Extending the coordination chemistry of molecular P(4)S(3): the polymeric Ag(P(4)S(3))(+) and Ag(P(4)S(3))(2)(+) cations

Upon reacting P(4)S(3) with AgAl(hfip)(4) and AgAl(pftb)(4) [hfip = OC(H)(CF(3))(2); pftb = OC(CF(3))(3)], the compounds Ag(P(4)S(3))Al(hfip)(4) 1 and Ag(P(4)S(3))(2)(+)[Al(pftb)(4)](-) 2 formed in CS(2) (1) or CS(2)/CH(2)Cl(2) (2) solution. Compounds 1 and 2 were characterized by single-crystal X-ray structure determinations, Raman and solution NMR spectroscopy, and elemental analyses. One-dimensional chains of [Ag(P(4)S(3))(x)](infinity) (x = 1, 1; x = 2, 2) formed in the solid state with P(4)S(3) ligands that bridge through a 1,3-P,S, a 2,4-P,S, or a 3,4-P,P eta(1) coordination to the silver ions. Compound 2 with the least basic anion contains the first homoleptic metal(P(4)S(3)) complex. Compounds 1 and 2 also include the long sought sulfur coordination of P(4)S(3). Raman spectra of 1 and 2 were assigned on the basis of DFT calculations of related species. The influence of the silver coordination on the geometry of the P(4)S(3) cage is discussed, additionally aided by DFT calculations. Consequences for the frequently observed degradation of the cage are suggested. An experimental silver ion affinity scale based on the solid-state structures of several weak Lewis acid base adducts of type (L)AgAl(hfip)(4) is given. The affinity of the ligand L to the silver ion increases according to P(4) < CH(2)Cl(2) < P(4)S(3) < S(8) < 1,2-C(2)H(4)Cl(2) < toluene.     

Hexacyanometalate molecular chemistry: di-, tri-, tetra-, hexa- and heptanuclear heterobimetallic complexes; control of nuclearity and structural anisotropy

Following a bottom-up approach to nanomaterials, we present a rational synthetic route to high-spin and anisotropic molecules based on hexacyanometalate [M(CN)(6)](3-) cores. Part 1 of this series was devoted to isotropic heptanuclear clusters; herein, we discuss the nuclearity and the structural anisotropy of nickel(II) derivatives. By changing either the stoichiometry, the nature of the terminal ligand, or the counterion, it is possible to tune the nuclearity of the polynuclear compounds and therefore to control the structural anisotropy. We present the synthesis and the characterisation by mass spectrometry, X-ray crystallography and magnetic susceptibility of bi-, tri-, tetra-, hexa- and heptanuclear species [M(CN)(n)(CN-M'L)(6-n)](m+) (with n=0-5; M=Cr(III), Co(III), M'=Ni(II); L=pentadentate ligand). Thus, with M=Cr(III), d(3), S=3/2, a dinuclear complex [Cr(III)(CN)(5)(CN-NiL(n))](9+), (L(n)=polydentate ligand) was built and characterised, showing a spin ground state, S(G)=5/2, with a ferromagnetic interaction J(Cr,Cu)=+18.5 cm(-1). With M=Co(III) (d(6), S=0) were built di-, tri-, tetra-, hexa and hepanuclear CoNi species: CoNi, CoNi(2), CoNi(3), CoNi(5) and CoNi(6). By a first approximation, they behave as one, two, three, five and six isolated nickel(II) complexes, respectively, but more accurate studies allow us to evaluate the weak antiferromagnetic coupling constant between two next-nearest neighbours M'-Co-M'.     

Biological applications of amide and amino acid containing synthetic macrocycles

ABSTRACT

Amino acid derived macrocycles with elaborate well-defined stereochemistry are a unique class of compounds that have been isolated from natural sources. Macrocycles like cyclosporine, octreotide, and valinomycin have been used in multiple applications, like drugs or ion sensors. Chemists have long been fascinated by the unique molecular recognition capabilities of these macrocycles and tried to design synthetic analogs with similar functions. This article is focused on reviewing current research on amide and amino acid containing macrocycles that have been developed in research laboratories for biological recognition, specifically for anion sensing, ion transport, carbohydrate sensing, and peptide sensing.     

Uniform random colored complexes

We present here random distributions on (D + 1)‐edge‐colored, bipartite graphs with a fixed number of vertices 2p. These graphs encode D‐dimensional orientable colored complexes. We investigate the behavior of those graphs as p→∞. The techniques involved in this study also yield a Central Limit Theorem for the genus of a uniform map of order p, as p→∞.     

Metabolism of synthetic cannabinoids PB-22 and its 5-fluoro analog, 5F-PB-22, by human hepatocyte incubation and high-resolution mass spectrometry

Background

PB-22 (1-pentyl-8-quinolinyl ester-1H-indole-3-carboxylic acid) and 5F-PB-22 (1-(5-fluoropentyl)-8-quinolinyl ester-1H-indole-3-carboxylic acid) are new synthetic cannabinoids with a quinoline substructure and the first marketed substances with an ester bond linkage. No human metabolism data are currently available, making it difficult to document PB-22 and 5F-PB-22 intake from urine analysis, and complicating assessment of the drugs’ pharmacodynamic and toxicological properties.

Methods

We incubated 10 μmol/l PB-22 and 5F-PB-22 with pooled cryopreserved human hepatocytes up to 3 h and analyzed samples on a TripleTOF 5600+ high-resolution mass spectrometer. Data were acquired via TOF scan, followed by information-dependent acquisition triggered product ion scans with mass defect filtering (MDF). The accurate mass full scan MS and MS/MS metabolite datasets were analyzed with multiple data processing techniques, including MDF, neutral loss and product ion filtering.

Results

The predominant metabolic pathway for PB-22 and 5F-PB-22 was ester hydrolysis yielding a wide variety of (5-fluoro)pentylindole-3-carboxylic acid metabolites. Twenty metabolites for PB-22 and 22 metabolites for 5F-PB-22 were identified, with the majority generated by oxidation with or without glucuronidation. For 5F-PB-22, oxidative defluorination occurred forming PB-22 metabolites. Both compounds underwent epoxide formation followed by internal hydrolysis and also produced a cysteine conjugate.

Conclusion

Human hepatic metabolic profiles were generated for PB-22 and 5F-PB-22. Pentylindole-3-carboxylic acid, hydroxypentyl-PB-22 and PB-22 pentanoic acid for PB-22, and 5′-fluoropentylindole-3-carboxylic acid, PB-22 pentanoic acid and the hydroxy-5F-PB-22 metabolite with oxidation at the quinoline system for 5F-PB-22 are likely the best targets to incorporate into analytical methods for urine to document PB-22 and 5F-PB-22 intake.

MALDI-TOF-MS Directly Combined with TLC: A Review of the Current State

Thin-layer chromatography (TLC) is a widely used, fast and inexpensive method for separating complex mixtures. Unfortunately, the quality of achievable separation represents only one side. An additional problem is the unambiguous assignment of the obtained spots to defined compounds. Clear identification of spots is often not possible by common staining methods and comparison with a known reference compound. Therefore, further analytical techniques are mostly required for further structural elucidation. Mass spectrometry (MS) is a suitable method due to its high sensitivity. In particular, matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) MS is a modern soft-ionization technique that may be easily combined with TLC. This review summarizes the so far available knowledge about direct TLC–MALDI combination and gives an overview about different molecule classes that have already been successfully analyzed by this approach. This review critically summarizes the capabilities and limitations of the direct MALDI–TLC combination and highlights in particular the problems related to sample preparation and instrumentation.

     

LC-MS/MS screening method for designer amphetamines, tryptamines, and piperazines in serum

Since the late 1990s and early 2000s, derivatives of well-known designer drugs as well as new psychoactive compounds have been sold on the illicit drug market and have led to intoxications and fatalities. The LC-MS/MS screening method presented covers 31 new designer drugs as well as cathinone, methcathinone, phencyclidine, and ketamine which were included to complete the screening spectrum. All but the last two are modified molecular structures of amphetamine, tryptamine, or piperazine. Among the amphetamine derivatives are cathinone, methcathinone, 3,4-DMA, 2,5-DMA, DOB, DOET, DOM, ethylamphetamine, MDDMA, 4-MTA, PMA, PMMA, 3,4,5-TMA, TMA-6 and members of the 2C group: 2C-B, 2C-D, 2C-H, 2C-I, 2C-P, 2C-T-2, 2C-T-4, and 2C-T-7. AMT, DPT, DiPT, MiPT, DMT, and 5MeO-DMT are contained in the tryptamine group, BZP, MDBP, TFMPP, mCPP, and MeOPP in the piperazine group. Using an Applied Biosystems LC-MS/MS API 365 TurboIonSpray it is possible to identify all 35 substances. After addition of internal standards and mixed-mode solid-phase extraction the analytes are separated using a Synergi Polar RP column and gradient elution with 1 mM ammonium formate and methanol/0.1% formic acid as mobile phases A and B. Data acquisition is performed in MRM mode with positive electro spray ionization. The assay is selective for all tested substances. Limits of detection were determined by analyzing S/N-ratios and are between 1.0 and 5.0 ng/mL. Matrix effects lie between 65% and 118%, extraction efficiencies range from 72% to 90%.     

Relèvements des revêtements de courbes faiblement ramifiés

Let X be a smooth projective curve over a perfect field of characteristic p>0 and G a finite group of automorphism of X. Let ν(X,G) be the characteristic of the versal equivariant deformation ring R(X,G) of (X,G). When the ramification is weak (i.e., all second ramification groups are trivial), we prove that ν(X,G) ∈ {0,p} and we compute R(X,G).

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Résumé Soit X une courbe projective lisse sur un corps parfait de caractéristique p>0 et G un groupe fini d'automorphismes de X. Nous considérons la caractéristique ν(X,G) de l'anneau versel R(X,G) de déformations équivariantes de (X,G). Dans le cas d'une ramification faible (où tous les seconds groupes de ramification sont triviaux), nous démontrons que ν(X,G) ∈ {0,p} et nous calculons R(X,G).