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The combustion of mercury(II) thiocyanate to form 'Pharaoh's serpents' is a spectacular reaction first described nearly two centuries ago. The large volume of distinctive yellow branches that grow from a tiny quantity of flaming reactants makes this an enchanting demonstration, often used to depict the magic of chemistry. In recent years several videos of this bizarre process have 'gone viral' online. Formally, the reaction should yield a carbon nitride with the ideal formula C3N4 along with HgS. However, since early characterization attempts there has been little further study of the materials produced. Herein we apply modern characterization techniques to reinvestigate the nature of the carbon nitride and its intimate relationship to the HgS produced. The HgS phase forms nanoparticles that decorate the surfaces of a C3N4 foam matrix. Both of these compounds are important wide-gap semiconductors and we propose that the 'Pharaoh's serpents reaction' could be used to produce a potentially important heterojunction nanocomposite materials that could be useful optoelectronic and photocatalytic applications. [ABSTRACT FROM AUTHOR]

A comparative study using NMR spectroscopy and designed top-pan molecular balances demonstrates that the noncovalent interaction of a hydroxy group with p-deficient pyrazine and quinoxaline units involves a lone pair-heteroarene interaction which is much stronger and solvent independent when measured relative to the classical p-facial hydrogen bond to a benzene ring. Alkyl fluorides also prefer the heteroarene rings over the benzene ring. The attractive interaction between a quinoxaline and a terminal alkyne is also stronger than the intramolecular hydrogen bond to an arene. [ABSTRACT FROM AUTHOR]

N-Cinnamoyl-1-naphthylamines undergo a cyclization reaction with triflic acid to form 4-phenyl-3,4-dihydro-1H-naphth[1,8-bc]azepin-2-ones and 4-phenyl-3,4-dihydro-1H-benzo[h]quinolin-2-ones. However, the N-benzyl analogues also undergo a unique cascade reaction to form novel heptacyclic structures via a 1,2-addition followed by a 4-addition to the naphthalene. With an electron-rich N-benzyl substituent, the heptacycle is the sole product. [ABSTRACT FROM AUTHOR]

X-ray photoelectron spectroscopy (XPS) allows the analysis of the surface atomic composition of a solid and can be used for mechanistic studies of solid–gas and solid–liquid reactions. The change of atomic composition of a surface after a reaction can be calculated considering hypothetical mechanisms based on the known reactivity of the organic moieties bound to the solid surface. Atom inventory of the elements involved in the reactions was used to quantify the components of the XPS spectrum after the reaction and consequently the change of concentration in at%. The method was used to study the basic hydrolysis and photolysis of the intermediates bound to the carbon matrix after the reduction of SO2 on activated carbon. Consistent mechanisms were postulated for these reactions. Basic hydrolysis hydrolyzed the sultine intermediate, and the attack of hydroxide ion on the episulfide formed a sulfide anion, eliminating S2- in a consecutive step. Laser photolysis of modified activated carbon in t-butanol showed the insertion of the organic moiety in the carbon matrix with expulsion of an SO2 radical anion that oxidized to ${\rm SO}_4^{2 - } $. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: A novel approach to the epidithiodiketopiperazine nucleus, incorporating two three-component reactions in a four-step synthetic sequence is reported. [Copyright &y& Elsevier]

2-Ureido-4-[1H]-pyrimidinones have been reported to dimerize via quadruple hydrogen bonding systems with dimerization constants > 106 M-1 in CDCl3. The dimerization constant, Kdim, is dependent on the solvent as well as the ring-substituents present, where previously alkyl (e.g., R1 = Me) and aromatic moieties (e.g., R1 = p-NO2C6H4, R1 = C6H2(OC13H27)3) have been incorporated at the C-6 position. To assess the influence of alternative, functionalizable, electron-donating groups on the dimerization motif and tautomeric distribution of isomers, the synthesis of compounds possessing aminophenyl functionality at the C-6 position has been achieved. NMR spectroscopy chemical shift analysis revealed that compound 2 (R1 = p-NH2C6H4, R2 = C6H13) existed as the 2-ureido-4-pyrimidinol dimeric DADA array in DMSO-d6, where a dimerization constant of 46 M-1 was determined. This is the first time that a ureidopyrimidinone quadruple hydrogen bonding DADA array has been observed in pure DMSO, a highly polar solvent. The azo-derivative 5 of compound 2 was prepared which also adopted the pyrimidin-4-ol form in DMSO-d6. Compounds 7, 10 and 11 were then synthesized containing a more hydrophilic PEG unit in the lateral chain and the tautomeric distributions were determined. [ABSTRACT FROM AUTHOR]

Abstract: Intramolecular amidocyclopropanation reactions of diethoxymethyl-lactams containing a pendant alkene were examined using zinc/TMSCl. With a range of 4–6-membered lactams, bicyclic amidocyclopropanes were obtained with very high diastereoselectivity with a preference for the formation of the more hindered endo-cyclopropane. [Copyright &y& Elsevier]

Photolyses at 254 nm of phenylalanine(Phe) in aqueous solutions,were carried out in the presence of oxidized carbon nanotubes modifiedby the reaction with SO2(mNTO). Kinetics of the photolyseswere followed by UV spectrophotometry at 220 nm, and the productswere characterized by HPLC, XPS, and 13C-SSNMR. The ratioof the initial rates of photolysis in the presence and absence ofmNTO, k*/ko*, showeda systematic decrease. The photolytic decay of Phe occurs with minorformation of tyrosine. The mass of nanotubes produced an exponentialattenuation of the photolytic decomposition of Phe. Total carbon analyses(TCA) showed no inorganic carbon formation after the photolyses. Thefirst-order rate constant of photofunctionalization of mNTO by theinsertion of phenylalanine onto the nanotube matrix was calculatedfrom TCA to be kin= 30.1 min–1. Comparison of the XPS spectra of the mNTO before and after thephotolysis, using the atom inventory technique, suggests the insertionof Phe along with the extrusion of a sulfide radical anion (•S–) which undergo subsequent oxidation to SO42–. The obtained results show the effectsof mNTO on the photolysis of Phe and provide a new method of photofunctionalizationof carbon materials, modified by the intermediates of the reductionof SO2, with an organic moiety. [ABSTRACT FROM AUTHOR]