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15in which the metal-metal separation more closely approaches that of the bis-(dipyrromethene) macrocycles at 5.145 (1) A, the copper(I1) ions are reduced to copper(1) via one dielectronic step.The variability of the nature of the two one-electron reductions of the dicopper(I1) sites suggests the utility of these complexes as catalysts for the activation of small molecules via concurrent two-electron reductions. Of considerable interest, in view of the simultaneous one-electron reduction steps in the CI-, N3-, and NCSsalts, is the potential of these complexes to catalyze the oxidation of organic substrates. Preliminary results in this direction indicate that the azido complex catalyzes the oxidation of 3,5di-tert-butylcatechol in the presence of molecular oxygen. These studies will be reported in detail elsewhere. (28) Agnus, Y . ; Remy, L.; Gisselbrecht, J.-P.; Weiss, R. J. Am. Chem. SOC. 1984, 106, 93-102.Acknowledgment. Support of this research by the University of Kansas Biomedical Sciences Support Grant 4306-071 1-9 is gratefully acknowledged. K.B.M. thanks Prof. Reynold T. Iwamoto for helpful discussions.Registry No. 1 ( n = 3), 98737-20-3; 3,3'-diethyl-5,5'-diformyl-4,4'dimethyldipyrromethane, 967-68-0; 1,3-propanediamine, 109-76-2; Pb2-(bi-dptmd)(SCN),, 98759-99-0; Zn,(bi-dptmd)(CI),, 98760-00-0; Cu2-(bi-dptmd)(CI),, 98760-01-1; Cu2(bi-dptmd)(CIO4),, 98760-02-2; Cu,-(bi-dptmd)(BF,),, 9308 1-48-2; C~2(bi-dptmd)(N~)~.'/~CH,OH, 98760-04-4; Cu2(bi-dptmd)(SCN),, 98760-05-5; Zn2(bi-dpen)(C1),, 98760-06-6; C~~(bi-dpen)(ClO,)~, 98777-04-9; C~~(bi-dptmd)(N,)~, 98760-03-3; ethylenediamine, 107-1 5-3.

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The reactions of the dinuclear phosphorus ylide gold(I) complexes (II) with the alkyl halides RZX, yielding the Au(II) alkyl halide adducts (I), are studied.

sition state the four phosphorus atoms are coplanar with the central metal atom, and the H4 tetrahedron was twisted through 45°with respect to the P4 tetrahedron so that the former is staggered with respect to the latter. The transition state has S4 symmetry. There was no indication in the solution nmr spectra of the departure from symmetry observed in the X-ray crystal structure. The deviation from D2i symmetry is small, and even if the solution structure exhibited the same distortion the effective nmr Hamiltonian would probably have Did symmetry due to rapid intramolecular processes averaging the deviations to zero on the nmr time scale. In this physical process, the PP repulsions are maximized in the transition state, whereas they are minimized in the transition state for the tetrahedral jump mechanism.29 (29) The MPi skeleton in HjMo[P(CeH5)2CHs]« is about midway between a regular tetrahedron and a square plane. Hence the tetrahedral jump mechanism and this one physical alternative require phosphorus atom motions that are antipodal in character.