2 NEW TETRANUCLEAR RUTHENIUM COMPLEXES - [RU2(CO)5(PPH2)(C2PPH2)]2 WITH 2 DINUCLEAR UNITS LINKED BY 2 PHOSPHINOACETYLIDE BRIDGES AND [RU4(CO)10(PPH)(PHC2PPH2)], A FLATTENED BUTTERFLY WITH A SIGMA-PI-PHENYL(DIPHENYLPHOSPHINO)ETHYNE AND A MU-4 PHOSPHINIDENE EXTRACTED FROM THE BIS(DIPHENYLPHOSPHINO)ETHYNE REACTANT