Size-Controlled Synthesis of Ag Nanoparticles Functionalized by Heteroleptic Dipyrrinato Complexes Havingmeso-Pyridyl Substituents and Their Catalytic Applications

Abstract

The syntheses of heteroleptic dipyrrinato nickel(II) complexes [Ni(4-pydpm)(dedtc)] (1) and [Ni(4-pydpm)(dipdtc)] (2) [4-pydpm = 5-(4-pyridyl)dipyrromethene; dedtc = diethyldithiocarabamate; and dipdtc = diisopropyldithiocarbamate] and the thorough characterization of these complexes by satisfactory elemental analyses, electrospray ionization mass spectrometry, Fourier-transform infrared, NMR ((1)H, (13)C), and UV-vis spectroscopies, and electrochemical studies was achieved. Structure of 1 was authenticated by X-ray single-crystal analysis. Both the complexes 1 and 2 were successfully utilized as a capping agent in the preparation of silver nanoparticles. Availability of free pyridyl nitrogen on the dipyrrin core of these complexes was meticulously exploited in functionalization and stabilization of the silver nanoparticles (AgNPs). Morphological and structural investigations on colloidal nanoparticles were followed by UV-vis spectroscopy and transmission electron microscopy (TEM). Overall results revealed that average size of the silver nanoparticles (∼10, 15, 20 nm, and aggregation) is strongly influenced by ratio of Ag/[1/2] (03, 06, 10, 20). Correlation between particle size and capping agents was realized by UV-vis and TEM studies. Catalytic activity of the AgNPs obtained through this route was successfully employed in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). It was established that reduction process follows a pseudo-first-order kinetics.

Molecular and Nanoaggregation in Cyclometalated Iridium(III) Complexes through Structural Modification

“…One of the finest tools for the characterization of AuNPs is UV/Vis absorption spectroscopy. The position and shape of a surface plasmon band depends on the particle size, shape, and dielectric constant of the medium . The requisite reducing agent NaBH 4 for the creation of nanoparticles has been optimized by UV/Vis spectral studies.…”

Catalytic Hydrogenation of Nitrophenols by Cubic and Hexagonal Phase Unsupported Ni Nanocrystals

“…To well utilize this hydrogenation process, the key lies on finding high‐efficient and robust catalysts to improve the reaction kinetics. Up to now, several kinds of nanomaterials, such as single‐metal nanocrystals and related nanocomposites (e. g., Pd, Au, Ag, Ni, Pd/graphene, Au/ g ‐C 3 N 4 , Ni/C), bimetallic nanoalloys or nanohybrids (e. g., AgNi, Au@Ni, AuPd, TiO 2 nanowire@hollow AgPt, Ag x Ni 100‐x /RGO), metal oxides nanostructures or heterojunctions (e. g., MFe 2 O 4 (M=Cu, Zn, Co, Mn),, Cu 2 O@h‐BN, Co 0.85 Se‐Fe 3 O 4 ), and carbon‐based nanostructures, have been explored as the catalysts for hydrogenation of NP by using NaBH 4 as the hydrogen carrier. Among them, Ni and Ni‐based bimetallic nanostructures have garnered much attention due to their low cost, high catalytic activity, ease of availability and magnetic separation features …”

Facile synthesis of magnetically separable reduced graphene oxide/magnetite/silver nanocomposites with enhanced catalytic activity

“…The ratio of C t to C 0 (C t /C 0 ), where C t and C 0 stand for the concentration of 4-nitrophenol at time t and 0, respectively, was measured from the relative intensity of the respective absorbances A t /A 0 at peak of 400 nm. Table 2, the rate constants are higher than those of Ag/Au nanoparticles and their multifunctional hybrid systems [47][48][49], especially the RGO/Ag and Fe 3 O 4 supported Ag nanoparticles with rate constants of 0.444 and 0.16 min -1 , respectively [50,51].…”