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Background: The cobas c 111, a new low volume bench-top analyzer from Roche Diagnostics (Indianapolis, IN), was evaluated to determine whether the operational and performance characteristics of the system would make it a good fit for the physicians' office laboratories and hospital stat labs in the Laboratory Corporation of America (LabCorp) network. Methods: Twenty-five frequently ordered analytes were evaluated relative to the published specifications of the cobas c 111. Additionally correlation studies, using patient serum samples, were used to determine inter-instrument comparability between 2 cobas c 111 instruments and accuracy relative to the standardized assays at LabCorp. Results: Precision, linearity, method comparison to another large Roche system, inter-instrument comparability, potential carryover, and time to result studies met or exceeded expectations. Additionally, sigma metrics analyses graded the overall performance of this analyzer as world class. Conclusions: The analytical performance, compact size, intuitive operation along with the expected low maintenance and reliability make the cobas c 111 a good fit for the intended small laboratory niche environment at LabCorp. [ABSTRACT FROM AUTHOR]

The macrocyclic receptors 4-6 were synthesized via the anion-templated condensation of appropriately chosen dialdehyde and diamine building blocks. Whereas all three products could be obtained directly via the appropriate choice of reaction conditions, the larger [3+3] product, 6, which incorporates three of each precursor subunit, could also be obtained conveniently via an indirect procedure involving ring expansion of the smaller [2+2] macrocycle 4. As detailed earlier (Sessler, J. L.; Katayev, E. A.; Pantos, G. D.; Reshetova, M. D.; Khrustalev, V. N.; Lynch, V. M.; Ustynyuk, Y. A. Angew. Chem. 2005, 117, 7552-7556; Angew. Chem., tnt. Ed. 2005, 44, 7386-7390), this ring expansion occurs under thermodynamic control in the presence of HSO4 and H2PO4 anions in acetonitrile solution and serves to effect the conversion of 4 to 6. An analysis of the X-ray crystal structure of complex 6H22+·HPO42- revealed a strong resemblance to the active site of the phosphate binding protein (PBP) with similar structural analogies being drawn between the active site of the sulfate binding protein (SBP) and the corresponding hydrogensulfate anion complex. In both cases, the anions are bound in a 1:1 fashion in the solid state through a complementary hydrogen bond network involving both the receptor 6 and the anions. UV-vis spectroscopic titrations provide support for the conclusion that macrocycle 6 binds the hydrogensulfate and dihydrogenphosphate anion (studied as the corresponding tetrabutylammonium salts) with high selectivity and affinity in acetonitrile (log Ka for the first binding interaction approaching 7), albeit with different receptor-to-anion binding stoichiometries (1:1 vs 1:3 for HSO4- and H2PO4-, respectively). [ABSTRACT FROM AUTHOR]

Three new amido-imine-type hybrid macrocycles based on substituted pyrrole units have been synthesized and shown to act as effective receptors for oxoanions in the solid state and in acetonitrile solution. One of the macrocycles in question, compound 15, was characterized by X-ray diffraction analysis as the free macrocycle and as a complex with sulfuric acid. A comparison of the resulting structures reveals that this receptor is capable of undergoing a conformational change and, as a consequence, varying the number of donor sites that can interact with a bound substrate. This system and the other two new receptors described in this work (macrocycles 14 and 16, respectively) display a high affinity toward oxoanions (studied as their tetrabutylammonium (TBA) salts), with association constants on the order of 107 M-1 being determined in acetonitrile solution using standard UV-vis spectroscopic titration methods. A competitive titration method was used to determine affinity constants in excess of Ca. 106 M-1. Two of the receptors (14 and 15) were found to bind acetate, hydrogen sulfate, and dihydrogen phosphate anion well, and the bipyrrole-based receptor (14) was also found to bind the perrhenate anion. In contrast, the bis-dipyrromethane-derived receptor (16) was found to bind chloride anion preferentially. The unusual selectivity displayed by 16 for this spherical anion was rationalized on the basis of single-crystal X-ray diffraction data and DFT modeling calculations, which revealed a rigid structure appropriately suited for chloride anion recognition. [ABSTRACT FROM AUTHOR]

Very high asymmetric inductions result in the Pd-catalyzed intramolecular arylation of amides to give 3,3-disubstituted oxindoles when new in situ-generated chiral N-heterocyclic carbene (NHC*) ligands are employed. Structural studies show that conformational locking to minimize allylic strain is the key to understanding the function of these ligands. New applications of these ligands in the frontier area of asymmetric coupling reactions involving C(sp³)--H bonds are detailed. Highly enantioenriched fused indolines are accessible using either preformed- or in situ-generated Pd-NHC* catalysts. Remarkably, this occurs at high temperature (140--160 °C) via excellent asymmetric recognition of an enantiotopic C--H bond in an unactivated methylene unit. [ABSTRACT FROM AUTHOR]