Complexes with perchlorate ion

In TT-complexes formed from aromatic compounds and halogens, the halogen is not bound to any single carbon atom but to the 7r-electron structure of the aromatic, though the precise geometry of the complexes is uncertain. The complexes with silver ions also do not have the silver associated with a particular carbon atom of the aromatic ring, as is shown by the structure of the complex from benzene and silver perchlorate. ... 

Dissertation Washington University St. Louis, 1979]. From data for the analogous cobalt(III) complex with perchlorate and hexafluorophosphate as anions, he found association constants of about 900 and 300, with distances of closest approach of 5 or 6 8, respectively. These values seem reasonable. For the iron(II) compound with the hexafluorophosphate or perchlorate, the ion association constants were too small to measure (< - 50). 

The catalysis of the cleavage of carbon-halogen bonds by complexation with metal ions such as silver or mercuric ion is a well-known phenomenon. The compounds susceptible to this action are alkyl halides capable of forming car-bonium ions. The complexed anions such as in mercuric nitrate, mercuric perchlorate, or hydrated mercuric ion do not exhibit a simple relationship between their effect on the total rate and on the relative distribution of products stemming from water or the anion. This evidence is indicative of the following catalytic mechanism ... 

The only complex of a linear quadridentate that has been studied by X-ray tecWques is that of [Pd(as4me)Cl]C104-CeHe (as4me = o-phenylenebis-o-dimethylarsinophenylmethylarsine) (XVI) (26). The pentacoordinate complex cation crystallizes with perchlorate ions in an ionic lattice in which benzene molecules are included as a clathrate. The cation has a square-pyramidal coordination (XVII), with a chlorine atom in the basal plane in which the palladium atom is coplanar with the four attached atoms (the palladium, chlorine, and three arsenic... 

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