In a new oxidative route, Ag(+)[Al(OR(F))(4)](-) (R(F)=C(CF(3))(3)) and metallic indium were sonicated in aromatic solvents, such as fluorobenzene (PhF), to give a precipitate of silver metal and highly soluble [In(PhF)(n)](+) salts (n=2, 3) with the weakly coordinating [Al(OR(F))(4)](-) anion in quantitative yield. The In(+) salt and the known analogous Ga(+)[Al(OR(F))(4)](-) were used to synthesize a series of homoleptic PR(3) phosphane complexes [M(PR(3))(n)](+), that is, the weakly PPh(3)-bridged [(Ph(3)P)(3)In-(PPh(3))-In(PPh(3))(3)](2+) that essentially contains two independent [In(PPh(3))(3)](+) cations or, with increasing bulk of the phosphane, the carbene-analogous [M(PtBu(3))(2)](+) (M=Ga, In) cations. The M(I)-P distances are 27 to 29 pm longer for indium, and thus considerably longer than the difference between their tabulated radii (18 pm). The structure, formation, and frontier orbitals of these complexes were investigated by calculations at the BP86/SV(P), B3LYP/def2-TZVPP, MP2/def2-TZVPP, and SCS-MP2/def2-TZVPP levels.
The reaction products and intermediates of the three CO-releasing manganese(i) coordination compounds [Mn(tpm)(CO)], [Mn(bpza)(CO)] and [Mn(tpa)(CO)] were analysed by combining IR-spectroscopy, electrochemical measurements and single-crystal XRD. The intermediate formation of manganese(i) biscarbonyl compounds and the rather facile oxidation of these species were identified as key reaction steps that accompany CO liberation. For the use of [Mn(CO)] complexes as light-triggered CO sources, the results indicate that in this case photo- and redox-chemistry seem to be strongly coupled which could be important and potentially even useful in the pharmacological context. Additionally, one has to be aware of the fact that [Mn(κ-L)(solv)] complexes, the primary reaction products after CO substitution, are able to bind to proteins, which was demonstrated using bovine serum albumin as a model. And finally it could be shown that the CO-release reactions can be used as a new synthetic route to prepare multinuclear μ-oxido-bridged manganese complexes: the mixed-valence compound [Mn(μ-O)(tpa)] could be prepared in a single step from [Mn(tpa)(CO)]via photo- or electrochemically induced CO substitution.
All square: The polyinterhalide [Cl(I2)4]− is square‐planar in the crystal structure of [(H5O2)(I2b15c5)2][Cl(I2)4] (I2b15c5=diiodobenzo‐15‐crown‐5), although it would be tetrahedral in the gas phase. Along with other effects, such as electrostatic attractions between the cationic and planar anionic layers, iodine–iodine bonding with σ‐hole interactions plays a considerable role is stabilizing the square‐planar configuration.
Formation of picolinic acid esters of hydroxylated drugs or their biotransformation products is a promising tool to improve their mass spectrometric ionization efficiency, alter their fragmentation behaviour and enhance sensitivity and specificity of their detection. The procedure was optimized and tested for the detection of cannabinoids, which proved to be most challenging when dealing with alternative specimens, for example hair and oral fluid. In particular, the detection of the THC metabolites hydroxyl-THC and carboxy-THC requires ultimate sensitivity because of their poor incorporation into hair or saliva. Both biotransformation products are widely accepted as incorporation markers to distinguish drug consumption from passive contamination. The derivatization procedure was carried out by adding a mixture of picolinic acid, 4-(dimethylamino)pyridine and 2-methyl-6-nitrobenzoic anhydride in tetrahydrofuran/triethylamine to the dry extraction residues. Resulting derivatives were found to be very stable and could be reconstituted in aqueous or organic buffers and subsequently analyzed by liquid chromatography-mass spectrometry (LC-MS). Owing to the complex consecutive fragmentation patterns, the application of multistage MS3 proved to be extremely useful for a sensitive identification of doubly picolinated hydroxy-THC in complex matrices. The detection limits - estimated by comparison of corresponding signal-to-noise ratios - increased by a factor of 100 following picolination. All other species examined, like cannabinol, THC, cannabidiol, and carboxy-THC, could also be derivatized exhibiting only moderate sensitivity improvements. The assay was systematically tested using hair samples and exemplarily applied to oral fluid. Concentrations of OH-THC identified in THC-positive hair samples ranged from 0.02 to 0.29pg/mg.
Professor Werner Uhl zum 60. Geburtstag gewidmet In geeigneten Lçsungsmitteln bilden Halogenid-Ionen und Halogen-Moleküle hçhere Aggregate, so genannte Polyhalogenide, und kristallisieren mit geeigneten Kationen als Salze. Das stabilste Polyhalogenid, das seit fast zweihundert Jahren bekannte Triiodid, [I 3 ] À , entsteht in einfacher Weise durch Addition von Iod an Iodid; es wurde allerdings erst 1935 in der Kristallstruktur von (NH 4 )[I 3 ] eindeutig nachgewiesen. [1] Triiodid-Ionen, wie man sie aus hunderten von Salzen kennt, sind oft unsymmetrisch, weshalb man sie als Donor-Akzeptor/Säure-Base-Komplexe von I À und I 2 auffasst. Es gibt allerdings auch viele symmetrische lineare Triiodide, wie man auch aus Raman-Spektren weiß. Das Triiodid, [I 3 ] À , kann als eigenständige Spezies angesehen werden. Hçhere Polyiodide mit bis zu 29 Iodatomen mit Ladungen bis 3À kommen weniger häufig vor, insbesondere nicht als isolierte Spezies. [2, 3] Polybromide und -chloride sind deutlich seltener als Polyiodide. Das Trifluorid-Anion, [F 3 ] À , wurde bislang nur in einer festen Edelgasmatrix spektroskopisch nachgewiesen. [4] Polyinterhalogenide wie die klassischen [ICl 2 ] À (linear) oder [ICl 4 ] À (tetraedrisch) sind gut bekannt. [5, 6] Man weiß jedoch wenig über die Natur der chemischen Bindung in solchen Verbindungen. Üblicherweise schreibt man dem Zentralatom eine positive Oxidationsstufe zu und das komplexe Anion wird wiederum als Donor-Akzeptor/Säure-Base-Komplex aufgefasst. Addukte aus einem elektronegativen Zentralteilchen wie Cl À und Halogen-Molekülen wie I 2 sind unbekannt. Wir haben nun bei Versuchen zur Synthese von Polyiodid-Netzwerken, die Hohlräume für Kationen aus Metallkationen komplexiert durch Kronenether bereithalten, das neue Anion [ClI 8 ] À = [Cl(I 2 ) 4 ] À entdeckt. Das Anion [Cl(I 2 ) 4 ] À wurde erstmals bei der Umsetzung von YI 3 mit Benzo-15-Krone-5 (b15c5), Natriumchlorid und Iod in Methanol unter Zugabe von einigen Tropfen Iodwasserstoffsäure hergestellt. Dabei entstanden neben schwarzroten bis schwarzen Platten von [(H 5 O 2 )(I 2 b15c5) 2 ][Cl(I 2 ) 4 ] (1; für Details der Kristallstrukturbestimmung, siehe die Hintergrundinformationen) auch gelbe Nadeln oder Platten von [(H 5 O 2 )(I 2 b15c5) 2 ][ICl 2 ](I 2 b15c5) 2 (2). Zur gezielten Synthese von 1 setzt man ICl, Iod und b15c5 in Methanol um. Sowohl bei der Reaktion mit YI 3 als auch mit ICl werden zwei Wasserstoffatome in den Positionen 3 und 4 des Benzo-Rings in einer Friedel-Crafts-Reaktion durch Iodatome substituiert. Zwei dieser I 2 b15c5-Moleküle schließen mit entgegengesetzter Orientierung ein (H 5 O 2 ) + -Kation ein, wodurch das in Abbildung 1 gezeigte große Kation entsteht. Der O-O-Abstand in der O···H··O-Brücke ist mit 244(1) pm derselbe wie in (H 5 O 2 )(b15c5) 2 [AuCl 4 ], [7] 242.0(6) pm. Man beobachtet zwei kleine O-O-Abstände zu Sauerstoffatomen des Kronenethers, 266 pm; jene zu den übrigen drei Sauerstoffatomen von I 2 b15c5 liegen zwischen 292 und 308 pm. Die [(H 5 O 2 )-(I 2 b15c5) 2 ] + -Kationen ordnen sich in 1 in ...
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