Synthesis of 1,3-diynes via detelluration of bis(ethynyl)tellurides

The synthesis of symmetric conjugated diyne systems with electron-withdrawing or electron-donating substituents via a palladium-catalyzed detelluration of bis(arylethynyl)tellurides and bis(alkylethynyl)tellurides is described. This procedure is effected under atmospheric conditions in DMF using Pd(OAc)2 as a catalyst and AgOAc as an additive in the presence of triethylamine. This route offers efficient access to conjugated diyne systems in short reaction time. X-ray crystallographic structure and solid-state conformation of bis(p-tolylethynyl)telluride show a supramolecular chain aligned along the b axis, sustained by C-H...π interactions.Neste artigo é descrita a síntese de sistemas diínicos conjugados contendo substituintes elétronatratores e elétron-doadores via a deteluração catalizada por paládio de bis-(ariletinil)teluretos e bis-(alquiletinil)teluretos. Este procedimento foi realizado sob condições atmosféricas em DMF usando Pd(Oac)2 como catalisador e AgOAc como um aditivo na presença de trietilamina. Esta rota oferece acesso eficiente a sistemas diínicos conjugados em um curto período de tempo. A estrutura cristalográfica por difração de raios X do telureto de bis(p-toluiletinila) e a conformação no estado sólido mostram uma cadeia supramolecular alinhada ao longo do eixo b, sustentada por interações CH...π.FAPESPCNP

2-[(4-Chlorophenyl)sulfanyl]-2-methoxy-1-phenylethan-1-one: crystal structure and Hirshfeld surface analysis

The title compound, C15H13ClO2S, comprises (4-chlorophenyl)sulfanyl, benzaldehyde and methoxy residues linked at a chiral methine-C atom (the crystal is racemic). A twist in the methine-C—C(carbonyl) bond [O—C—C—O torsion angle = 19.3 (7)⁰] leads to a dihedral angle of 22.2 (5)⁰ between the benzaldehyde and methine+methoxy residues. The chlorobenzene ring is folded to lie over the O atoms, with the dihedral angle between the benzene rings being 42.9 (2)⁰. In the crystal, the carbonyl-O atom accepts two C—H...O interactions with methyl- and methine-C—H atoms being the donors. The result is an helical supramolecular chain aligned along the c axis; chains pack with no directional interactions between them. An analysis of the Hirshfeld surface points to the important contributions of weak H...H and C...C contacts to the molecular packing

7-Methyl-5-[(4-methylbenzene)sulfonyl]-2H,5H-[1,3]dioxolo[4,5-f]indole: crystal structure and Hirshfeld analysis

In the title indole derivative, C17H15NO4S, the fused dioxolo-indole system is essentially planar [r.m.s. deviation of the 12 fitted atoms = 0.0249 A ˚ ] and is effectively perpendicular to the appended 4-tolyl ring, forming a dihedral angle of 89.95 (6). Overall, the molecule has the shape of the letter L. In the crystal, supramolecular layers in the ab plane are formed via weak 4-tolyl-C—H....(C6ring of indole) and S—O.... 1,3-dioxole) contacts. The aforementioned interactions along with interatomic H...H and H...O contacts are all shown to make significant contributions to the calculated Hirshfeld surfaces

2-[(4-Chlorophenyl)selanyl]-3,4-dihydro-2H-benzo[h]chromene-5,6-dione: crystal structure and Hirshfeld analysis

The title organoselenium compound, C19H13ClO3Se {systematic name: 2-[(4-chlorophenyl)selanyl]-2H,3H,4H,5H,6H-naphtho[1,2-b]pyran-5,6-dione}, has the substituted 2-pyranyl ring in a half-chair conformation with the methylene-C atom bound to the methine-C atom being the flap atom. The dihedral angle between the two aromatic regions of the molecule is 9.96 (9)° and indicates a step-like conformation. An intramolecular Se...O interaction of 2.8122 (13) Å is noted. In the crystal, π–π contacts between naphthyl rings [inter-centroid distance = 3.7213 (12) Å] and between naphthyl and chlorobenzene rings [inter-centroid distance = 3.7715 (13) Å], along with C—Cl...π(chlorobenzene) contacts, lead to supramolecular layers parallel to the ab plane, which are connected into a three-dimensional architecture via methylene-C—H...O(carbonyl) interactions. The contributions of these and other weak contacts to the Hirshfeld surface is described

Ethyl 2-(4-methoxyphenyl)-6-oxa-3-azabicyclo[3.1.0]hexane-3-carboxylate: crystal structure and Hirshfeld analysis

The title compound, C14H17NO4, features an epoxide-O atom fused to a pyrrolidyl ring, the latter having an envelope conformation with the N atom being the flap. The 4-methoxyphenyl group is orthogonal to [dihedral angle = 85.02 (6)°] and lies to the opposite side of the five-membered ring to the epoxide O atom, while the N-bound ethyl ester group (r.m.s. deviation of the five fitted atoms = 0.0187 Å) is twisted with respect to the ring [dihedral angle = 17.23 (9)°]. The most prominent interactions in the crystal are of the type methine-C—H...O(carbonyl) and these lead to the formation of linear supramolecular chains along the c axis; weak benzene-C—H...O(epoxide) and methine-C—H...O(methoxy) interactions connect these into a three-dimensional architecture. The analysis of the Hirshfeld surface confirms the presence of C—H...O interactions in the crystal, but also the dominance of H...H dispersion contacts.</jats:p

(1R,2S,5R)-5-Methyl-2-[2-(4-nitrophenyl)propan-2-yl]cyclohexyl 2-(4-methoxyphenyl)-2,5-dihydro-1H-pyrrole-1-carboxylate: crystal structure and Hirshfeld analysis

In the title compound, C28H34N2O5, the adjacent ester and nitrobenzene substituents are connected via an intramolecular methylene-C—H. ...(nitrobenzene) interaction and the molecule approximates to a U-shape. The dihydropyrrole ring (r.m.s. deviation = 0.003 A ˚ ) is almost co-planar with the carboxylate residue [Cm—N—C1—Oc (m = methine, c = carboxyl) torsion angle = 1.8 (4).] but is orthogonal to the 4-methoxybenzene ring [dihedral angle = 84.34 (17).]. In the crystal, methylene-C—H. ...O(carbonyl) interactions lead to linear supramolecular chains along the b-axis direction, which pack without directional interactions between them. The analysis of the calculated Hirshfeld surface points to the importance of weak interatomic H. . .H, O. . .H/H. . .O and C. . .H/H. . .C contacts in the crystal

(4-Nitrophenyl)methyl 2,3-dihydro-1H-pyrrole-1-carboxylate: crystal structure and Hirshfeld analysis

In the title compound, C12H12N2O4, the dihydropyrrole ring is almost planar (r.m.s. deviation = 0.0049 A ˚ ) and is nearly coplanar with the adjacent C2O2 residue [dihedral angle = 4.56 (9˚)], which links to the 4-nitrobenzene substituent [dihedral angle = 4.58 (8˚)]. The molecule is concave, with the outer rings lying to the same side of the central C2O2 residue and being inclined to each other [dihedral angle = 8.30 (7˚)]. In the crystal, supramolecular layers parallel to (105) are sustained by nitrobenzene-C—H...O(carbonyl) and pyrrole-C—H...O(nitro) interactions. The layers are connected into a three- dimensional architecture by π(pyrrole)–π(nitrobenzene) stacking [inter-centroid separation = 3.7414 (10) A ˚ ] and nitro-O...π(pyrrole) interactions

3-Hydroxy-2-phenyl-2,3,3a,7a-tetrahydro-1H,5H-pyrano[3,2-b]pyrrol-5-one: crystal structure and Hirshfeld surface analysis

The title isoaltholactone derivative, C13H13NO3, has an NH group in place of the ether-O atom in the five-membered ring of the natural product. The five-membered ring is twisted about the N—C bond linking it to the six-membered ring, which has a half-chair conformation with the O atom connected to the ether-O atom lying above the plane defined by the remaining atoms. The dihedral angle between the mean planes of the rings comprising the fused-ring system is 75.10 (8)°. In the crystal, hydroxy-O—H...N(amine) hydrogen bonding sustains linear supramolecular chains along the a axis. Chains are linked into a three-dimensional architecture via amine-N—H...π(phenyl) and phenyl-C—H...O(hydroxy) interactions. The influence of the amine-N—H...π(phenyl) contact on the molecular packing is revealed by an analysis of the Hirshfeld surface

Structural, Hirshfeld surface and theoretical analysis of two conformational polymorphs of N,N′-bis(pyridin-3-ylmethyl)oxalamide

The common feature of two conformational polymorphs of N,N′-bis(pyridin-3-ylmethyl)oxalamide is their crystallisation in the monoclinic space group P21/c with Z=4. In low symmetry form 1, the central core is effectively planar and the terminal pyridyl rings adopt a syn-periplanar conformation. In the high symmetry form, 2, there are two independent molecules in the asymmetric unit but each is located about a centre of inversion. The rings again are almost perpendicular to the central plane but, from symmetry are anti-periplanar. Computational chemistry shows that symmetric molecules with syn (two-fold) and anti (centrosymmetric) conformations have nearly identical energies. In the molecular packing of each of 1 and 2, supramolecular tapes based on amide-N–H···O(amide) hydrogen bonding are found. In 1, these are connected into layers by C–H···N(pyridyl) interactions, while in 2, the chains are linked into a three-dimensional architecture by C–H···N(pyridyl) interactions. The importance of hydrogen bonding is emphasised in the analysis of the Hirshfeld surfaces