64723-93-9

Upstream product

• 75-07-0 acetaldehyde 
• 74586-02-0 phenylnitrene anion radical 
• 60375-60-2 3-methyl-2-butoxide 
• 117951-43-6 1-methyl-1-butoxide 
• 75-21-8 oxirane 
• 4729-01-5 cyclopentadienylidene anion radical 
• 109-99-9 tetrahydrofuran 
• 10368-73-7 2-bromo-1,3,5-triphenylbenzene 
• 41084-91-7 deprotonated ketene anion 
• 62268-73-9 diphenylcarbene 
• 77354-32-6 N-methylacetamide anion 
• 113534-04-6 1-Phenyl-ethanol anion 

Downstream Products

• 64723-97-3 1,1,1-trifluoroacetone enolate anion 
• 75-07-0 acetaldehyde 
• 119-65-3 isoquinoline 
• 100-46-9 benzylamine 
• 5868-58-6 3-phenyl-5-hydroxy-4,5-dihydroisoxazole 
• 27547-14-4 Aniline monoanion 
• 33567-59-8 (2-methoxy-phenyl)-acetaldehyde 
• 41084-91-7 deprotonated ketene anion 

Relevant academic research and scientific papers

Hypovalent Radicals. 4. Gas-Phase Studies of the Ion-Molecule Reactions of Cyclopentadienylidene Anion Radical in a Flowing Afterglow

The carbene anion radical, cyclopentadienylidene-.(c-C5H4-., 1), was generated by dissociative electron attachment with diazocyclopentadiene (2) in a flowing afterglow apparatus.The ion-molecule reaction of 1 with 2 produced c-C5H4N=N-c-C5H4-., c-C5H4=c-C5H4-., and c-C5H5- by coupling at Nβ and C1 of 2 and H. abstraction from 2, respectively.The PA(1) = 377 +/- 2 kcal mol-1 was determined from bracketing reactions of ROH + 1 -> RO- + c-C5H5., which gives ΔHf0(1) = 70.7 +/- 3.2 kcal mol-1.Although the H. abstraction process by 1 was observed in most of its ion-molecule reactions, 1 failed to react with CH4, C2H4, and c-C3H6 probably because of an activation barrier of (*) 3 kcal mol-1 in these cases.With dipolar CH3OH and 1, the only observed reaction was H. abstraction from the O-H bond (shown with CH3OD).This lower limit of the H. affinity of 1 gives ΔHf0(1) (*) 67.7 +/- 3 kcal mol-1, in excellent agreement with the value derived from protonation studies.The reactions of 1 with CH3X (Cl, Br) occur by H. abstraction and halide ion (SN2) displacement.Anion radical 1 adds to activated olefins H2C=CHX (CN, CO2CH3, Cl) by a nucleophilic Michael addition mechanism.The EA of the carbene c-C5H4 was bracketed by charge-transfer reactions between 1 and C6F6 and NO2.All of these and certain other results are consistent with the ?1?2 electronic configuration as the ground state of 1.The reactions of 1 with alcohols are postulated to proceed via a hydrogen-bonded complex.

Stable "Inverse" sandwich complex with unprecedented organocalcium(I): Crystal structures of [(thf)Mg(Br)-CH-2,4,6-Ph] and [(thf)Ca{μ-CH-1,3,5-Ph}Ca(thf)]

The reaction of bromo-2,4,6-triphenylbenzene with activated magnesium inTHF yielded the Grignard reagent [(thf)2Mg(Br)-C6 H 2-2,4,6-Ph3] (1) with a Mg-C bond length of 214.8(3) pm. A similar reaction of bromo-2,4,6-triphenylbenzene with activated calcium led to an "inverse" sandwich complex [(thf)3Ca{μ-C 6H3-1,3,5-Ph3}Ca(thf)3] (2) with the calcium atoms on opposite sides of the central arene ring showing small Ca-Ca and Ca-C distances of 427.9(3) and 259.2(3) pm. This extremely air- and moisture-sensitive complex exhibits thermochomic and solvatochromic behavior. It is paramagnetic with spin of S = 1 (triplet)with an ESR resonance at g = 2.0023. Quantum chemical calculations shed light on the bonding situation in this very unusual dinuclear Ca(I) com pound.

Unimolecular rearrangements and fragmentations in the gas phase: [1,3] sigmatropic isomerizations and [2+2] cycloreversions

Trimethylsilyl ethers of 3-buten-2-ol, 1-vinylcyclopropanol, 1-vinylcyclobutanol, and cyclobutanol were treated with fluoride over a wide temperature range (-40 to 300°C) in a variable-temperature flowing afterglow-triple quadrupole device. The structures of the resulting alkoxides and enolates were probed by ion-molecule reactions and their collision-induced dissociation (CID) spectra. Activation energies were obtained for several anion-accelerated [1,3] sigmatropic rearrangements and [2+2] cycloreversions. The mechanisms for these isomerizations and fragmentations (stepwise versus concerted) and their synthetic potential are discussed.

Fragmentation of alkoxide ions following collisional activation. An energy-resolved study

The collisionally activated dissociation reactions of the C2 to C5 alkoxide ions have been studied for collisons occurring at 8 keV kinetic energy and also over the range 5 to 100 eV kinetic energy.The alkoxide ions fragment by 1,2-elimination of H2 and/or an alkane.Thus, primary alkoxide ions fragment by elimination of H2 only, secondary alkoxide ions show elimination of H2 and alkane molecules, while tertiary alkoxide ions show elimination of alkanes only.In alkane elimination, loss of CH4 is much more facilie than loss of larger alkanes.For secondary alkoxide ions, where more than one elimination reaction occurs, the energy dependence of fregmentation has been explored over the collision energy range 5 to 100 eV.The results are interpreted in terms of a step-wise mechanism involving formation of an anion-carbonyl compound ion-dipole complex, followed by proton abstraction by the H- or alkyl anion leading to the final products.The relative importance of the reaction channels is determined by the relative stabilities of these ion-dipole complexes.

Models for Strong Interactions in Proteins and Enzymes. 1. Enhanced Acidities of Principal Biological Hydrogen Donors

The acid dissociation energies of several key biological hydrogen donors are found to fall into a narrow range, ΔHoacid=352-355 kcal/mol.The strong acidities of these donor groups enhance the hydrogen bond strengths involved in the protein α-helix, imidazole enzyme centers and DNA.Specifically, the peptide link is modeled by the dipeptide analogue CH3CO-Ala-OCH3.Its acidity is strengthened, i.e. ΔHoacid is decreased by 8 kcal/mol compared with other amides, due to electrostatic stabilization by the second carbonyl in the peptide -CON-CH(CH3)CO- grouping.The acidity of imidazole is also strengthened by 8 kcal/mol compared with that of the parent molecule, pyrrole, primarily due to resonance stabilization of the ion.Hydrogen donor NH2 groups of adenine and cytosine are modeled by 4-aminopyrimidine, and the acidity of this amine group is strengthened by ring aza substitution.An intrinsic acidity optimized for hydrogen bonding strength therefore emerges as a common property of the diverse hydrogen donors in the protein α-helix, enzymes and DNA.This property may therefore be in part responsible for the natural selection of these molecules as principal biological hydrogen donors.

Mechanistic Studies of Gas-Phase Negative Ion Unimolecular Decompositions. Alkoxide Anions

The unimolecular decompositions of 15 gas-phase alkoxide negative ions have been studied by infrared multiple photon photochemical activation in an ion cyclotron resonance spectrometer.Upon pulsed CO2 laser irradiation, alkoxide anions undergo elimination of neutral molecules (e.g., alkanes RH) to yield enolate anions.The observed reactivity patterns and kinetic isotope effects further establish a stepwise decomposition mechanism involving initial heterolytic cleavage to an intermediate anion-ketone complex followed by proton transfer to give the ultimate products.A relative order of leaving group propensities CF3 > Ph > H > t-Bu > Me > i-Pr > Et was observed.The apparent anomalous reactivity order for the alkyl groups can be rationalized by invoking a change in mechanism to one involving an intermediate in which an electron is not bound specifically by the eliminated alkyl group for R + t-Bu, i-Pr, and Et: either a radical-ketone radical anion complex produced by homolytic cleavage or an anionic cluster.This order also leads to the conclusion that methane elimination from alkoxide anions proceeds via the pathway involving heterolytic cleavage.The results of this study have implications for bimolecular ion-molecule reaction dynamics, since the photochemically generated intermediates are also intermediates in bimolecular proton transfer reactions.

Generation, Thermodynamics, and Chemistry of the Diphenylcarbene Anion Radical (Ph2C.-)

Dissociative electron attachment with Ph2C=N produced Ph2C.- (m/z 166).The reactions of Ph2C.- with potential proton donors of known gas-phase acidity were used to bracket PA(Ph2C.-) = 380 +/- 2 kcal mol-1 from which ΔHf0(Ph2C.-) = 81.8 +/- 2 kcal mol-1 was calculated.The reactions of Ph2C.- with CH3OH and C2H5OH proceeded with major and minor amounts, respectively, of a H2.+-transfer channel, forming Ph2CH2, RCHO, and an electron.The kinetic nucleophilicity of Ph2C.- in SN2 displacement reactions with CH3X and C2H5X molecules was shown to be medium, which requires a significant intrinsic barrier in these reaction.The reactions of Ph2C.- with various aldehydes, ketones, and esters were fast and established two principal product-forming channels: (1) H+ transfer if the neutral reactant contains activated C-H bonds and (2) carbonyl addition followed by radical β-fragmentation of one of the groups originally attached to the carbonyl carbon.The order for the ease of radical β-fragmentation in the tetrahedral intermediates was RO > alkyl >> H, and CO2CH3 > CH3.Since the reactions of Ph2C.- with the simple esters HCO2CH3 and CH3CO2CH3 were fast, it should now be possible to examine the reactions of carbonyl-containing organic molecules, which are expected to react slower than these esters and obtain their relative reactivities.

Photoelectron Spectroscopy of CCO- and HCCO-

Using negative ion photoelectron spectroscopy we have measured the electron affinities (EA) of CCO and HCCO.We find EA(CCO) = 1.848 +/- 0.027 eV and EA(HCCO) = 2.350 +/- 0.020 eV.In separate experiments with a flowing afterglow device, we have determined the gas-phase acidity of ketene and report it as ΔH0acid(CH2CO) = 365 +/- 2 kcal/mol.These data afford the ketene bond dissociation energy, DH0298(H-CHCO) = 105.9 +/- 2.1 kcal/mol, and the heats of formation: ΔHf0298(HCCO) = 42.4 +/- 2.1 kcal/mol and ΔHf0298(HCCO-) = -13.3 +/- 2.1 kcal/mol.