1126410-18-1Relevant academic research and scientific papers
Three 2,5-dialkoxy-1,4-diethynyl-benzene derivatives
Figueira, Joao,Rodrigues, Joao,Russo, Luca,Rissanen, Kari
, p. o33-o36 (2008)
2,5-Dieth-oxy-1,4-bis-[(trimethyl-silyl)ethyn-yl]benzene, C 20H30O2Si2, (I), constitutes one of the first structurally characterized examples of a family of compounds, viz. the 2,5-dialk-oxy-1,4-bis-[(trimethyl-silyl)ethyn-yl]benzene derivatives, used in the preparation of oligo(phenyl-ene-ethynylene)s via Pd/Cu-catalysed cross-coupling. 2,5-Dieth-oxy-1,4-diethynylbenzene, C14H 14O2, (II), results from protodesilylation of (I). 1,4-Diethynyl-2,5-bis-(hept-yloxy)benzene, C24H34O 2, (III), is a long alk-yloxy chain analogue of (II). The molecules of compounds (I)-(III) are located on sites with crystallographic inversion symmetry. The large substituents either in the alkynyl group or in the benzene ring have a marked effect on the packing and inter-molecular inter-actions of adjacent mol-ecules. All the compounds exhibit weak inter-molecular inter-actions that are only slightly shorter than the sum of the van der Waals radii of the inter-acting atoms. Compound (I) displays C - H...π inter-actions between the methyl-ene H atoms and the acetyl-enic C atom. Compound (II) shows π-π inter-actions between the acetyl-enic C atoms, complemented by C - H...π inter-actions between the methyl H atoms and the acetyl-enic C atoms. Unlike (I) or (II), compound (III) has weak nonclassical hydrogen-bond-type inter-actions between the acetyl-enic H atoms and the ether O atoms.
Encapsulation-induced remarkable stability of a hydrogen-bonded heterocapsule
Ichihara, Keisuke,Kawai, Hidetoshi,Togari, Yuka,Kikuta, Emi,Kitagawa, Hitomi,Tsuzuki, Seiji,Yoza, Kenji,Yamanaka, Masamichi,Kobayashi, Kenji
supporting information, p. 3685 - 3692 (2013/04/10)
Remarkably enhanced stability of the self-assembled hydrogen-bonded heterocapsule 1×2 by the encapsulation of 1,4-bis(1-propynyl)benzene 3 a was found with Ka=1.14×109 M-1 in CDCl3 and Ka2=1.59×108 M-2 in CD3OD/CDCl3 (10 % v/v) at 298 K. The formation of 3 a(1×2) was enthalpically driven (ΔH°0 and ΔS°0) and there was a unique inflection point in the correlation between ΔH° versus ΔS° as a function of polar solvent content. The ab initio calculations revealed that favorable guest-capsule dispersion and electrostatic interactions between the acetylenic parts (triple bonds) of 3 a and the aromatic inner space of 1×2, as well as less structural deformation of 1×2 upon encapsulation of 3 a, play important roles in the remarkable stability of 3 a(1×2). Copyright
