2,6-Lutidine metal complexes

N-Do/Jor Ligands. The full account of the preparation and properties of V[N(SiMc3)2]3 has been published. (Et4N)3[V(NCSe)e] has been prepared and its electronic spectrum reported in several solvents. The electronic spectra of fVL lfNCSij complexes (L = py, 3-picoline, 3,4-lutidine, or 3,5-lutidine) are consistent with tetrahedral microsymmetry about the V " atom, and the magnetic properties of V complexes with the thiosemicarbazones of salicylaldehyde and pyruvic acid have been interpreted in terms of a tetragonal environment about the metal. ... 

Only for lutidine has this been confirmed, wherein the isomerizations occur with specific rate constants of >103 sec-1 (172— tj1) and 36 10 sec-1 (tj1 — r)2) for the Os(III) and Os(II) complexes, respectively. It is worth noting that the resulting complex, [Os(NH3)5(Af-2,6-lutidine) ]3+, cannot be made by conventional, substitution-based, synthetic methods for Os(III), and is likely to be the only reported example of this molecule bonding to a transition metal through nitrogen. 

Not only complexes but also metal salts that complex with the compounds to be separated can be used as selective complexing stationary phases. For example, Phillips [91] described the use of zinc and copper stearates and nickel oleate for the selective separation of amines. The retentions of aliphatic amines decrease in the order primary > secondary > tertiary. The separation of 7-picoline and 2,6-lutidine on a zinc stearate column is possible if the column efficiency is only 4 theoretical plates and the column is 1 cm long. To effect this separation on a non-selective silicone stationary phase a column with an efficiency of 250,000 theoretical plates is required. Some amines (e.g., ethanolamine... 

The reactivity of [Mo(r] -C5H3N-2,6-Me2)2] is summarized in Scheme 8. The solid-state structure of [ Mo(/x-Cl)(r -C3H5) (r -C5H3N-2,6-Me2) 2] has been determined and shows that the 2,6-lutidine ring is not planar. The nitrogen atom and the /rara-carbon bend in toward the metal center and the two-methyl groups bend away, and differs from the arene systems where the ring remains planar on complexation. 

Various reactivities have been observed for cycloheptatrienylidene palladium complexes in the presence of nitrogen heterocyclic aromatics. Unhindered bases such as pyridines unsubstituted on positions 2 and 6 added to the unsaturations of the carbene backbone leading to a dinuclear allyl palladium complex, whereas 2,6-lutidine reacted with the metal centre to yield a mononuclear carbene complex. Reactions with methylim-idazole were found to give the mononuclear complex when up to two equivalents of imidazole were reacted, but addition on the carbene backbone was observed with 2.5 equivalents. 

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