DEHYDRATION, HYDRATION AND SUBSTITUTION-REACTIONS OF THE HYDRIDO ACETYLIDE COMPLEXES HRU3(CO)(9)(C2CR(OH)R') - X-RAY STRUCTURES AND NMR FLUXIONALITY OF HRU3(CO)(7)(DPPM) (C2CME(OH)PH) AND HRU3(CO)(7)(DPPM) (C2C(=CH2)PH)

The complexes HRu3(CO)(9){C2CR(OH)R'} (1) have been obtained by reacti on, in hydrocarbon solution, of Ru,(CO),, with propargyl alcohols of g eneral formula HC,CR(OH)R'. In contrast, reaction of Ru-3(CO)(12) with the alcohols (R = R' = Me, R = Me, R' = Ph) in CH3OH/KOH solution lea ds to formation of the corresponding allenylidene complexes HRu3(CO)(9 ){HC2C(R)R'} (2). The H-1 and C-13 NMR fluxional behaviour of the comp lexes are discussed. The acetylide clusters are stable species and los e water only under drastic conditions (i.e. in the presence of strong acids or on TLC silica), to form vinylacetylide or allenylidene deriva tives according to the nature of the acetylide substituents. The rever se hydration reactions occur with some difficulty. The chiral cluster HRu3(CO)(9){C2CMe(OH)Ph} (1d) reacts with dppm forming the ''bridged'' complex HRu3(CO)(7)(dppm){C2CMe(OH)Ph} (3) which exists bath in the s olid state and in solution as two diastereoisomeric pairs of enantiome rs. The X-ray structure and the NMR fluxionality of complex 3 is discu ssed. Protonation of complex 3 leads to loss of water and formation of HRu3(CO)(7)(dppm){C2C(=CH2)Ph} (4), the X-ray structure of which is a lso discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.