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The first example of polycarbonate membranes (PC) modified using layer-by-layer (LBL) adsorption of a polyelectrolyte (PE)/Au NPs system [PE ) poly(ethylenimine), PEI; poly(acrylic acid) sodium salt, PAA] in which the Au NPs formation occurs via the in situ postdeposition reduction of the incorporated novel gold(III)-aminoethylimidazolium aurate salt [Cl 3 AuNH 2 (CH 2 ) 2 ImMe)][AuCl 4 ] (1) is reported. The reduction of 1 to give gold nanoparticles stabilized by an amino-functionalized ionic liquid (ILNH 2 -Au NPs ), was carried out either by the PAA itself during the LBL deposition or by the combined action of PAA and ascorbic acid, the latter added at the end of the deposition process. The different membranes were characterized with AFM, SEM, TEM, UV-vis, and XRD. The XRD analysis revealed that the presence of ILNH 2 caused a remarkable increase of gold nanoparticles with (111) planes parallel to the PC film. The catalytic activity of the modified membranes in the reduction of 4-nitrophenol to 4-aminophenol by NaBH 4 was investigated and found higher than membranes modified with preformed citrate-stabilized gold nanoparticles (citr-Au NPs ) solutions.

The new tricyclopentadienyllanthanoid metal(III) complexes [LnCp‘ ‘3] are obtained in good yields from the appropriate anhydrous metal(III) triflate or chloride and 3/2 MgCp‘ ‘2 or 3 KCp‘ ‘ in tetrahydrofuran at ambient temperature [Cp‘ ‘ = η5-C5H3(SiMe3)2-1,3 and Ln = La (1) or Pr (3)]. Treatment of the appropriate compound 1 or 3, or [CeCp‘ ‘3] (2) or [NdCp‘ ‘3] (4), with 2 equiv of each ([18]-crown-6) and potassium in benzene at ambient temperature affords the red or red-brown (7) crystalline salts [K([18]-crown-6)][Ln{η5-C5H3(SiMe3)2-1,3}2(C6Η6)] [Ln = La (5), Ce (6), Pr (7), Nd (8)], with [K([18]crown-6)][Cp‘ ‘] as a coproduct. Each of 5−8 is soluble in hot benzene, which allowed the 1H NMR spectra to be recorded. The salt 5 is diamagnetic, consistent with its containing a lanthanate(III) anion. For 6−8, the 1H NMR spectral signals of the ([18]-crown-6) moiety are only slightly paramagnetically shifted. Hydrolysis of 5 (or 6−8) yields cyclohexa-1,4-diene. The molecular structures of the isomorphous salts 5, 6, and 8 reveal that each comprises a tight ion pair, a C6H6 ligand bridging the K and Ln atoms. The potassium atom has close contacts to the six crown ether oxygen atoms and the centroids of the 2,3- and 5,6-carbon atoms of the C6H6 ligand. The latter is boat-shaped, the shortest C−Ln distances being those to the 1- and 4-carbon atoms; the endocyclic bond angles at the 1- and 4-carbon atoms are narrower (110.65 ± 1.15°) than those at the other four (122.4 ± 1.2°), while the four C−C bonds to the 1- and 4-carbon atoms are longer (1.46 ± 0.02 Å) than the remaining two (1.350 ± 0.013 Å). The reaction of [LaCp‘ ‘3] (1) with K and ([18]-crown-6) in benzene, monitored by EPR spectroscopy, reveals the presence of at least four La(II) paramagnetic intermediate species prior to formation of 5.