A first principles methodology, aimed at understanding the roles of molecular conformation and energetics in host-guest binding interactions, is developed and tested on a system that pushes the practical limits of ab initio methods. The binding behavior between the [2.2.2]-cryptand host (4,7,13,16,21,24-hexaoxa-1,10-diaza-bicyclo[8.8.8]hexacosane) and alkali metal cations (Li(+), Na(+), and K(+)) in gas, water, methanol, and acetonitrile is characterized. Hartree-Fock and density functional theory methods are used in concert with crystallographic information to identify gas phase, energy-minimized conformations. Gas phase free energies of binding, with vibrational contributions, are compared to solution-state binding constants through relative binding selectivity analysis. Calculated relative binding free energies qualitatively correlated with solution state experiments only after gas phase metal desolvation is considered. The B3LYP exchange-correlation functional improves theoretical correlations with experimental relative binding free energies. The relevance of gas phase calculations towards understanding binding in condensed phases is discussed. Natural bond orbital methods highlights previously unidentified intramolecular and intermolecular M(+)(222) chemistries, such as an intramolecular n'(O)-->sigma*(CH) hydrogen bond.

Crystallographic analyses at 100 and 200 K are reported for the macrobicyclic polyether 4,7,13,16,21,24-hexaoxa-1,10-diaza-bicyclo[8.8.8]hexacosane (denoted as 222-cryptand) that encapsulates a Li+ cation and then forms a complex (I) with ClO4-. Compound (I) undergoes a reversible second-order k phase transition at 253 (2) K from an almost ordered structure [space group P2(1)2(1)2(1)] at 100 K to a more disordered structure that exhibits a different unit cell [P2(1)2(1)2 (2c'=c)] above 253 (2) K. At 295 K the Li+ cation and five atoms of the perchlorate anion are each disordered over at least two positions about a crystallographic twofold axis [Chekhlov (2003). Russ. J. Coord. Chem. 29, 828-832]; as the temperature decreases the dynamic positional disorder is slowly frozen out, but is still observed for lithium even at 100 K. Based upon DFT computations, it seems that in the solid state the position of the Li+ cation in the cavity of the 222-cryptand below 253 (2) K likely corresponds to a local energy minimum; the global minimum in the gas phase corresponds to a near D3 symmetrical conformation of the 222-cryptand with the undersized Li+ cation residing in the center of its cavity.

Chronic inflammatory diseases occur in a large portion of the population and are associated with a poor diet. Key natural products found in fruits and vegetables may assist in lowering inflammation associated with chronic diseases such as obesity, diabetes, cardiovascular diseases, and cancer. This review seeks to examine the roles of several natural products, resveratrol (RES), quercetin (QUE), curcumin (CUR), piperine (PIP), epigallocatechin gallate (EGCG), and gingerol (GIN), in their ability to attenuate inflammatory markers in specific diseases states. Additionally, we will discuss findings in past and ongoing clinical trials, detail possible phytochemical–drug interactions, and provide a brief resource for researchers and healthcare professionals on natural product and supplement regulation as well as names of databases with information on efficacy, indications, and natural product–drug interactions. As diet and over-the-counter supplement use are modifiable factors and patients are interested in using complementary and alternative therapies, understanding the mechanisms by which natural products have demonstrated efficacy and the types of drugs they interact with and knowing where to find information on herbs and supplements is important for practicing healthcare providers and researchers interested in this field.

Key indicators: single-crystal X-ray study; T = 100 K; mean (Na-O) = 0.002 Å; disorder in main residue; R factor = 0.037; wR factor = 0.113; data-to-parameter ratio = 9.5.The title compound, [Na(C 18 H 36 N 2 O 6 )]ClO 4 , was isolated and crystallized to understand more fully the ligand's binding specificity to cations. The cation and anion reside at an intersection of crystallographic twofold and threefold axes. The carbon atoms in the cation are disordered over two positions in a 3:2 ratio, and the anion is equally disordered over two positions. The geometries of the cation and anion are typical. The compound packs in alternating sheets of discrete cations and anions stacked along the c axis, separated by a distance equal to one-sixth the length of the c axis.