ETA(2)-ALKINYL AND VINYLIDENE TRANSITION- METAL COMPLEXES .3. REACTIVITY OF ACETYLIDE [(ETA(5)-C5H5)(CO)(NO)W(C-C-R)](-) WITH [(ETA(5)-C5H5)(CO)(2)FE(THF)]BF4 - SYNTHESIS, STRUCTURE AND PHOTOCHEMICAL BEHAVIOR OF A TUNGSTEN IRON ACETYLIDE

Reaction of metalate anion [(eta(5)-C5H5)(CO)(NO)W(C=C-R)](-) (6a R = C6H5, 6b R = C6H4-CH3, 6c R = C(CH3)(3), 6d R = Si(CH3)(3)) with [(eta (5)-C5H5)(CO)(2)Fe(THF)]BF4 as electrophile leads to bimetallic eta(2) -alkyne complexes H5)(CO)(NO)W]eta(2)-(eta(5)-C5H5)(CO)(2)Fe-C=C-R]} 8 a-d in 47-57% yields as brown-red, air-stable crystals. These complexe s are converted to the diastereomeric mixtures of bridged sigma, pi-ac etylides 9a-d/10a-d upon photodecarbonylation. The crystal structures of {[(eta(5)- CO)(NO)W]eta(2)-[(eta(5)-C5H5)(CO)(2)Fe-C=C-C6H5]} 8a an d u-(CO)(NO)W]eta(2)-(eta(5)-C5H5)(CO)Fe-C=C-C6H5)]} 10a were determin ed.