Mathieu Razavet

All-iron hydrogenase: synthesis, structure and properties of {2Fe3S}-assemblies related to the di-iron sub-site of the H-clusterElectronic supplementary information (ESI) available: crystal and structure refinement data for complexes 4a, 4b and 5a. See http://www.rsc.org/suppdata/dt/b2/b209690k/

Tripodal dithiolate thioether ligands MeC(CH2SH)2CH2SR (R = Me or Ph) provide a route to {2Fe3S}-complexes and syntheses are described. X-Ray crystal structures for two {2Fe3S}-pentacarbonyl derivatives and that for the first carbonyl cyanide are reported, together with temperature dependent 1H-NMR, Mossbauer, FTIR and redox potential data. The NMR data establish fluctionality associated with inversion at the thioether sulfur in the carbonyl complexes. The Mossbauer data affirm that the coordination environment of the two iron atoms in a dicyanide bridging carbonyl intermediate are differentiated. Bridging carbonyl intermediates have been structurally and spectroscopically identified in resting and CO inhibited forms of the sub-site of all-iron hydrogenases; the observation of a thermally unstable {2Fe3S}-bridging carbonyl intermediate is discussed in this context.

The di-iron subsite of all-iron hydrogenase: Mechanism of cyanation of a synthetic {2Fe3S} - carbonyl assembly

This paper describes the kinetics and intimate mechanisms associated with cyanation of [2Fe3S] assemblies to give species structurally related to the subsite of all-iron hydrogenase. Stopped-flow FTIR spectroscopy has enabled the quantitation of the dynamics of five well-defined steps that experimentally illustrate the role of bridging carbonyls in the assembly of the dicyanide species, how on-off sulfur ligation can have a dramatic effect on cyanation kinetics and how the [2Fe3S] core stabilises bridging carbonyl species.

{2Fe3S} clusters related to the di-iron sub-site of the H-centre of all-iron hydrogenases

The first synthetic {2Fe3S} clusters structurally related to the sub-site of the H-centre of the all-iron hydrogenases are described: tripodal dithiolate thioether ligands allow the synthesis of di-iron pentacarbonyls with differential (2∶3) S ligation of the Fe atoms.

Transient FTIR spectroelectrochemical and stopped-flow detection of a mixed valence {Fe(I)–Fe(II)} bridging carbonyl intermediate with structural elements and spectroscopic characteristics of the di-iron sub-site of all-iron hydrogenase

Iron(I) in biology?: one-electron oxidation of an (Fe(I)-Fe(I)) carbonyl cyanide precursor bearing a proximal thioether group leads to an (Fe(I)-Fe(II)) bridging carbonyl transient with spectral features similar to the di-iron sub-site of the CO inhibited paramagnetic centre of all-iron hydrogenase.

On the structure of a proposed mixed-valent analogue of the diiron subsite of [FeFe]-hydrogenase

We show that a dinuclear assembly apparently providing the first example of a synthetic molecule exhibiting key features of the diiron subsite of [FeFe] hydrogenase, viz. CO-bridging of a coordinatively unsaturated, dithiolate-bridged mixed-valence diiron centre, is in fact a diamagnetic tetranuclear complex.

Synthesis, characterisation and properties of bismuth(iii) ester pendant arm picket porphyrinsElectronic supplementary information (ESI) available: characterisation data for the remainder of the compounds. See http://www.rsc.org/suppdata/dt/b3/b308776j/

A series of porphyrins bearing ester pendant arms has been synthesised. The number of potential coordinating groups was varied from one to four. In the case of the four-picket compounds, the arm length was also investigated. Structural properties towards the coordination of the bismuth(III) cation were studied. In the particular case of the two-picket molecules, the substitution isomers (5,10 or 5,15) were also prepared. An improvement of the rate of metallation was detected in the case of the single-picket porphyrin.