A Semi‐Empirical Model of the Energy Barrier of Proton Transfer Reactions

Abstract

In the final structure about half the positive charge is located at the iron atom and the other half distributed uniformly over both rings (see table). For comparison the charge at the iron atom in ferrocene is calculated to be + 0.3. This result compares favourably with Mossbawer experiments 1131. Another interesting result of these calculations is that a planar structure (111) should have a triplet groundstate (1.4 eV difference between highest occupied and lowest unoccupied MO) 1141 while the bent structure (V) should have a singlet ground state. Some experiments carried out by Cais et al. 1151 may be explained in this wap. This work is p a r t of project No. SR 2.120.69 of t h e Schweizerzsche Satzolzalfonds. W e wish t o thank thc S A N D O Z AG for computer-time on the U N I V A C 1108.

A Simple and Efficient Method for the Nickel‐Catalyzed Synthesis of Azines from Aldehydes and Hydrazines

“…The lower reaction energy barriers indicate that the cat. 1 surface has highly active sites that accelerate the reaction [15] …”

“…1 surface has highly active sites that accelerate the reaction. [15] It is established from the formula for the reaction of benzaldehyde with hydrazine that two molecules of benzaldehyde are required to participate in the reaction. Therefore, the second stage of the reaction is the formation of the PhCH=NÀ N=CHPh (IM3-TS2-IM4) product.…”

“…entry 13 provides verification of this fact. It should be noted that when no catalyst is used or when (NH 4 ) 6 Mo 7 O 24 or NiSO 4 is used as catalyst, the yields remain relatively unsatisfactory (Table1, entries[13][14][15]. When other POMs were used as catalysts, a significant increase in product was found, suggesting that the central heteroatom of the ligand has an effect on yield in inorganic ligand-loaded catalysts (Table1, entries 16-18).…”