2136-69-8Relevant academic research and scientific papers
Third-Generation Light-Driven Symmetric Molecular Motors
Kistemaker, Jos C. M.,?tacko, Peter,Roke, Diederik,Wolters, Alexander T.,Heideman, G. Henrieke,Chang, Mu-Chieh,Van Der Meulen, Pieter,Visser, Johan,Otten, Edwin,Feringa, Ben L.
, p. 9650 - 9661 (2017)
Symmetric molecular motors based on two overcrowded alkenes with a notable absence of a stereogenic center show potential to function as novel mechanical systems in the development of more advanced nanomachines offering controlled motion over surfaces. Elucidation of the key parameters and limitations of these third-generation motors is essential for the design of optimized molecular machines based on light-driven rotary motion. Herein we demonstrate the thermal and photochemical rotational behavior of a series of third-generation light-driven molecular motors. The steric hindrance of the core unit exerted upon the rotors proved pivotal in controlling the speed of rotation, where a smaller size results in lower barriers. The presence of a pseudo-asymmetric carbon center provides the motor with unidirectionality. Tuning of the steric effects of the substituents at the bridgehead allows for the precise control of the direction of disrotary motion, illustrated by the design of two motors which show opposite rotation with respect to a methyl substituent. A third-generation molecular motor with the potential to be the fastest based on overcrowded alkenes to date was used to visualize the equal rate of rotation of both its rotor units. The autonomous rotational behavior perfectly followed the predicted model, setting the stage for more advanced motors for functional dynamic systems.
INTERMEDIATES IN THE ELECTROLYTIC REDUCTION OF 2-PYRIDYL-1,3-INDANDIONES IN APROTIC MEDIA
Benders, Yu. A.,Stradyn', Ya. P.,Baider, L. M.,Baumane, L. Kh.,Gavar, R. A.
, p. 193 - 200 (1983)
The character of the products of one-electron reduction of 2-pyridinia-1,3-indandiones (of the phthalone and ylid types) in aprotic media was studied by means of EPR spectroscopy.Free radicals with semidione structures are formed; their hfs constants are presented.Radicals with pyridinium structures are formed only under the condition of the presence of a strong electron acceptor (a cyano group) in the pyridinium ring of the molecule.The formation of unstable intermediates with dimeric structures is postulated as a result of studies by means of cyclical voltammetry.
α-Vinylation of 1,3-Dicarbonyl Compounds with Alkenyl(aryl)iodonium Tetrafluoroborates: Effects of Substituents on the Aromatic Ring and of Radical Inhibitors
Ochiai, Masahito,Shu, Toshifusa,Nagaoka, Takema,Kitagawa, Yutaka
, p. 2130 - 2138 (2007/10/03)
Direct α-vinylations of enolate anions derived from 1,3-dicarbonyl compounds with 4-teri-butyl-1- cyclohexenyl(aryl)iodonium 2 and 1-cyclopentenyl(aryl)iodonium tetrafluoroborates 3 are reported. Frequently, α-phenylations compete with the vinylations in the reaction of 1,3-dicarbonyl compounds with alkenyl(phenyl)iodonium salts 2a and 3a. Use of alkenyl(p-methoxyphenyl)iodonium salts 2b and 3b, however, leads to selective α-vinylation at the expense of the competing arylation of 1,3-dicarbonyl compounds. Use of an efficient aryl radical trap, 1,1-diphenylethylene, inhibits radical-induced decomposition of the alkenyl(aryl)iodonium salts, thereby improving the yields of α-vinylations of enolate anions derived from 1,3-dicarbonyl compounds.
Sigmatropic Indenyl Rearrangements Induced by Electronic Excitation
Padwa, Albert,Goldstein, Steven,Loza, Roman,Pulwer, Mitchell
, p. 1858 - 1868 (2007/10/02)
The photochemical rearrangement of several arylalkyl substituted indenes has been studied.The rearrangements were shown to be derived from the ?,?* singlet state since triplet sensitization led to no reaction or else resulted in a Paterno-Buchi
