Some Y-Groups

We call a Y-group a quotient of a Coxeter group with a Y _pqr -diagram in accordance with the ATLAS terminology. Here we prove, without computer aid, that some 3-transposition groups are also Y-groups. For each of these groups, the arms of the Coxeter diagram Y _pqr are such that (1 = r q p 5) or (2 = r q 3, q p 5) holds, the additional relations generally describe the center or the Schur multiplier.     

Comparison of sub-2-microm particle columns for fast metabolite ID

The use of sub-2-microm particle columns for fast high throughput metabolite ID applications was investigated. Three LC-MS methods based on different sub-2-microm particle size columns using the same analytical 3 min gradient were developed (Methods A, B, and C). Method A was comprised of a 1.8 microm particle column coupled to an MS, methods B and C utilized a 1.7 microm particle column (BEH 50 x 2.1 mm2 id) and 1.8 microm particle column coupled to a Q-TOF MS. The precision and the separation efficiency of the methods was compared with repeated standard injections (N=10) of reference compounds verapamil (VP), propranolol, and fluoxetine. Separation efficiency and MS/MS spectral quality were also evaluated for separation and detection of VP and its two major metabolites norverapamil (NVP) and O-demethylverapamil (ODMVP) in human-liver microsomal incubates. Results show that 1.8 microm particle columns show similar performance for separation of VP and its major metabolites and comparable spectral quality in MS(E) mode of the Q-TOF instrument compared to 1.7 microm particle columns. Additionally, the study also confirmed that sub-2-microm particle size columns can be operated with standard analytical HPLC but that performance is maximized by integrating column in UPLC method with reduced void volumes. All the methods are suitable for the determination of major metabolites for compounds with high metabolic turnover. The high throughput metabolite profile analysis using 384-well plate format of up to 48 compounds in incubates of human-liver microsomes was discussed.     

Dimorphic Modification of the Trinuclear Nickel(II) Complex [Ni3(NCS)6(pdz)6]: Synthesis,Crystal Structure,Thermal, Magnetic and Spectroscopic Properties

Reaction of nickel(II) thiocyanate and pyridazine (pdz) as organic spacer ligand leads to the formation of the ligand‐rich 1:2 (1:2 = metal to ligand ratio) trinuclear nickel(II) complex of composition [Ni₃(NCS)₆(pdz)₆]. Depending on the reaction solvent, different polymorphic modifications are obtained: Reaction in acetonitrile leads to the formation of the new modification 1I and reaction in ethanol leads to the formation of modification 1II reported recently. In their crystal structures discrete [Ni₃(NCS)₆(pdz)₆] units are found, in which each of the Ni²⁺ cations exhibits a NiN₆ distorted octahedral arrangement. The central Ni²⁺ cation is coordinated by four bridging pdz ligands and two thiocyanato anions in trans positions. Both thiocyanato anions exhibit the end‐on bridging mode. The peripheral Ni²⁺ cations are bridged by one thiocyanato anion and by two pdz ligands with the central Ni²⁺ cation. Further they are coordinated by two terminal N‐bonded thiocyanato anions and one terminal N‐bonded pdz ligand. The structure of 1I was determined by X‐ray single crystal structure investigation and emphasized by infrared spectroscopy. Magnetic measurements revealed a quasi Curie behavior with net ferromagnetic interactions for 1I and net antiferromagnetic interactions for 1II . Solvent‐mediated conversion experiments clearly show that modification 1I represents the thermodynamic most stable form at room temperature and that modification 1II is metastable. On thermal decomposition, both modification transform quantitatively in a new ligand‐deficient intermediate. Elemental analysis revealed a 3:4 compound of composition [Ni₃(NCS)₆(pdz)₄]. A structure model supported by IR spectroscopic investigations was assumed, in which three coordination modes of the thiocyanato anion exist, resulting in a 2D polymeric network.     

The Combination of 4‐Hydroxythiazoles with Azaheterocycles: Efficient Bidentate Ligands for Novel Ruthenium Complexes

Herein the syntheses of three novel ligands, in which an azaheterocycle is connected with a thiazole subunit: 4‐methoxy‐5‐methyl‐2‐pyridine‐2‐yl‐1,3‐thiazole ( 1 ), 4‐methoxy‐5‐methyl‐2‐pyrimidine‐2‐yl‐1,3‐thiazole ( 2 ) and 4‐methoxy‐5‐phenyl‐2‐pyridine‐2‐yl‐1,3‐thiazole ( 3 ) are reported. Because these ligands are cyclic versions of 1,4‐diazadienes, they offer good prerequisites for the synthesis of metal complexes and were employed as chelating ligands. Three novel heteroleptic cationic complexes of the type Ru(bpy)₂( L ), with bpy = 2,2′‐bipyridine were successfully synthesised. The Ru^II complexes as well as the ligands were characterised by means of mass spectrometry, NMR, UV/Vis and IR spectroscopy and elemental analysis. Furthermore, an X‐ray structure of Ru(bpy)₂ 2 (PF₆), as far as we know the first example where a thiazole is directly connected to a Ru^II core, is presented in this paper.     

New Ionic Liquid Compounds Based on Tantalum Pentachloride TaCl5: Synthesis,Structural, and Spectroscopic Elucidation of the (μ‐Oxido)‐Chloridotantalates(V) [BMPy][TaCl6], [BMPy]4[(TaCl6)2(Ta2OCl10)], and [EMIm]2[Ta2OCl10]

1‐Butyl‐4‐methylpyridinium hexachloridotantalate(V), [BMPy][TaCl₆] ( 1 ), tetrakis(1‐butyl‐4‐methylpyridinium) bis(hexachloridotantalate(V) (μ‐oxido)‐decachloridotantalate(V), [BMPy]₄[(TaCl₆)₂(Ta₂OCl₁₀)] ( 2 ), and bis(1‐ethyl‐3‐methylimidazolium)‐(μ‐oxido)‐decachloridoditantalate(V), [EMIm]₂[Ta₂OCl₁₀] ( 3 ) were synthesized and characterized by single‐crystal X‐ray diffraction and vibrational spectroscopy. Compounds 1 and 3 crystallize in the monoclinic space group P2₁/c (no. 14), whereas compound 2 crystallizes in the triclinic space group P (no. 2). All compounds are built up by the mentioned bulky organic cations and octahedral [TaCl₆]^– respective linear [Ta₂OCl₁₀]^2– anions. Coulomb interactions are dominant between the ionic species. FT‐IR and FT‐Raman spectra were recorded and interpreted, especially with respect to the inorganic species [TaCl₆]^– (O_h) and [Ta₂OCl₁₀]^2– (C_i symmetry, approximately D_4h). The melting temperatures of compounds 1 – 3 are given.     

Dehydropolymerisation of Methylamine Borane and an N-Substituted Primary Amine Borane Using a PNP Fe Catalyst

Dehydropolymerisation of methylamine borane (H₃B⋅NMeH₂) using the well-known iron amido complex [(PNP)Fe(H)(CO)] (PNP=N(CH₂CH₂PiPr₂)₂) ( 1 ) gives poly(aminoborane)s by a chain-growth mechanism. In toluene, rapid dehydrogenation of H₃B⋅NMeH₂ following first-order behaviour as a limiting case of a more general underlying Michaelis–Menten kinetics is observed, forming aminoborane H₂B=NMeH, which selectively couples to give high-molecular-weight poly(aminoborane)s (H₂BNMeH)_n and only traces of borazine (HBNMe)₃ by depolymerisation after full conversion. Based on a series of comparative experiments using structurally related Fe catalysts and dimethylamine borane (H₃B⋅NMe₂H) polymer formation is proposed to occur by nucleophilic chain growth as reported earlier computationally and experimentally. A silyl functionalised primary borane H₃B⋅N(CH₂SiMe₃)H₂ was studied in homo- and co-dehydropolymerisation reactions to give the first examples for Si containing poly(aminoborane)s.     

Design of Turn‐On Near‐Infrared Fluorescent Probes for Highly Sensitive and Selective Monitoring of Biopolymers

Simple, sensitive, and selective detection of specific biopolymers is critical in a broad range of biomedical and technological areas. We present a design of turn‐on near‐infrared (NIR) fluorescent probes with intrinsically high signal‐to‐background ratio. The fluorescent signal generation mechanism is based on the aggregation/de‐aggregation of phthalocyanine chromophores controlled by selective binding of small‐molecule “anchor” groups to a specific binding site of a target biopolymer. As a proof‐of‐concept, we demonstrate a design of a sensor for EGFR tyrosine kinase—an important target in cancer research. The universality of the fluorescent signal generation mechanism, as well as the dependence of the response selectivity on the choice of the small‐molecule “anchor” group, make it possible to use this approach to design reliable turn‐on NIR fluorescent sensors for detecting specific protein targets present in the low‐nanomolar concentration range.     

Oligosilane‐ and Oligosiloxane‐bridged Phosphines – Synthesis,Structures, and Metalation

The range of molecular silicon phosphorus compounds has been extended by some new species containing oligosilane ((R₂Si)_n; n ≥ 2) or oligosiloxane ((R₂SiO)_mSiR₂; m ≥ 1) fragments bound to phosphorus atoms. Primary and secondary compounds of these types allow for the synthesis of metal derivatives. Such metalated species usually form oligomers and exhibit a versatile structural chemistry with cyclic, polycyclic, and cage‐like patterns. The main results obtained in the field of oligosilane‐ and oligosiloxane‐bridged phosphines will be presented below and the structures of the metal derivatives will be discussed. Moreover, the synthesis of an inorganic ligand on the basis of siloxane‐bridged phosphines will be presented. This compound opens up a new chapter in host‐guest chemistry.     

Dimorphic ErAgSn and TmAgSn – High‐Pressure and High‐Temperature Driven Phase Transitions

The stannides ErAgSn and TmAgSn have been investigated under high‐temperature (HT) and high‐pressure (HP) conditions in order to investigate their structural chemistry. ErAgSn and TmAgSn are dimorphic: normal‐pressure (NP) ErAgSn and HT‐TmAgSn crystallize into the NdPtSb type structure, P6₃mc, a = 466.3(1), c = 729.0(2) pm for NP‐ErAgSn and a = 465.4(1), c = 726.6(2) pm for HT‐TmAgSn. NP‐ErAgSn was obtained via arc‐melting of the elements and subsequent annealing at 970 K, while HT‐TmAgSn crystallized directly from the melt by rapidly quenching the arc‐melted sample. HT‐TmAgSn transforms to the ZrNiAl type low‐temperature modification upon annealing at 970 K. The high‐pressure (HP) modification of ErAgSn was synthesized under multianvil high‐pressure (11.5 GPa) high‐temperature (1420 K) conditions from NP‐ErAgSn: ZrNiAl type, , a = 728.7(2), c = 445.6(1) pm. The silver and tin atoms in NP‐ErAgSn and HT‐TmAgSn build up two‐dimensional, puckered [Ag₃Sn₃] networks (277 pm intralayer Ag–Sn distance in NP‐ErAgSn) that are charge‐balanced and separated by the erbium and thulium atoms. The fourth neighbor in the adjacent layer has a longer Ag–Sn distance of 298 pm. The [AgSn] network in HP‐ErAgSn is three‐dimensional. Each silver atom has four tin neighbors (281–285 pm Ag–Sn). The [AgSn] network leaves distorted hexagonal channels, which are filled with the erbium atoms. The crystal chemistry of the three phases is discussed.