The present contribution reports experimental and theoretical mechanistic investigations on a normal-to-abnormal (C2-to-C4-bonded) NHC rearrangement processes occurring with bulky group 13 metal NHC adducts, including the scope of such a reactivity for Al compounds. The sterically congested adducts (nItBu)MMe3 (nItBu=1,3-di-tert-butylimidazol-2-ylidene; M=Al, Ga, In; 1 a-c) readily rearrange to quantitatively afford the corresponding C4-bonded complexes (aItBu)MMe3 (4 a-c), a reaction that may be promoted by THF. Thorough experimental data and DFT calculations were performed on the nNHC-to-aNHC process converting the Al-nNHC (1 a) to its aNHC analogue 4 a. A nItBu/aItBu isomerization is proposed to account for the formation of the thermodynamic product 4 a through reaction of transient aItBu with THF-AlMe3 . The reaction of benzophenone with (nItBu)AlMe3 afforded the zwitterionic species (aItBu)(CPh2 -O-AlMe3 ) (6), reflecting the unusual reactivity that such bulky adducts may display. Interestingly, the nItBu/Al(iBu)3 Lewis pair behaves like a frustrated Lewis pair (FLP) since it readily reacts with H2 under mild conditions. This may open the way to future reactivity developments involving commonly used trialkylaluminum precursors.

Polyesters are omnipresent in our everyday lives and their synthesis via eco-friendly methods is becoming a major challenge today. The co-polymerization of cyclic anhydrides and epoxides was first reported by...

A series of cationic gold(I/III) pyridine complexes of the type [(L)Au(pyr)](PF 6 ) and [(L)AuCl 2 (pyr)](PF 6 ), where L = IPr, (1, 5); L = IMes (2, 6); L = I t Bu, (3, 7); L = ICy (4, 8); and L = PPh 3 , (9, 10), were synthesized and characterized by NMR spectroscopy and single-crystal X-ray diffraction. The stability of the new complexes and their catalytic activity in five well-established organic transformations were assessed.

The employment of the hexyl-substituted anion [HexCB 11 Cl 11 ] À allowed the synthesis of a Zn II species, Zn[HexCB 11 Cl 11 ] 2 , 3, in which the Zn 2+ cation is only weakly coordinated to two carborate counterions and that is soluble in low polarity organic solvents such as bromobenzene. DOSY NMR studies show the facile displacement of at least one of the counterions, and this near nakedness of the cation results in high catalytic activity in the hydrosilylation of 1-hexene and 1methyl-1cyclohexene. Fluoride ion affinity (FIA) calculations reveal a solution Lewis acidity of 3 (FIA = 262.1 kJ mol À1) that is higher than that of the landmark Lewis acid B(C 6 F 5) 3 (FIA = 220.5 kJ mol À1). This high Lewis acidity leads to a high activity in catalytic CO 2 and Ph 2 CO reduction by Et 3 SiH and hydrogenation of 1,1-diphenylethylene using 1,4-cyclohexadiene as the hydrogen source. Compound 3 was characterized by multinuclear NMR spectroscopy, mass spectrometry, single crystal X-ray diffraction, and DFT studies.

A set of molecules including a majority of metal-N-heterocyclic carbene (NHC) complexes (metal=Ag, Cu, and Au) and azolium salts were evaluated by high-throughput screening of their activity against biofilm formation associated with pathogenic bacteria. The anti-planktonic effects were compared in parallel. Representative biofilm-forming strains of various genera were selected (Listeria, Pseudomonas, Staphylococcus, and Escherichia). All the compounds were tested at 1 mg L(-1) by using the BioFilm Ring Test. An information score (IS, sum of the activities) and an activity score (AS, difference between anti-biofilm and anti-planktonic activity) were determined from normalized experimental values to classify the most active molecules against the panel of bacterial strains. With this method we identified lipophilic Ag(I) and Cu(I) complexes possessing aromatic groups on the NHC ligand as the most efficient at inhibiting biofilm formation.

Substitution of a trans chloride ligand in the Nheterocyclic carbene (NHC) Au III complexes (NHC)AuCl 3 in the presence of AgNTf 2 yields a new family of (NHC)AuCl 2 (NTf 2 ) complexes. They display a moderate stability in solution but are stable once crystallized. These new organogold(III) complexes could be fully characterized by NMR, IR, and single crystal X-ray diffraction. They exhibit in 13 C{ 1 H} NMR an unusually upfield-shifted resonance associated with the carbene center.

The synthesis, characterization, and PGSE ((1)H and (19)F) NMR diffusion studies on the cationic [(eta(6)-arene)Mn(CO)(3)][X] (arene = anisole, 4-chloroanisole, and 1,3,5-trimethoxybenzene; X = BPh(4) and BArF) are reported. The tetraphenyl borate complexes of anisole and 4-chloroanisole show surprisingly strong ion pairing in dichloromethane solution, whereas the BArF salts do not. (1)H,(1)H-NOESY data support this anion selectivity. In chloroform solution one finds the usual strong ion pairing for both anions. The solid-state structure of [(eta(6)-1,3,5-trimethoxybenzene)Mn(CO)(3)][BPh(4)] has been determined. (13)C NMR and IR data for the new complexes are reported. The observed IR frequencies are higher for the BArF complexes than for the BPh(4) complexes.

The synthesis of (eta5-cyclohexadienyl)Mn(CO)3-based planar chiral ligands is realized by an efficient lithiation/electrophilic quench procedure, and the coordinating properties of one of them are highlighted together with its optical resolution.