Facile Nucleophilic Substitution Reaction Research Articles

Cyclotriphosphazene: A Versatile Building Block for Diverse Functional Materials.

Cyclotriphosphazene (CP) is a cyclic inorganic compound with the chemical formula N3P3. This unique molecule consists of a six-membered ring composed of alternating nitrogen and phosphorus atoms, each bonded to two chlorine atoms. CP exhibits remarkable versatility and significance in the realm of materials chemistry due to its easy functionalization via facile nucleophilic substitution reactions in mild conditions as well as intriguing properties of resultant final CP-based molecules or polymers. CP has been served as an important building block for numerous functional materials. This review provides a general and broad overview of the synthesis of CP-based small molecules through nucleophilic substitution of hexachlorocyclotriphosphazene (HCCP), and their applications, including flame retardants, liquid crystals (LC), chemosensors, electronics, biomedical materials, and lubricants, have been summarized and discussed. It would be expected that this review would offer a timely summary of various CP-based materials and hence give an insight into further exploration of CP-based molecules in the future.

Partially fluorinated poly(arylene-alkane)s containing cobaltocenium for alkaline-stable anion exchange membranes.

Alkali-resistant metal-based cationic polyelectrolytes are designed as anion exchange membranes. After grafting aminocobaltocene hexafluorophosphates onto partially fluorinated ether-free poly(arylene-alkane)s via a simple nucleophilic substitution reaction, the membrane exhibits excellent chemical, thermal and mechanical stability, high hydroxide conductivity, as well as durability of single cells for 400 h.

One-step fabrication of polymeric self-solidifying ionic liquids as the efficient catalysts for biodiesel production

Polymeric self-solidifying ionic liquids (PSILs) were simply fabricated by the facile nucleophilic substitution reaction between polyethyleneimine (PEI) and 1,3-propanesultone (PS). Because of the presence of less-substituted amino groups in PEI chain, more than 1 equivalents of sulfonic groups (–SO3H) per amino group were grafted onto PEI chain. Part of –SO3H groups could be bonded with amino groups to form –SO3–…N+– zwitterions, the presence of zwitterion and the high molecular of PEI could make PSILs become solid, while the left free –SO3H groups played a role in the acid catalysis and therefore no additional acids were required. The final PSILs showed high catalytic activity, stability and generality as the heterogeneous catalysts for biodiesel production via the esterification of a variety of free fatty acids (FFAs), as well as the transesterification of waste cooking oil and palm oil. Moreover, the one-step fabrication process of PSILs is much simpler than the multi-step fabrication process of traditional ionic liquids, suggesting potential benefits.

Covalently functionalized graphene by thiourea for enhancing H2-evolution performance of TiO2 photocatalyst

Graphene as a well-known electron cocatalyst can enhance the hydrogen-production performance of photocatalysts due to its excellent conductivity. For highly efficient graphene-modified TiO2 photocatalyst, besides the speedy electron transfer via graphene, it is significant to raise the interfacial hydrogen-generation reaction rate on the graphene surface. In this paper, thiourea (TU) can covalently functionalize graphene and act as effective H+-adsorbed active sites to improve the hydrogen-production efficiency of graphene-modified TiO2 (TiO2/rGO-TU). The TiO2/rGO-TU sample was successfully prepared by a facile nucleophilic substitution reaction between the thiol (-SH) of thiourea and carboxyl (-COOH) of graphene. The TiO2/rGO-TU could possess the maximum H2-generation rate of 241.83 μmol h−1 g−1, which was 2.33 and 6.60 times greater than that of TiO2/rGO and TiO2, respectively. The enhanced photocatalytic activity of TiO2/rGO-TU can be ascribed to the synergistic effect of graphene and thiourea, namely, the graphene functions as a cocatalyst to capture the photoexcited electrons of TiO2 and the thiourea acts as effectual H+-adsorbed active sites to promote interfacial hydrogen generation. This study presents a feasible strategy for developing grephene-based photocatalysts for prospective applications in the hydrogen-production field.

One‐Step Synthesis of Janus Fluorographene Derivatives

Fluorographene, a two-dimensional derivative of graphene, is an excellent starting material for synthesis of graphene derivatives. Herein, we describe a one-step, substrate-free method for an asymmetric functionalization of fluorographene layers with hydroxyl groups by a facile nucleophilic substitution reaction. Such a chemical modification occurs in a biphasic aqueous-organic system under mild conditions, leading to Janus graphene nanosheets functionalized by hydroxyl groups on one side and retaining fluorine atoms on the other. The reported experimental route paves the way for two-dimensional bifacial graphene templates, thus broadening the application potential of graphene materials.

Highly Selective Capture of the Greenhouse Gas CO2 in Polymers

Owing to their high physicochemical stability and low skeleton density, polymers are highly promising for capturing the greenhouse gas CO2. However, complicated monomers, expensive catalysts, and/or severe conditions are usually required for their synthesis, which makes the process costly, tedious, and hard to scale up. In this paper, a facile nucleophilic substitution reaction is developed to synthesize polymers from low-cost monomers, namely chloromethylbenzene and various diamines. Due to the appropriate reactivity of monomers, the polymerization takes place at a low temperature of about 60 °C in the absence of any catalysts. A series of polymers containing plentiful secondary amines are successfully fabricated; these secondary amines provide a proper adsorbate–adsorbent interaction from the viewpoints of selective capture of CO2 and energy-efficient regeneration of adsorbents. Moreover, the materials possess well-defined micropores with the dimension close to the size of adsorbate molecules and subseq...

ChemInform Abstract: Halogenated Boron‐Dipyrromethenes: Synthesis, Properties and Applications

AbstractReview: [112 refs.

Chlorizidine, a cytotoxic 5H-pyrrolo[2,1-a]isoindol-5-one-containing alkaloid from a marine Streptomyces sp.

Cultivation of an obligate marine Streptomyces strain has provided the cytotoxic natural product chlorizidine A. X-ray crystallographic analysis revealed that the metabolite is composed of a chlorinated 2,3-dihydropyrrolizine ring attached to a chlorinated 5H-pyrrolo[2,1-a]isoindol-5-one. The carbon stereocenter in the dihydropyrrolizine is S-configured. Remarkably, the 5H-pyrrolo[2,1-a]isoindol-5-one moiety has no precedence in the field of natural products. The presence of this ring system, which was demonstrated to undergo facile nucleophilic substitution reactions at the activated carbonyl group, is essential to the molecule's cytotoxicity against HCT-116 human colon cancer cells.

Facile preparation of α,β-unsaturated O,S-acetals and mixed acetals via 3-alkoxy-2-alkenylenesulfonium salts.

Reaction of α,β-unsaturated acetals with dimethyl sulfide in the presence of TMSOTf in tetrahydrofuran at −78 °C, affords 3-alkoxy-2-alkenylenesulfonium salts which undergo facile nucleophilic substitution reactions with lithium thioalkoxides and trialkyltin alkoxides to yield α,β-unsaturated O,S-acetals and mixed acetals.

Solvolysis of di‐2‐pyridylketone methiodide

AbstractDi‐2‐pyridylketone methiodide undergoes a facile nucleophilic substitution reaction with various alcohols followed by subsequent cleavage and elmination of pyridinium methiodide and the correspoing picolinates.