Pentamethylcyclopentadienyl Molybdenum(V) Complexes Derived from Iodoanilines: Synthesis, Structure, and ROP of ε-Caprolactone

The reaction of [Mo(η-C5Me5)Cl4] with the ortho-, meta-, or para-iodo-functionalized anilines 2-IC6H4NH2, 3-IC6H4NH2, 4-IC6H4NH2 yields imido or amine products of the type [Mo(η-C5Me5)Cl2(IC6H4N)] (2-I, 1, 3-I, 3, 4-I, 5) or [Mo(η-C5Me5)Cl4(IC6H4NH2)] (3-I, 2, 4-I, 4), respectively, depending on the reaction stoichiometry/conditions; we were unable to isolate an amine complex of the 2-I derivative. The reaction of [Mo(η-C5Me5)Cl4] with one equivalent of 2-I,4-FC6H3NH2 in the presence of Et3N afforded [Mo(η-C5Me5)Cl2(2-I,4-FC6H3N)]·MeCN (6·MeCN), which, upon exposure to air, afforded the Mo(VI) imido complex [Mo(η-C5Me5)Cl3(2-I,4-FC6H3N)] (7). For comparative studies, the structure of the aniline (C6H5NH2)-derived complex [Mo(η-C5Me5)Cl2(2-C6H3N)] (8) has also been prepared. The molecular structures of 1–8 have been determined and reveal packing in the form of zig-zag chains or ladders. The complexes catalyze, in the presence of benzyl alcohol under N2, the ring-opening polymerization (ROP) of ε-caprolactone affording relatively low molecular weight products. The MALDI-ToF spectra indicate that a number of polymer series bearing a variety of end groups are formed. Conducting the ROPs as melts or under air results in the isolation of higher molecular weight products, again bearing a variety of end groups. Kinetic studies reveal the aniline-derived imido complex 8 performs best, whilst a meta-iodo substituent and a Mo(V) centre are also found to be beneficial. The structures of the side products 2-IC6H4NH3Cl and 3-IC6H4NH3Cl are also reported.

Synthesis of silk sericin stabilized silver (Ag-Ser) nanoparticles using Tollens’ method and investigation of its colloidal stability

In this study, sericin extracted from Bombyx mori silk cocoons was integrated into the well-known Tollens’ method for synthesizing Ag-NPs. Sericin successfully acted as a stabilizer while silver amine complex [Ag(NH3)2]+ was reduced by maltose. As a result, silver nanoparticles with high stability are formed. Possible functional groups related to the stabilization of NPs were investigated by Fourier-transforms infrared spectroscopy (FT-IR). Ag-Ser NPs were characterized by using particle size measurements based on dynamic light scattering (DLS) and transmission electron microscopy (TEM). According to the characterization investigations, Ag-Ser NPs have characteristic (111) face-centered cubic (FFC) plane and were spherical in shape with a narrow size distribution of 20.23 ±6.25 nm. Overall, the sericin-modified Tollens’ method for synthesizing Ag-NPs offers a simple and non-toxic production method to form nanoparticles. Colloidal stability of nanoparticles displays an essential role since their enhanced nano-properties can be diminished by an increase in size due to aggregation and agglomeration. Therefore, the effect of pH on particle stability was investigated through the surface charge of Ag-Ser NPs that was measured using a Zeta-potential analyzer. Results obtained from this study may extend the applicability of silver nanoparticles in biotechnological researches and a potential synthesis route for the application of Ag-Ser NPs as aseptic and therapeutic usages.

Understanding the role of fluorination on the mechanistic nature of the water splitting process catalyzed by cobalt tris-(2-pyridylmethyl) amine complex

We report the reaction mechanism of the oxygen evolution reaction catalyzed by penta-coordinated [(CoV(TPA-αF3)(O)]3+ (TPA=tri-(2-pyridylmethyl) amine) and hexa-coordinated [(CoV(TPA-αF3)(O)OH]2+ cobalt complexes for the formation of the oxygen-oxygen bond and role...

One-pot synthesis of Ag@silicalite-1 with different silver amine complexes and the performance for styrene oxidation

A facile one-pot strategy was used to successfully synthesize Ag@silicalite-1 using different silver amine complex mixtures as precursors via a hydrothermal synthesis method. Ag@silicalite-1 was characterized by X-ray diffraction (XRD),...

Remarkable thermal stability of light-induced Ru–ON linkage isomers in mixed salts of a ruthenium amine complex with a trans-ON–Ru–F coordinate

The novel complexes with trans-ON–Ru–F coordinate exhibit the highest thermal stability of Ru–ON photoinduced isomers.