Human malaria, one of the most striking, reemerging infectious diseases, is caused by several types of Plasmodium parasites. As the parasite digests hemoglobin in human red blood cells, the heme byproduct crystallizes into micron-sized malaria-pigment (hemozoin). Making use of a recently reported powder-crystal structure determination of synthetic hemozoin (β-hematin), we describe here its theoretical growth form and show it to be similar in habit and form to that of natural hemozoin. With this information, we propose a noncovalent binding site for the quinoline drug family at the end face of the fastest-growing direction of β-hematin. This adsorption mechanism is examined in terms of crystal growth inhibition vis-à-vis published data. The surface binding site elucidates the difference in activity of various quinolines, revealing the importance of the different quinoline functionalities. The interplay between molecular chirality of quinolines and the chirality of centrosymmetric β-hematin crystal faces is analyzed in terms of crystal growth inhibition. We additionally propose a molecular isomerism of the crystalline building blocks, with implications on quinoline surface binding, as well as on nucleation and size of β-hematin crystals.

0.80 mol) were added and the mixture was stirred for 30 min at room temperature. DBADH 2 (4.60 g, 20 mmol) and p-chlorobenzyl alcohol (57.0 g, 0.40 mol) were added successively, and the mixture was heated for 1.5 hours on an oil-bath between 80°to 90°C while O 2 was gently bubbled through the reaction mixture. After cooling to room temperature, the mixture was diluted by addition of Et 2 O (500 ml; Et, ethyl) and filtered through a pad of Celite. The solution was washed successively with water (200 ml), 1 M HCl (200 ml), and 200 ml of saturated aqueous NaCl solution, dried over MgSO 4 , and evaporated in vacuo. Thin interdigitated films composed of a long-chain, water-insoluble chiral acid (p-pentadecylmandelic acid of absolute configuration R) and a water-soluble chiral base (phenylethylamine, RЈ) were constructed at the air-solution interface. The (R, RЈ) structure was characterized to near-atomic resolution by grazing-incidence x-ray diffraction (GIXD). The two diastereomeric systems, (R, RЈ) and (R, SЈ), demonstrate similar surface pressure-molecular area isotherms, but their structures are completely different on the molecular level, as monitored by GIXD. Complementary data on these two architectures were provided by atomic force microscopy.8.4 Hz). 13 C NMR (CDCl 3 , 75.5 MHz) ␦ C 191.3, 141.5, 135.4, 131.5, and 130.0

Five bifunctional α-amino acid-ε-carboxy bolaamphiphiles [(2-R,S, or RS)−(HOOC)−(CH2)m-CONH−(CH2) n -CH(COOH)(NH2) m=20,22, n=3,4 labeled (l), (d,l)-C22Orn (l), (d), (d,l)-C22Lys, (d,l)-C24Lys respectively] were synthesized. These molecules were deposited on different aqueous subphases, and studied by means of grazing incidence X-ray diffraction (GIXD). On deionized water, the bolaamphiphiles (d,l)-C22Lys yield a mixture of crystallites:  both a monolayer, in which the chains are tilted from the normal, and a multilayer in which the molecules lie parallel to the water. On the other hand, when deposited on mono- or bi-metal ionic subphases, they self-assemble into crystalline multilayer films in which the molecules lie parallel to the aqueous solution surface, linked head-to-head and tail-to-tail in the form of extended chains. The latter are juxtaposed such that the metal ions form sheets separated by the organic molecules, aligned perpendicular to the plane of the aqueous solution. Deposition of either the enantiomerically pure or racemic bifunctional bolaamphiphiles on an aqueous solution of mixed Cu(Acetate)2 and Pb(Acetate)2, yields self-assembled crystalline films composed of the two different metal cations, arranged in alternating sheets, separated by the organic spacer. Both GIXD and X-ray-photoelectric-spectroscopy (XPS) studies (after deposition on solid support) demonstrate that the structures of these films differ form the ones formed on either pure Pb(Ac)2 or on Cu(Ac)2 solutions, thus excluding the simultaneous formation of the two monometallic crystalline phases.

Elliptically shaped (Pb1–xCdx)S nanoparticles (NPs) of average size 2.3 × 2.9 nm (minor axis × major axis) have been prepared via reaction of a solid [oligo(p‐phenylene‐ethynylene) dicarboxylate]Pb0.9Cd0.1 salt matrix, with gaseous H2S. A significantly long emission lifetime, with multi‐exponential behavior, is detected in time‐resolved photoluminescence measurements, substantially different from the decay patterns of pure PbS and CdS NPs within the same organic matrix. Evidence for the co‐existence of Cd and Pb within the same particle is provided by light‐induced X‐ray photoelectron spectroscopy.

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