The solubility parameters of multiwalled carbon nanotubes (CNTs) was tuned via their chemical modification with pyrrole compounds (PyCs), by means of a simple and sustainable methodology. PyCs were synthesized with high atom efficiency through the Paal–Knorr reaction of primary amines with 2,5-hexanedione, in the absence of solvents and catalysts. Methylamine, 1-dodecylamine, 2-amino-1,3-propanediol, and 3-(triethoxysilyl)propan-1-amine were selected. PyCs are characterized by two moieties, the pyrrole ring and the substituent of the nitrogen atom, and can be considered as Janus molecules. The functionalization of CNTs occurred with a high yield by simply heating CNTs and PyC. The whole reaction pathway did not produce any waste and was characterized by a carbon efficiency up to almost 100%. Thanks to the variety of PyC chemical structures, the CNT solubility parameter was modified in a pretty broad range of values, in the expected direction. Stable CNT dispersions were prepared in different solvents. From the aqueous dispersion, coating layers were prepared with high electrical conductivity, larger with respect to a top commercial product. The “pyrrole methodology” reported here is based on one reaction and allows almost infinite variations of the CNT solubility parameter, thus promoting their compatibility with target matrices and allowing the preparation of nanocomposite materials with improved properties. This work thus paves the way for a highly efficient exploitation of CNTs.

The reaction between [Re,(~-H),(CO),] and [Pt(PPh3),(C,H4)] at 273 K results in the insertion of the [Pt(PPh3),] fragment into a Re(pH)Re bond, giving the triangular cluster [RezPt(p-H)z(CO),(PPh3)2], characterized spectroscopically. On increasing the temperature, an irreversible transformation occurs, due to the exchange of one phosphine and one carbonyl between platinum and rhenium. Two other isomers are formed in this way, characterized by 'H and 31P NMR, which differ in the location of the phosphine bound to rhenium. They equilibrate slowly on the NMR time scale, and variable-temperature experiments allowed the estimation of the thermodynamic parameters of this isomerization: AHe = -1.72 f 0.04 kcal mol-', ASe = -4.56 f 0.14 cal mol-' K-l. NMR 2D reverse correlation experiments were performed to detect lg5Pt chemical shifts of the three isomers and to measure the passive couplings with 31P not observable in the 1D spectra. The relative signs of these couplings are discussed. One of the isomers has been investigated by X-ray single-crystal analysis. It gives monoclinic crystals, space group B l / c (No. 14), with a = 14.044 (3), b = 19.343 (5), c = 16.391 (3) A, 0 = 93.69 ( 2 ) O , 2 = 4. The refinements, based on 5306significant observations, gave a final R value of 0.031. It contains a PtRez triangle with the Re-Re edge and one of the Pt-Re edges supposed to be bridged by hydride ligands. The Pt atom bears one PPh3 and one CO ligand and exhibits approximately a square-planar coordination. The two Re atoms show octahedral environments, one bearing four CO and the second one three CO and a PPh3 ligand, coordinated in the axial direction with respect to the cluster plane. The hydrogen-bridged Re-Re bond is 3.203 (1) A long; the two Pt-Re bond lengths are 2.906 (1) and 2.788 (1) A, for the hydrogen-bridged edge and for the unbridged one, respectively.

N-(4-aminophenyl)aniline oxidative polymerization is optimized to produce polyaniline (PANI) free from carcinogenic and/or polluting coproducts. The resulting polymer is electrospun using polymethyl methacrylate (PMMA) as the supporting polymer, with different weight ratios (1:0, 4:1, 3:1, 2:1, 1:1, and 0.5:1 w/w PANI/PMMA). By rinsing with a selective solvent, PMMA is removed while maintaining the fibrous morphology. Ultrathin (65 6 14 nm) and defect-free PANI nanofiber mats are obtained for the blend containing a high relative content of PANI (2:1 w/w, namely F 2:1 ). Two different solvents are tested to remove PMMA, namely acetone and isopropanol, the former giving better results, as highlighted by infrared spectroscopy (FTIR). X-ray diffraction (XRD) demonstrates that the electrospun PANI is amorphous. The thin fiber mats are robust and sterilization both by autoclave and UV irradiation can be carried out. UV irradiation is preferred since no modification of the fibrous morphology is detectable. In vitro biocompatibility of the electrospun F 2:1 fibers has been evaluated with SH-SY5Y neuronal-like cells. Indirect cytocompatibility tests show that no cytotoxic leachable is released by the electrospun mats at both short and longer times, while direct cytocompatibility investigations indicate that only F 2:1 fibers washed in isopropanol do not reduce cell proliferation rate with respect to controls on tissue culture plates. Globally, these results suggest that the proposed electrospun nanostructures are promising materials for neuronal tissue engineering.

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