Palladium Nanoparticles Supported on Cellulosic Paper as Multifunctional Catalyst for Coupling and Hydrogenation Reactions.

Hallmark of a successful catalyst is its high efficiency, economic aspects, operational simplicity, extensive reusability, higher environment friendliness, and potential use in multiple industrial applications. Herein, a facile protocol involving a catalyst with Pd nanoparticles supported on cellulose paper (also known as a "dip-catalyst") for the hydrogenation of a series of quinolines, nitroarene, and C-C bond formation reactions in most benign solvents such as water is described. The mere insertion/removal of the "dip-catalyst" strip enables instantaneous start/stop of the reaction, which enhances its reusability and ease of separation of products. Cellulose paper (CP) strips decorated with Pd nanoparticles (Pd/CP) are prepared by the reduction of K2 PdCl4 soaked strips using formic acid as reductant. The resulting spherical shaped Pd particles, confirmed by scanning electron microscopy, form stable catalysis centers on the support. XRD signature confirms the crystallinity of the Pd nanoparticles and the TEM images display 15-20 nm size particles uniformly decorating CP. X-ray photoelectron spectroscopy indicates the formation of metallic Pd. The catalyst is tested for the C-C bond formation reactions. Pd/CP catalyzed Suzuki-Miyaura coupling reaction demonstrate >99% conversion with optimum selectivity. On the other hand, Mizoroki-Heck reaction produced 87% conversion with the reaction of 4-methoxycarbonyl phenylboronic acid and iodobenzene in ethanol:water (1 : 1 v/v) using KOH as base. The developed Pd/CP construct produces >99% of the pyridine-ring hydrogenated product on quinoline hydrogenation using tetrahydroxydiboron (THDB) as the hydrogen source. Diverse and highly reducible functional groups were also evaluated for transfer hydrogenation, which demonstrates a high efficiency in terms of both reactivity and selectivity. The used catalysts are recyclable for the multiple cycles.

Crystal structure of 3,9,9-trimethyl-2,3,3a,4,9,9a-hexa-hydro-1H-cyclo-penta[b]quinolin-4-ium chloride.

The title mol-ecular salt, C15H22N(+)·Cl(-), arose as an unexpected product of the reaction between aniline and melanol in the presence of HCl. The central heterocyclic ring has a half-chair conformation and the five-membered ring has an envelope conformation, with the C atom linked to the N atom as the flap. In the crystal, the ions are linked by N-H⋯Cl hydrogen bonds, generating chains propagating in the [100] direction. The crystal studied was a merohedral twin with a 0.64 (3):0.36 (3) domain ratio.

(E)-4-Bromo-2-[(2,6-diisopropyl-phen-yl)imino-meth-yl]phenol.

In the title compound, C(19)H(22)BrNO, the dihedral angle between the benzene rings is 76.17 (14)° and an intra-molecular O-H⋯N hydrogen bond with an S(6) graph-set motif is present. One methyl group is disordered over two sets of sites with site occupancies of 0.66 (3) and 0.34 (3). A weak inter-molecular C-H⋯π inter-action is observed in the crystal structure.