Ab initio structure determination of 5-anilinomethylene-2,2-dimethyl-1,3-dioxane-4,6-dione from laboratory powder data – a combined use of X-ray, molecular and solid-state DFT study

The crystal structure of the title compound was solved from laboratory powder diffraction data in the triclinic group by simulated annealing using the program DASH. Since Rietveld refinements yielded inaccurate geometries the structure was finally refined by geometry optimization using energy minimization in the solid state with the DFT/plane-waves approach. The molecule is essentially planar and its Meldrum's acid moiety (2,2-dimethyl-1,3-dioxane-4,6-dione) has a flattened boat conformation. The bond orders in the molecule estimated using a natural bond-orbitals formalism correlate with the optimized bond lengths. The structure in the solid state is based on dimer units in which the molecules are held by N—H...O and C—H...O hydrogen bonds in addition to electrostatic interactions. These units interact through weak C—H...O hydrogen bonds. It is suggested that structure refinement by energy minimization at the DFT level of theory may in many cases successfully replace Rietveld refinement.

Computing details

Figures

5-anilinomethylene-2,2-dimethyl-1,3-dioxane-4,6-dione

Crystal data

C13H13NO4	V = 621.43 Å^3
Mr = 247.24	Z = 2
Triclinic, P1	The cell parameters are from structure solution by DASH. T
Hall symbol: -P 1	Melting point: 156C K
a = 10.60310 Å	? radiation, λ = 1.78892 Å
b = 11.59680 Å	θ = 3–80°
c = 5.50320 Å	T = 300 K
α = 97.8790°	, yellow
β = 103.8910°	× × mm
γ = 71.4570°

Data collection

Stoe Stadi-P diffractometer	h = ?→?
Radiation source: fine-focus sealed tube	k = ?→?
Ge(111) monochromator	l = ?→?

Refinement

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
o1	−0.18118	0.25399	0.11553	0.0500*
o3	−0.08713	0.34986	−0.12582	0.0500*
o4	0.12844	0.27052	−0.18054	0.0500*
o6	−0.05771	0.07945	0.29910	0.0500*
n1	0.21464	−0.00098	0.30875	0.0500*
c10	0.34367	−0.08712	0.37325	0.0500*
c11	0.44853	−0.10153	0.24797	0.0500*
c12	0.57416	−0.18704	0.32315	0.0500*
c13	0.59601	−0.25921	0.52160	0.0500*
c14	0.49046	−0.24573	0.64318	0.0500*
c15	0.36453	−0.16019	0.56993	0.0500*
c9	0.18392	0.09045	0.16347	0.0500*
c5	0.05623	0.17490	0.10000	0.0500*
c4	0.04008	0.26530	−0.07128	0.0500*
c6	−0.05895	0.16536	0.18156	0.0500*
c2	−0.17708	0.37087	0.05006	0.0500*
c7	−0.12772	0.44246	0.28472	0.0500*
c8	−0.31854	0.43254	−0.09035	0.0500*
h1	0.13591	−0.00757	0.38154	0.0600*
h11	0.43256	−0.04794	0.08957	0.0600*
h12	0.65688	−0.19845	0.22797	0.0600*
h13	0.69517	−0.32536	0.57951	0.0600*
h14	0.50525	−0.30095	0.79856	0.0600*
h15	0.28141	−0.14945	0.66329	0.0600*
h9	0.26529	0.10139	0.08850	0.0600*
h71	−0.02579	0.39201	0.38223	0.0750*
h72	−0.12580	0.53058	0.23641	0.0750*
h73	−0.19648	0.45794	0.41412	0.0750*
h81	−0.32100	0.51943	−0.15133	0.0750*
h82	−0.38963	0.45051	0.03538	0.0750*
h83	−0.34917	0.37437	−0.25374	0.0750*