Reaction of Fe 3(CO) 12 with but-2-yn-1,4-diol, 1,4-dichloro-but-2-yne, propargyl-alcohol and propargyl-chloride. : The X-ray structures of [Fe 2(CO) 6{H 2CCCCH 2}], [Fe 2(CO) 6{H 2CCC(H)C(OCH 3)O}] and Fe 3(CO) 10{H 2CCC(H)C(O)C{CH 2(O)CH 3}CCH 2}

Abstract

The reactions of Fe 3(CO) 12 with but-2-yn-1,4-diol (BUD), 1,4-dichloro-but-2-yne (DCB), propargyl alcohol (PA) and propargyl chloride (PC) in KOH/CH 3OH solutions (followed by acidification with HCl) and under thermal conditions have been examined. The complex Fe 2(CO) 6{H 2CCCCH 2} is the main product of the reactions with BUD or DCB in all conditions. The complexes Fe 2(CO) 6{H 2CCC(H)C(OMe)O} and Fe 3(CO) 10{H 2CCC(H)C(O)C{CH 2(O)CH 3}CCH 2} are the main products obtained respectively in the reactions with propargyl chloride (PC) or propargyl alcohol (PA) in basic methanolic solution. The structures of the three complexes have been determined by means of X-ray analysis. Complex Fe 2(CO) 6{H 2CCCCH 2} contains a butatrienyl ligand in an uncommon structural arrangement. The formation of complex Fe 2(CO) 6{H 2CCC(H)C(OMe)O} requires CO and methanol activation; its ferrole like structure contains a coordinated acetate group. Complex Fe 3(CO) 10{H 2CCC(H)C(O)C{CH 2(O)CH 3}CCH 2} contains one Fe(CO) 4 and one Fe 2(CO) 6 fragments linked through a carbon atom chain derived from the insertion of CO and dimerization of propargyl alcohol (with substitution of OCH 3 from methanol in the place of OH). Comments on the syntheses and on the reaction pathways leading to the complexes are made.