The Sweet Spirits of the Mineral Acids: Diethyl Ether, Ethyl Nitrite, and Chloroethane. Late Medieval-Early Modern Organic Chemistry.

The "sweet spirits" of sulfuric, nitric, and hydrochloric acids, viz. diethyl ether, ethyl nitrite, and chloroethane, have a history dating back to the late Middle Ages. The compound variously known as philosophorum spiritus vini, aqua Lulliana, Paracelsus' Schwefel süss, Cordus' dulce Vitrioli oleum, and Frobenius' æther is identical with diethyl ether.

Nitrile Imine Cyclizations and Rearrangements: -Phenyl--styrylnitrile Imine and -Phenyl--phenylethynylnitrile Imine.

The formation and rearrangements of nitrile imines are of ongoing synthetic and theoretical interest. In this paper, we report a computational investigation at the M06/6-311 + G(d,p) level of the formation and rearrangement of propargylic phenylstyrylnitrile imine from 2-phenyl-5-styryltetrazole by flash vacuum pyrolysis (FVP). Nitrile imine cyclizes to 3a-3-styrylindazole , which is also generated by H-shifts in the FVP of 3-styrylindazole .

The Transition from Alchemical to Modern Chemical Symbolism: from Bergman and Guiton de Morveau to Hassenfratz and Adet, Higgins, Richter, Dalton, and Berzelius.

The alchemical concepts of chemical symbolism, nomenclature, and affinity underwent fundamental changes between the 1770s and the 1820s, roughly simultaneously with the Chemical Revolution (ca. 1772-89), i. e.

Formation of (Aza)fulvenallene, Cyanocyclopentadiene, and (Aza)fluorenes in the Thermal Rearrangements of Indazoles, Azaindazoles, and Homoquinolinic Anhydride.

Flash vacuum pyrolysis (FVP) of pyrazoles and indazoles constitutes a valuable route to carbenes and nitrenes. In this study, we employed M062X and CCSD(T) calculations to provide a mechanistic rationale for the formation of fulvenallene and fluorenes from indazoles and the corresponding formation of azafulvenallene , cyanocyclopentadiene , and azafluorenes, e.g.

CHNO - Formylnitrene, Cyanic, Isocyanic, Fulminic, and Isofulminic Acids and their Interrelationships at DFT and CASPT2 Levels of Theory.

Fulminic and cyanic acids played a decisive role in the conception of isomerism 200 years ago. Cyanic (HOCN), isocyanic (HNCO), and fulminic (HCNO) acids have been detected in several interstellar sources, but isofulminic acid (HONC) is little known. Here we examine the interrelationships between the four acids and formylnitrene, HC(O)N, at the CASPT2 and three DFT levels.

The Alchemist, Metal-Divider and Transmuter Carl F. Wenzel and his 1776 Award from the Royal Danish Academy of Sciences through Professor C. G. Kratzenstein.

C. F. Wenzel was a chemist and an alchemist.

Chemistry, Medicine, and Gold-Making: Tycho Brahe, Helwig Dieterich, Otto Tachenius, and Johann Glauber.

17 century chemistry was concerned largely with iatrochemistry (medicinal chemistry) and the transmutation of metals, especially with the purpose of making gold. Thus, Johann Rudolph Glauber made a living making and selling chemicals such as nitric acid and medicaments such as aurum potabile (drinkable gold), but he also believed in the transmutation or "improvement" of metals and the "augmentation" of gold, and he sold recipes for such processes. This perspective aims to provide a snapshot of the range of 17 century chemistry by analysis of the efforts of four representatives to make drugs, chemicals, and gold.

Fidelity varies in the symbiosis between a gutless marine worm and its microbial consortium.

Background: Many animals live in intimate associations with a species-rich microbiome. A key factor in maintaining these beneficial associations is fidelity, defined as the stability of associations between hosts and their microbiota over multiple host generations. Fidelity has been well studied in terrestrial hosts, particularly insects, over longer macroevolutionary time.

Validation of the AquaCHROM™ ECC for the Detection and Enumeration of Coliforms and Escherichia coli in Water Samples: AOAC Performance Tested MethodSM 072202.

Background: The AquaCHROM™ ECC method from CHROMagar is intended for the detection and enumeration of Escherichia coli and coliform bacteria in 100 mL water samples after 18-24 h of incubation at 35-37°C.

Objective: To validate the AquaCHROM ECC method for qualitative and quantitative detection of E. coli and coliforms with different water matrixes.

Azulene-Naphthalene, Naphthalene-Naphthalene, and Azulene-Azulene Rearrangements.

The mechanism(s) of thermal rearrangement of azulenes have been enigmatic for several decades. Herein, we have employed density functional theory (DFT) calculations at the M06-2X/6-311+G(d,p) level together with single-point calculations at the CCSD(T) level to assess possible mechanisms of the experimentally observed azulene and naphthalene automerizations. Of the two mechanisms proposed for naphthalene automerization, it is found that the benzofulvene (BF) route is favored over the naphthvalene mechanism by ∼6 kcal/mol and is energetically lower than the norcaradiene-vinylidene mechanism (NVM) for the azulene-naphthalene rearrangement ( ∼ 76.

Thermal Rearrangement of Azulenes to Naphthalenes: A Deeper Insight into the Mechanisms.

The thermal rearrangement of azulene to naphthalene has been the subject of several experimental and computational studies. Here, we reexamine the proposed mechanisms at the DFT level. The use of different functionals showed that the HF-exchange contribution significantly affects reaction energies and barrier heights.

Benzotriazoles and Triazoloquinones: Rearrangements to Carbazoles, Benzazirines, Azepinediones, and Fulvenimines.

The denitrogenative rearrangements of several types of benzotriazoles were investigated by DFT (B3LYP/6-311G(d,p)) and CASPT2(10,10)sp/6-311G(d,p) calculations. The Graebe-Ullmann synthesis of carbazoles by pyrolysis or photolysis of 1-arylbenzotriazoles proceeds without the involvement of benzazirines and without Wolff-type ring contraction to fulvenimines. However, 1-aryltetrahydrobenzotriazoles undergo both cyclization to tetrahydrocarbazole and ring contraction.

When a "Dimroth Rearrangement" Is Not a Dimroth Rearrangement.

In the Dimroth rearrangement of heterocycles, often pyrimidines, an exocyclic and a ring substituent are interchanged. However, the term Dimroth rearrangement is frequently used even when there is no knowledge of the reaction mechanism and alternatives are likely. Here, we have employed density functional theory (DFT) calculations at the M06-2X/6-311+G(d,p) level to determine the most plausible rearrangement pathways of 3-aminothiocarbonylquinazoline , tetrahydrofuranylpyrimidine , and 5-allyltriazocine .

Bunsen the Geochemist: Icelandic Volcanism, Geyser Theory, and Gas, Rock and Mineral Analyses.

Following the eruption of Hekla in 1845-1846 Bunsen was invited by King Christian VIII of Denmark and Iceland to participate in a geochemical expedition to Iceland together with the geologist Sartorius von Waltershausen and the physiologist Carl Bergmann from Göttingen. The French mineralogist Des Cloizeaux went to Iceland separately and joined the expedition. The eudiometer invented by Bunsen was crucial for his accurate characterization of volcanic gases and determination of the composition of mixtures.

Rearrangements of Aromatic Nitrile Oxides and Nitrile Ylides: Potential Ring Expansion to Cycloheptatetraene Derivatives Mimicking Arylcarbenes.

Nitrile imines, nitrile oxides and nitrile ylides are widely used in 1,3-dipolar cycloaddition reactions. They also undergo thermal and photochemical rearrangements to carbodiimides, isocyanates, and ketenimines, respectively. Calculations at DFT and CASPT2 levels of theory reveal novel, potential rearrangements, in which the aromatic 1,3-dipoles mimic phenylcarbene and undergo ring expansion to cycloheptatetraene derivatives.

Molecular causes of an evolutionary shift along the parasitism-mutualism continuum in a bacterial symbiont.

Symbiosis with microbes is a ubiquitous phenomenon with a massive impact on all living organisms, shaping the world around us today. Theoretical and experimental studies show that vertical transmission of symbionts leads to the evolution of mutualistic traits, whereas horizontal transmission facilitates the emergence of parasitic features. However, these studies focused on phenotypic data, and we know little about underlying molecular changes at the genomic level.

High-Quality Draft Genome Sequences of the Uncultured Delta3 Endosymbiont (Deltaproteobacteria) Assembled from Metagenomes of the Gutless Marine Worm Olavius algarvensis.

Here, we present two high-quality, draft metagenome-assembled genomes of deltaproteobacterial OalgDelta3 endosymbionts from the gutless marine worm Their 16S rRNA gene sequences share 98% identity with Delta3 endosymbionts of related host species (GenBank accession no. AJ620501) and (GenBank accession no. FM202060), for which no symbiont genomes are available.

Ørsted and Bunsen: Voltaic Batteries, Electric Arcs, Electromagnetism, and Electrolysis.

200 years ago Ørsted laid the foundation of electromagnetism in his famous experiment in which a magnetic needle is deflected in the electrical field of a platinum wire. For this he used his own Cu-Zn trough battery, which was among the best then available, but 21 years later it was surpassed by the coal-zinc battery invented by Bunsen, which became highly successful and acclaimed. That year, 1841, Bunsen made his first direct contact with Scandinavia when he visited Berzelius in Stockholm, Palmstedt in Gothenburg, and Ørsted, Scharling, and Zeise in Copenhagen.

Aryl Nitrile Imines and Diazo Compounds. Formation of Indazole, Pyridine -Imine, and 2-Pyridyldiazomethane from Tetrazoles.

Both photolysis and flash vacuum pyrolysis (FVP) of tetrazoles (/) are known to generate nitrile imines (, , and ), which rearrange to 1-diazirines, imidoylnitrenes, and carbodiimides. Moreover, FVP of 5-aryltetrazoles is a convenient source of aryldiazo compounds (/) and arylcarbenes, including pyridylcarbenes. The factors that determine which path is followed are poorly understood.

High-Quality Draft Genome Sequences of Two Deltaproteobacterial Endosymbionts, Delta1a and Delta1b, from the Uncultured Sva0081 Clade, Assembled from Metagenomes of the Gutless Marine Worm Olavius algarvensis.

Here, we present high-quality metagenome-assembled genome sequences of two closely related deltaproteobacterial endosymbionts from the gutless marine worm (Annelida). The first is an improved draft genome sequence of the previously described sulfate-reducing symbiont Delta1. The second is from a closely related, recently discovered symbiont of .

Zeise, Liebig, Jensen, Hückel, Dewar, and the Olefin π-Complex Bonds.

Zeise's salt, KPt(C H )Cl , was the first characterized organometallic compound; it was also the first olefin π-complex. It was published in 1825-1830 in the middle of a fight between Dumas on the one hand and Berzelius and Liebig on the other, who defended the etherin (ethylene) and radical theories, respectively. Although Zeise's formulation as a compound containing ethylene was vindicated, the fight went on for many years.

Rearrangements of Nitrile Imines: Ring Expansion of Benzonitrile Imines to Cycloheptatetraenes and Ring Closure to 3-Phenyl-3 H-diazirines.

Nitrile imines are important intermediates in 1,3-dipolar cycloaddition reactions, and they are also known to undergo efficient, unimolecular rearrangements to carbodiimides via 1 H-diazirines and imidoylnitrenes under both thermal and photochemical reaction conditions. We now report a competing rearrangement, revealed by CASPT2(14,12) and B3LYP calculations, in which C-phenylnitrile imines 8 undergo ring expansion to 1-diazenyl-1,2,4,6-cycloheptatetraenes 12 akin to the phenylcarbene-cycloheptatetraene rearrangement. Amino-, hydroxy-, and thiol-groups in the meta positions of C-phenylnitrile imine lower the activation energies for this rearrangement so that it becomes potentially competitive with the cyclization to 1 H-diazirines and hence rearrange to carbodiimides.

Fulminating Gold and Silver.

This Essay deals with the fascinating and highly explosive compounds fulminating gold and fulminating silver, which are easily made by treatment of gold dissolved in aqua regia with ammonia, and by reaction of silver oxide or silver salts with ammonia, respectively. Fulminating gold in particular captivated the alchemists in the 16th to 18th centuries. Numerous preparations were described, as well as numerous attempts to make volatile, sublimable or distillable gold, and to use the products so obtained (which were most likely gold chlorides) to make the sought-after tincture, which would "heal" the "impure" metals and transform them into gold, and equally be a panacea to cure all human illnesses.

Symbiont-Mediated Defense against Legionella pneumophila in Amoebae.

is an important opportunistic pathogen for which environmental reservoirs are crucial for the infection of humans. In the environment, free-living amoebae represent key hosts providing nutrients and shelter for highly efficient intracellular proliferation of , which eventually leads to lysis of the protist. However, the significance of other bacterial players for ecology is poorly understood.