cyclocondensation Reactions

The first three-membered P2C heterocycles, 1,2-di-tert-butyl-3,3-dimethyl-diphosphirane, (t-BuP)2CMe2 (1), and 1,2-di-tert-butyl-diphosphirane, (t-BuP)2CH2 (2), were synthesized by [2 + 1] cyclocondensation reactions of K(t-Bu)P-P(t-Bu)K with 2,2-dichloropropane and dichloromethane, respectively. Both compounds could be isolated in a pure state by vacuum distillation. Whereas 1 is surprisingly stable under inert condi­tions, 2 dimerizes already at room temperature to form the six-membered cyclocarbaphosphane 1,2,4,5-tetra-tert-butyl-cyclo-3,6-dicarba-1,2,4,5-tetraphosphane, (t-BuP)4(CH2)2 (3).The diphosphiranes 1 and 2 were characterized by elemental analysis, osmometric molecular mass determination, mass, NMR, and IR spectra. The t-butyl groups are situated on opposite sides of the P2C ring, whereas the dimeric compound 3 possesses an “all-trans” configuration of the organyl substituents.

scholarly journals A Bridging Carbonyl of Unlikely Geometry: On the True Nature of the Technetium Complex [Tc2(μ-CO)2(CO)6(NC5H5)2]

2020 ◽  
Author(s):  
Miguel Ruiz ◽  
Daniel García-Vivó
Keyword(s):  
Density Functional Theory ◽  
Title Compound ◽  
Density Functional ◽  
Room Temperature ◽  
Main Product ◽  
Density Functional Theory Calculations ◽  
Crystallographic Data ◽  
Chemical Information ◽  
Functional Theory ◽  
True Nature

The title compound was reported a decade ago by Zuhayra et al as the main product of the reaction of [Tc2(CO)10] with pyridine at room temperature. Chemical information, coupled to density functional theory calculations, have now been used to show that the "bridging carbonyls" then proposed from the crystallographic data most likely correspond to bridging hydroperoxide groups. <br>

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