Mass spectrometry has become an important analytical tool in biology in the past two decades. In principle, mass spectrometry offers high-throughput, sensitive and specific analysis for many applications in microbiology, including clinical diagnostics and environmental research. Recently, several mass spectrometry methods for the classification and identification of bacteria and other microorganisms, as well as new software analysis tools, have been developed. In this Review we discuss the application range of these mass spectrometry procedures and their potential for successful transfer into microbiology laboratories.

Mass spectrometry tools for the classification and identification of bacteria

Although transition metal dichalcogenides such as MoS2 have been recognized as highly potent two-dimensional nanomaterials, general methods to chemically functionalize them are scarce. Herein, we demonstrate a functionalization route that results in organic groups bonded to the MoS2 surface via covalent C–S bonds. This is based on lithium intercalation, chemical exfoliation and subsequent quenching of the negative charges residing on the MoS2 by electrophiles such as diazonium salts. Typical degrees of functionalization are 10–20 atom % and are potentially tunable by the choice of intercalation conditions. Significantly, no further defects are introduced, and annealing at 350 °C restores the pristine 2H-MoS2. We show that, unlike both chemically exfoliated and pristine MoS2, the functionalized MoS2 is very well dispersible in anisole, confirming a significant modification of the surface properties by functionalization. DFT calculations show that the grafting of the functional group to the sulfur atoms of ...

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Basal-Plane Functionalization of Chemically Exfoliated Molybdenum Disulfide by Diazonium Salts

The utility of electrospray and tandem mass spectroscopy (ES-MS and MS-MS) in anthocyanin characterization was tested using different anthocyanin extracts. Anthocyanins were semipurified by using a C-18 resin, washed with acidified water followed by ethyl acetate, and recovered with acidified methanol. Samples were directly injected into a mass spectrometer in either aqueous or methanolic solutions. The positive charge of anthocyanins favored fast and effective ES-MS detection of intact molecular ions. Little interference from other compounds was observed when the ethyl acetate cleaning procedure was used. Tandem mass spectroscopy provided clear and characteristic fragmentation patterns. The voltage used affected only the proportions at which these fragments were present. ES-MS may be used as a fast procedure for identification of anthocyanins, requiring minimal sample preparation. In combination with HPLC, ES-MS and MS-MS could be very powerful tools for anthocyanin characterization and monitoring the authenticity of anthocyanin-containing fruit juices and vegetable extracts.

Electrospray and Tandem Mass Spectroscopy As Tools for Anthocyanin Characterization

PREFACE. 1 GENERAL INTRODUCTION. 1.1. Why Fluorinated Compounds are Interesting. 1.2. Introduction to Fluorine NMR. References. 2 AN OVERVIEW OF FLUORINE NMR. 2.1. Introduction. 2.2. Fluorine Chemical Shifts. 2.3. Spin-Spin Coupling Constants to Fluorine. 2.4. 1 H Spectra of Fluoroorganic Compounds. 2.5. 13 C NMR Spectra of Fluoroorganic Compounds. 2.6. Isotope Effects on Chemical Shifts. 2.7. Advanced Topics. References. 3 THE SINGLE FLUORINE SUBSTITUENT. 3.1. Introduction. 3.2. Saturated Hydrocarbons. 3.3. Influence of Substituents/Functional Groups. 3.4. Carbonyl Functional Groups. 3.5. Nitriles. 3.6. Alkenes with a Single Fluorine Substituent. 3.7. Acetylenic Fluorine. 3.8. Allylic, Propargylic, and Benzylic Fluorides. 3.9. Fluoroaromatics. 3.10. Fluoroheterocycles. 3.11. Other Common Groups with a Single Fluorine Substituent. References. 4 THE CF 2 GROUP. 4.1. Introduction. 4.2. Saturated Hydrocarbons Containing a CF 2 Group. 4.3. Influence of Substituents/Functional Groups. 4.4. Carbonyl Functional Groups. 4.5. Nitriles. 4.6. Bifunctional CF 2 Compounds. 4.7. Alkenes and Alkynes. 4.8. Benzenoid Aromatics Bearing a CF 2 Group. 4.9. Heteroaromatic CF 2 Groups. References. 5 THE TRIFLUOROMETHYL GROUP. 5.1. Introduction. 5.2. Saturated Hydrocarbons Bearing a CF 3 Group. 5.3. Influence of Substituents and Functional Groups. 5.4. Carbonyl Compounds. 5.5. Nitriles. 5.6. Bifunctional Compounds. 5.7. Sulfonic Acid Derivatives. 5.8. Allylic and Propargylic Trifluoromethyl Groups. 5.9. Aryl-Bound Trifluoromethyl Groups. 5.10. Heteroaryl-Bound Trifluoromethyl Groups. References. 6 MORE HIGHLY FLUORINATED GROUPS. 6.1. Introduction. 6.2. The 1,1,2- and 1,2,2-Trifluoroethyl Groups. 6.3. The 1,1,2,2-Tetrafluoroethyl and 2,2,3,3-Tetrafluoropropyl Groups. 6.4. The 1,2,2,2-Tetrafluoroethyl Group. 6.5. The Pentafluoroethyl Group. 6.6. The 2,2,3,3,3-Pentafluoropropyl Group. 6.7. The 1,1,2,3,3,3-Hexafluoropropyl Group. 6.8. The Hexafluoro- iso -Propyl Group. 6.9. The Heptafluoro- n -Propyl Group. 6.10. The Heptafluoro- iso -Propyl Group. 6.11. The Nonafluoro- n -Butyl Group. 6.12. Fluorous Groups. 6.13. 1-Hydro-Perfluoroalkanes. 6.14. Perfluoroalkanes. 6.15. Perfluoro- n -Alkyl Halides. 6.16. Perfluoroalkyl Amines, Ethers, and Carboxylic Acid Derivatives. 6.17. Polyfluoroalkenes. 6.18. Polyfluorinated Aromatics. 6.19. Polyfluoroheterocyclics. References. 7 COMPOUNDS AND SUBSTITUENTS WITH FLUORIDE DIRECTLY BOUND TO A HETEROATOM. 7.1. Introduction. 7.2. Boron Fluorides. 7.3. Fluorosilanes. 7.4. Nitrogen Fluorides. 7.5. Phosphorous Fluorides. 7.6. Oxygen Fluorides (Hypofluorites). 7.7. Sulfur Fluorides. 7.8. The Pentafluorosulfanyl (SF 5 ) Group. 7.9. Bromine Trifluoride and Iodine Pentafluoride. 7.10. Aryl Halogen Difluorides and Tetrafluorides. 7.11. Xenon Difluoride. References. GENERAL INDEX. COMPOUND INDEX.

Guide to fluorine NMR for organic chemists

The bis(ortho-)chelated platinum complex (PtCl(NCN)), 1 (NCN ) (C6H3(CH2NMe2)2-2,6) - ), has been used as a novel metal precursor for C-H bond activation and subsequent cyclometalation of the potentially terdentate coordinating pincer ligand PCHP (PCP ) (C6H3(CH2PPh2)2-2,6) - ). Depending on the reaction temperature various intermediates, each with unique structural features, could be isolated and identified during the formation of the final, bis(ortho-)cyclometalated product (PtCl(PCP)), 2. These results provide valuable insight into the intimate steps of this reaction for which we like to introduce the term transcyclometalation process (see note). At room temperature, a sparingly soluble dimetallic complex is formed, which comprises a 1 -monodentate C-bound NCN ligand and a bridging, P,P 2 - 2 -coordinating PCHP ligand. Solution spectroscopy and X-ray analysis of this platinum dimer established a C-H bond which is interacting by intramolecular noncovalent H‚‚‚Cl hydrogen bonding with the Pt-Cl motif. As a further intermediate, the formation of a trans-bis(phenyl) complex (Pt( 3 -PCP)( 1 -HNCN))Cl, 5, has been identified, which is characterized by a bis(ortho-)cyclometalated PCP ligand which is 3 -P,C,Pcoordinated to the platinum center as well as an 1 -monodentate C-bound NCN ligand. The equivalent HCl, which is formally released during the formation of 5, is intramolecularly trapped by one of the basic amine groups, as is apparent from the identification of precursors of 5, i.e., compounds in which either one ((3)Cl) or two ((4)X2) of the NMe2 groups have become protonated (see Scheme 5). Remarkably, the proton in (4)X2 is not only bound to the nitrogen lone pair but also interacts with the filled d z2 orbital of the nucleophilic platinum(II) center, thus disclosing complex 5 as an organometallic proton sponge that is able to sequester protons due to Pt,N-bidentate chelating properties. Prolonged exposure of the reaction mixture at 80 °C or performing the reaction at 110 °C afforded the transcyclometalated complex 2 and 1 equiv of the diaminoarene NCHN as the two ultimate products.

Transcyclometalation Processes with Late Transition Metals: CarylH Bond Activiation via Noncovalent CHCl Interactions

Download Area for Lecturers: www.thieme.de/specials/hmz_en.html This book provides the necessary equipment for the application of spectroscopic methods in organic chemistry, as required as part of chemistry courses in all universities. The following methods are explained and examples given: * UV/Vis Spectroscopy, derivative Spectroscopy, chirooptical methods CD and ORD. * Aggregated molecules, charge transfer complexes, conjugated oligomers. * Infrared (IR) and Raman Spectroscopy, Fourier transform IR spectroscopy, and GC/IRcombination methods. * Nuclear Magnetic Resonance Spectroscopy (NMR), 1H-, 13C-, 19F-, 15N- und 31P-NMR, spin decoupling, triple resonance, INDOR difference spectroscopy, 2D- and 3D-NMR, COSY, TOCSY, ROESY and NOESY spectra, NOE, INEPT, and DEPT technique, DEPTQ, HETCOR, HRMAS, INADEQUATE and lanthanide shift reagents, simulation and calculation of spectra, and the combination of separation and NMR methods. The new 2D NMR techniques TOCSY, HMQC and HMBC, more examples and a guide to completely assign all 1H and 13C NMR signals of a given substrate. * Mass spectrometry (MS), electron impact and chemical ionization (EI and CI), fast atom bombardment (FAB), electrospray und thermospray ionization (ESI and TSI), MS/MS technique (MSn), field ionization and field desorption (FI and FD), atmospheric pressure chemical ionization (APCI), MALDI TOF technique, GC/MS, LC/MS, and HPLC-UV(DAD)-APCI combination MS/MS technique. Fourier transform ion cyclotron resonance MS (FT-ICR-MS). The layout and many tables help to introduce the reader to spectroscopy. The extensive and thorough approach makes the text the first choice both as a companion for the professional chemists and as a refresher course in practical spectroscopy. The second English edition is a translation of the 7th German edition, in which several major alterations and didactic improvements have been made. For further information on our chemistry products, please visit: Thieme Chemistry.</p

Richard Dunmur

Papers

Spectroscopic Methods in Organic Chemistry