The first of four articles on cancer treatments. This article provides an overview of traditional anticancer therapies, their mechanisms of action and their limitations.

Attaching electron-rich 1,3-dithiol-2-ylidene moieties to polynitrofluorene electron acceptors leads to the formation of highly conjugated compounds 6 to 11, which combine high electron affinity with a pronounced intramolecular charge transfer (ICT) that is manifested as an intense absorption band in their visible spectra. Such a rare combination of optical and electronic properties is beneficial for several applications in optoelectronics. Thus, incorporation of fluorene-dithiole derivative 6a into photoconductive films affords photothermoplastic storage media with dramatically increased photosensitivity in the ICT region. A wide structural variation of the dithiole and fluorene parts of the molecules reveals excellent correlation between the ICT energy and the reduction potential with the Hammett's parameters for the substituents. Although only a small solvatochromism of the ICT band was observed, heating the solution led to a pronounced blueshift, which was probably as a result of increased twisting around the C9=C14 bond that links the fluorene and dithiole moieties. X-ray crystallographic analysis of 7a, 8a, 10a, 11a and 13a confirms an ICT interaction in the ground state of the molecules. The C9=C14 double bond between the donor and acceptor is substantially elongated and its length increases as the donor character of the dithiole moiety is enhanced.

SummaryBlasting is often used in construction, quarrying and mining to fracture rock and remove overburden. While blasting is an efficient method for carrying out these tasks, there are often severe restriction on the size of blasts and distance to surrounding structures and infrastructure. In the case of buildings, such as residential and commercial structures, there are national and international standards available that set the maximum levels of allowable ground vibrations due to blasting. For most civil infrastructure, such as pipelines and transmission towers, there are no such standards. The maximum allowable ground vibration levels are normally set by the operators of such facilities and are typically based on historical practice. Due to lack of data and industry standards, these limits vary from one operator to another and are normally extremely conservative.This paper reviews the performance of pipelines during past earthquakes and estimates the possible range for blast induced ground motions that would not cause any damage to pipelines of various materials. Results from a field study on the response of a water pipeline to blast vibrations are also presented with the aim of establishing a rational method for determining the effect of blasting on surface mounted pipelines. A lead-jointed mild-steel cement-lined (MSCL) pipe was subjected to controlled blasts in order to assess the blast induced stresses on the pipe. It has been found from this study the vibration limits, in terms of peak particle velocity, can be increased to more than 10 times the currently imposed level without compromising the integrity of the pipeline.

The title compound, C10H9NO3S4, has a nearly planar tetrathiafulvalene-amide moiety and an ester group normal to it. Molecules in the crystal structure are linked by S...O interactions and N-H...O hydrogen bonds.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Syntheses of tetrathiafulvalene substituted with four side-chains terminating in hydrophilic amidoalcohol groups are reported. These tetrathiafulvalene-arborols form films by spin-coating. Optical properties before and after chemical doping along with conductivity studies are also shown.

The synthesis of O4S2-crown annelated derivatives of 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene using the novel Horner-Wadsworth-Emmons reagent 7 is reported. The bis- and mono-crown systems 9 and 12 function as efficient Ligands in the voltammetric and UV/Vis spectroscopic recognition of Na+ and Ag+. Solution electrochemical studies reveal that metal complexation to the crown unit(s) leads to a significant positive shift in the potential of the first, two-electron oxidation wave of 9 and 12 [maximum shift E-1(OX) = 115 mV for 9 in the presence of Ag+ (ca. 10 molar equivalents)]. Considerably smaller shifts (< 30 mV) were observed for complexation of Li+, K+ and Ba2+. UV/Vis spectrophotometric studies of metal binding (Na+ and Ag+) to 9 are consistent with the simultaneous formation of 1:1 and 1:2 complexes. The X-ray crystal structures of compounds 10 and 12CH2Cl2 are reported. The anthracenediylidene moiety of 12 is U-shaped due to the boat conformation of the central (quinodimethane) ring and folding of both 1,3-dithiole rings, providing an overall saddle conformation. The folding in 10 is reduced as steric crowding is relieved by removal of one of the 1,3-dithiole units.

The synthesis of 4,4',5-trimethyl-5'-(4-pyridyl)tetrathiafulva- lene (3), has been accomplished by reaction of the stannylated precursor 2 with 4-bromopyridine. Alkylation of 3 affords the N-methylpyridinium salt 4 which displays intramolecular charge transfer properties in solution as deduced from UV/Vis spectra, cyclic voltammetric data, and semiempirical quantum mechanical calculations. The X-ray crystal structures of neutral molecule 3, the salt (4(+))I- and the charge transfer salt (4(+))(2)(TCNQ(3))(2-) are reported. The positive charge in (4(+))I- and (4(+))(2)(TCNQ(3))(2-) is predominantly confined on the pyridinium ring. The structure of (4(+))(2)(TCNQ(3))(2-) comprises segregated stacks of cations and TCNQ radical anions, with the anions overlapping in the usual ring-over-bond fashion. This salt is a semiconductor (sigma (rt) = 10(-2) S cm(-1)).

Electron donor-pi -acceptor chromophores 5, 9, 11, 18-20, 21, 22, 27, 28a, 28c, 31, 32, 34-36, 38a-c, 41a, 41c, and 42 have been synthesised. The donor units are 1,3-dithiole and ferrocene; conjugated ethylenic, phenyl, phenylenevinylene, thienyl, bithienyl, terthienyl, or thienylenevinylene linkers act as a central pi -electron relay unit, and dicyanomethylene and polynitrofluorene groups as the acceptor unit. The electronic absorption spectra display a broad low-energy intramolecular charge transfer band in the visible region (500-700 nm) the energy (hv(1CT) approximate to 1.7-2.5eV) and intensity (epsilon approximate to 5000-50000 m(-1)cm(-1)) of which depend substantially on the nature of both D and A moieties and on the structure of the linker unit. Nonlinear optical properties have been evaluated using the EFISH technique: the highest mu beta (0) values are observed for 38b [(900 +/- 300)x10(-48) esu] and 42 [(1800 +/- 300)x10(-48) esu] establishing that polynitrofluorene is a promising acceptor terminal moiety in this context. The molecular and electronic structures of 49 and 50 have been calculated by the RHF/6-31G(d)//RHF/6-31G(d) ab initio method. The HOMO is located mostly in the 1,3-dithiolium ring, and the LUMO mostly at the dicyanomethylene fragment (and the phenyl ring of 50) although the population at C2 of the 1,3-dithiolium rings is also considerable. The X-ray crystal structures of 9, 18 and 27 are reported. In all three structures the conjugated pi -systems effectively planar with extensive pi -electron delocalisation between the donor and acceptor moieties, The planar conformation of 18 gives rise to a close intramolecular S . . .S contact of 3.095(3) Angstrom between the dithiole and thiophene units.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Efficient syntheses are reported for tetraiodotetrathiafulvalene 2, 4-iodo-5-methyl-4',5'-bis(methylsulfanyl)TTF 3, and 4-iodo-4',5'-bis(methylsulfanyl)TTF 4 by iodination, using perfluorohexyl iodide, of lithiated derivatives of the corresponding TTF system. Bromination and chlorination of lithiotrimethylTTF using 1,2-dibromotetrafluoroethane and hexachloroethane gave 4-bromo- and 4-chloro-4',5,5'-trimethylTTF 6 and 7, respectively. Phosphite-induced self-coupling or cross-coupling reactions of 4-iodo-1,3-dithiole-2-thione or 4,5-diiodo-1,3-dithiole-2-thione(one) half-units resulted in TTF derivatives with partial loss of the iodine substituent(s). 4,5-Dibromo-4',5'-bis(cyanoethylsulfanyl)TTF 15 was prepared by cross-coupling methodology, and converted into 4,5-dibromo-4',5'-bis(1-methylsulfanyl)TTF 16 by reaction with caesium hydroxide and then methyl iodide. EPR data are reported for the electrochemically generated cation radicals of trimethylTTFX derivatives (X=I, Br and Cl) 5-7, respectively. For the neutral donors, the X-ray crystal structures are reported for 2, 5, 6, tetramethylTTF 8 and 15. Structure 2 is characterised by a particularly dense packing with continuous chains of intra-stack I . . .I contacts (4.17-4.19 Angstrom). The crystals of 6 and 8 are isomorphous, while the structure of 5 is different. The iodo-substituent in 5 affects the packing in a way the bromo-substituent in 6 does not, due to differences in specific interactions rather than steric demands of I and Br, which are similar. Structure 15 comprises face-to-face dimers with inter-dimer Br . . . Br (3.57 Angstrom) and Br . . .S (3.55 Angstrom) contacts: a remarkable difference in bond distances between the Br and S-substituted dithiole rings is observed. The 1 : 1 charge-transfer (CT) complexes 3.TCNQ and 4.TCNQ (TCNQ=7,7,8,8-tetracyano-p-quinodimethane, 17) display mixed stair-like stacks of alternating D and A moieties: the overall degree of CT is estimated from bond length analysis to be 0.2 e and 0.3 e, respectively. In 3.TCNQ either position of the disordered iodine atom has one short (inter-stack, but intra-layer) contact with a cyano group (I . . .N distances of 3.14 and 3.18 Angstrom). In 4.TCNQ a similar I . . .N contact is much longer (3.35 Angstrom). In the structure of 5(+).I-3(-).1/2 I-2 the cation radical is disordered; dimeric cation radicals display short intra-dimer contacts (S . . .S 3.38-3.39 Angstrom, C . . .C 3.35 Angstrom) consistent with electron coupling. Each dimer is surrounded by four I-3(-) anions. The crystal structure of 16(+).I-3(-) is comprised of layers with interplanar separations of 3.55 Angstrom. Cations of one layer overlap with anions of the next, and the packing can be described as mixed stacks parallel to the a axis. The remarkably high conductivity of this salt for a system of 1 : 1 stoichiometry (sigma (rt) = 8 x 10(-2) S cm(-1)) is ascribed to partial charge transfer (the charge on the TTF moiety is estimated as +2/3 from bond length analysis) and a continuous system of short non-bonding contacts.

We have synthesised new conjugated donor-pi -acceptor (D-pi -A) chromophores 7, 9, and 12-15 in which monosubstituted tetrathiafulvalene (TTF) and trimethyl-TTF units are the donor moieties, connected by ethylenic bridges to electron-deficient benzene derivatives as the acceptor moieties. These compounds display a broad intramolecular charge transfer (ICT) band in their solution UV/Vis spectra at lambda (max) = ca.

The synthesis, electrochemistry, and electron absorption spectra of the novel push-pull type acceptor, 9-{[4,5-bis(hexylthio)-1,3-dithiol-2-ylidene]ethylidene}-2,4,5,7-tetranitrofluorene 3 is reported. A bathochromic shift and increased intensities of intramolecular charge transfer bands (compared to 1) are well-balanced with the electron affinity of the acceptor, which results in a pronounced increase of the photoresponse of carbazole-containing photothermoplastic optical information storage materials in the long wavelength visible and near infrared regions.