Pyrrole and a Co-crystal of 1<i>H</i>- and 2<i>H</i>-1,2,3-Triazole

Goddard, Richard; Heinemann, Oliver; Krüger, Christoph

doi:10.1107/s0108270197009682

Cited by 57 publications

(71 citation statements)

References 6 publications

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“…15,20 The ring proton was not located, 15 however, the sum of the bond angles at the diaminocarbon centre C(1) is 324.5(3)° (Table 2), reflecting its distorted tetrahedral geometry. The intraannular N-CO bond distance in 1a is relatively short (1.372(4) Å), and comparable to the N-C bond distances of pyrroles, 21 imidazoliums,15…”

Section: Figurementioning

confidence: 96%

The influence of electron delocalization upon the stability and structure of potential N-heterocyclic carbene precursors with 1,3-diaryl-imidazolidine-4,5-dione skeletons

et al. 2010

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(2010). The influence of electron delocalization upon the stability and structure of potential N-heterocyclic carbene precursors with 1,3-diaryl-imidazolidine-4,5-dione skeletons. New Journal of Chemistry, 34 (7), 1295-1308. doi:10.1039 Aiming to develop synthetic protocols for the preparation of N-heterocyclic carbenes (NHCs) with increased π-acceptor character featuring N-pentafluorophenyl substituents, the molecular 2-chloro-1,3-bis(pentafluorophenyl)imidazolidine-4,5-dione (1a) was isolated from the condensation reaction of the corresponding formamidine with o xalyl chloride, instead of the expected, ionic 1,3-10 bis(pentafluorophenyl)-4,5-dioxo-4,5-dihydro-3H-imidazolium chloride. The nature of the extraannular N-substituents does not appear to exercise a significant influence on the structure of the products of this reaction, as evidenced by the similar structures observed with 2,6-dimethylphenyl (1b) and 2,6-diisopropylphenyl (1c) N-substituted analogues. These formal adducts of NHCs with hydrogen chloride demonstrate reactivity akin to that expected of alkyl halides. For instance, 1,3,1',3'-tetrakis(2,6-dimethylphenyl)-[2,2']diimidazolidinyl-4,5,4',5'-tetraone (2b) is formed via the reductive coupling of two units of 1b, while 1,3-15 bis(2,6-diisopropylphenyl)-4,5-dioxoimidazolidin-2-yl acetate (3c) is formed as the result of a metathesis reaction with mercury acetate. Chloride abstraction results in the formation of unstable imidazolium-4,5-dione salts (4a-c) that decompose rapidly, except in the case of the kinetically-stabilized 1,3-bis(2,6-diisopropylphenyl)imidazolium-4,5-dione hexafluorophosphate 4c, which could be observed spectroscopically. All imidazolium-4,5-dione hexafluorophosphate salts decompose to neutral 2-fluoro-1,3-bis(aryl)imidazolidine-4,5-diones (5a-c) via fluoride abstraction, demonstrating a clear preference for a four-coordinate 20 geometry about the diaminocarbon center in these compounds. 2-Methoxy-1,3-di(aryl)imidazolidine-4,5-diones (6a-c) were also prepared and they proved to be highly stable, failing to undergo thermolysis and yield the free NHCs. Computational analyses revealed that the instability of NHCs with an oxalamide skeleton, as well as that of their precursors, imidazolium-4,5-diones, results from a π-framework which extends over both carbonyl moieties and gives rise to a very low energy LUMO, rendering the compounds in question highly electrophilic.25

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Section: Figurementioning

confidence: 96%

The influence of electron delocalization upon the stability and structure of potential N-heterocyclic carbene precursors with 1,3-diaryl-imidazolidine-4,5-dione skeletons

et al. 2010

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“…In (I), an O atom facilitates N--H...O hydrogen bonding. In contrast, the presence of unusual Npyrrole--H" " "Trpyrrolc hydrogen bonding has thus far only been noted in crystal structures where stronger acceptors are absent (Linet al, 1996;Goddard et al, 1997;Bennis & Gallagher, 1998). Further comparative studies are in progress on related systems.…”

Section: (A)mentioning

confidence: 99%

“…phenyl rings (Allen et al, 1997;Starikov & Steiner, 1998). Atypical heteroaromatic N--H donors with 71-acceptor systems have been described recently (Lin et al, 1996;Goddard et al, 1997;Bennis & Gallagher, 1998) where pyrrole groups participate both as N--H donor and 71-pyrrol e acceptor groups. The title compound, (I), a pyrrole derivative, is of interest in hydrogen-bonding studies for an understanding of the role which pyrrole groups play in molecular recognition processes.…”

Section: Introductionmentioning

confidence: 99%

Intermolecular N—H...O and C—H...O interactions form a two-dimensional network in (2S,4S,5R)-(–)-3,4-dimethyl-5-phenyl-2-(pyrrol-2-yl)-1,3-oxazolidine

Gallagher¹,

Fitzsimons²

1999

Acta Crystallogr C

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“…This hydrogen-bonding arrangement contrasts with the two-dimensional network of (pyrrole)N--H...Tr(pyrrole) hydrogen bonds in (II) and the onedimensional relay of (pyrrole)N--H...Tr(pyrrole) and (pyrrole)N--H..-Tr(phenyl) interactions in (III). Intermolecular (pyrrole)N--H...Tr(pyrrole) interactions generate a one-dimensional chain in pyrrole (Goddard et al, 1997). A search of the Cambridge Structural Database (Allen & Kennard, 1993) for molecules containing the pyrrolyl (C4H3NH) group shows that the majority of such structures display conventional N--H..-{O, N, S, X (= halide)}-type hydrogen bonding when such acceptors are available.…”

Section: N35b~mentioning

confidence: 99%

“…phenyl rings (Allen et al, 1997;Starikov & Steiner, 1998). Atypical heteroaromatic N--H donor and acceptor systems have also been described, where indole groups (Krishna et al, 1999), pyrrole groups (Lin et al, 1996;Goddard et al, 1997;Bennis & Gallagher, 1998) and pyrazole ligands (Beringhelli et al, 1998) take part in (heteroaromatic)N--H...Tr(heteroaromatic) interactions. These unusual examples of hydrogen bonds are important in facilitating our understanding of important molecular-recognition processes in biological systems, as well as in advancing crystal engineering studies.…”

mentioning

confidence: 99%

Intermolecular (pyrrole)N—H...π(pyrrole) interactions in bis(2-pyrrolyl)methylferrocene, an organometallic porphyrin precursor

Gallagher¹,

Moriarty²

1999

Acta Crystallogr C

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The title compound, C19HI8FeN2 or [Fe(CsHs)(CI4HI3-N2)], crystallizes in space group P2~/n with two molecules in the asymmetric unit. The pyrrole groups take part in intermolecular (pyrrole)N--H...Tr(pyrrole) interactions through a hydrogen-bonded ring system involving four pyrrole groups, with N..-(pyrrole centroid) distances in the range 3.209(3)-3.427 (3)/k and N--H.--(pyrrole centroid) angles in the range 127-139 °.

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Pyrrole and a Co-crystal of 1H- and 2H-1,2,3-Triazole

Cited by 57 publications

References 6 publications

The influence of electron delocalization upon the stability and structure of potential N-heterocyclic carbene precursors with 1,3-diaryl-imidazolidine-4,5-dione skeletons

The influence of electron delocalization upon the stability and structure of potential N-heterocyclic carbene precursors with 1,3-diaryl-imidazolidine-4,5-dione skeletons

Intermolecular N—H...O and C—H...O interactions form a two-dimensional network in (2S,4S,5R)-(–)-3,4-dimethyl-5-phenyl-2-(pyrrol-2-yl)-1,3-oxazolidine

Intermolecular (pyrrole)N—H...π(pyrrole) interactions in bis(2-pyrrolyl)methylferrocene, an organometallic porphyrin precursor

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