Organic chemistry of dinitrogen and related ligands. Part 2. Non-radical acylation of ligating dinitrogen

Summary Ligating dinitrogen, in the complexes,trans-M(N₂)₂(Ph₂PCH₂CH₂PPh₂)₂ (where M=Mo or W) may be acylated by trifluoroacetic anhydride, to give trifluoroacetyldiazenido complexes in high yield. Unlike corresponding reactions with acyl halides, trifluoroacetylation proceeds under nonradical conditions, and a mechanism analogous to that of protonation is suggested.Dinitrogen-derived ligands may also be acylated by (CF₃CO)₂O, so that the methyldiazenido ligand is converted into a methyl (trifluoroacetyl) hydrazido (2-) ligand, and the acetyldiazenido ligand undergoes transacylation to give a trifluoroacetyl diazenido derivative.New complexes were characterised by i.r.,¹⁹F and¹H n.m.r. spectra, and by elemental analysis.Part 1 is ref. 10     

Transition Metal Substituted Phosphanes: Synthesis,Reactivity and Pyramidal Inversion

Abstract

The synthesis of transition metal substituted phosphanes C₅H₅(CO)₂M-PPh₂, C₅H₅(CO)₂(Me₃P)M-PPh₂ (M [dbnd] Mo, W) and C₅H₅(CO)(Me₃P)FePPhR (R [dbnd] Me, Ph) is described as well as their reactivity towards a series of electrophilic and oxidizing reagents.     

The isolation and X-ray structure of a complex between lithium picrate and dibenzo-36-crown-12

The crystal structure of 2Li picrate.dibenzo-36-crown-12.2H₂O was determined by X-ray diffraction methods. The 2:1 (metal:ligand) complex crystalli     

Prediction of cathodic E1/21 and E1/22 values for viologen-containing conjugated unimers and dimers from calculated pKb values of the aromatic substituents

A library of 18 conjugated, rod-like compounds with either one or two viologen residues were synthesized and characterized electrochemically. Containing up to 8 aromatic/heterocyclic rings in conjugation, the members of the library differ in the substitution pattern of electron-withdrawing or -donating groups on the aromatic substituents of the viologen units. The first and second half-wave potentials of each member were found to be linearly correlated with the calculated pK_b values of the aromatic end-groups. This relationship will enable the half-wave potentials of related, novel, substituted viologen species to be predicted using a simple, empirical formula.