Hydrocarbon-bridged metal complexes .39. Chemistry of pentacarbonyl-rhenium-acetylides.

Hydrocarbon-bridged Metal Complexes, XXXIX. Chemistry of Pentacarbonyl-rhenium-acetylides. As a by-product in the preparation of (OC)(5)Re-C=C-Re(CO)(5) (1) from [(OC)(5)Re(mu-eta(1):eta(2)-C=CH)Re(O)(5)]BF4 and K[KBEt3] the new fluxional hydride-bridged cluster (OC)(5)Re-C=C-Re(CO)(4)[HRe(CO)(4)] (2) is obtained. (OC)(5)Mn-C=C-Mn(CO)(5) (4) is available from [(OC)(5)Mn(eta(1):eta(2)-C=CH)Mn(CO)(5)]BF4 (3) and K[HBEt3]. Reaction of 1 with Me3O+BF4- gives the sigma,pi-bridged complex [(OC)(5)Re(mu-eta(1):eta(2)-C=CMe)Re(CO)(5)]BF4 (5). The alkynyl complex (OC)(5)Re-C=C-SiMe3 (6) can be prepared by reaction of Na[Re(CO)(5)] with 1-tosyl-2-trimethylsilyl-ethyne. The reaction of tosylethyne with Na[Re(CO)(5)] affords (OC)(5)Re-C=CH (7) and (OC)(5)Re-C(H)=C(H)(tosyl) (9). Complex 7 is also formed by cleavage of the Me3Si group from 6. (OC)(5)ReOSO2CF3 reacts with Li(en)C=CH to give the chelate carbamoyl complex (OC)(4) ReNH2CH2CH2NHCO (8). Elimination of CO from (OC)(5)Re-C=C-Re(CO)(5) gives the tetrameric sigma,pi-acetylide-bridged cluster [(OC)(5)Re-C=C-Re(CO)(4)](2) (11). Similarly, [Me3Si-C=C-Re(CO)(4)](2) (12) is formed from Me3Si-Re(CO)(5). The structures of 2, 9, 11 and 12 were determined by X-ray diffraction. As by-products from the thermolysis of 1 and 7, [Re(CO)(3)OH](4) . 4H(2)O and [(OC)(3)ReOH](4).4(OC)(5)ReCOCH3 were obtained. (C) 1997 Elsevier Science S.A.