CHARGE STABILIZATION IN CATIONIC ANTHRONYL-SUBSTITUTED ALKYNES - SYNTHESIS, CHARACTERIZATION AND X-RAY MOLECULAR-STRUCTURES OF M2L6 COMPLEXED ALKYNYL-SUBSTITUTED C10-ANTHRONE [M2L6(MU,ETA(2),ETA(2)-(RC)-C-2-C-C(OR1)(C13H8O))] (M2L6 = CO-2(CO)(6), MOCOCP(CO)(5))

A series of the novel M2L6-complexed alkynyl-substituted C10-anthrone derivatives were prepared and fully characterized. Furthermore, the X- ray molecular structures of three complexes belonging to this family w ere determined with the general formula M2L6(mu,eta(2),eta(2)-(RC)-C-2 =C-C(OR1)(C13H8O))], M2L6 = Co-2(CO)(6), R-1 = CH3, R-2 = H 5; M2L6 = MoCoCp(CO)(5), R-1 = CH3, R-2 = H 7 and M2L6 = Co-2(CO)(6), R-1 = CH3, R-2 = C6H5 8. Addition of HBF4 to the compounds oCp(CO)(5)(mu,eta(2), eta(2)-HC=C-C(OR1)(C13H8O))], R-1 = H 6; R-1 = CH3 7, produced the cat ionic counterpart CoCp(CO)(5)(mu,eta(2),eta(2)-HC=C-C(C13H8O))]+BF4- 9 . The charge stabilization in this novel carbenium ion possessing an a nthrone fragment was investigated and showed that the dinuclear cluste r alleviates the positive charge at the C10 carbon center. Further, th e reactivity of these carbenium ion towards nucleophiles was also exam ined. (C) 1997 Elsevier Science S.A.