Marie-Pierre Santoni

Pentacoordinate iron complexes as functional models of the distal iron in [FeFe] hydrogenases

Mononuclear pentacoordinate iron complexes with a free coordination site were prepared as mimics of the distal Fe (Fe(d)) in the active site of [FeFe] hydrogenases. The complexes catalyze the electrochemical reduction of protons at mild overpotential.

Cascade Reactions Forming Highly Substituted, Conjugated Phospholes and 1,2-Oxaphospholes

More than just a carbon copy: The reaction of a phospha-Wittig-Horner reagent with diacetylenic ketones (see scheme) results in a cascade of reactions that can lead to both an oxaphosphole-terminated cumulene system and an alkene-bridged bis-phosphole. The reaction outcome is determined by the nature of the acetylene termini, with phenyl groups stabilizing a carbene intermediate that dimerizes to give the bis-phosphole product.

C,C-Diacetylenic phosphaalkenes in palladium-catalyzed cross-coupling reactions

The reactivity of bis-TMS-substituted C,C-diacetylenic phosphaalkene (A(2)PA) 1 in Sonogashira-Hagihara cross-coupling reactions has been examined. The selective and successive deprotection of the two silyl groups in 1 is enabled by the steric bulk of the Mes* group which renders the acetylene trans to Mes* more reactive and thereby facilitates selective and consecutive couplings with iodoarenes. In situ transformation of the TMS-protected acetylenes into Cu(i)acetylides is the key step in the synthetic sequence and enables the preparation of the first dimeric A(2)PA linked by a phenylene spacer. cis-trans Isomerization across the P[double bond, length as m-dash]C bond is triggered by a tertiary amine and exclusively observed in the case of nitrophenyl-substituted A(2)PAs. The introduced aryl groups are integral parts of the entire π-system as evidenced by spectroscopic and electrochemical studies.

Cooperative Gold Nanoparticle Stabilization by Acetylenic Phosphaalkenes

Acetylenic phosphaalkenes (APAs) are used as a novel type of ligands for the stabilization of gold nanoparticles (AuNP). As demonstrated by a variety of experimental and analytical methods, both structural features of the APA, that is, the P=C as well as the C≡C units are essential for NP stabilization. The presence of intact APAs on the AuNP is demonstrated by surface-enhanced Raman spectroscopy (SERS), and first principle calculations indicate that bonding occurs most likely at defect sites on the Au surface. AuNP-bound APAs are in chemical equilibrium with free APAs in solution, leading to a dynamic behavior that can be explored for facile place-exchange reactions with other types of anchor groups such as thiols or more weakly binding phosphine ligands.

Toward Metathesis Reactions on Vinylphosphaalkenes

Abstract Attempts to utilize C-ethylenic phosphaalkenes in metathesis reactions are discussed. Unprecedented reactivity is observed where the vinylphosphaalkene undergoes the first step of the catalytic cycle and cross-metathesis with the phenylmethylene moiety of Grubbs 2nd generation catalyst. However, homo-metathesis reaction to form 1,6-diphosphahexa-1,3,5-triene is not observed, presumably due to steric constraints. GRAPHICAL ABSTRACT

CCDC 849360: Experimental Crystal Structure Determination

Related Article: Giovanny A. Parada, Lisa A. Fredin, Marie-Pierre Santoni, Michael Jager, Reiner Lomoth, Leif Hammarstrom, Olof Johansson, Petter Persson, and Sascha Ott|2013|Inorg.Chem.|52|5128|doi:10.1021/ic400009m