Synthesis and structures of three new pyridine-containing oxazoline ligands of complexes for asymmetric catalysis
Three new chiral pyridine-containing oxazoline derivatives with fluorine and perfluoromethyl groups, namely, 2-({2-[(4S)-4-phenyl-4,5-dihydro-1,3-oxazol-2-yl]phenyl}amino)-5-(trifluoromethyl)pyridine, C21H16F3N3O, 2-({5-fluoro-2-[(4S)-4-isopropyl-4,5-dihydro-1,3-oxazol-2-yl]phenyl}amino)-5-(trifluoromethyl)pyridine, C18H17F4N3O, and 2-({2-[(3aR,8aS)-8,8a-dihydro-3aH-indeno[1,2-d]oxazol-2-yl]phenyl}amino)-5-(trifluoromethyl)pyridine, C22H16F3N3O, as chiral ligands in metal-catalysed asymmetric reactions, were synthesized and characterized by spectral and X-ray diffraction methods. The conformation of the molecules is influe...
Source: Acta Crystallographica Section C - August 18, 2021 Category: Chemistry Authors: Woli ń ska, E. Wysocki, W. Branowska, D. Karczmarzyk, Z. Tags: oxazoline ligand asymmetric catalysis crystal structure Hirshfeld surface analysis DFT calculations research papers Source Type: research
Polyoxometalate-like structure of new potassium triphenylsiloxides: [K6(OSiPh3)6(C3H7OH)(H2O)] · 2C6H5CH3 and [K6(OSiPh3)6(H2O)2]
The synthesis and structural characterization of two new potassium triphenylsiloxides, namely, aqua(propan-2-ol)hexakis(triphenylsilanolato)hexapotassium toluene disolvate, [K6(C18H15OSi)6(C3H8O)(H2O)] · 2C7H8, and diaquahexakis(triphenylsilanolato)hexapotassium, [K6(C18H15OSi)6(H2O)2], are reported. Both compounds crystallize in the triclinic space group P\overline{1}. The structure in each case resembles an alkali metal polyoxometalate-like structure, in which electrostatic interactions are observed in the metal – oxygen core. Furthermore, both compounds also resemble a reverse micelles-like architecture, in which the...
Source: Acta Crystallographica Section C - August 17, 2021 Category: Chemistry Authors: Wytrych, P. Utko, J. Lis, T. John, Ł . Tags: potassium siloxide crystal structure alkali metal siloxide triphenylsilanol triphenylsiloxide reverse micelles alkali metal polyoxometalate POM research papers Source Type: research
Structural trends in a series of bulky dialkylbiarylphosphane complexes of CuI
CuI complexes containing the bulky dialkylbiarylphosphane 2-(di-tert-butylphosphanyl)-2 ′ ,4 ′ ,6 ′ -triisopropylbiphenyl (tBuXPhos, L) and an ancillary ligand (Cl − , Br − , I − , MeCN, ClO4 − or SCN − ) have been structurally characterized, namely, chlorido[2-(di-tert-butylphosphanyl)-2 ′ ,4 ′ ,6 ′ -triisopropylbiphenyl- κ P]copper(I), [CuCl(C29H45P)], 1, bromido[2-(di-tert-butylphosphanyl)-2 ′ ,4 ′ ,6 ′ -triisopropylbiphenyl- κ P]copper(I), [CuBr(C29H45P)], 2, [2-(di-tert-butylphosphanyl)-2 ′ ,4 ′ ,6 ′ -triisopropylbiphenyl- κ P]iodidocopper(I), [CuI(C29H45P)], 3, (acetonitrile- κ N...
Source: Acta Crystallographica Section C - August 16, 2021 Category: Chemistry Authors: Woodhouse, S.S. Buchanan, J.K. Dais, T.N. Ainscough, E.W. Brodie, A.M. Freeman, G.H. Plieger, P.G. Tags: metal – arene interaction CuI phosphane crystal structure catalysis research papers Source Type: research
Anthelmintic flavonoids and other compounds from Combretum glutinosum Perr. ex DC (Combretaceae) leaves
A chemical study of the hydro-ethanol extract of the leaves of Combretum glutinosum resulted in the isolation of nine compounds, including 5-demethylsinensetin (1), umuhengerin (2), (20S,24R)-ocotillone (3), lupeol (4), β -sitosterol (5), oleanolic acid (6), betulinic acid (7), corymbosin (8) and β -sitosterol glucoside (9). Four compounds have been isolated for the first time from the genus Combretum [viz. (1), (2), (3) and (8)]. The crystal structures of flavonoid (2), C20H20O8, Z ′ = 2, and triterpene (3), C30H50O3, Z ′ = 1, have been determined for the first time; the latter confirmed the absolute configuration o...
Source: Acta Crystallographica Section C - August 6, 2021 Category: Chemistry Authors: Toklo, P.M. Yayi Ladekan, E. Linden, A. Hounzangbe-Adote, S. Kouam, S.F. Gbenou, J.D. Tags: C. glutinosum flavonoids triterpenes crystal structure anthelmintic natural product absolute configuration research papers Source Type: research
Synthesis and spectroscopic and structural characterization of spiro[indoline-3,3 ′ -indolizine]s formed by 1,3-dipolar cycloadditions between isatins, pipecolic acid and an electron-deficient alkene
Five new spiro[indoline-3,3 ′ -indolizine]s have been synthesized with high regio- and stereospecificity in one-pot three-component reactions between a substituted indole-2,3-dione, (S)-pipecolic acid and trans-3-benzoylacrylic acid, and subsequently characterized using a combination of elemental analysis, IR and 1H and 13C NMR spectroscopy, mass spectrometry and crystal structure analysis. (1 ′ SR,2 ′ SR,3RS,8a ′ RS)-2 ′ -Benzoyl-5-fluoro-2-oxo-1 ′ ,5 ′ ,6 ′ ,7 ′ ,8 ′ ,8a ′ -hexahydro-2 ′ H-spiro[indoline-3,3 ′ -indolizine]-1 ′ -carboxylic acid, C23H21FN2O4, (I), and (1 ′ SR,2 ′ SR,3RS,8a ...
Source: Acta Crystallographica Section C - August 6, 2021 Category: Chemistry Authors: Romo, P.E. Quiroga, J. Cobo, J. Glidewell, C. Tags: synthesis heterocycle spiro[indoline-3,3 ′ -indolizine] NMR spectroscopy reaction mechanism crystal structure stereochemistry molecular conformation supramolecular assembly research papers Source Type: research
Approximate symmetry in the third reported structure of a metal complex of l-DOPA
(Source: Acta Crystallographica Section C)
Source: Acta Crystallographica Section C - July 30, 2021 Category: Chemistry Authors: Brock, C.P. Tags: commentary L-DOPA approximate symmetry MATCH scientific commentaries Source Type: research
Isopropyl 3-deoxy- α -d-ribo-hexopyranoside (isopropyl 3-deoxy- α -d-glucopyranoside): evaluating trends in structural parameters
Isopropyl 3-deoxy- α -d-ribo-hexopyranoside (isopropyl 3-deoxy- α -d-glucopyranoside), C9H18O5, (I), crystallizes from a methanol – ethyl acetate solvent mixture at room temperature in a 4C1 chair conformation that is slightly distorted towards the C5SC1 twist-boat form. A comparison of the structural parameters in (I), methyl α -d-glucopyranoside, (II), α -d-glucopyranosyl-(1 → 4)-d-glucitol (maltitol), (III), and 3-deoxy- α -d-ribo-hexopyranose (3-deoxy- α -d-glucopyranose), (IV), shows that most endocyclic and exocyclic bond lengths, valence bond angles and torsion angles in the aldohexopyranosyl rings are mor...
Source: Acta Crystallographica Section C - July 27, 2021 Category: Chemistry Authors: Lin, J. Oliver, A.G. Meredith, R.J. Carmichael, I. Serianni, A.S. Tags: crystal structure isopropyl 3-deoxy- α -d-ribo-hexopyranoside -d-glucopyranoside DFT chemical synthesis research papers Source Type: research
Conformational control through co-operative nonconventional C — H...N hydrogen bonds
We report the design, synthesis, and crystal structure of a conjugated aryleneethynyl molecule, 2-(2-{4,5-dimethoxy-2-[2-(2,3,4-trifluorophenyl)ethynyl]phenyl}ethynyl)-6-[2-(pyridin-2-yl)ethynyl]pyridine, C30H17F3N2O2, that adopts a planar rhombus conformation in the solid state. The molecule crystallizes in the space group P\overline{1}, with Z = 2, and features two intramolecular sp2-C — H...N hydrogen bonds that co-operatively hold the arylethynyl molecule in a rhombus conformation. The H atoms are activated towards hydrogen bonding since they are situated on a trifluorophenyl ring and the H...N distances are 2.470 ...
Source: Acta Crystallographica Section C - July 26, 2021 Category: Chemistry Authors: Bosch, E. Bowling, N.P. Oburn, S.M. Tags: crystal structure — H...N hydrogen bond intramolecular hydrogen bonding nonconventional hydrogen bond conformational control molecular rhombus self-complementary hydrogen bond research papers Source Type: research
A rare case of a 2:2:1 ternary cocrystal of pyridine sulfides and trithiocyanuric acid
We report a rare case of a 2:2:1 ternary cocrystal consisting of two trithiocyanuric acid molecules, two bis(pyridin-4-yl) sulfide molecules and 1,4-bis(pyridin-4-yl)tetrasulfane, namely, 1,3,5-triazinane-2,4,6-trithione – 4-(pyridin-4-ylsulfanyl)pyridine – 1,4-bis(pyridin-4-yl)tetrasulfane (2/2/1), 2C3H3N3S3 · 2C10H8N2S · C10H8N2S4. This interesting crystal structure with five neutral molecules per asymmetric unit was synthesized and characterized by means of X-ray diffraction (XRD) experiments and quantum-chemical modelling. Among various specific interactions, hydrogen and halogen bridges have a significant role i...
Source: Acta Crystallographica Section C - July 20, 2021 Category: Chemistry Authors: Wzgarda-Raj, K. Ksi ą ż kiewicz, O. Palusiak, M. Tags: 1,4-bis(pyridin-4-yl)tetrasulfane pyridine cocrystal hydrogen bonding supramolecular chemistry quantum-chemical calculations crystal structure research papers Source Type: research
Crystallographic studies of piperazine derivatives of 3-methyl-5-spirofluorenehydantoin in search of structural features of P-gp inhibitors
5-Spirofluorenehydantoin derivatives show efflux modulating, cytotoxic and antiproliferative effects in sensitive and resistant mouse T-lymphoma cells. In order to extend the knowledge available about the pharmacophoric features responsible for the glycoprotein P (P-gp) inhibitory properties of arylpiperazine derivatives of 3-methyl-5-spirofluorenehydantoin, we have performed crystal structure analyses for 1-[3-(3 ′ -methyl-2 ′ ,4 ′ -dioxospiro[fluorene-9,5 ′ -imidazolidin]-1 ′ -yl)propyl]-4-phenylpiperazine-1,4-diium dichloride monohydrate, C29H32N4O22+ · 2Cl − · H2O (1), 3 ′ -methyl-1 ′ -{3-[4-(4-nitrop...
Source: Acta Crystallographica Section C - July 8, 2021 Category: Chemistry Authors: Ż es ł awska, E. Szyma ń ska, E. Nitek, W. Handzlik, J. Tags: induced-fit docking hydantoin derivatives multidrug resistance P-glycoprotein crystal structure hydrogen bonding research papers Source Type: research
Ψ -Polyhedral symbols for coordination geometries of lead(II) with a stereochemically active lone pair
Because an IUCr/IUPAC-designated set of letters/numbers identifies the configuration of the atoms linked to the PbII atom in its coordination compounds, a Ψ prefix before such as a polyhedral symbol provides useful information when its lone pair is stereochemically active. Such notation is especially relevant when the metal atom is connected to eight or more atoms regardless of whether the lone pair is active or inert. The polyhedral symbols for the crystal structures in some 50 articles published after 2000 are reported here as the original studies did not expressly identify coordination geometries. (Source: Acta Crystal...
Source: Acta Crystallographica Section C - July 7, 2021 Category: Chemistry Authors: Ng, S.W. Tags: polyhedral symbol lead(II) coordination compound stereochemical activy lone pair crystal structure coordination geometry letters to the editor Source Type: research
Induction of Λ -helicity in a zinc complex with an alanine-appended aminopyridine ligand
The crystal structure of tris[dimethyl 5-({1-[(pyridin-2-yl- κ N)carbamoyl- κ O]ethyl}carbamoyl)benzene-1,3-dicarboxylate]zinc(II) dinitrate acetonitrile trisolvate, [Zn(C19H19N3O6)3](NO3)2 · 3CH3CN or [Zn(L)3](NO3)2 · 3CH3CN, (1), has been determined by single-crystal X-ray diffraction. The neutral ligand L coordinates to the Zn2+ cation in a bidentate fashion via the pyridine N atom and an amide O atom, forming a six-membered chelate ring. The Λ -helical chirality of the Zn2+ coordination sphere is induced by pendant l-alanine residues through stacking interactions between the arene groups of two coordinated ligands...
Source: Acta Crystallographica Section C - July 5, 2021 Category: Chemistry Authors: Peri ć , B. Kokan, Z. Kirin, S.I. Tags: alanine aminopyridine supramolecular chirality zinc complex crystal structure amino acid research papers Source Type: research
Ionic cocrystals of dithiobispyridines: the role of I...I halogen bonds in the building of iodine frameworks and the stabilization of crystal structures
It has been confirmed that mercaptopyridines undergo spontaneous condensation in redox reaction with iodine-forming dithiopyridines. In the solid state, these compounds are protonated at the N atoms and cocrystallize with iodine forming salt structures, namely, 2-[(pyridin-2-yl)disulfanyl]pyridinium triiodide sesquiiodine, C10H9N2S2+ · I3 − · 1.5I2, and 4,4 ′ -(disulfanediyl)dipyridinium pentaiodide triiodide, C10H10N2S22+ · I5 − · I3 − . Dithiopyridine cations are packed among three-dimensional frameworks built from iodide anions and neutral iodine molecules, and are linked by hydrogen, halogen and chalcogen i...
Source: Acta Crystallographica Section C - July 4, 2021 Category: Chemistry Authors: Wzgarda-Raj, K. Nawrot, M. Rybarczyk-Pirek, A.J. Palusiak, M. Tags: pyridine cocrystal salt hydrogen bonding halogen bonding supramolecular chemistry quantum chemistry proton transfer crystal structure proton sponge research papers Source Type: research
Phase behaviour and crystal structures of 2 ′ ,3 ′ -difluorinated p-terphenyl derivatives
The crystal structures of difluorine derivatives of p-terphenyls (nTm) have been determined by single-crystal X-ray diffraction. For the unsymmetrical substituted compounds 2 ′ ,3 ′ -difluoro-4-methyl-p-terphenyl (1T0, C19H14F2) and 4-ethyl-2 ′ ,3 ′ -difluoro-4 ′ ′ -methyl-p-terphenyl (1T2, C21H18F2), the crystal structure is disordered, with molecules statistically entering the crystal in up and down orientations, with full superposition of all the atoms, except for those of the terminal groups (H/methyl for 1T0 and methyl/ethyl for 1T2). For triclinic 2 ′ ,3 ′ -difluoro-4,4 ′ ′ -dimethyl-p-terphenyl (...
Source: Acta Crystallographica Section C - June 28, 2021 Category: Chemistry Authors: Gupta, S. Das, P.P. Kula, P. Parisi, E. Centore, R. Tags: difluorine p-terphenyl disorder crystal structure terminal groups nematic behaviour POM DSC Hirshfeld liquid crystal research papers Source Type: research
Structural investigations into a new polymorph of F4TCNQ: towards enhanced semiconductor properties
During the course of research into the structure of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), C12F4N4, an important compound in charge-transfer and organic semiconductor research, a previously unreported polymorph of F4TCNQ was grown concomitantly with the known polymorph from a saturated solution of dichloromethane. The structure was elucidated using single-crystal X-ray diffraction and it was found that the new polymorph packs with molecules in parallel layers, in a similar manner to the layered structure of F2TCNQ. The structure was analysed using Hirshfeld surface analysis, fingerprint plots and pa...
Source: Acta Crystallographica Section C - June 28, 2021 Category: Chemistry Authors: Johnson, N.T. Probert, M.R. Waddell, P.G. Tags: polymorphism F4TCNQ charge transfer pairwise interaction energies crystal structure semiconductor quinodimethane research papers Source Type: research
