Cations cationic monochloride complex

Furthermore, using low Fe/MAO ratios, it has been shown that the activation reaction of la by MAO does not reach completion, with a cationic monochloride complex [2,6- (2,6- Pr2QH3)N=CMe 2C5H3N]FeCl being the only species observed. 

The iodine cation forms iodine monochloride (IC1) in a medium having sufficiently high concentration of HC1 and the latter is subsequently stabilized by complex ion formation. Thus, we have ... 

The catalytically active species formed by the treatment of 2,6-bis(imino) pyridine iron(II) chloride complexes with MAO is generally proposed to be a highly reactive monomethylated iron(ll) cation [LFe-Me] (L = 2,6-bis(imino)pyridine ligand) bearing a weakly coordinating counteranion [Me-MAO]. Both monochloride and monoalkyl cationic species are expected to be present in the solution, their relative concentration depending on the MAO/Fe ratio [24]. 

Pyridine and iodine react in the vapour phase, giving small amounts of 3,5-di- and pentaiodopyridine. The use of iodine monochloride does not improve the yield, and considerable amounts of 2-chloropyridine result . Molten pyridine hydrochloride reacts with iodine to give some penta-iodopyridine , but the yield is better v when the very stable pyridine hydrochloride-iodine complex is heated at 280-290°. At 280° the hydrochloride is said also to form, with iodine or iodine monochloride, 2-pyridyl-pyridinium chloride, via 2-halogenation . Iodine in 50 per cent oleum at 300-320° converts pyridine into 3-iodo- (18 per cent) and some 3,5-di-iodo-pyridine, and 2-picoline at 200-210° gives 5-iodo-2-methylpyridine. It is probable that the oleum functions here rather like the aluminium chloride in the experiments discussed above, generating the reactive iodine cation . 

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