Azastilbenes. 1. Synthesis, characterization, and structure

Vansant, J.; Smets, G.; Declercq, Jean‐Paul; Germain, Gabriel; Vanmeerssche, M.

doi:10.1021/jo01297a002

Cited by 61 publications

(43 citation statements)

References 7 publications

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“…The pyridyl rings of each trans 1,2 bis(4 pyri dyl)ethylene molecule are twisted with respect to one another by ~22°, unlike free bpe in which all atoms are in a single plane. 23 The crystal packing of 3 has an island motif. The mo lecular packing of cucurbit [8]uril, like that of compound 2, does not give rise to channels.…”

Section: Aqueous Solutions Of Inclusion Compound 1 and 4 Cyanomentioning

confidence: 99%

Synthesis and guest exchange reactions of inclusion compounds of cucurbit[8]uril with nickel(II) and copper(II) complexes

et al. 2006

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Inclusion compounds of the macrocyclic cavitand cucurbit[8]uril (CB[8]) with the nickel(II) complex, {trans [Ni(en) 2 (H 2 O) 2 ]@CB[8]}Cl 2 •23.5H 2 O, the copper(II) com plex, {2[Cu(dien)(bipy)(H 2 O)]@CB[8]}(ClO 4 ) 4 •11H 2 O, and the organic molecules, 2(pyCN)@CB[8]}•16H 2 O and {2(bpe)@CB[8]}•17H 2 O, where bipy is 4,4´ bipyridyl, pyCN is 4 cyanopyridine, and bpe is trans 1,2 bis(4 pyridyl)ethylene, were synthesized. The inclusion compounds with organic molecules were synthesized starting from inclusion compounds of cucurbit[8]uril with cyclam and ethylenediamine complexes of copper(II) and nickel(II) by the guest exchange method, which is based on the replacement of one guest with another in the cavity of the cavitand The resulting compounds were characterized by X ray diffraction, ESR, 1 H NMR, IR, and electronic absorption spectroscopy, and electrospray mass spectrometry. Photochemically induced [2+2] cycloaddition of two 1,2 bis(4 pyridyl)ethylene molecules included in cucurbit[8]uril was studied.Inclusion compounds of organic macrocyclic cavitands with metal complexes is a new rapidly developing field of supramolecular chemistry. Inclusion of transition metal complexes in organic cavitands gives rise to a unique mi croenvironment of the metal ion similar to that observed in metalloenzymes. Hence, these compounds hold prom ise as model systems in studies of small molecule activa tion and metal ion transport in biological systems. Inclu sion compounds of metal complexes can find use in the design of a new generation of prolonged action pharma ceuticals based on biologically active metal compounds encapsulated within the cavity of a host, which prevents the guest complex from rapid decomposition and per forms transport of the active component in organisms. 1-6Studies of inclusion compounds of cucurbit[n]urils with metal complexes have been started in the last few years, 1-3,7,8 although encapsulation of neutral organic molecules and organic cations in these cavitands has been investigated in depth. 9-13 Cucurbit[n]urils (CB[n]) be long to a family of macrocyclic molecules of composition C 6n H 6n N 4n O 2n (n = 5-10) consisting of n glycoluril frag ments linked to each other by 2n methylene bridges. 14,15 Cucurbit[n]urils have a rigid (unlike such molecular con tainers as calixarenes and cyclodextrins) hydrophobic in ner cavity, which is of importance for selective inclusion of guests of particular size. Guests can enter the cavity through two hydrophilic portals formed by n carbonyl groups.Several inclusion compounds of cucurbit[n]urils with metal complexes have been structurally character ized. These are copper(II) and zinc(II) complexes with cyclam (1,4,8,11 tetraazacyclotetradecane) and cyclene (1,4,7,10 tetraazacyclododecane) encapsulated in the cav ity of cucurbit[8]uril (CB[8]), 1 the inclusion compound of CB[7] with the [cis SnCl 4 (H 2 O) 2 ] complex, 8 and in clusion compounds of CB[8] with the [Ni(cyclam)] 2+ and [trans Cu(en) 2 (H 2 O) 2 ] 2+ complexes, whose syn thesis has been described in o...

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Section: Aqueous Solutions Of Inclusion Compound 1 and 4 Cyanomentioning

confidence: 99%

Synthesis and guest exchange reactions of inclusion compounds of cucurbit[8]uril with nickel(II) and copper(II) complexes

et al. 2006

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“…It is not uncommon for molecules to adopt monolayer structures that approximate faces from their three-dimensional crystals [7,15], and in this current case the monolayer structure of bpe is similar to the [20-1] layer of the bulk crystal [17] (Cambridge Crystallographic Data Centre reference code AZSTBB; Figure 4(b)). Similarly to the monolayer, molecules in the bulk structure also only form a single nonbifurcated hydrogen bond between pyridine rings.…”

Section: Discussionmentioning

confidence: 80%

“…Because there are rather few diffracted X-ray maxima for monolayer systems, the fitting procedure must be constrained as much as possible. Hence, the molecular structure of bpe has been used unchanged from the bulk crystal structure [17]. Furthermore, high symmetry plane groups with few degrees of freedom are usually considered before plane groups with lower symmetry and accordingly more variables.…”

Section: Resultsmentioning

confidence: 99%

The monolayer structure of 1,2-bis(4-pyridyl)ethylene physisorbed on a graphite surface

Brewer¹,

Friščić²,

Day³

et al. 2012

Molecular Physics

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The crystalline monolayer of 1,2-bis(4-pyridyl)ethylene physisorbed on a graphite surface at 0.44 monolayers coverage has been observed and characterized by synchrotron X-ray diffraction and differential scanning calorimetry. The experimentally determined monolayer structure has p2 symmetry with lattice parameters a ¼ 17.77 Å , b ¼ 13.69 Å and ¼ 39.7 � . The unit cell contains two molecules, which are oriented in a plane parallel to the surface. It is proposed that the molecules are arranged such that they are able to form a weak C-H � � � N hydrogen bond between pyridine groups. The monolayer melts at 414 K, which is unusually close to the bulk melting point for a sub-monolayer coverage system. This molecule is chiral when adsorbed on the surface, but both isomers appear in the unit cell leading to no overall chirality in the monolayer.

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“…6.19 a). 92 Such a large distance does not allow dimerization. This molecule can be engineered to dimerize in the crystalline state if it is cocrystallized in the presence of 1,3 -dihydroxybenzene.…”

Section: Use Of Templates: Aligning Reactants Through Hydrogen Bondinmentioning

confidence: 99%

Bimolecular Photoreactions in the Crystalline State

Natarajan

Bhogala

2011

Supramolecular Photochemistry

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Azastilbenes. 1. Synthesis, characterization, and structure

Cited by 61 publications

References 7 publications

Synthesis and guest exchange reactions of inclusion compounds of cucurbit[8]uril with nickel(II) and copper(II) complexes

Synthesis and guest exchange reactions of inclusion compounds of cucurbit[8]uril with nickel(II) and copper(II) complexes

The monolayer structure of 1,2-bis(4-pyridyl)ethylene physisorbed on a graphite surface

Bimolecular Photoreactions in the Crystalline State

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