Crystals

190 KiB

Open AccessCommunication

Synthesis and Crystal Structure of 1-(3-Fluorophenyl)-2-thioxo-2,3-dihydroquinazolin-4(1H)-one

by Aamer Saeed and Ulrich Flörke

Crystals 2011, 1(4), 254-259; https://doi.org/10.3390/cryst1040254 - 08 Dec 2011

Cited by 4 | Viewed by 5308

The base catalyzed intramolecular nucleophilic cyclization of 1-(2-bromobenzoyl)-3-(2-fluorophenyl)thiourea (1) in the presence of N,N-dimethyl formamide (DMF) afforded the 1-(3-fluorophenyl)-2-thioxo-2,3-dihydroquinazolin-4(1H)-one (2) by an intramolecular nucleophilic substitution S_NAr mechanism. The structure was supported by thespectroscopic data and unambiguously confirmed bythesingle crystal X-ray diffraction data. It crystallizes in the orthorhombic space group P na2₁ with unit cell dimensions a = 22.430(4), b = 8.1478(16), c = 13.522(3) Å, V = 2471.2(9) Å³. There are two independent molecules per asymmetric unit that are linked to centrosymmetric AB-dimers via intermolecular N-H…S bonds. Full article

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1632 KiB

Open AccessArticle

Defect Scheelite-Type Lanthanoid(III) Ortho-Oxomolybdates(VI) Ln_0.667[MoO₄] (Ln = Ce, Pr, Nd, and Sm) and Their Relationship to Zircon and the NaTl-Type Structure

by Tanja Schustereit, Sabine L. Müller, Thomas Schleid and Ingo Hartenbach

Crystals 2011, 1(4), 244-253; https://doi.org/10.3390/cryst1040244 - 05 Dec 2011

Cited by 16 | Viewed by 8730

Abstract

The rare-earth metal(III) ortho-oxomolybdates with the formula Ln_0.667[MoO₄] (Ln = Ce, Pr, Nd, and Sm) and defect scheelite-type structure crystallize in the tetragonal space group I4₁/a (a = 533–525, c = 1183–1158 pm) with four formula units per unit cell. The Ln³⁺ cations at Wyckoff position 4b exhibit a coordination sphere of eight oxygen atoms in the shape of a trigonal dodecahedron. The same site symmetry (..) is observed for the tetrahedral oxomolybdate(VI) entities [MoO₄]^2–, since their central Mo⁶⁺ cation is situated at the 4a position. Due to this equal site multiplicity, the lanthanoid(III) cations have to be statistically under-occupied to maintain electroneutrality, thus a defect scheelite structure emerges. The partial structure of both the Ln³⁺ cations and the [MoO₄]^2– anions (if shrunk to their centers of gravity) can be best described as distorted diamond-like arrangements. Therefore, these two interpenetrating partial structures exhibit a similar setup as found in the zircon-type as well as in the NaTl-type structure. Full article

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605 KiB

Open AccessShort Note

Supramolecular Hydrogen-Bond Motifs in Chiral and Racemic Molecular Salts: A Comparison of (S)-2-Methyl Piperizinium Hydrogen Phosphite Monohydrate, C₅H₁₄N₂·HPO₃·H₂O and (R,S)-2-Methyl Piperizinium Hydrogen Phosphite 2.23 Hydrate, C₅H₁₄N₂·HPO₃·2.23H₂O

by William T. A. Harrison

Crystals 2011, 1(4), 236-243; https://doi.org/10.3390/cryst1040236 - 17 Nov 2011

Cited by 1 | Viewed by 5574

Abstract

The crystal structures of C₅H₁₄N₂·HPO₃·H₂O (1) and C₅H₁₄N₂·HPO₃·2.23H₂O (2) are described and compared. Compound 1 contains homochiral (S [...] Read more.

The crystal structures of C₅H₁₄N₂·HPO₃·H₂O (1) and C₅H₁₄N₂·HPO₃·2.23H₂O (2) are described and compared. Compound 1 contains homochiral (S)-2-methyl piperizinium cations, hydrogen phosphite ions and water molecules. The components are linked by N–H⋯O and O–H⋯O hydrogen bonds into a three-dimensional network. In compound 2, racemic (R,S)-2-methyl piperizinium cations combine with the same anions and water molecules to generate a far more complex, high symmetry “supramolecular” structure, which features distinctive R⁶₆(12) loops and helical C(2) chain hydrogen-bonding motifs involving the water molecules. Crystal data: 1 (C₅H₁₇N₂O₄P), M_r = 200.18, orthorhombic, P2₁2₁2₁ (No. 19), Z = 4, a = 8.564 (5) Å, b = 9.593 (6) Å, c = 11.607 (6) Å, V = 953.6 (9) Å³, R(F) = 0.066, wR(F²) = 0.081. 2 (C₅H_19.47N₂O_5.24P), M_r = 222.49, trigonal, (No. 148), Z = 18, a = 31.075 (2) Å, c = 6.1875 (4) Å, V = 5174.5 (6) Å³, R(F) = 0.044, wR(F²) = 0.107. Full article

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192 KiB

Open AccessArticle

The Crystal and Molecular Structure of (2Z)-2-[3-(4-Methoxybenzoyl)-4,4-dimethyl-1,2-oxazolidin-2-ylidene]-1-(4-methoxyphenyl)ethanone

by Anna Petrov, Roderick C. Jones, Douglas G. Vaughan, Alan J. Lough and Robert A. Gossage

Crystals 2011, 1(4), 229-235; https://doi.org/10.3390/cryst1040229 - 31 Oct 2011

Cited by 7 | Viewed by 6695

Abstract

The crystal and molecular structure of the title compound, viz., (2Z)-2-[3-(4-methoxybenzoyl)-4,4-dimethyl-1,2,-oxazolidin-2-ylidene]-1-(4-methoxyphenyl)ethanone (4), is reported. Compound 4 crystallises from toluene/hexanes mixtures in the P2₁/c space group with eight molecules in the unit cell. The unit cell parameters are: a = 20.9410(11) Å, b = 8.7523(5) Å, c = 21.2291(9) Å; β = 93.529(3)° and V = 3883.5(3) Å³. There are two structurally distinct molecules of 4 found in the solid-state which differ primarily in terms of the observed torsion angles and the overall intramolecular spacing between the aromatic groups. Bond lengths and angles of this tertiary amide are otherwise typical. This is the first crystallographically characterised example of this class of oxazoline precursors, which have previously found application in the syntheses of other heterocycles. Density functional theory (b3lyp 6-311++G** level of sophistication) has likewise been applied to estimate the gas-phase structure of the title compound. Full article

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1561 KiB

Open AccessArticle

(B15c5)BiI₃(I₂): Molecular Benzo-15-Crown-5―BiI₃ Complexes Bridged by Iodine Molecules to Chains

by Christoph Fiolka, Mark Richter, Ingo Pantenburg, Anja-Verena Mudring and Gerd Meyer

Crystals 2011, 1(4), 220-228; https://doi.org/10.3390/cryst1040220 - 24 Oct 2011

Cited by 4 | Viewed by 8233

Abstract

The reaction of bismuth triiodide with iodine and benzo-15-crown-5 in ethanol/dichloromethane yielded red single crystals of (b15c5)BiI₃(I₂) (monoclinic, P2₁/c (no. 14), a = 1376.9(1), b = 1172.7(1), c = 1700.2(2) pm, b = 115.197(6), V = 2484.1(4)·10⁶pm³, Z = 4). Neutral pseudo-octahedral complexes (b15c5)BiI₃ are connected by secondary bonding interactions via iodine molecules to chains. Electronic structure calculations of the neutral complex (b15c5)BiI₃ reveal that the compound can indeed be described as b15c5 interacting with a molecular BiI₃ unit. However, bonding has to be mainly electrostatic as the interactions of the bismuth 6s lone pair with the 2p orbitals of the oxygen atoms of the crown ether are clearly antibonding. Full article

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1365 KiB

Open AccessCommunication

Iodine Molecules Included in the Structure of Dibenzo-24-Crown-8, (I₂)@(db24c8)

by Christine Walbaum, Ingo Pantenburg and Gerd Meyer

Crystals 2011, 1(4), 215-219; https://doi.org/10.3390/cryst1040215 - 28 Sep 2011

Cited by 7 | Viewed by 8258

Abstract

A reaction of YI₃, dibenzo-24-crown-8 and iodine in ethanol yielded, as a by-product, red single crystals of (I₂)@(db24c8). In the triclinic crystal, P-1, a = 485.0(1), b = 1203.7(3), c = 1280.4(2) pm, α = 64.56(2)°, β = 86.82(2)°, γ = 83.89(2)°, V = 671.1(2) × 10^6.pm³, Z = 1, R₁= 0.0301 for 1965 reflections with I₀> 2σ(I₀), iodine molecules with an I–I distance of 268.39(7) pm, slightly longer than in the gas phase, are included in a matrix of db24c8 molecules. Full article

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Crystals, Volume 1, Issue 4 (December 2011) – 6 articles , Pages 215-259

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