Chemistry is an experimental science, and the best way to enjoy it and learn about it is performing experiments. category: catalyst-palladium. Introducing a new discovery about 72287-26-4, Name is [1,1′-Bis(diphenylphosphino)ferrocene]dichloropalladium(II)
Di([5]trovacenyl)ethyne, di([5]trovacenyl)butadiyne, and di-1,4-([5]trovacenylethynyl)benzene: Electrocommunication and magnetocommunication mediated by -C?C-, -C?C-C?C- and -C?C-C6H4-C?C- spacers
The synthesis of dinuclear derivatives of trovacene (eta7- C7H7)V(eta5-C5H5) (V) is reported, in which ethynyl (6..), butadiynyl (7..), and 1,4-di(ethynyl)phenyl (8..) groups serve as spacers between paramagnetic (S = 1/2) [5]trovacenyl units. The mononuclear precursors [5]trovacenylcarbaldehyde (2.) and [5]trovacenylacetylene (4 .) are also described. Structural characterization by X-ray diffraction has been performed for 4., 6.., 7 .., and 8… Electronic communication as gleaned from cyclic voltammetry only manifests itself in the reduction processes where redox splitting deltaE1/2(0/1-, 1-/2-) is resolved for 6.. (deltaE1/2 = 150 mV) and indicated for 7.. (deltaE1/2 ? 80 mV). Magnetocommunication leads to exchange coupling of the two electron spins which reside in vanadium centered orbitals. The values JEPR(6..) = (-)0.92, JEPR(7 ..) = (-)0.56, and JEPR(8..) = (-)0.005 cm -1 are derived from the 51V hyperfine patterns. Accordingly, attenuation of exchange interaction by oligoalkyne spacers is weak, corresponding to a factor of 0.6 only per added -C?C- unit. In the determination of very weak long distance exchange interactions, EPR excels because of the range 5 ¡Á 10-4 ? J ? 1.5 cm -1 accessible in the case of 51V as a reporting magnetic nucleus and because competing intermolecular exchange is quenched in dilute fluid solution. This is demonstrated by the value Jchi(7 ..) = -3.84 cm-1 obtained from a magnetic susceptibility study, which exceeds JEPR(7..) by a factor of 7. The small magnitude of spin exchange interaction between trovacene units reflects the fact that the spin bearing V3dz2 orbital is virtually orthogonal to the pi-perimeter ligand orbitals and weakly overlapping only with the a 1g(sigma) ring orbitals, creating two bottlenecks for spin-exchange in the spacer-containing ditrovacenes.
Note that a catalyst decreases the activation energy for both the forward and the reverse reactions and hence accelerates both the forward and the reverse reactions.category: catalyst-palladium, you can also check out more blogs about72287-26-4
Reference£º
Chapter 1 An introduction to palladium catalysis,
Palladium/carbon catalyst regeneration and mechanical application method