A mixture of the photocatalyst riboflavin tetraacetate (RFT) and the biomimetic non‐heme iron complex Fe(TPA)(MeCN)2(ClO4)2 (TPA=tris(2‐pyridylmethyl)amine) efficiently catalyzes the ...visible‐light‐driven aerobic oxidation of alkyl benzenes to ketones and carboxylic acids. An RFT‐catalyzed photocycle and the independent action of the iron complex as a catalyst for H2O2 disproportionation and alkyl benzene oxygenation ensure high yields and selectivities.
A dual catalyst system consisting of the photocatalyst riboflavin tetraacetate (RFT) and a tris(2‐pyridylmethyl)amine iron complex enables efficient visible‐light‐driven CH oxygenations of alkyl benzenes. The high catalyst efficiency is attributed to the oxygenation activity of the Fe complex and an increased durability of the photocatalyst owing to iron‐catalyzed H2O2 decomposition.
•We investigate brain function and structure in persons with “smartphone addiction” (SPA).•Persons with SPA showed lower gray matter volume in insula and temporal cortex.•Persons with SPA showed ...reduced resting-state activity of the anterior cingulate cortex.•Anterior cingulate cortex volume and activity was associated with SPA-severity.•The data suggest aberrant neural integrity of the salience network.
Popularity and availability of smartphones have dramatically increased in the past years. This trend is accompanied by increased concerns regarding potentially adverse effects of excessive smartphone use, particularly with respect to physical and mental health. Recently, the term “smartphone addiction” (SPA) has been introduced to describe smartphone-related addictive behavior and associated physical and psychosocial impairment. Here, we used structural and functional magnetic resonance imaging (MRI) at 3 T to investigate gray matter volume (GMV) and intrinsic neural activity in individuals with SPA (n = 22) compared to a control group (n = 26). SPA was assessed using the Smartphone Addiction Inventory (SPAI), GMV was investigated by means of voxel-based morphometry, and intrinsic neural activity was measured by the amplitude of low frequency fluctuations (ALFF). Compared to controls, individuals with SPA showed lower GMV in left anterior insula, inferior temporal and parahippocampal cortex (p < 0.001, uncorrected for height, followed by correction for spatial extent). Lower intrinsic activity in SPA was found in the right anterior cingulate cortex (ACC). A significant negative association was found between SPAI and both ACC volume and activity. In addition, a significant negative association between SPAI scores and left orbitofrontal GMV was found. This study provides first evidence for distinct structural and functional correlates of behavioral addiction in individuals meeting psychometric criteria for SPA. Given their widespread use and increasing popularity, the present study questions the harmlessness of smartphones, at least in individuals that may be at increased risk for developing smartphone-related addictive behaviors.
Psychomotor abnormalities have been abundantly observed in psychiatric disorders like major depressive disorder (MDD), bipolar disorder (BD), and schizophrenia (SCH). Although early ...psychopathological descriptions highlighted the truly psychomotor nature of these abnormalities, more recent investigations conceive them rather in purely motor terms. This has led to an emphasis of dopamine-based abnormalities in subcortical-cortical circuits including substantia nigra, basal ganglia, thalamus, and motor cortex. Following recent findings in MDD, BD, and SCH, we suggest a concept of psychomotor symptoms in the literal sense of the term by highlighting three specifically psychomotor (rather than motor) mechanisms including their biochemical modulation. These include: (i) modulation of dopamine- and substantia nigra-based subcortical-cortical motor circuit by primarily non-motor subcortical raphe nucleus and serotonin via basal ganglia and thalamus (as well as by other neurotransmitters like glutamate and GABA); (ii) modulation of motor cortex and motor network by non-motor cortical networks like default-mode network and sensory networks; (iii) global activity in cortex may also shape regional distribution of neural activity in motor cortex. We demonstrate that these three psychomotor mechanisms and their underlying biochemical modulation are operative in both healthy subjects as well as in MDD, BD, and SCH subjects; the only difference consists in the fact that these mechanisms are abnormally balanced and thus manifest in extreme values in psychiatric disorders. We conclude that psychomotor mechanisms operate in a dimensional and cross-nosological way as their degrees of expression are related to levels of psychomotor activity (across different disorders) rather than to the diagnostic categories themselves. Psychomotor mechanisms and their biochemical modulation can be considered paradigmatic examples of a dimensional approach as suggested in RDoC and the recently introduced spatiotemporal psychopathology.
Recently there has been great interest in the reactivity of transition‐metal (TM) centers towards white phosphorus (P4). This has ultimately been motivated by a desire to find TM‐mediated ...alternatives to the current industrial routes used to transform P4 into myriad useful P‐containing products, which are typically indirect, wasteful, and highly hazardous. Such a TM‐mediated process can be divided into two steps: activation of P4 to generate a polyphosphorus complex TM‐Pn, and subsequent functionalization of this complex to release the desired phosphorus‐containing product. The former step has by now become well established, allowing the isolation of many different TM‐Pn products. In contrast, productive functionalization of these complexes has proven extremely challenging and has been achieved only in a relative handful of cases. In this review we provide a comprehensive summary of successful TM‐Pn functionalization reactions, where TM‐Pn must be accessible by reaction of a TM precursor with P4. We hope that this will provide a useful resource for continuing efforts that are working towards this highly challenging goal of modern synthetic chemistry.
The activation of P4 by transition‐metal complexes has become well established, due to a desire to find new and improved routes for its transformation into useful P‐containing compounds. However, the next necessary step—functionalization of the resulting metal‐bound Pn moieties—has proven extremely challenging and has only occasionally been achieved. Herein, a comprehensive review of these important transformations is provided.
Monophosphorus compounds are of enormous industrial importance due to the crucial roles they play in applications such as pharmaceuticals, photoinitiators and ligands for catalysis, among many ...others. White phosphorus (P
) is the key starting material for the preparation of all such chemicals. However, current production depends on indirect and inefficient, multi-step procedures. Here, we report a simple, effective 'one-pot' synthesis of a wide range of organic and inorganic monophosphorus species directly from P
. Reduction of P
using tri-n-butyltin hydride and subsequent treatment with various electrophiles affords compounds that are of key importance for the chemical industry, and it requires only mild conditions and inexpensive, easily handled reagents. Crucially, we also demonstrate facile and efficient recycling and ultimately catalytic use of the tributyltin reagent, thereby avoiding the formation of substantial Sn-containing waste. Accessible, industrially relevant products include the fumigant PH
, the reducing agent hypophosphorous acid and the flame-retardant precursor tetrakis(hydroxymethyl)phosphonium chloride.
AbstractAt the beginning of the 20th century, genuine motor abnormalities (GMA) were considered to be intricately linked to schizophrenia. Subsequently, however, GMA have been increasingly regarded ...as unspecific transdiagnostic phenomena or related to side effects of antipsychotic treatment. Despite possible medication confounds, within the schizophrenia spectrum GMA have been categorized into three broad categories, i.e. neurological soft signs, abnormal involuntary movements and catatonia. Schizophrenia patients show a substantial overlap across a broad range of distinct motor signs and symptoms suggesting a prominent involvement of the motor system in disease pathophysiology. There have been several attempts to increase reliability and validity in diagnosing schizophrenia based on behavior and neurobiology, yet relatively little attention has been paid to the motor domain in the past. Nevertheless, accumulating neuroscientific evidence suggests the possibility of a motor endophenotype in schizophrenia, and that GMA could represent a specific dimension within the schizophrenia-spectrum. Here, we review current neuroimaging research on GMA in schizophrenia with an emphasis on distinct and common mechanisms of brain dysfunction. Based on a dimensional approach we show that multimodal neuroimaging combined with fine-grained clinical examination can result in a comprehensive characterization of structural and functional brain changes that are presumed to underlie core GMA in schizophrenia. We discuss the possibility of a distinct motor domain, together with its implications for future research. Investigating GMA by means of multimodal neuroimaging can essentially contribute at identifying novel and biologically reliable phenotypes in psychiatry.
Clinical features and genetics overlap in schizophrenia (SCZ) and bipolar disorder (BD). Identifying brain alterations associated with genetic vulnerability for SCZ and BD could help to discover ...intermediate phenotypes, quantifiable biological traits with greater prevalence in unaffected relatives (RELs), and early recognition biomarkers in ultrahigh risk populations. However, a comprehensive meta-analysis of structural and functional magnetic resonance imaging (MRI) studies examining relatives of patients with SCZ and BD has not been performed yet.
We systematically searched PubMed, Scopus, and Web of Science for structural and functional MRI studies investigating relatives and healthy control subjects. A total of 230 eligible neuroimaging studies (6274 SCZ-RELs, 1900 BD-RELs, 10,789 healthy control subjects) were identified. We conducted coordinate-based activation likelihood estimation meta-analyses on 26 structural MRI and 81 functional MRI investigations, including stratification by task type. We also meta-analyzed regional and global volumetric changes. Finally, we performed a meta-analysis of all MRI studies combined.
Reduced thalamic volume was present in both SCZ and BD RELs. Moreover, SCZ-RELs showed alterations in corticostriatal-thalamic networks, spanning the dorsolateral prefrontal cortex and temporal regions, while BD-RELs showed altered thalamocortical and limbic regions, including the ventrolateral prefrontal, superior parietal, and medial temporal cortices, with frontoparietal alterations in RELs of BD type I.
Familiarity for SCZ and BD is associated with alterations in the thalamocortical circuits, which may be the expression of the shared genetic mechanism underlying both disorders. Furthermore, the involvement of different prefrontocortical and temporal nodes may be associated with a differential symptom expression in the two disorders.
Catatonia is a complex psychomotor disorder characterized by motor, affective, and behavioral symptoms. Despite being known for almost 150 years, its pathomechanisms are still largely unknown.
A ...systematic research on PubMed, Web of Science, and Scopus was conducted to identify neuroimaging studies conducted on group or single individuals with catatonia. Overall, 33 studies employing structural magnetic resonance imaging (sMRI, n = 11), functional magnetic resonance imaging (fMRI, n = 10), sMRI and fMRI (n = 2), functional near-infrared spectroscopy (fNIRS, n = 1), single positron emission computer tomography (SPECT, n = 4), positron emission tomography (PET, n = 4), and magnetic resonance spectroscopy (MRS, n = 1), and 171 case reports were retrieved.
Observational sMRI studies showed numerous brain changes in catatonia, including diffuse atrophy and signal hyperintensities, while case-control studies reported alterations in fronto-parietal and limbic regions, the thalamus, and the striatum. Task-based and resting-state fMRI studies found abnormalities located primarily in the orbitofrontal, medial prefrontal, motor cortices, cerebellum, and brainstem. Lastly, metabolic and perfusion changes were observed in the basal ganglia, prefrontal, and motor areas. Most of the case-report studies described widespread white matter lesions and frontal, temporal, or basal ganglia hypoperfusion.
Catatonia is characterized by structural, functional, perfusion, and metabolic cortico-subcortical abnormalities. However, the majority of studies and case reports included in this systematic review are affected by considerable heterogeneity, both in terms of populations and neuroimaging techniques, which calls for a cautious interpretation. Further elucidation, through future neuroimaging research, could have great potential to improve the description of the neural motor and psychomotor mechanisms underlying catatonia.
Chlorine gas or electropositive chlorine reagents are used to prepare chlorinated aromatic compounds, which are found in pharmaceuticals, agrochemicals, and polymers, and serve as synthetic ...precursors for metal‐catalyzed cross‐couplings. Nature chlorinates with chloride anions, FAD‐dependent halogenases, and O2 as the oxidant. A photocatalytic oxidative chlorination is described based on the organic dye riboflavin tetraacetate mimicking the enzymatic process. The chemical process allows within the suitable arene redox potential window a broader substrate scope compared to the specific activation in the enzymatic binding pocket.
Chlorination of arenes with chloride anions: The photochemical analogue of the enzymatic chlorination of Flavin‐adenine dinucleotide (FAD)‐dependent halogenases is possible in the presence of riboflavin, air, acetic acid, and blue light (see scheme; RFT=riboflavin tetraacetate).
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