strength 0.1 F. The spectrophotometric pKa values were obtained at two different "wavelengths, agreement always being better than ±0.03 units. The error in reported p2fa values is estimated to be less than ±0.05 pKa units. Solubilities were determined spectrophotometrically at 27 ± 2°and are estimated to be accurate to within ±5%.

SzamnaryThe tetrapyridine copper (I) cation has been WE have prepared several relatively stable copper (I)synthesized, characterized and found to have a regular perchlorate complexes which have nitrogen heterocycle tetrahedral structure ; no infrared active Cu-N stretching ligands. The unexpected properties of some of these comvibration was observed. pounds suggested an investigation of their structure ; we

Ionic copper(1) perchlorates, trico-ordinated by heterocyclic amines, have been prepared, characterized, and found to have trigonal hybridization about Cu; unusually high magnetic moments and Cu-N stretching frequencies are associated with some of these complexes.

No abstract

Reduction products are observed in amine-copper(I) perchlorate promoted decomposition of aryldiazonium salts when the amine ligands are capable of hydrogen atom donation. The effective reducing agents evidently are the complexed rather than the free ligands, i.e., the tris(amine)copperd) cation in the case of tetraand tricoordinated salts and the bis(amine)copper(I) cation in the dicoordinated systems, in the presence of excess ligand a new product is obtained, which is probably an ammonium salt formed from the amine and the incipient aryl cation. In the absence of hydrogen-donating ligands it has been shown that the small but consistent amount of benzophenone formed in the copper®-promoted decomposition of 2-diazobenzophenone tetrafluoroborate arises from (a) the precursor to 9-fluorenone and (b) the solvent, water. Hydrogen atom abstraction from both these sources is rate determining and subject to a kinetic isotope effect. Since water is a notoriously poor hydrogen atom donor, transfer of a hydrogen atom from the equated coordination sphere of copper® via a bridged intermediate is postulated.