A new family of long-lived alkane sigma-complexes of the type (L-OEt)Re(CO)(2)(alkane) [alkane = cyclopentane, cyclohexane, pentane; L-OEt = cyclopentadienyltris(diethylphosphito)cobaltate(III)] has been observed using both IR and NMR spectroscopies and computationally interrogated with DFT methods. The oxygen-rich coordination spheres makes these complexes perhaps more relevant as models for intermediates in metal oxide mediated hydrocarbon transformations than other known alkane sigma-complexes.