16574-56-4Relevant academic research and scientific papers
Experimental Evaluation of (L)Au Electron-Donor Ability in Cationic Gold Carbene Complexes
Carden, Robert G.,Lam, Nathan,Widenhoefer, Ross A.
supporting information, p. 17992 - 18001 (2017/11/27)
29Si NMR spectroscopy was employed to evaluate the electron donor properties of the (L)Au fragments in the cationic gold (β,β-disilyl)vinylidene complexes [(L)Au=C=CSi(Me)2CH2CH2Si(Me)2]+B(C6F5)4? [L=P(tBu)2o-biphenyl or NHC] relative to the p-substituted aryl group in the α-aryl-(β,β-disilyl)vinyl cations [(p-C6H4X)-C= CSi(Me)2CH2CH2Si(Me)2]+B(C6F5)4?. Similarly, 19F NMR was employed to evaluate the σ- and π-electron donor properties of the (L)Au fragments in the neutral gold fluorophenyl complexes (L)Au(C6H4F) and in the cationic (fluorophenyl)methoxycarbene complexes [(L)AuC(OMe)(C6H4F)]+SbF6? [L=P(tBu)2o-biphenyl or IPr] relative to the p-substituted aryl group of the protonated monofluorobenzophenones [(p-C6H4X)(C6H4F)COH]+OTf?. The results of these studies indicate that relative to p-substituted aryl groups, the gold (L)Au fragments [L=P(tBu)2o-biphenyl or NHC] are significantly more inductively electron donating and are comparable π-donors and for this reason, the extent of (L)Au→C1 electron donation in gold carbene complexes appears to exceed that provided by a p-(dimethyamino)phenyl group. Furthermore, the [L=P(tBu)2o-biphenyl]Au fragment is a nominally stronger electron donor than the (IPr)Au fragment, and both are significantly more inductively electron donating than the (PPh3)Au and [P(OMe)3]Au fragments.
Preparation of aryl carbonyl compounds
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, (2008/06/13)
Friedel Crafts preparation of aryl carbonyl compounds having an exceptionally high degree of isomeric purity and freedom from by-products can be achieved by adding to the Lewis acid reaction system a protic controlling agent selected from ROX, water, RCOOX, RSO3 X, and ROY, wherein R is organic, X is hydrogen or metal, and Y is metal. Contrary to conventional expectation, the protic agent does not significantly alkylate or acylate the Friedel Crafts reaction product.
Polymerisation and Related Reactions involving Nucleophilic Aromatic Substitution. Part 1. The Rates of Reaction of Substituted 4-Halogenobenzophenones with the Potassium Salts of Substituted 4-Hydroxybenzophenones
Ridd, John H.,Yousaf, Taher I.,Rose, John B.
, p. 1729 - 1734 (2007/10/02)
The rate of displacement of fluorine from 4'-X,4-fluorobenzophenones by the potassium salts of 4'-X,4-hydroxybenzophenones (X = CF3, Cl, F, H, OPh, and OMe) has been studied at 175-225 deg C in diphenyl sulphone as solvent.Comparison with the corresponding rate of displacement of chlorine indicates that the reaction is a bimolecular nucleophilic aromatic substitution.The reaction obeys the Hammett equation using normal ? values for substitution in both the substrate (ρ 1.19) and the phenolate (ρ -0.53).There is also a marked salt effect on the reaction rate and this has been included with the substituent constants in a general equation for the calculation of rate coefficients.The effect of an O- substituent is more marked than would have been expected from the previous range of ? values ascribed to this substituent.
Polimerisation and Related Reactions involving Nucleophilic Aromatic Substitution. Part 2. The Rates of Reaction of Substituted 4-Halogenobenzophenones with the Salts of Substituted Hydroquinones
Lovering, Jonathan R.,Ridd, John H.,Parker, David G.,Rose, John B.
, p. 1735 - 1738 (2007/10/02)
4-X-4'-fluorobenzophenones undergo the expected nucleophilic substitution reactions with the alkali metal salts of 4-Y-4'-hydroxydiphenyl ethers at 140 deg C in diphenyl sulphone as solvent: the Hammett ρ value is 1.02 for the X substituents and -0.34 for the Y substituents.The order of reactivity of the alkali metal salts is Cs > K > Na.The related reaction of fluorobenzophenone with potassium 4-Z-phenolates under the same conditions gives a ρ value of -2.28.This result has been used to calculate the corresponding rate coefficients for the reaction of the mono- and di-potassium salts of hydroquinone with fluorobenzophenone.
