J. Appl. Cryst.の発刊に際して

This paper describes the validation of a dispersion-corrected density functional theory (d-DFT) method for the purpose of assessing the correctness of experimental organic crystal structures and enhancing the information content of purely experimental data. 241 experimental organic crystal structures from the August 2008 issue of Acta Cryst. Section E were energy-minimized in full, including unit-cell parameters. The differences between the experimental and the minimized crystal structures were subjected to statistical analysis. The r.m.s. Cartesian displacement excluding H atoms upon energy minimization with flexible unit-cell parameters is selected as a pertinent indicator of the correctness of a crystal structure. All 241 experimental crystal structures are reproduced very well: the average r.m.s. Cartesian displacement for the 241 crystal structures, including 16 disordered structures, is only 0.095 A (0.084 A for the 225 ordered structures). R.m.s. Cartesian displacements above 0.25 A either indicate incorrect experimental crystal structures or reveal interesting structural features such as exceptionally large temperature effects, incorrectly modelled disorder or symmetry breaking H atoms. After validation, the method is applied to nine examples that are known to be ambiguous or subtly incorrect.

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Validation of experimental molecular crystal structures with dispersion-corrected density functional theory calculations

There are very few people who have lived the allotted time but have an interesting biography, and there are very few congregations but have a very profitable history. The church at Leiper’s Fork, now known as Hillsboro, TN, has a most interesting history. There are few, if any, who know the history of their congregation. It seems that it would be encouraging to the congregation if its history would be kept fresh in the minds of its members.

A Short History Of...

Homo- and heteronuclear group 12 metal (Zn2+, Cd2+, and Hg2+) complexes 1–6 containing a newly designed 18-membered N2O2S2 macrocycle incorporating two pyridine subunits (L) were prepared and structurally characterized. The individual complexes isolated exhibit unusual stoichiometries, geometries, oxidation states, and structural topologies and include an infinite mercurous complex and a heteronuclear dumbbell-shaped complex. Both the Zn(II) complex [Zn(L)][ZnBr4] (1) and the Cd(II) complex [Cd(L)Br2] (2) are mononuclear, with the metal ion located inside the macrocyclic cavity. The six-coordinated Zn(II) center in 1 adopts an octahedral geometry and is shielded from the anion and solvent by the strongly bound macrocycle. The Cd(II) center in 2 is seven-coordinate, being bound equatorially to two N donors, two O donors, and a S donor from the macrocycle and axially to two bromide ions on opposite sides of the macrocyclic plane, adopting a pentagonal-bipyramidal geometry. In the Hg(II) complexations, the c...

Group 12 Metal Complexes of an 18-Membered N2O2S2 Macrocycle Incorporating Two Pyridines: First Examples of an Infinite Mercury(I) Complex and a Dumbbell-Shaped Heteronuclear Complex with a Macrocyclic Ligand

Conformational stability, spectroscopic (FT-IR, FT-Raman and UV-Vis) analysis, NLO, NBO, FMO and Fukui function analysis of 4-hexylacetophenone by density functional theory.

Abstract C10H12O5, monoclinic, P21/c (no. 14), a = 5.6706(16) Å, b = 32.091(9) Å, c = 6.5636(14) Å, β = 123.733(17)°, V = 993.3(5) Å3, Z = 4, Rgt(F) = 0.0359, wRref(F2) = 0.0893, T = 296(2) K.

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Crystal structure of 2-(furan-2-yl)-5-methyl-1,3-dioxane-5-carboxylic acid, C10H12O5

Abstract C13H17BrO3, triclinic, P1̅ (No. 2), a = 9.8235(7) Å, b = 10.3354(7) Å, c = 13.9981(10) Å, α = 99.853(3)°, β = 95.106(3)°, γ = 108.139(3)°, V = 1315.22(16) Å3, Z = 4, Rgt(F) = 0.0340, wRref(F2) = 0.1245, T = 296(2) K.

Crystal structure of (2-(4-bromophenyl)-5-ethyl-1,3-dioxan-5-yl)methanol, C13H17BrO3

The four six-membered rings all adopt chair conformations in the two independent mol­ecules of the title cyclo­hexa­none cyclic diacetal with penta­erythritol, C17H28O4.

https://journals.iucr.org/e/issues/2009/11/00/tk2552/tk2552.pdf

7,11,18,21-Tetra­oxatrispiro­[5.2.2.5.2.2]heneicosa­ne

Abstract C16H19ClO6, triclinic, P1̅ (no. 2), a = 7.905(3) Å, b = 9.194(4) Å, c = 13.094(5) Å, α = 99.928(4)°, β = 105.341(4)°, γ = 109.283(4)°, V = 830.2(6) Å3, Z = 2, Rgt(F) = 0.0343, wRref(F2) = 0.0898, T = 296(2)K.

Crystal structure of diethyl 2-(2-chlorophenyl)-1,3-dioxane-5,5-dicarboxylate, C16H19Cl1O6

Two dinuclear carbonato-bridged nickel(II) complexes formulated as [Ni(rac-L)]2(µ-CO3)(H2O)(im)4(ClO4)2 (1) and [Ni(SS-L)]2(µ-CO3)(H2O)(im)4(ClO4)2 (2) (L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, im = imidazole) were isolated from the reactions of [Ni(rac-L)](ClO4)2 and [Ni(SS-L)](ClO4)2 with imidazole in the air, respectively, and a hydrocarbonato-coordinated nickel(II) complex formulated as [Ni(rac-L)](HCO3)(ClO4) (3) was reacted with obtained when [Ni(rac-L)](ClO4)2 reacted with l-cysteine under weakly basic conditions in the air. We found that the macrocyclic nickel(II) complexes can easily take up and fix atmospheric CO2 at room temperature. Single-crystal X-ray diffraction analyses revealed of all three complexes that the central Ni(II) atoms all have a six-coordinated distorted octahedral coordination geometry, and the carbonate anion bridges two Ni(II) atoms in a tridentate fashion to form dimers in complexes 1 and 2, and the hydrocarbonate coordinates with Ni(II) in a didentate fashion in complex 3. The monomers of {[Ni(RR-L)]2(µ-CO3)(H2O)}2+/{[Ni(SS-L)]2(µ-CO3)(H2O)}2+ are connected through hydrogen bonds to generate one-dimensional right- and left-handed helical chains in complex 1. The chiral nature of complex 2 has been confirmed by CD spectroscopy.

Xian-You Yuan

Papers

Crystal structure of 2-(furan-2-yl)-5-methyl-1,3-dioxane-5-carboxylic acid, C10H12O5

Crystal structure of (2-(4-bromophenyl)-5-ethyl-1,3-dioxan-5-yl)methanol, C13H17BrO3

7,11,18,21-Tetraoxatrispiro[5.2.2.5.2.2]heneicosane

Crystal structure of diethyl 2-(2-chlorophenyl)-1,3-dioxane-5,5-dicarboxylate, C16H19Cl1O6

CO 2 fixation by macrocyclic nickel(II) complexes: synthesis and structures of helical chains constructed via hydrogen bonds involving imidazole

Xian-You Yuan

Papers

Crystal structure of 2-(furan-2-yl)-5-methyl-1,3-dioxane-5-carboxylic acid, C10H12O5

Crystal structure of (2-(4-bromophenyl)-5-ethyl-1,3-dioxan-5-yl)methanol, C13H17BrO3

7,11,18,21-Tetra­oxatrispiro­[5.2.2.5.2.2]heneicosa­ne

Crystal structure of diethyl 2-(2-chlorophenyl)-1,3-dioxane-5,5-dicarboxylate, C16H19Cl1O6

CO 2 fixation by macrocyclic nickel(II) complexes: synthesis and structures of helical chains constructed via hydrogen bonds involving imidazole

7,11,18,21-Tetraoxatrispiro[5.2.2.5.2.2]heneicosane