Brick crystallization

AgC104 (41.5 mg, 0.20 mmol) and L (20.2 mg, 0.202 mmol) were reacted in acetone (10 mL) under Ar. The colorless solution was sealed in a 7-mm glass tube together with the layered n-pentane. After standing at room temperature for a week, colorless brick crystals were obtained. Yield 10 mg (14%). 

JD Goldberg, T Yoshida, P Brick. Crystal structure of a NAD-dependent D-glycerate dehydrogenase at 2.4 A resolution. J Mol Biol 236 1123-1140, 1994. 

E Conti, NP Franks, P Brick. Crystal structure of firefly luciferase throws light on a superfamily of adenylate-forming enzymes. Structure 4 287-298, 1996. 

Up to now, three silverd) and one copper(I) complexes of L38 have been synthesized and crystallographically characterized. They display a variety of one- to three-dimensional frameworks based on coordination bonds as well as intermolecular S—-S contacts. Reaction of AgC104 H20 and in acetonitrile gave red brick crystals of [Ag(L38)3]C104-CH3CN 2 (115). The compound has a dimeric structure... 

Sodium fluoride is normally manufactured by the reaction of hydrofluoric acid and soda ash (sodium carbonate), or caustic soda (sodium hydroxide). Control of pH is essential and proper agitation necessary to obtain the desired crystal size. The crystals are centrifuged, dried, sized, and packaged. Reactors are usually constmcted of carbon brick and lead-lined steel, with process lines of stainless, plastic or plastic-lined steel diaphragm, plug cock, or butterfly valves are preferred. 

Packing of the cyclodexthn molecules (a, P, P) within the crystal lattice of iaclusion compounds (58,59) occurs in one of two modes, described as cage and channel stmctures (Fig. 7). In channel-type inclusions, cyclodextrin molecules are stacked on top of one another like coins in a roU producing endless channels in which guest molecules are embedded (Fig. 7a). In crystal stmctures of the cage type, the cavity of one cyclodextrin molecule is blocked off on both sides by neighboring cyclodextrin molecules packed crosswise in herringbone fashion (Fig. 7b), or in a motif reminiscent of bricks in a wall (Fig. 7c). 

Different indices are used in hexagonal cells (we build a c.p.h. crystal up by adding bricks in four directions, not three as in cubic). We do not need them here - the crystallography books listed under Further Reading at the end of this chapter do them more than justice. 

The eluate is concentrated to dryness under reduced pressure, taken up in 25 cc of hot acetone, filtered, and diluted with ether. The pigment which crystallizes as red-brick colored platelets is essentially pure but may be recrystallized if desired from hot ethyl acetate. An analysis of the product showed C = 59.01 H = 6.B1 N=13.3B. 

Curry, S., Mandelkow, H., Brick, P. and Franks, N. (1998) Crystal structure of human serum albumin complexed with fatty acid reveals an asymmetric distribution of binding sites. Nature Structural Biology 5, 827-835. 

Clear white to yellow-pink deliquescent crystals with an odor like rotten eggs due to formation of hydrogen sulfide. Commercial material may be yellow or brick-red lumps or flakes. It is unstable and discolors upon exposure to air. It undergoes autoxidation to form polysulfur, thiosulfate, and sulfate. It absorbs carbon dioxide from the air to form sodium carbonate. Moist sodium sulfide is spontaneously flammable upon drying in air. This material is hazardous through ingestion and produces local skin/eye impacts. 

One of the important consequences of studying catalysis by mutant enzymes in comparison with wild-type enzymes is the possibility of identifying residues involved in catalysis that are not apparent from crystal structure determinations. This has been usefully applied (Fersht et al., 1988) to the tyrosine activation step in tyrosine tRNA synthetase (47) and (49). The residues Lys-82, Arg-86, Lys-230 and Lys-233 were replaced by alanine. Each mutation was studied in turn, and comparison with the wild-type enzyme revealed that each mutant was substantially less effective in catalysing formation of tyrosyl adenylate. Kinetic studies showed that these residues interact with the transition state for formation of tyrosyl adenylate and pyrophosphate from tyrosine and ATP and have relatively minor effects on the binding of tyrosine and tyrosyl adenylate. However, the crystal structures of the tyrosine-enzyme complex (Brick and Blow, 1987) and tyrosyl adenylate complex (Rubin and Blow, 1981) show that the residues Lys-82 and Arg-86 are on one side of the substrate-binding site and Lys-230 and Lys-233 are on the opposite side. It would be concluded from the crystal structures that not all four residues could be simultaneously involved in the catalytic process. Movement of one pair of residues close to the substrate moves the other pair of residues away. It is therefore concluded from the kinetic effects observed for the mutants that, in the wild-type enzyme, formation of the transition state for the reaction involves a conformational change to a structure which differs from the enzyme structure in the complex with tyrosine or tyrosine adenylate. The induced fit to the transition-state structure must allow interaction with all four residues simultaneously. 

The solution is stirred slowly and ca. 25 ml. of 2N cupric chloride solution is added slowly. The blue-green color of the cupric chloride is rapidly discharged and a brick red coloration occurs, followed by the precipitation of voluminous bright red crystals of the cuprous chelate of 2,3-diazabicyclo[2.2.1]hept-2-ene. The pH is adjusted to 5-6 by the addition of 5N ammonium hydroxide. Addition of 25 ml. of the cupric chloride solution followed by neutralization of the generated hydrochloric acid with 5iV ammonium hydroxide is repeated five times. The precipitate is collected by filtration and the filtrate is again treated with 25-ml. portions of cupric chloride solution and 5N ammonium hydroxide. The procedure is repeated until the filtrate is clear red at pH 3-4 and returns to a cloudy green at pH 6 with no further formation of precipitate (Note 5). 

Damage to houses, buildings and other structures caused by the deterioration of brick, mortar, and concrete, resulting from saline water crystallizing in brickwork (e.g.. Cole and Ganther 1996). 

Quite a few complexes with the bidentate pentasulfido ligand are also known. The first reported was the homoleptic and optically active complex [Pt(85)3] (15) (53, 64, 65, 68, 69, 176). Brick-red (NH4)2[Pt(85)3] 2H20 is formed from the reaction of K2[PtCl6] with aqueous (NH4)28 solution. Addition of concentrated HCl results in the separation of maroon (NH4)2[Pt8i7] 2H20 (54). The [Pt(85)3] ion crystallizes from the solution as a racemate, which can be resolved by forming diastereoisomers. Upon crystallization, [Pt8,7] undergoes a second-order asymmetric transformation, so that the solid contains an excess of the (—) enantiomer (54). 

Bright, silvery-white metal face-centered cubic crystal structure (a = 0.5582 nm) at ordinary temperatures, transforming to body-centered cubic form (a= 0.4407) at 430°C density 1.54 g/cm at 20°C hardness 2 Mohs, 17 Brinnel (500 kg load) melts at 851°C vaporizes at 1,482°C electrical resistivity 3.43 and 4.60 microhm-cm at 0° and 20°C, respectively modulus of elasticity 3-4x10 psi mass magnetic susceptibility -i-1.10x10 cgs surface tension 255 dynes/cm brick-red color when introduced to flame (flame test) standard reduction potential E° = -2.87V... 

RuC1 (CH3CN)3 is made from RuCl with and CH CN it is brick-red. The X-ray crystal structure of RuCljCCHjCbOj.dCHjCN shows a mer-octahedral geometry. The electrochemistry of the complex was stucUed as were IR and mass spectra. As RuCljCCHjCbOj/aq. L CIO )/ electrodes it oxidised tetralin to tetralone [786].. ... 

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