The Reaction of Ru3(CO)12 with 1,4-dichloro-but-2-yne in basic methanolic solution. Synthesis and crystal structure of (m-H)2Ru3(CO)9{m3-h2-[H2C=C(H)CºCC(=O)OCH3]}.

The title complex is obtained by reacting Ru3(CO)12 with 1,4-dichloro-but-2-yne (ClCH2C„CCH2Cl, DCB) in CH3OH/KOH solution (followed by acidification with HCl). The X-ray structure analysis shows that (l-H)2Ru3(CO)9{l3-g2- [H2C@C(H)CCC(@O)OCH3]} complex contains a ‘‘parallel’’ ene-yne acetyl substituent, H2C@C(H)C„CC(@O)OCH3; the formation of such a ligand starting from DCB is – to our knowledge – unprecedented. The synthesis of complex (l- H)2Ru3(CO)9{l3-g2-[H2C@C(H)CCC(@O)OCH3]} occurs through the activation of CO and methanol. This process has been found for other reactions of functionalized alkynes with M3(CO)12 carbonyls (M = Fe, Ru) under basic methanolic conditions. The known hydridic cluster, (l-H)Ru3(CO)9[l3-g3-(MeCCHCH)] has been identified as the minor reaction product.