scholarly journals Synthesis of New Derivatives of BEDT-TTF: Installation of Alkyl, Ethynyl, and Metal-Binding Side Chains and Formation of Tris(BEDT-TTF) Systems

2021 ◽  
Vol 7 (8) ◽  
pp. 110
Author(s):  
Songjie Yang ◽  
Matteo Zecchini ◽  
Andrew Brooks ◽  
Sara Krivickas ◽  
Desiree Dalligos ◽  
...  
Keyword(s):  
Metal Binding ◽  
Tricarboxylic Acid ◽  
Metal Salts ◽  
Side Chain ◽  
Side Chains ◽  
Ethynyl Group ◽  
X Ray ◽  
Transition Metal Salts ◽  
Alkyl Side Chains ◽  
Derivatives Of

The syntheses of new BEDT-TTF derivatives are described. These comprise BEDT-TTF with one ethynyl group (HC≡C-), with two (n-heptyl) or four (n-butyl) alkyl side chains, with two trans acetal (-CH(OMe)2) groups, with two trans aminomethyl (-CH2NH2) groups, and with an iminodiacetate (-CH2N(CH2CO2−)2 side chain. Three transition metal salts have been prepared from the latter donor, and their magnetic properties are reported. Three tris-donor systems are reported bearing three BEDT-TTF derivatives with ester links to a core derived from benzene-1,3,5-tricarboxylic acid. The stereochemistry and molecular structure of the donors are discussed. X-ray crystal structures of two BEDT-TTF donors are reported: one with two CH(OMe)2 groups and with one a -CH2N(CH2CO2Me)2 side chain.

Synthesis and radiosensitizing properties of brominated tetrapyridine porphyrins

2007 ◽  
Vol 11 (08) ◽  
pp. 549-555 ◽  
Author(s):  
Rosalie Lemay ◽  
Jean-Philippe Tremblay-Morin ◽  
Hasrat Ali ◽  
Darel Hunting ◽  
Johan E. van Lier ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Breast Cancer Cells ◽  
High Energy ◽  
Side Chains ◽  
X Ray ◽  
Radiosensitizing Effect ◽  
Copper Porphyrin ◽  
Alkyl Side Chains ◽  
Derivatives Of

Brominated derivatives of tetrapyridinium copper porphyrin were prepared via bromination of the β-positions (pyrrole rings) and/or the peripheral alkyl side-chains attached to the pyridine moieties. The radiosensitizing properties of these new cationic, brominated porphyrins were tested on MDA-MB-231 breast cancer cells in vitro using a 60 Co source or an X-ray irradiator. The non-brominated porphyrin and the porphyrin containing bromines at β-positions only were devoid of any radiosensitizing activity. However, a pronounced radiosensitizing effect was observed with the porphyrin containing bromo atoms at both β-positions and the peripheral side-chains. A similar radiosensitizing effect was detected for different radiation energies, suggesting that high energy photons could be used to treat tumors in conjunction with this novel brominated, porphyrin-based radiosensitizer.

scholarly journals NMR and X-ray studies of apetalic acid isolated from Calophyllum brasiliense and of its chiral amides

2021 ◽  
Author(s):  
Marie-Rose Van Calsteren ◽  
Ricardo Reyes-Chilpa ◽  
Chistopher K Jankowski ◽  
Fleur Gagnon ◽  
Simón Hernández-Ortega ◽  
...  
Keyword(s):  
Antimycobacterial Activity ◽  
Side Chain ◽  
Carboxyl Group ◽  
X Ray Diffraction ◽  
Rain Forests ◽  
X Ray ◽  
X Ray Crystallography ◽  
Calophyllum Brasiliense ◽  
Derivatives Of

The tropical tree Calophyllum brasiliense (Clusiaceae) grows in the rain forests from Brazil to Mexico. Its leaves, as well as those of other Calophyllum species, are rich sources of chromanone acids, such as apetalic acid, isoapetalic acid, and their derivatives. Apetalic acid has shown significant antimycobacterial activity. The biological activity of apetalic acid has been related to the configuration of three asymmetric centers and the stereochemistry of the molecule; however, the C-19 configuration in the acidic side chain has not been fully resolved. For this reason, the unequivocal determination of the absolute configuration by means of X-ray crystallography in a sample of unique homogeneous apetalic acid stereoisomer was the most important point to start this study. We prepared some chiral amides using the carboxyl group. We determined the C-19 stereochemistry of apetalic acid, and its specific chiral derivatives, using NMR, X-ray diffraction methods, and molecular mechanics. Finally, we observed that steric hindrance in the side chain of apetalic acid leads to restriction of rotation around the pivotal link C-10 and C-19 establishing chiral centers at C2(R), C3(S), and C19(R). We were able to separate derivatives of these two high-rotatory-barrier conformers of apetalic acid by forming diastereoisomeric amides with phenylglycine methyl ester having a chiral center at C-2’. Our results allowed the conclusion of the existence of atropisomerism in the apetalic acid molecule.

Cyclic hexapeptoids with N-alkyl side chains: solid-state assembly and thermal behaviour

CrystEngComm ◽  
2020 ◽  
Vol 22 (38) ◽  
pp. 6371-6384 ◽  
Author(s):  
Giovanni Pierri ◽  
Rosaria Schettini ◽  
Jürgen Nuss ◽  
Robert E. Dinnebier ◽  
Francesco De Riccardis ◽  
...  
Keyword(s):  
Solid State ◽  
Thermal Behaviour ◽  
Lattice Energy ◽  
Side Chains ◽  
X Ray Diffraction ◽  
Energy Calculations ◽  
X Ray ◽  
Alkyl Side Chains

The solid state assembly of two cyclic hexapeptoids decorated respectively with five and six carbon N-alkyl side chains is analyzed by X-ray diffraction, intermolecular energies and lattice energy calculations.

Structural studies on monofluorinated derivatives of the phytohormone indole-3-acetic acid (auxin)

1996 ◽  
Vol 52 (4) ◽  
pp. 651-661 ◽  
Author(s):  
A. Antolić ◽  
B. Kojić-Prodić ◽  
S. Tomić ◽  
B. Nigović ◽  
V. Magnus ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Side Chain ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Molecular Conformations ◽  
X Ray ◽  
Structure Activity ◽  
Planar Conformation ◽  
Derivatives Of ◽  
Indole 3 Acetic Acid

As part of the molecular recognition studies on the phytohormone indole-3-acetic acid (IAA) a series of fluorinated IAA's has been examined. The phenyl ring substitution at positions 4, 5, 6 and 7 resulted in four compounds, which were analyzed. Structure–activity correlation includes the analysis of their molecular conformations, based on the X-ray diffraction and computational chemistry results, and bioactivity determinations in the Avena coleoptile and the Pisum sativum stem straight-growth tests, lipophilicity and UV absorbance. The conformations of monofluorinated IAA's and a free hormone are defined by rotations about two bonds: one describes the relative orientation of a side chain towards the indole plane and the second the orientation of the carboxylic group. The results of X-ray structure analysis revealed the folded shape of the molecules in all compounds studied. Molecular mechanics and dynamics located the folded conformation as the local minimum, but failed to detect the planar conformation as one of the local minima, which according to ab initio results on IAA and 4-CI-IAA could also be possible. Crystal data at 295 K for 4-F-IAA and at 297 K for 5-F-IAA, and at 100 K for 6-F-IAA and 7-F-IAA using Mo Kα radiation (λ = 0.71073 Å) and Cu Kα (λ = 1.5418 Å, for 7-F-IAA), are as follows: 4-F-IAA, C10H8NO2F, Mr = 193.18, monoclinic, C2/c, a = 17.294 (5), b = 13.875 (4), c = 7.442 (4) Å, β = 103.88 (6)°, V = 1734 (1) Å3, Z = 8, Dx = 1.480 g cm−3, μ = 1.1 cm−1, F(000) = 800, R = 0.043, wR = 0.044 for 823 symmetry-independent [I ≥ 3σ(I)] reflections; 5-F-IAA, C10H8NO2F, monoclinic, P21/c, a = 19.284 (5), b = 5.083 (4), c = 9.939 (4) Å, β = 117.28 (6)°, V = 865.9 (1) Å3, Z = 4, Dx = 1.482 g cm−3, μ = 1.1  cm−1, F(000) = 400, R = 0.062, wR = 0.057 for 729 symmetry-independent [I ≥ 3σ(I)] reflections; 6-F-IAA, C10H8NO2F, monoclinic, P21/a, a = 9.360 (1), b = 5.167 (4), c = 17.751 (4) Å, β = 93.75 (1)°, V = 856.7 (8) Å3, Z = 4, Dx = 1.498 g cm−3, μ = 1.1 cm−1, F(000) = 400, R = 0.048, wR = 0.048 for 1032 symmetry-independent [I ≥ 2σ(I)] reflections; 7-F-IAA, C10H8NO2F, monoclinic, P21/a, a = 9.935 (5), b = 5.0059 (4), c = 17.610 (1) Å, β = 102.13 (1)°, V = 856.3 (1) Å3, Z = 4, Dx = 1.498 g cm−3, μ = 9.8 cm−1 (Cu Kα, F(000) = 400, R = 0.035, wR = 0.040 for 1504 symmetry-independent [I ≥ 2σ(I)] reflections.

scholarly journals Controlled steric selectivity in molecular doping towards closest-packed supramolecular conductors

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Shinya Kohno ◽  
Yu Yamashita ◽  
Naotaka Kasuya ◽  
Tsubasa Mikie ◽  
Itaru Osaka ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Steric Effects ◽  
Side Chain ◽  
Side Chains ◽  
Void Space ◽  
Alkyl Side Chains ◽  
Recent Developments ◽  
High Carrier ◽  
Molecular Doping ◽  
Steric Selectivity

Abstract Recent developments in molecular doping technologies allow extremely high carrier densities in polymeric semiconductors, exhibiting great diversity because of the unique size, conformation, and steric effect of molecular dopants. However, it is controversial how steric effects can limit the doping efficiency and to what extent dopants can be accommodated in polymers. Here, we employ two distinct conjugated polymers with different alkyl side-chain densities, where polymers are doped via anion-change, allowing greater variation in the incorporation of molecular dopants having different electrostatic potentials and shapes. We characterize the doping efficiency with regard to steric effects, considering the unique void space in the conjugated polymers. Our study reveals that doping efficiency of polymers with sparse alkyl side-chains is significantly greater than that with dense side-chains. A closest-packed supramolecule is realized with a particular combination of a sparse polymer and a large dopant, giving rise to high conductivity, air stability, and remarkably high work function. This work provides a critical insight into overcoming steric effects in molecular doping.

X-ray crystal structure analysis of a bisepoxide derived from secologanin: the structure and absolute configuration

1983 ◽  
Vol 61 (2) ◽  
pp. 282-283 ◽  
Author(s):  
Stanley C. Nyburg ◽  
Pik Y. Siew ◽  
Gavin N. Saunders ◽  
John R. Purdy ◽  
Stewart McLean
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Absolute Configuration ◽  
Dimethyl Acetal ◽  
Crystal Structure Analysis ◽  
Side Chain ◽  
Bench Mark ◽  
Chemical Transformations ◽  
X Ray ◽  
Derivatives Of

The structure and absolute configuration of a bisepoxide (2) produced by oxidation of tetraacetylsecologanin dimethyl acetal (1) with m-chloroperbenzoic acid have been established by X-ray crystal structure analysis. Epoxidation of the vinyl side chain is unexceptional; epoxidation of the β-alkoxyacrylate moiety is novel. This determination represents a valuable bench mark for configurational assignments, since the bisepoxide has been correlated by chemical transformations with a number of synthetic and naturally-occurring derivatives of secologanin.

n-Alkylresorcinol Occurrence in Mercurialis perennis L. (Euphorbiaceae)

2010 ◽  
Vol 65 (3-4) ◽  
pp. 174-179 ◽  
Author(s):  
Peter Lorenz ◽  
Matthias Knödler ◽  
Julia Bertrams ◽  
Melanie Berger ◽  
Ulrich Meyer ◽  
...  
Keyword(s):  
Side Chain ◽  
Side Chains ◽  
Alkyl Side Chain ◽  
Alkyl Side Chains ◽  
Chain Lengths ◽  
New View

Investigation of the dichloromethane extracts from herbal and root parts of Mercurialis perennis L. afforded a mixture of 11 homologous n-alkylresorcinols (ARs) with saturated odd-numbered alkyl side chains (C15:0-C27:0). In addition to three predominant ARs (C19:0, C21:0 and C23:0), a number of minor ARs were identified by use of LC-MS/MS and GC-MS techniques. Among the compounds detected, four uncommon ARs with evennumbered alkyl side chain lengths were also determined. The overall AR concentration in herbal parts was 7 to 9 times higher compared to that of the roots. The results presented may open a new view on the phytochemistry and pharmacognosy of M. perennis and other members of the Euphorbiaceae family.

Optimal side-chain packing in proteins and crystallographic refinement

2008 ◽  
Vol 41 (2) ◽  
pp. 319-328 ◽  
Author(s):  
Swanand Gore ◽  
Tom Blundell
Keyword(s):  
Homology Modelling ◽  
Side Chain ◽  
Side Chains ◽  
X Ray ◽  
Parameter Ratio ◽  
Correct Sequence ◽  
Protein X ◽  
Density Map ◽  
Electron Density Map ◽  
Sequence Assignment

Amino acid side chains often adopt one of a few distinct, physicochemically favourable conformational states called rotamers. Rotameric preferences and compact packing are sufficient to estimate the conformations of most side chains, as demonstrated by approaches such asSCWRLin homology modelling, but such algorithms have not yet been applied to protein crystallographic refinement.SCWRL's combinatorial optimization algorithm was adapted for assigning side-chain rotameric states that maximize the electron density map occupation while minimizing steric clashes. Our program (OPSAX) was tested on five proteins by introducing error in main chains and comparing the subsequentCNS-only andCNS/OPSAXrefinements. The latter refinement was also extended to multiconformer models. A sequence-assignment exercise examined whetherCNS/OPSAXrefinement can discriminate between correct and incorrect assignments at various artificially lowered resolutions. The compositeCNS/OPSAXrefinement yielded better R_{\rm free} values thanCNS-only refinement. A further drop in R_{\rm free} was observed with multiconformer refinement. For complete main chains, the correct sequence could be discriminated efficiently in most cases even for a low observation-to-parameter ratio of 4, indicating that theOPSAXapproach should find useful applications in protein X-ray refinement.

Comparative study of dG affinity vs. DNA methylation modulating properties of side chain derivatives of procainamide: insight into its DNA hypomethylating effect

RSC Advances ◽  
2016 ◽  
Vol 6 (7) ◽  
pp. 5350-5358 ◽  
Author(s):  
R. L. Gawade ◽  
D. K. Chakravarty ◽  
J. Debgupta ◽  
E. Sangtani ◽  
S. Narwade ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Comparative Study ◽  
Structural Features ◽  
Side Chain ◽  
Side Chains ◽  
Hypomethylating Agents ◽  
Derivatives Of ◽  
Insight Into

Structural features of side-chains govern the association of procainamide and its derivatives with dG base of CpG rich DNA, which may differentially hinder the activity of DNMT-1, thereby they act as DNA hypomethylating agents.

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