General Types Of Reactions Research Articles

GANGGUAN PSIKOGENIK LATAH GARY ISKAK: KAJIAN PSIKOLINGUISTIK

This research is motivated by the stigma of talkativeness suffered by women, people with low education, and belonging to the lower economic class category. The research entitled "Psychogenic Disorder of Talkative Gary Iskak (Psycholinguistic Study)" aims to describe the talkative and the background of talkative sufferers towards artist Gary Iskak. The theory used in this research is the talkative theory of Abdul Chaer and Soenjono Darjowidjodjo with a psycholinguistic approach. The data collection method used is the referential method with the note-taking technique. In contrast, the data analysis method is the referential method with the determining determinants or the PUP technique. The results found in this study are that there are four general reaction types: Ekolalia, Ekopraxia, Auto Ekolalia, and Automatic Obedience. Then the two types of talkative reactions that are not included in the four categories are a mixture of Ekolalia and Ekopraxia talkative and the impact of voice talk. In addition to the type of talkativeness, it was also found that the factors causing the talkativeness experienced by Gary Iskak when he was in several events found four causes of talkativeness. Among the four, the most frequent cause of talkativeness is being surprised by other people's movements.

Catalytic Reactions Directed by a Structurally Well-Defined Aminomethyl Cyclopalladated Complex.

The introduction of N-containing moieties into feedstock molecules to build nitrogenated functional molecules has always been widely studied by the organic chemistry community. Progress in this field paves new roads to the synthesis of N-containing molecules, which are of significant importance in biological activities and play vital roles in pharmaceuticals and functional materials. Remarkable progress has been achieved in the field of transition metal-catalyzed C-N bond-forming reactions, typified by alkene hydroamination and the aza-Wacker reaction. However, the poisoning effect of electron-donating amine substrates on late transition metal catalysts presents a key impediment to these reactions, thus limiting the scope of amine substrates to electron-deficient amide derivatives. To address this problem, our group developed a palladium-aminomethyl complex with a three-membered palladacycle structure that allowed for the incorporation of electron-rich amine building blocks via C-C bond instead of C-N bond construction. This Account details the discovery of the well-defined aminomethyl cyclopalladated complex and recapitulates its applications for the catalysis of a series of aminomethylation reactions. We highlight how the understanding of the fundamental structural properties of the defined complex guided us toward tuning the reactivity of nucleophiles to initiate aminomethylation in different modes. Moreover, principles of designing and establishing further cascade reactions are also described.Aminomethyl cyclopalladated complexes can be prepared via the oxidative addition of aminals or N,O-acetals to Pd0 species. Thorough structural investigations by single-crystal X-ray diffraction analysis of the cyclopalladated complex suggest the presence of both aminomethylene-PdII (3-membered-ring) and Pd0-iminium (π-ligated) resonance forms, which indicates that both the palladium center and the methylene site are electrophilic. This is further verified by analysis of charge distribution. Two general types of reactions can be established, differing by the selective affinity of the nucleophiles to the two electrophilic positions, which is relevant to the "hardness suitability" of the nucleophiles with each electrophilic site. Softer nucleophiles such as alkenes prefer to attack the palladium center to initiate the reaction, mainly via migratory insertion into the Pd-C bond on the 3-membered ring with high strain. Through tandem β-hydride or reductive elimination, the Heck-type aminomethylation of styrenes, the aminomethylalkoxylation of electron-rich olefins, and even the aminomethylamination of allenes, dienes, enynes, and carbenoids with full atom-economy have been realized in line with this reaction mode. In contrast, harder nucleophiles tend to attack the harder electrophilic methylene site, leading to the aminomethylation of electron-deficient dienes. For secondary amines, a "C-N bond metathesis" process would be furnished through a reductive elimination, 1,3-proton transfer, and oxidative addition sequence. More intriguingly, when using appropriate "dinucleophile" substrates such as electron-rich amine-tethered dienes, sequential C-N bond metathesis and intramolecular insertion would occur to furnish Pd-catalyzed annulation reactions, which exhibits both the hard and soft nucleophile reactivities mentioned above. These transformations provide convenient methods for the preparation of N-containing molecules, such as amines, diamines, amino acetals, and multiple types of N-heterocycles.

The synthesis and versatile reducing power of low-valent uranium complexes.

This Perspective provides a detailed overview of the chemistry of low-valent (di- and trivalent) uranium. The reactivity of uranium(ii) and uranium(iii) complexes is discussed both to illustrate the general types of reactions that might be expected and to highlight the many unusual modes of reactivity observed with this element. A particular emphasis is given to redox reactions with uranium(iii) species, including reduction of small molecules, multi-electron reductions involving redox-active ligands, and formation of uranium-ligand multiple bonds. In addition, redox-neutral adduct formation with uranium(iii) complexes as well as the current state of the young field of uranium(ii) redox chemistry are also covered. Synthetic protocols to prepare a wide range of low-valent compounds are presented.

Atlas of the Radical SAM Superfamily: Divergent Evolution of Function Using a "Plug and Play" Domain.

The radical SAM superfamily contains over 100,000 homologous enzymes that catalyze a remarkably broad range of reactions required for life, including metabolism, nucleic acid modification, and biogenesis of cofactors. While the highly conserved SAM-binding motif responsible for formation of the key 5'-deoxyadenosyl radical intermediate is a key structural feature that simplifies identification of superfamily members, our understanding of their structure-function relationships is complicated by the modular nature of their structures, which exhibit varied and complex domain architectures. To gain new insight about these relationships, we classified the entire set of sequences into similarity-based subgroups that could be visualized using sequence similarity networks. This superfamily-wide analysis reveals important features that had not previously been appreciated from studies focused on one or a few members. Functional information mapped to the networks indicates which members have been experimentally or structurally characterized, their known reaction types, and their phylogenetic distribution. Despite the biological importance of radical SAM chemistry, the vast majority of superfamily members have never been experimentally characterized in any way, suggesting that many new reactions remain to be discovered. In addition to 20 subgroups with at least one known function, we identified additional subgroups made up entirely of sequences of unknown function. Importantly, our results indicate that even general reaction types fail to track well with our sequence similarity-based subgroupings, raising major challenges for function prediction for currently identified and new members that continue to be discovered. Interactive similarity networks and other data from this analysis are available from the Structure-Function Linkage Database.

The decapitation of Slovenia’s Catholic Church: social factors and consequences

ABSTRACTThis article discusses the financial collapse of Slovenia’s Catholic Church, a scandal which resulted in the deposition of the country’s archbishops, and its impact on religious belief and on the relations within the Slovenian Catholic establishment and community. Trust in the Church and religious participation have dropped markedly in Slovenia over recent years. While there are no significant changes in religious belief, other religious indicators continue to reflect an ongoing moderate trend towards secularisation that is characteristic of Slovenia in the post-socialist era. The public discourse of the Church’s leadership and lay Catholics reveals tensions on the reasons behind the fall of the Church’s financial empire and on the question of responsibility in the removal of Slovenia’s archbishops. Two general types of reactions were identified in a content analysis of texts from a five-month period after the last depositions. Views within the Slovene Catholic Church, which uphold the institution’s traditional stance, tend to explain these developments as part of a conspiracy against the Church. Others that are more open and reflective are critical towards the actions of the Church and demand change from within the institution.

Mammalian aldehyde oxidases: genetics, evolution and biochemistry.

Mammalian aldehyde oxidases are a small group of proteins belonging to the larger family of molybdo-flavoenzymes along with xanthine oxidoreductase and other bacterial enzymes. The two general types of reactions catalyzed by aldehyde oxidases are the hydroxylation of heterocycles and the oxidation of aldehydes into the corresponding carboxylic acids. Different animal species are characterized by a different complement of aldehyde oxidase genes. Humans contain a single active gene, while marsupials and rodents are characterized by four such genes clustering at a short distance on the same chromosome. At present, little is known about the physiological relevance of aldehyde oxidases in humans and other mammals, although these enzymes are known to play a role in the metabolism of drugs and compounds of toxicological importance in the liver. The present article provides an overview of the current knowledge of genetics, evolution, structure, enzymology, tissue distribution and regulation of mammalian aldehyde oxidases.

Transition metals in organic synthesis: cross-coupling, C–H activation processes and cyclisation strategies

The number of reports on transition metal mediated cross-coupling reactions continues to expand, and 2006 represents an exciting and productive year for this area. Use of metal catalysed C–H activation in synthesis (direct functionalisation of C–H bonds) continues to increase, which is beginning to challenge the dominance of cross-coupling reactions for the synthesis of biaryl and related compounds. Some quite remarkable cyclisation methodologies have also been reported this year. A snap-shot of this chemical literature is reviewed herein. Reactions involve a metal component either catalytically or stoichiometrically and the review is divided into general reaction types. The author has emphasised reactions of current interest in academic and industrial sectors in the fields of organic, organometallic and bioorganic chemistry. The style of the review is similar to previous review articles written by the author (see ref. 1).

Rhenium-Catalyzed 1,3-Isomerization of Allylic Alcohols: Scope and Chirality Transfer

The scope of the triphenylsilyl perrhennate (O3ReOSiPh3, 1) catalyzed 1,3-isomerization of allylic alcohols has been thoroughly explored. It was found to be effective for a wide variety of secondary and tertiary allylic alcohol substrates bearing aryl, alkyl, and cyano substituents. Two general reaction types were found which gave high levels of product selectivity: those driven by formation of an extended conjugated system and those driven by selective silylation of a particular isomer. The efficiency of chirality transfer with various substrates was investigated, and conditions were found in which secondary and tertiary allylic alcohols could be formed with high levels of enantioselectivity. Consideration of selectivity trends with respect to the nature of the substituents around the allylic system revealed that this is a reliable and predictable method for allylic alcohol synthesis.

3 Transition metals in organic synthesis

The number of reports of transition metal mediated reactions continues to expand at a rapid rate. 2004 represents an exciting and productive year for this fundamental area of research, and a snap-shot of the chemical literature from 2004 is reviewed herein. Reactions involve a metal component either catalytically or stoichiometrically and the review is divided into general reaction types. The author has endeavoured to emphasise reactions of current interest in academic and industrial sectors in the fields of organic, organometallic and bioorganic chemistry. The style of the review is similar to previous review articles written by the author (see I. J. S. Fairlamb, Annu. Rep. Prog. Chem., Sect. B, 2004, 100, 113 and references cited therein).

Reactions of CH 3OCH 2+ with hydrocarbons and O, N, and S compounds: applications for chemical ionization in selected ion flow tube studies

We report the results of a flowing afterglow ion source-selected ion flow tube study (FA-SIFT) of the reactions of the methoxymethyl cation, CH 3OCH 2 +. Rate coefficients and product branching ratios are reported for twenty nine reagent molecules including those that constitute the major ingredients of air, the hydrocarbons CH 4, C 2H 6, C 3H 8, n-C 4H 10, C 2H 2, C 2H 4, C 3H 4 (allene and propyne), C 6H 6, and the S-containing molecules H 2S, CH 3SH, C 2H 5SH, (CH 3) 2SH, and (C 2H 5) 2SH. In addition, we examined the reactions with the N-containing molecules NH 3, CH 3NH 2, (CH 3) 2NH, (CH 3) 3N, pyrrole, pyridine as well as CH 3COCH 3. The results can be summarized under three general reaction types: Reaction at the CH 3 carbon, reaction at the CH 2 carbon, and association. The results also indicate that the methoxymethyl cation can be used as a chemical ionization source for the detection of trace levels of S-containing compounds in saturated hydrocarbons.

A two‐phase model for variable‐density fluidized bed reactors with generalized nonlinear kinetics

AbstractA model based on the classical two‐phase concept is developed for the simulation of variable‐density reaction with generalized nonlinear kinetics in a bubbling fluidized bed. The influence of reaction density parameter on the fluidodynamics and performance of the reactor for four general types of reactions was explored. The results show that the expansion factor has a significant effect on both fluidodynamic characteristics and reaction conversion. In all types of reactions, higher values of hydro‐dynamic variables were obtained when ϵ ≥ 0. Reaction conversion, however, dropped as the expansion factor increased. This trend was more pronounced for reaction orders higher than unity. This suggests that bubbling fluidized operations are probably not optimal and applicable for certain types of reactions. Comparative analysis between reaction type and implications for optimum fluidized bed reactor are discussed.

Reactions and Intermediates at the Metal-Polymer Interface as Observed by XPS and NEXAFS Spectroscopy

Potassium or chromium were evaporated by means of a Knudsen effusion cell under ultra-high vacuum conditions onto a number of common polymers, prepared as stretched foils and spin-coated films. The metal-polymer interface was studied by X-ray Absorption and X-ray Photoelectron Spectroscopy. Evaporated samples were analyzed without exposure to the atmosphere. Different general types of reactions of the metal atoms with the polymers were observed. With deposited K and Cr a redox process including the transfer of substrate oxygen atoms across the interface was found. The formation of π-electron complexes and covalent metal-carbon bonds were obtained exclusively with chromium. Aromatic rings, carbonyl groups and, to a lesser extent, ether linkages are scissioned by metal-polymer interactions. The fourfold substitution of aromatic rings and the exclusive existence of C ─ O ─ C structures within polyphenylene ether (PPE) make this polymer most stable toward reactions with chromium. In contrast, bisphenol-A polycarbonate is susceptible to redox reactions with the carbonate group and to forming Cr complexes with aromatic rings using the chromium 3d orbitals. The result is a succession of complex formation, followed by Cr substitution onto aromatic rings and destruction of rings with the formation of chromium carbides.

Construction of complex reaction systems—I. Reaction description language

A new computer language has been designed to describe general types of reactions. These descriptions are used to generate the specific reactions in complex reaction systems. A wide range of reaction networks may be represented using the commands in the reaction description language (RDL). The reaction types are defined by using a sequence of commands to locate the reaction site, manipulate the reactant to form the product, and to prune the reaction network. The syntax of the language was designed to mimic the way reactions are normally described. Therefore, debugging a program written in RDL is simply a matter of proofreading. Optimization methods are employed, transparent to the user, to reorder inefficient reaction descriptions. Reaction types may be easily added, deleted, and modified to adjust the level of detail within a specific reaction network.

Gas Phase Reactions of the Met-Cars Ti8C12+, Nb8C12+, and Ti7NbC12+ with Acetone and Methyl Iodide

Gas phase reactions of the metallocarbohedrenes Ti[sub 8]C[sub 12][sup +], Nb[sub 8]C[sub 12][sup +], and Ti[sub 7]NbC[sub 12][sup +] with two different types of molecules, namely, acetone and methyl iodide, are investigated at near thermal energy by employing a laser-induced plasma source coupled with a triple quadrupole mass spectrometer. Two general types of reactions are observed: molecular associations and atom abstraction reactions. In agreement with earlier studies on the interaction of Ti[sub 8]C[sub 12][sup +]/with polar molecules, association reactions are found to dominate in the case of acetone. But, the incorporation of even one Nb greatly affects the reactivity. For example, the extraction of one and two oxygen atoms from acetone is also observed for Nb[sub 8]C[sub 12][sup +] and Ti[sub 7]NbC[sub 12][sup +]; these products are found to sequentially associate with acetone to form Nb[sub 8]C[sub 12][sup +](O)[sub 1[minus]2](acetone)[sub n] and Ti[sub 7]NbC[sub 12][sup +](O)[sub 1[minus]2](acetone)[sub n]. The reaction involves breaking C=O bonds and forming M-O bonds, evidently due to the presence of the dipole-induced charge center of Nb[sub 8]C[sub 12][sup +] and Ti[sub 7]NbC[sub 12][sup +]. Possible reaction mechanisms are proposed which take into account the electronic structures of Nb[sub 8]C[sub 12][sup +], Ti[sub 7]NbC[sub 12][sup +], andmore » Ti[sub 8]C[sub 12][sup +]. 36 refs., 6 figs.« less

Histochemical classification based upon reaction types and its application to carbohydrate histochemistry

A method of classification is presented, which divides histochemical visualization reactions into categories based on general reaction types. This scheme is dependent upon the reaction between two elements, the substrate and the probe. The substrate represents a tissue component(s) with one or more reactive groups that can combine directly with the probe. Alternatively, the substrate reactive groups are chemically modified (activation) with a suitable reagent before reaction with the probe. Probes are of three types: those that yield a coloured product, those that result in a colourless product, and those that produce a coloured product only after a further reaction. Methods used in carbohydrate histochemistry are divided into one, two and three probe reactions. Two probe reactions are further subdivided into sequences involving one or two coloured products (one and two dye sequences); three probe reactions into sequences involving one, two or three coloured products (one, two and three dye sequences). This classification permits the rationalization and organization of methods, and provides a framework for the examination of existing methods and the development of new ones.

Magnetic resonance methods in the mechanistic photochemistry of ketones, olefins, and oximes

Abstract

Immune responses in the central nervous system.

Immune responses occurring within the central nervous system (CNS) have unique features attributable to the cellular and functional organization of the CNS and to the presence of the blood-brain barrier. Immune responses to viral infection of the CNS involve the participation of most immunologically important cells: T and B lymphocytes, monocytes, and natural killer cells. Normally, helper/inducer T lymphocytes are predominant in the cerebrospinal fluid (CSF) and in perivascular cuffs. After stimulation with antigen in tissue, these cells produce lymphokines, which stimulate mast cells to open capillary tight junctions, stimulate proliferation of lymphocytes, and attract monocytes and B lymphocytes. B lymphocytes mature into immunoglobulin-producing cells that secrete antibody locally which appears in the CSF. Cytotoxic/suppressor T lymphocytes, which damage antigen-containing cells, are predominant in immunopathologic reactions. In other situations the immune response targets normal CNS tissue rather than foreign antigens. Two general types of reactions may be seen: (1) vasculitis with destruction of vessel walls and infarction, and (2) perivascular inflammation with demyelination. The former is associated with immune complex deposition, and the cellular infiltrate includes polymorphonuclear leukocytes. The inflammation associated with perivenular demyelination is composed almost exclusively of mononuclear leukocytes. In the diseases for which pathogenetic mechanisms are understood, cells become sensitized to myelin constituents and induce local demyelinating lesions in which the damage is effected by macrophages. It is not clear whether macrophages are directed in this destructive effort by lymphokines or immunoglobulins or both.

Principles of lanthanide chemistry

A proposal for distinguishing between the two general types of reactions exhibited by the lanthanide elements.

Marine organic photochemistry previewed

Sunlight photolyzes organic compounds in surface waters of the marine environment, destroying some substances and synthesizing others. Such reactions may proceed at high rates and have biological, chemical, and geological implications; the subject is in its infancy. Models are presented that estimate the maximum realistic rates of photochemical transformations at the sea surface and in a 40-meter thick mixed layer; typical rates vary widely and an average cannot be specified. The maximal rates are extremely high at the surface and throughout the layer, corresponding to daylight photodestruction times in the seconds minutes range. Highly photosensitive materials will thus have vanishingly small steady-state concentrations in surface waters. Actual rates ranging from 1 to 10 −8 times the modelled ones may, depending on the rates of competing processes, be significant in the marine environment. The rate of a photoprocess is the product of the excitation rate for light absorption and the chemical efficiency (quantum yield) of ensuing reactions. Mechanistic description of marine photoreactions involves three basic component processes: light absorption, primary photochemical reactions, and secondary reactions. Water, dissolved organic matter, and living and dead particulate matter are the principal absorbers in seawater. The chemical structures of the chromophores involved are not well known, even for the dissolved organic “Gelbstoffe” that color seawater. Most simple organic compounds known in seawater are not effective absorbers. The ensuing reactions of excited states include, beside may specific transformations, general reaction types such as free-radical formation by bond cleavages and by electron transfer redox reactions. Electronic energy transfer also excites other solute molecules. Both of these general primary process types lead to secondary reactions. It is proposed here that secondary reactions are of general importance in marine photochemistry, that they have a net oxidative character in seawater, and that such reactions may provide one sink for both colored and non-absorbing refractory organic molecules in the marine environment. For chromophores, there may be a self-destroying negative feedback effect. Organic radicals produced directly, or indirectly by interaction with inorganic radicals such as O 2 −, CO 3 −, NO, NO 2, OH, Br 2 − are expected to react semiquantitatively with dissolved oxygen, leading to unstable organoperoxy radicals. One photon may thus result in the oxidation of several carbon atoms by short-chain auto-oxidations. Similarly, electronic energy transfer in seawater should result almost exclusively in formation of electronically excited singlet molecular oxygen, a reactive but selective oxidant. Progress in marine organic photochemistry can be anticipated, but artifacts arising from inappropriate light intensities and wavelengths, trace contaminant effects, and photobiological processes must be avoided. Methods for overcoming these difficulties are available for some solution reactions, but potentially important particulate photochemistry studies are much less tractable. Conceptually, marine photochemistry may develop fruitful ties with solution-free radical and radiation chemistry on the one hand, and optical oceanography and euphotic zone biology and chemistry on the other.

Radical ions as reactive intermediates in oxidation, substitution and electron transfer reactions

Typical reactions of radical cations and anions have been summarized, and specific examples of these general reaction types in oxidation, substitution, and electron transfer reactions have been presented. The mechanism, scope and synthetic utility of the numerous reactions now believed to proceedvia radical ion intermediates have been discussed.