Three products Re-2[Pt(PBu3t)](mu-SbPh2)(CO)(8)(mu-H), 2, Re-2[Pt(CO)(PBu3t)]Ph(CO)(8)(mu(3)-SbPh)(mu-H), 3, and Re-2[Pt(PBu3t)](2)-(CO)(8)(mu(4)-Sb2Ph2)(mu-H)(2), 4, were obtained from the reaction of Re-2(CO)(8)(mu-SbPh2)(mu-H), 1, with Pt(PBu3t)(2). Compound 3 was also obtained from 2 by further reaction with Pt(PBu3t)(2). Compound 2 is a Pt(PBu3t) adduct of 1 formed by the insertion of the platinum atom into one of the Re-Sb bonds of 1 with formation of two Pt-Re bonds. Compound 3 contains an open Re2Pt cluster and was also obtained in a low yield by the addition of CO to 2. The addition of SbPh3 to 2 yielded the compound Re2Pt(PBu3t)(Ph)(CO)(8)(SbPh3)(mu(3)-SbPh)(mu-H), 5, a SbPh3 derivative of 3. Compound 4 can be viewed as a dimer of the fragment Re[Pt(PBu3t)](CO)(4)(SbPh)(mu-H). The two halves of the molecule are held together by Pt-Sb bonds and a significant interaction directly between the Sb atoms, Sb-Sb distance, 2.9834(7) angstrom. The Sb-Sb bonding in 4 was explained by density functional calculations. Compound 4 adds 2 equiv of CO at 1 atm/25 degrees C, one to each platinum atom, to yield the compound [Re(CO)(4)Pt(H)(CO)(PBu3t)(mu(3)-SbPh)](2) which exists as a mixture of two noninterconverting isomers, cis-6 and traps-6. Both isomers of 6 were isolated and structurally characterized. Each isomer of 6 consists of a central planar Re2Sb2 core composed of two Re(CO)(4) groups with two bridging SbPh ligands. There is a Pt(H)(CO)(PBu3t) group coordinated to each antimony atom of 6. In the cis-isomer both Pt(H)(CO)(PBu3t) groups lie on the same side of the Re2Sb2 plane. In the transisomer the Pt(H)(CO)(PBu3t) groups lie on opposite sides of the Re2Sb2 plane.