Refernces
10.1016/j.ica.2011.06.024
The research presents the synthesis, characterization, and study of a new 2D copper(II)-Schiff base coordination polymer with magnetic and catalytic properties. The complex was prepared using the Schiff base ligand NN0-bis(salicylidene)-1,3-diaminopentane (H2L) and sodium dicyanamide (dca), resulting in a 2D hexagonal structure formed by helical chains connected through double 1,5-dca bridges. The complex exhibited strong antiferromagnetic coupling and was tested for its ability to catalyze the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butylquinone (3,5-DTBQ), showing catecholase-like activity. Various analyses were employed, including Fourier transform infrared spectroscopy (FTIR), UV–Vis spectroscopy, cyclic voltammetry, electrospray ionization mass spectrometry (ESI-MS), X-ray crystallography, and magnetic susceptibility measurements, to characterize the complex and monitor the catalytic oxidation reaction. The study also involved kinetic studies to determine the catalytic activity and compared the complex's performance to that of natural catechol oxidase.
10.1016/S0040-4039(00)98584-8
The research aimed to investigate the complexation of diquat by disubstituted dibenzo-30-crown-10 derivatives. The purpose was to understand the stability and binding mechanisms of 1:1 crystalline complexes formed between diquat bishexafluorophosphate, [Diquat][PF6]2, and two specific derivatives: the bisformyl dibenzo-30-crown-10 derivative (2) and the dimethyl dibenzo-30-crown-10 derivative (4). The study utilized X-ray structural investigations to reveal that charge transfer, electrostatic binding, and weak C-H...O hydrogen bonding contribute to the complexes' remarkable stabilities. The chemicals used in the process included diquat bishexafluorophosphate, the bisformyl and dimethyl derivatives of dibenzo-30-crown-10, and various solvents such as acetone, CH3CN, CH3OH, and CH3COCH3. The conclusions drawn from the study were that the stability constants for the 1:1 complexes involving the derivatives 2, 3, and 4 were 2100, 50000, and 48000 dm3 mol-1, respectively, indicating a strong binding affinity. The research also suggested that the presence of electron-donating or withdrawing groups at the 2 and 20 positions of the catechol rings influenced the complexes' stabilities, with electron-donating groups enhancing the r-donor capabilities of the catechol rings towards the electron-deficient bipyridinium dication.
10.1021/acs.orglett.9b01082
This study explores a ruthenium-catalyzed ligand-promoted coupling reaction for the synthesis of quinazoline and quinazolinone derivatives. The in situ formed ruthenium catalytic system ([Ru]/L) selectively catalyzes the dehydrogenative coupling of 2-aminophenyl ketones with amines to quinazoline products and the deaminogenic coupling of 2-aminobenzamides with amines to quinazolinone products. This approach is highly efficient and avoids reactive reagents and toxic byproducts. Quinazolines and quinazolinones are nitrogen heterocyclic scaffolds with various pharmacological activities used as therapeutics for diseases such as benign prostatic hyperplasia, cancer, and antimicrobial infections. This study optimizes the reaction conditions using a cationic ruthenium hydride complex and a catechol ligand, demonstrating broad substrate scope and scalability. Mechanistic insights indicate the formation of an imine intermediate that undergoes isomerization, cyclization, and dehydrogenation steps to generate the final product.
10.3762/bjoc.6.45
The research explores the synthesis of a tricyclic 9,10-dioxa-1,2-diaza-anthracene system from tetrafluoropyridazine and catechol through a sequential nucleophilic aromatic substitution ring annelation process. The purpose of this study is to further utilize perfluoroheteroaromatic derivatives for the creation of unusual polyfunctional heterocyclic architectures, which could be valuable in drug discovery programs. The researchers successfully synthesized the tricyclic scaffold and reacted it with various nucleophiles, including amines and sodium ethoxide, to produce a series of functional 9,10-dioxa-1,2-diaza-anthracene systems. The study concludes that a small range of dioxa-1,2-diaza-anthracene analogues can be efficiently synthesized from tetrafluoropyridazine in two steps, expanding the application of highly fluorinated heterocycles for the synthesis of rare heterocyclic architectures.
10.1002/anie.201101521
The study reports the development of a poly(l-3,4-dihydroxyphenylalanine) (polyDOPA) based multiple-interaction ligand (MIL) for creating ultrastable and biocompatible nanoparticles. The MIL is composed of methoxy poly(ethylene glycol) (mPEG) grafted cationic hyperbranched polyethylenimine (bPEI) and the multi-initiated peptide domain of polyDOPA. This ligand mimics the structure of mussel adhesive protein (MAP) and binds to nanoparticles through multiple modes: catechol and amine binding onto hydrophobic nanoparticles, micelle formation via its amphiphilic structure, and electrostatic interaction with negatively charged nanoparticles. The MIL was synthesized by ring-opening polymerization of di-O,O’-acetyl-l-DOPA-N-carboxylanhydride (DOPA-NCA) initiated from mPEG-grafted bPEI. It was used to functionalize various nanoparticles including Fe3O4, MnO, and Au nanoparticles, replacing their original hydrophobic ligands. The resulting nanoparticles were highly stable in harsh biological environments, showed excellent biocompatibility, and had potential applications in biomedical fields such as MRI.
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