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4-[(4-Chloro­phen­yl)(hy­droxy)methyl­idene]isochromane-1,3-dione

In the title compound, C16H9ClO4, the six-membered heterocyclic ring adopts a screw-boat conformation. The benzene rings are oriented to each other at a dihedral angle of 59.26 (9)°. The mol­ecular structure exhibits a ring motif, viz. S(6), owing to an intra­molecular O—H⋯O hydrogen bond. The presence of C—H⋯O contacts generates an infinite chain along [001]. Also present are π–π stacking inter­actions between neighbouring isochromanedione benzene rings [centroid–centroid distance = 3.746 (1) Å], and C—O⋯π inter­actions [O⋯centroid = 3.934 (2) Å]

4-[(Hy­droxy)(4-methyl­phen­yl)methyl­idene]isochroman-1,3-dione

In the title compound, C17H12O4, the six-membered heterocyclic ring adopts a distorted screw-boat conformation. The mol­ecular structure exhibits an S(6) ring motif, owing to an intra­molecular O—H⋯O hydrogen bond. In the crystal, weak C—H⋯O contacts generate an infinite chain along the c axis. There are also π–π stacking inter­actions between neighbouring isochromanedione benzene rings, with a centroid–centroid distance of 3.755 (1) Å, and C—O⋯π inter­actions with an O⋯centroid distance of 3.964 (2) Å

2-Oxochromen-4-yl 4-(dimethyl­amino)­benzoate

In the title mol­ecule, C18H15NO4, the benzoate ring is oriented at a dihedral angle of 43.43 (6)° with respect to the planar [maximum deviation = 0.038 (2) Å] chromene ring. The crystal structure features R 2 2(12) centrosymetric dimers formed via C—H⋯O inter­actions and these dimeric aggregates are connected by C—H⋯π inter­actions

2-Oxo-2H-chromen-4-yl 4-tert-butyl­benzoate

In the title mol­ecule, C20H18O4, the three methyl groups of the tert-butyl substituent show rotational disorder. Each methyl group is split over three positions, with refined site-occupation factors of 0.711 (4), 0.146 (3) and 0.144 (4). The benzene ring of the benzoate group is oriented at a dihedral angle of 60.70 (7)° with respect to the planar chromene ring [maximum deviation = 0.046 (2) Å]. The crystal structure features centrosymmetric R 2 2(8) dimers formed via C—H⋯O inter­actions, and these dimeric aggregates are connected by C—H⋯π inter­actions

Synthesis, Spectrometric Characterization (ESI-MS, NMR, IRTF), X-Ray Study and Quantum Chemical Calculations of 2-oxo-2H-chromen-7-yl Benzoate

International audienceThe paper presents a combined experimental and computational study of 7-substituted coumarin derivative, the 2-oxo-2H-chromen-7-yl benzoate (I). The compound was prepared in the laboratory by linking the coumarin system (7-hydroxycoumarin) to benzoyl chloride and crystallized in the monoclinic space group P2 1 with = 3.86010(10), = 27.7876(9), = 5.7453(2) Å, = = 90, =91.063(3)° and = 2. The compound has been characterized structurally by spectroscopy and by single-crystal X-Ray diffraction. In the latter, the structure of (I) was solved by direct methods and refined to a final R value of 0.038 for 2260 independent reflections. Its structure is stabilized by intramolecular C-H•••O and intermolecular C-H•••O hydrogen bonds that extended as infinite 1D chain along [001]. Stabilization is also ensured by oxygen-π stacking interaction between the aromatic ring and oxygen of the benzoate moiety. The analysis of intermolecular interactions through the mapping of d norm and shape-index revel that the most significant contributions to the Hirshfeld surface 36.2 and 27.9% are from H•••H and O•••H contacts, respectively. Besides, the molecular geometry of (I) was also optimized using density functional theory (DFT/RB3LYP), the basic ab initio model i.e the restricted Hartree-Fock (RHF) methods with the 6-311 ++ G(d, p) basis set in ground state and frequency calculations with RB3LYP method using 6-31G(d,p) basis set. The theoretical data resulting from these quantum chemical calculations are generally in good agreement with the observed structure. The only significant observed difference is in the torsion angles between the coumarin ring system and the benzoate ring, where the observed CO -CC value (59.6 (4)°) is slightly lower than the DFT/RB3LYP calculated value (54.32°) and the frequency calculations (41.23°) value and larger than that of the RHF computed value (110.63°). The non-linear optical effects (NLO), molecular electrostatic potential (MEP), frontier molecular orbitals (FMO), and the Mulliken charge distribution were also investigated theoretically. The theoretical HOMO-LUMO energy gap values originating from these calculations are 4.465 eV (DFT/RB3LYP/6-311++G(d,p)) and 4.434 eV (FREQ/ RB3LYP/6-31G(d,p))

2-Oxo-2H-chromen-7-yl 4-methylbenzoate

In the title compound, C17H12O4, the benzoate ring is oriented at an acute angle of 60.14 (13)° relative to the coumarin plane (r.m.s. deviation = 0.006 Å). This conformation is stabilized by an intramolecular C—H...O weak hydrogen bond, which forms a five-membered ring. Also present are π–π stacking interactions between neighbouring pyrone and benzene rings [centroid-to-centroid distances in the range 3.6286 (1)–3.6459 (1) Å] and C=O...π interactions [O...centroid distances in the range 3.2938 (1)–3.6132 (1) Å]. Hirshfeld surface analysis has been used to confirm and quantify the supramolecular interactions

Crystal structure of 2-oxo-2H-chromen-3-yl propanoate

In the title compound, C12H10O4, the dihedral angle between the coumarin ring system [maximum deviation = 0.033 (8) Å] and the propionate side chain is 78.48 (8)°. In the crystal, weak C—H...O hydrogen bonds generate inversion dimers and and C—H...π and π–π interactions link the dimers into a three-dimensional network. A quantum chemical calculation is in good agreement with the observed structure

2-Oxo-2H-chromen-3-yl benzoate

In the title compound, C16H10O4, the dihedral angle between the coumarin ring system (r.m.s. deviation = 0.015 Å) and the benzoate group is 83.58 (9)°, which compares to a value of 81.8° obtained from a DFT calculation at the B3LYP/6–311 G(d,p) level. In the crystal, C—O...π and C—H...π interactions and aromatic π–π [Cg...Cg = 3.7214 (14) and 3.7059 (14) Å] stacking generate a three-dimensional network

AM1 and electron impact mass spectrometry study of the fragmentation of 4-acyl isochroman-1,3-diones

Recently, in electron impact mass spectrometry (EIMS), it has been found a good correlation between the fragmentation processes of coumarins and the electronic charges of the atoms of their skeleton. In this paper, the same analytical method has been applied to 4-acyl isochroman-1,3-diones, whose mass spectra had been studied earlier and described for the very first time from our laboratory. Results obtained are in good agreement with the last study.DOI: http://dx.doi.org/10.4314/bcse.v26i2.1