摘要：

The interaction between Cu(I) centers is studied by means of molecular orbital calculations on Cunn+, n = 2-4, model dimers with phosphonium ylide bridges, and tetramers with alkyl bridges. In the absence of metal s and p functions the expected closed-shell repulsion between the d10 centers is evident. Mixing of metal s and p orbitals converts this repulsion into a slight attraction in Cu(I) clusters of any size. A severe perturbation is caused by the introduction of the bridging ligands, which impose their own stereochemical requirements. Nevertheless, weak attractive Cu(I)-Cu(I) interactions remain.

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