Related Products of 111153-74-3, Catalysts are substances that increase the reaction rate of a chemical reaction without being consumed in the process. 111153-74-3, Name is 1-Phenylpiperidine-4-carbaldehyde, molecular formula is C12H15NO. In a Article£¬once mentioned of 111153-74-3
Self-activated supramolecular reactions: Effects of host-guest recognition on the kinetics of the Diels-Alder reaction of open-chain oligoether quinones with cyclopentadiene
Diels-Alder reactions of acyclic oligoether-substituted quinones 1b, 1c, 2b, and 2c with cyclopentadiene were accelerated by the addition of alkali and alkaline earth metal perchlorates, and scandium trifluoromethane sulfonate (kc/kf = 1.2-23 for univalent cations, 11-1160 for divalent cations, and 1700-192 000 for Sc3+, where kc and kf are the rate constants for the metal complexed and uncomplexed quinones, respectively). The shorter-armed 1a, 2a, and 3, however, exhibited no such acceleration effects. The rate accelerations can be rationalized by the FMO consequence in which the bound guest cation withdraws electron density from the quinone dienophile and lowers the LUMO energy suitable for the orbital interaction with the HOMO of cyclopentadiene. Despite the poor cation selectivity, these acyclic oligoether quinones showed larger rate accelerations than the relevant quinocrown ethers 4 (kc/kf = 1.3-3.0 for univalent cations, 5.0-160 for divalent cations, and 100-2020 for Sc3+). The effective electron withdrawal, which leads to the enhanced rate acceleration, can be caused by the direct interaction between the metal cation accommodated in the pseudo-cyclic oligoether linkage and the quinone carbonyl oxygen, as indicated by 1H NMR spectroscopy. In addition, the larger rate enhancement is rather achieved in the complex with low binding constant K, because the strong encapsulation of metal cation by the oligoether chain diminishes the crucial interaction to the quinone carbonyl oxygen. As a whole, the smaller and higher valent cations tend to bring about notable rate acceleration due to the more enhanced ion- dipole interaction with the quinone carbonyl oxygen. Spectroscopic titration (absorption and 1H NMR) and kinetic experiments indicated that only the longest di-armed 2c constructs 1:1, and then 1:2, host/guest complexes with Ca2+, Sr2+, and Ba2+. These 1:2 complexes exhibited the most effective acceleration for the respective metal cations.
Sometimes chemists are able to propose two or more mechanisms that are consistent with the available data. Related Products of 111153-74-3, If a proposed mechanism predicts the wrong experimental rate law, however, the mechanism must be incorrect.Welcome to check out more blogs about 111153-74-3, in my other articles.
Reference£º
Piperidine – Wikipedia,
Piperidine | C5H11751N – PubChem