Hexafluoro-2-butyne, CF(3)Cequivalent toCCF(3), reacts with the triangulo-clusters [Pt-3 (mu-CO)(3)(PR3)(3)] to give the diplatinum(o) compounds [Pt-2(CO)(2)(PR3)(2)(mu-eta(2):eta(2)-CF(3)Cequivalent toCCF(3))] {PR3=PPh3 (1), PBzPh(2) (2), PCy3 (3), (PPr3)-Pr-i (4)}. Spectroscopic properties are reported which are in accord with the molecular structures for 1 and 3, both having the acetylenic C-C axis perpendicular to the Pt-Pt axis, bridging two [Pt(CO)(PR3)] fragments in a mu-eta(2):eta(2) fashion. A large excess of hexafluorobutyne slowly converts 1 and 2 to the diplatinum(II) complexes [Pt-2(CO)(2)(PR3)(2) (mu-eta(1):eta(1)-CF(3)Cequivalent toCCF(3))(2)]{PR3=PPh3 (5), PBzPh(2) (6)}, having two planar hexflauorobutyne bridges. This stereochemistry has been established by NMR and IR spectra, and confirmed by single-crystal X-ray diffraction.