Chemistry is the experimental science by definition. We want to make observations to prove hypothesis. For this purpose, we perform experiments in the lab. 14187-32-7, Name is Dibenzo-18-crown-614187-32-7, introducing its new discovery.
The photochemical substitution of benzene in [Cb*Co(C 6H6)]+ (Cb* = C4Me 4) with benzo-15-crown-5 (1) gives the corresponding pi-complex [Cb*Co(eta6-C6H4(OCH2CH 2C)CH2CH2)2O)]+ (2). A similar reaction with dibenzo-18-crown-6 (3) produces cation [Cb*Co(eta6-C6H4(OCH2CH 2OCH2CH2O)2C6H 4)]+ (4). Arene exchange is reversible, and both 1 and 3 can be regenerated by irradiation of 2 and 4 with excess benzene. The reaction of [Cb*Co(C6H6)]+ with 0.5 equiv of 3 gives dinuclear complex [trans-Cb*Co(mu-eta6, eta6-C6H4(OCH2CH 2OCH2CH2O)2C6H 4)CoCb*]2+ (5). The structures of cations 4 and 5 were confirmed by X-ray diffraction. The electrochemical behavior of complexes prepared was studied. The sodium-binding ability of cobalt complexes 2,4, and 5 (determined by NMR titration; Ka = 2500, 800, and 50, respectively) was found to be much smaller than that of the free crown ethers 1 and 3 (K a, -200 000 and 5 000 000). DFT calculations suggest that this decrease is mainly due to electrostatic repulsion of Co+ and Na + centers.
Sometimes chemists are able to propose two or more mechanisms that are consistent with the available data.14187-32-7, If a proposed mechanism predicts the wrong experimental rate law, however, the mechanism must be incorrect.Welcome to check out more blogs about 14187-32-7, in my other articles.
Reference£º
Chiral Catalysts,
Chiral catalysts – SlideShare