The trans-influence: its measurement and significance

Towards a rigorously defined quantum chemical analysis of the chemical bond in donor–acceptor complexes☆

Mehrfachbindungen zwischen Hauptgruppenelementen und Übergangsmetallen: CXXVI. Heterocyclen-Carbene als phosphananaloge Liganden in Metallkomplexen

Reactions of β-functional phenyl isocyanides

The iron−sulfur-cluster-free hydrogenase Hmd (H2-forming methylenetetrahydromethanopterin dehydrogenase) from methanogenic archaea has recently been found to contain one iron associated tightly with an extractable cofactor of yet unknown structure. We report here that Hmd contains intrinsic CO bound to the Fe. Chemical analysis of Hmd revealed the presence of 2.4 ± 0.2 mol of CO/mol of iron. Fourier transform infrared spectra of the native enzyme showed two bands of almost equal intensity at 2011 and 1944 cm-1, interpreted as the stretching frequencies of two CO molecules bound to the same iron in an angle of 90°. We also report on the effect of extrinsic 12CO, 13CO, 12CN-, and 13CN- on the IR spectrum of Hmd.

Carbon monoxide as an intrinsic ligand to iron in the active site of the iron-sulfur-cluster-free hydrogenase H2-forming methylenetetrahydromethanopterin dehydrogenase as revealed by infrared spectroscopy.

F. A. Cotton

Papers

Vibrational Spectra and Bonding in Metal Carbonyls. I. Infrared Spectra of Phosphine-substituted Group VI Carbonyls in the CO Stretching Region