Synthesis, characterization and chemistry of some long chain alkoxycarbonyl manganese pentacarbonyl complexes [Mn(CO) 5{C(O)OR}] (where R= n-C 7H 15 to n-C 10H 21, n-C 12H 25, n-C 14H 29, and n-C 16H 33)

Abstract

The long chain alkoxycarbonyl complexes, [Mn(CO) 5{C(O)OR}], where R=CH 2R′, and R= n-C 7H 15 to n-C 10H 21, n-C 12H 25 and n-C 16H 33, have been synthesized by the reactions of the acyl complexes [Mn(CO) 5{C(O)R′}], where R′= n-C 6H 13 to n-C 9H 19, n-C 11H 23 and n-C 15H 31, with synthesis gas in hexane. In addition, the complexes [Mn(CO) 5{C(O)OR}] (R= n-C 9H 19 and n-C 14H 29) have been synthesized by the reactions of the alkyl complexes [Mn(CO) 5R′′], where R′′= n-C 8H 17 and n-C 13H 27, with synthesis gas in hexane. These new alkoxycarbonyl complexes have been fully characterized by elemental analysis, melting point, IR, 1H-NMR, 13C-NMR and mass spectroscopy. The thermal behaviour of these complexes has been investigated by differential scanning calorimetry and thermal gravimetry analysis. The reaction of the acyl complex [Mn(CO) 5{C(O)C 11H 23}] with synthesis gas in THF gave [Mn 2(CO) 10] (95%) and the alcohol n-C 12H 25OH (92%). The reaction of the alkoxycarbonyl complex [Mn(CO) 5{C(O)OC 12H 25}] with synthesis gas in hexane at 85°C gave the formate HCO 2C 12H 25 (66%), the alcohol n-C 12H 25OH (33%) and [Mn 2(CO) 10] (96%). The same reaction as above in THF yielded the formate HCO 2C 12H 25 (12%), the alcohol n-C 12H 25OH (46%) and the ester CH 3(CH 2) 3CO 2C 12H 25 (43%) as well as [Mn 2(CO) 10] (63%). These studies show that the reactions of the acyl complexes [Mn(CO) 5{C(O)R′}], the alkyl complexes [Mn(CO) 5R′′] and the alkoxycarbonyl complexes [Mn(CO) 5{C(O)OR}] with synthesis gas are both solvent and temperature dependent.