16529-66-1Relevant articles and documents
Conformational stability from variable temperature FT-IR spectra of xenon solutions and ab initio calculations of trans 3-pentenenitrile and 3-methyl-3-butene nitrile
Guirgis,Shen,Drew,Durig
, p. 551 - 554 (2001)
The infrared (3500-40 cm-1) spectra of gaseous, liquid and solid 3-methyl-3-butene nitrile, CH2C(CH3)CH2CN, and trans 3-pentenenitrile, CH3CHCHCH2CN, have been recorded. Both the cis and ga
Rational design of efficient steric catalyst for isomerization of 2-methyl-3-butenenitrile
Han, Minghan,Liu, Kaikai,Wang, Tiefeng
, (2020)
The catalytic isomerization of 2-methyl-3-butenenitrile (2M3BN), a model reaction in the DuPont process, has been performed using NiL4 (L=tri-O-p-tolyl phosphite) as a catalyst. The lowered catalytic activity in the isomerization with coexistence of 2-pentenenitrile (2PN) and 2-methyl-2-butenenitrile (2M2BN) indicates that both 2PN and 2M2BN are the catalyst inhibitors, and the quantitative relationship between the conversion of 2M3BN and the content of 2M2BN and 2PN is provided. DFT calculation results suggest that the inhibition effect is attributed to the generation of dead-end intermediates (2PN)NiL2 and (2M2BN)NiL2, both of which take nickel atom out of the catalytic cycle in the isomerization process. To suppress the inhibition effect, new catalytic intermediates are rationally designed based on their computational %Vbur. An efficient method that adding extra ligand 1, 5-bis(diphenylphosphino)pentane (dppp5) to the NiL4 catalyst is selected experimentally. Compared to the results obtained with NiL4 as catalyst, the (dppp5)NiL2 increases the conversion of 2M3BN from 74.5 % to 93.4 % at 3 h of reaction and provides a high selectivity to 3PN (> 98 %) at optimal conditions.
Solvent effects and activation parameters in the competitive cleavage of C-CN and C-H bonds in 2-methyl-3-butenenitrile using [(dippe)NiH]2
Swartz, Brett D.,Reinartz, Nicole M.,Brennessel, William W.,Garcia, Juventino J.,Jones, William D.
, p. 8548 - 8554 (2008)
The reaction of [(dippe)NiH]2 with 2-methyl-3-butenenitrile (2M3BN) in solvents spanning a wide range of polarities shows significant differences in the ratio of C-H and C-CN activated products. C-H cleavage is favored in polar solvents, whereas C-C cleavage is favored in nonpolar solvents. This variation is attributed to the differential solvation of the transition states, which was further supported through the use of sterically bulky solvents and weakly coordinating solvents. Variation of the temperature of reaction of [(dippe)NiH]2 with 2M3BN in decane and N,N-dimethylformamide (DMF) allowed for the calculation of Eyring activation parameters for the C-CN activation and C-H activation mechanisms. The activation parameters for the C-H activation pathway were ΔH? = 11.4 ± 5.3 kcal/mol and ΔS? = -45 ± 15 e.u., compared with ΔH? = 17.3 ± 2.6 kcal/mol and ΔS ? = -29 ± 7 e.u. for the C-CN activation pathway. These parameters indicate that C-H activation is favored enthalpically, but not entropically, over C-C activation, implying a more ordered transition state for the former.
Ni(4?Tbustb)3: A robust 16-electron Ni(0) olefin complex for catalysis
Nattmann, Lukas,Cornella, Josep
supporting information, p. 3295 - 3300 (2020/10/12)
Sixteen-electron Ni(0) complexes bearing trans-stilbene derivative ligands have been shown to display a high degree of stability toward oxidation in the solid state. A structural analysis of a unique family of tris Ni(0) stilbene complexes revealed a remarkable effect of the steric hindrance of the substituents at the para position of the stilbene unit to temperature, oxidation, and degradation in solution. From these analyses, Ni(4?tBustb)3 arose as a long-term air-, bench-. and temperature-stable Ni(0) complex. Importantly, Ni(4?tBustb)3 presents faster kinetic profiles and a broader scope as a Ni(0) source, thus outperforming the previously described Ni(4?CF3stb)3 in a variety of relevant Ni-catalyzed transformations.
δ-deuterium isotope effects as probes for transition-state structures of isoprenoid substrates
Choi, Seoung-Ryoung,Breugst, Martin,Houk, Kendall N.,Poulter, C. Dale
, p. 3572 - 3580 (2014/05/06)
The biosynthetic pathways to isoprenoid compounds involve transfer of the prenyl moiety in allylic diphosphates to electron-rich (nucleophilic) acceptors. The acceptors can be many types of nucleophiles, while the allylic diphosphates only differ in the number of isoprene units and stereochemistry of the double bonds in the hydrocarbon moieties. Because of the wide range of nucleophilicities of naturally occurring acceptors, the mechanism for prenyltransfer reactions may be dissociative or associative with early to late transition states. We have measured δ-secondary kinetic isotope effects operating through four bonds for substitution reactions with dimethylallyl derivatives bearing deuterated methyl groups at the distal (C3) carbon atom in the double bond under dissociative and associative conditions. Computational studies with density functional theory indicate that the magnitudes of the isotope effects correlate with the extent of bond formation between the allylic moiety and the electron-rich acceptor in the transition state for alkylation and provide insights into the structures of the transition states for associative and dissociative alkylation reactions.
