Acetonitrile

About: Acetonitrile is a research topic. Over the lifetime, 11298 publications have been published within this topic receiving 175275 citations. The topic is also known as: cyanomethane & ethyl nitrile.

Effect of Polar Protic and Polar Aprotic Solvents on Negative-Ion Electrospray Ionization and Chromatographic Separation of Small Acidic Molecules

Abstract: A comprehensive study investigated the effect of polar protic (methanol and water) and polar aprotic (acetonitrile and acetone) solvents on the chromatographic separation and negative-ion electrospray (ESI) response of 49 diverse small, acidic molecules. Flow injection experiments on a triple quadrupole were used to measure the response in neat solvents after optimization of source conditions and implementation of a rigorous quality control program (the later ensured that changes in analyte response were due to the analyte/solvent measured and not changes in instrument performance over time). In all solvents, compounds with electron-withdrawing groups and extended conjugation ionized best due to resonance and inductive effects. Ionization was greatest in methanol or water for all compounds that elicited a response, thus revealing that enhanced sensitivity and lower limits of detection are achieved with polar protic solvents. Response in acetone was equal to or slightly lower than response in acetonitrile ...

C-H activation of acetonitrile at nickel: ligand flip and conversion of N-bound acetonitrile into a C-bound cyanomethyl ligand.

Abstract: Nickel joins the fairly exclusive list of metals that can activate nitrile C−H bonds. We report the first example of the C−H activation of an acetonitrile ligand on a nickel center. The acetonitrile ligand formally loses a proton and undergoes a sharp flip to give a cyanomethyl ligand that is coordinated to the nickel atom. Structures of an initial N-bound acetonitrile−nickel complex and of a final cyanomethyl−nickel complex are both presented.

High turnover catalysis at bimetallic sites of the hydration of nitriles to carboxamides co-catalysed by acid. Highly specific hydration of acrylonitrile to acrylamide

Abstract: LPd2(MeCONH) and L*Pd2(MeCONH), where L and L* are the binucleating ligands in (1) and (2), respectively, both catalyse hydration of acetonitrile, the acid dependence of which indicates a bimetallic pathway involving concerted action by the two metals and L*Pd2(CH2CHCONH) catalyses specific hydration of acrylonitrile to acrylamide.

Kinetic and thermodynamic character of reducing species produced on pulse radiolysis of acetonitrile

Abstract: During nanosecond pulse radiolysis of liquid acetonitrile a transient optical absorption was observed in the spectral range 500 to 1500 nm. The extreme reactivity of this species towards solutes capable of accepting electrons allowed its assignment as a reducing entity. In the purest liquid prepared this species had a half-life of some 900 ns. Variable temperature studies showed that this reducing species, having an intense maximum near 1450 nm at + 62°C, was drastically reduced in absorption intensity at –40°C, where the decay character changed and a weak maximum was observed near 550 nm. It was concluded that the two species are different chemical forms of a reducing entity joined by an equilibrium. Tentative identification of the reversible change according to (CH3CN)–+ CH3CN ⇌(CH3CN)–2 with the monomeric anion as the infrared absorbing entity was based on thermodynamic considerations and the effects of adding polar liquids. Quantitative examination of the data allowed a value of –34.9 kJ mol–1 to be extracted for the binding energy of the anion dimer. Measurements of the yields of pyrene and trans-stilbene radical anion formed after pulse radiolysis of appropriate solutions led to the evaluation of G(reducing entity)= 1.03. In addition it was found that O– radicals, formed by reaction between (CH3CN)– and N2O, reacted with acetonitrile via both addition and abstraction routes. Further, in solutions containing tetracyanobenzene (TCNB) and O2, capture of the negative entity by O2 was followed by electron transfer from O–2 to TCNB.