Substituent

About: Substituent is a research topic. Over the lifetime, 42877 publications have been published within this topic receiving 516716 citations. The topic is also known as: side chain & side group.

Rhodium‐Catalyzed Direct Addition of Aryl C ? H Bonds to N‐Sulfonyl Aldimines

Abstract: The selective C—H activation in directed by the ortho 2-pyridyl substituent followed by nucleophilic addition to N-sulfonyl arylaldimines.

Boron derivatives of high molecular weight mannich condensation products

Abstract: High molecular weight Mannich condensation products of (1) high molecular weight alkyl-substituted hydroxyaromatic compounds whose alkyl substituent has upward from 40 to 20,000 carbon atoms, (2) an amine which contains an AND (3) AN ALDEHYDE IN THE RESPECTIVE REACTANT MOLAR RATIO OF 1: 0.1-10:1.0-10 CONDENSED WITH A BORON COMPOUND ARE NOVEL DISPERSANT-DETERGENT LUBRICANT OIL ADDITION AGENTS. Solutions of those addition agents in lubricant oil are novel and unique compositions affording anti-sludge and varnish deposition and corrosion inhibition.

Aryl-substituted C3-bridged oligopyrroles as anion receptors for formation of supramolecular organogels.

Abstract: BF2 complexes of aryl-substituted dipyrrolyldiketones (3a-c, 5a-d) have been synthesized by the condensation of arylpyrroles obtained by Suzuki cross-coupling reactions with malonyl chloride, followed by treatment with BF3.OEt2. The binding constants (Ka11) of the BF2 complexes (3a-c) for various anions (Cl-, Br-, CH3CO2-, H2PO4-, and HSO4-) in CH2Cl2 decrease in the order Ph (3a) > o-tolyl (3b) > 2,6-Me2Ph (3c), possibly because of differences in the planarity and the number of interacting o-CH units at the binding sites. Aryl-substituted receptors exhibit a [1+1] binding mode with Cl- as well as a [2+1] binding mode under conditions of high concentration and low temperature, as suggested by 1H NMR studies in CD2Cl2. These receptors, especially phenyl-substituted (3a) and o-tolyl (3b), exhibit drastic colorimetric and fluorescent changes in the presence of F- due to extended pi-conjugation, as compared to 2,6-dimethylphenyl (3c) and the previously reported derivatives (1a-c). Aryl-substitution at the alpha-positions of pyrrole is an excellent means for the introduction of various substituents at the periphery of the anion receptors. For example, derivatives with long alkoxy chains at 3,4,5-positions of the substituent aryl rings (5b-d) afford emissive gel structures in hydrocarbon solvents, such as octane, based on the stacking of slipped H- and J-aggregates at the core pi-plane. The structural organization of the supramolecular gels was investigated by AFM, SEM, and XRD measurements as well as by considering the solid-state packing of crystalline derivatives. The slow transformation of the gel to the solution phase by the addition of various anions, possibly except for F-, is correlated with the unique properties of these acyclic receptors where inversions of pyrrole rings are required for anion binding. Boron complexes of 1,3-dipyrrolyl-1,3-propanediones with aryl-substituents, as a new class of acyclic anion receptors, have shown efficient binding due to the interacting o-CH units and, in the case of the derivative with long aliphatic chains, afforded the emissive supramolecular organogels using stacking of core pi-planes controlled by external chemical stimuli.

Intermolecular olefin functionalisation involving aryl radicals generated from arenediazonium salts.

Abstract: This minireview is aimed at giving an overview of recent advances in olefin functionalisation reactions involving aryl radicals generated from arenediazonium salts. Based on the well-known Meerwein arylation, in which an aryl and a halogen substituent are coupled to an olefinic substrate, new reaction types have been developed that allow the introduction of a broad spectrum of other atoms and functional groups at the place of the original halogen atom and that are applicable to an extended range of olefinic substrates.

Complexes with Substituent-free Acyclic and Cyclic Phosphorus, Arsenic, Antimony, and Bismuth Ligands

Abstract: Until recently, phosphorus, arsenic, antimony and bismuth ligands were nearly always understood to be molecules such as R3E, R2E(CH2)nER2, and RC[(CH2)nER2]3(E = P, As, Sb, Bi) in which the lone pair of the atom E functions as a 2e donor. Current research interests, however, increasingly involve substituent-free En ligands (n = 1–6), the various types of which are mainly accessible via EX3 (X = F,Cl,Br,Ph), E (SiMe3)3, (RAs)n, P4S3, As4S4, gray arsenic, and especially P4 and As4; these ligands can be stabilized in the coordination spheres of certain transition metal fragments. P1, As1 and Sb1 units with multiple M-E bonds are found in bi- and trinuclear complexes; E1 units can also be encapsulated (partially or completely) in cavities of a variety of metal cluster frameworks. Metallatetrahedranes with up to three E atoms are especially common. Besides E1 units, the greatest variety of coordination modes is exhibited by E4 ligands, which are found as intact tetrahedra and also as parts of chains, polycycles, cubes and a trigonal prism. The phosphorus and arsenic species cyclo-En, isoelectronic to the carbocyclic (CH)n species, are suitable ligands for forming sandwich complexes (n =3, 4, 5) and triple-decker sandwich complexes (n = 3, 5, 6). In addition to the wide variety of chemical reactions, remarkable parallels are found in organic chemistry as well as in solid-state chemistry for many of these substance classes. Some of the molecules have received lively interest from theoretical chemists.