Five pseudopolymorphs of 6-amino-2-thiouracil: absence of N—H...S hydrogen bonds

Hützler, Wilhelm Maximilian; Bolte, Michael

doi:10.1107/s010827011204930x

Cited by 2 publications

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“…However, intramolecular NH(cpl)...O(cpl) hydrogen bonds arise only in monoclinic 2b phase in addition to four intermolecular NH(cpl)...S hydrogen bonds ( Figure 5) that are rather weak in comparison with those found in a series of organic compounds containing NH…O = C (2.66-3.18 Å) and NH…S = C (3.26-3.42 Å) hydrogen bonds [32]. The corresponding distances for NH…S hydrogen bonds in 1Ln series (3.36-3.49 Å) are comparable with those in polymorphs 2, while intramolecular NH…O hydrogen bonds are shorter, 2.77-3.27 Å.…”

Section: Hydrogen Bondingmentioning

confidence: 96%

Hydrogen bonding induced polymorphism in the scandium(III) complex with ε-caprolactam

Вировец¹,

Cherkasova

Peresypkina³

et al. 2015

Zeitschrift Für Kristallographie - Crystalline Materials

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Two polymorphs of [Sc(cpl) 6 ][Cr(NCS) 6 ] (cpl = ε-C 6 H 11 NO), trigonal and monoclinic, form purple elongated narrow plates and brownish-purple prisms and are formed concomitantly irrespectively of the crystallization conditions. In the trigonal polymorph both cation and anion possess C 3i site symmetry while in the monoclinic form cation and anion lie on inversion centre and 2-fold axis respectively. The nature of the polymorphism traces back to a redistribution of inter-and intramolecular hydrogen bonds that causes different conformation of the complex cations, different hydrogen bonding and different molecular packings. The [Sc(cpl) 6 ] 3+ cations in the structure of the trigonal polymorph form intermolecular N(H)…S, and in the monoclinic form both N(H)…S inter-and N(H)… O intramolecular hydrogen bonds with NCS groups of [Cr(NCS) 6 ] 3− and cpl ligands. This aggregation leads to chains, where the cations and the anions alternate, in the trigonal modification and to layers, in which each ion is surrounded by four counterions, in the monoclinic form. Both polymorphs possess thermochromic properties, and a reversible color change from light purple to dark green takes place at 470-475 K.

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Section: Hydrogen Bondingmentioning

confidence: 96%

Hydrogen bonding induced polymorphism in the scandium(III) complex with ε-caprolactam

Вировец¹,

Cherkasova

Peresypkina³

et al. 2015

Zeitschrift Für Kristallographie - Crystalline Materials

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N—H...S and N—H...O hydrogen bonds: `pure' and `mixed'R²₂(8) patterns in the crystal structures of eight 2-thiouracil derivatives

Hützler

Egert

2014

Acta Crystallogr C

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The preferred hydrogen-bonding patterns in the crystal structures of 5-propyl-2-thiouracil, C7H10N2OS, (I), 5-methoxy-2-thiouracil, C5H6N2O2S, (II), 5-methoxy-2-thiouracil-N,N-dimethylacetamide (1/1), C5H6N2O2S·C4H9NO, (IIa), 5,6-dimethyl-2-thiouracil, C6H8N2OS, (III), 5,6-dimethyl-2-thiouracil-1-methylpyrrolidin-2-one (1/1), C6H8N2OS·C5H9NO, (IIIa), 5,6-dimethyl-2-thiouracil-N,N-dimethylformamide (2/1), 2C6H8N2OS·C3H7NO, (IIIb), 5,6-dimethyl-2-thiouracil-N,N-dimethylacetamide (2/1), 2C6H8N2OS·C4H9NO, (IIIc), and 5,6-dimethyl-2-thiouracil-dimethyl sulfoxide (2/1), 2C6H8N2OS·C2H6OS, (IIId), were analysed. All eight structures contain R(2)(2)(8) patterns. In (II), (IIa), (III) and (IIIa), they are formed by two N-H···S hydrogen bonds, and in (I) by alternating pairs of N-H···S and N-H···O hydrogen bonds. In contrast, the structures of (IIIb), (IIIc) and (IIId) contain 'mixed' R(2)(2)(8) patterns with one N-H···S and one N-H···O hydrogen bond, as well as R(2)(2)(8) motifs with two N-H···O hydrogen bonds.

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Five pseudopolymorphs of 6-amino-2-thiouracil: absence of N—H...S hydrogen bonds

Cited by 2 publications

References 40 publications

Hydrogen bonding induced polymorphism in the scandium(III) complex with ε-caprolactam

Hydrogen bonding induced polymorphism in the scandium(III) complex with ε-caprolactam

N—H...S and N—H...O hydrogen bonds: `pure' and `mixed'R²₂(8) patterns in the crystal structures of eight 2-thiouracil derivatives

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Five pseudopolymorphs of 6-amino-2-thiouracil: absence of N—H...S hydrogen bonds

Cited by 2 publications

References 40 publications

Hydrogen bonding induced polymorphism in the scandium(III) complex with ε-caprolactam

Hydrogen bonding induced polymorphism in the scandium(III) complex with ε-caprolactam

N—H...S and N—H...O hydrogen bonds: `pure' and `mixed'R22(8) patterns in the crystal structures of eight 2-thiouracil derivatives

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N—H...S and N—H...O hydrogen bonds: `pure' and `mixed'R²₂(8) patterns in the crystal structures of eight 2-thiouracil derivatives