Reactions of aluminium(i) with transition metal carbonyls: scope, mechanism and selectivity of CO homologation† † Electronic supplementary information (ESI) available: X-ray crystallographic data for 2–4 are available from the Cambridge Crystallographic Data Centre (CCDC 2095244–2095254) as a .cif file, full details of the experiments and calculations are available as a .pdf. Primary data (NMR, IR, and xyz coordinates) can be downloaded from DOI: 10.14469/hpc/8698. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/d1sc04940b

ABSTRACT: Over the past few decades, numerous model systems have been discovered that create carbon–carbon bonds from CO. These reactions are of potential relevance to the Fischer–Tropsch process, a technology that converts syngas (H2/CO) into mixtures of hydrocarbons. In this paper, a homogeneous model system that constructs carbon chains from CO is reported. The system exploits the cooperative effect of a transition metal complex and main group reductant. An entire reaction sequence from C1 → C2 → C3 → C4 has been synthetically verified. The scope of reactivity is broad and includes a variety of transition metals (M = Cr, Mo, W, Mn, Re, Co), including those found in industrial heterogeneous Fischer–Tropsch catalysts. Variation of the transition metal fragment impacts the relative rate of the steps of chain growth, allowing isolation and structural characterisation of a rare C2 intermediate. The selectivity of carbon chain growth is also impacted by this variable; two distinct isomers of the C3 carbon chain were observed to form in different ratios with different transition metal reagents. Based on a combination of experiments (isotope labelling studies, study of intermediates) and calculations (DFT, NBO, ETS-NOCV) we propose a complete mechanism for chain growth that involves defined reactivity at both transition metal and main group centres. A homogeneous model system that constructs carbon chains from CO is reported. The system exploits the cooperative effect of a transition metal complex and main group reductant. An entire reaction sequence from C1 → C2 → C3 → C4 has been synthetically verified.

SUBMITTER: Kong R 

PROVIDER: S-EPMC8597845 | biostudies-literature |

REPOSITORIES: biostudies-literature