In the title compound, C17H13NO5, the coumarin ring system is essentially planar (r.m.s. deviation = 0.008 Å). The nitro-phenyl ring makes a dihedral angle of 25.27 (9)° with the coumarin ring plane. The nitro group is almost coplanar with the phenyl ring to which it is attached, making a dihedral angle of 4.3 (3)°. The eth-oxy group is inclined to the coumarin ring plane by 4.1 (2)°. Electron ...

The 1,3-diketone group of the title compound, C21H20O6, exists in a keto-enol form stabilized by a strong intra-molecular O-H⋯O hydrogen bond. As a result, a planar (mean deviation = 0.0099 Å) six-membered hydrogen-bonded ring is formed. The C-O and C-C bond lengths suggest significant electron delocalization in the ring. The dihedral angle between the six-membered hydrogen-bonded ring and its ...

From time to time I have the opportunity to give lectures on topics related to aromaticity. Quite often in these occasions I get comments from the audience complaining about the fact that aromaticity is not a well-defined concept. My usual answer is that the most fruitful concepts in chemistry share the same lack of strict definition (Grunenberg, 2017). In one of these occasions, the comment wa...

The single crystal X-ray analysis of the ester-functionalized 2-oxazoline, methyl 3-(4,5-dihydrooxazol-2-yl)propanoate, revealed π-electron delocalization along the N-C-O segment in the 2-oxazoline pentacycle to significant extent, which is comparable to its counterpart along the O-C-O segment in the ester. Quantum chemical calculations based on the experimental X-ray geometry of the molecule s...

In the present article we report the dynamical behavior of entanglement between π-electrons and photons in Graphene. It is shown that the degree of such entanglements depend on the orientation of π-electron momenta relative to the photonic polarization. Moreover, we show that as the detuning between the π-electron transition frequencies and that of the photons is increased, the degree of entang...

Noncovalent interactions are important for determining the assembling modes of materials. Electronically neutral π-systems form stacking structures based on π–π interactions, which mainly derived from dispersion forces. Introducing charges into would affect interaction, owing to increased contribution electrostatic This unique we have proposed as iπ–iπ can provide ion pairs that assembled struc...

Localization and delocalization indices derived in the framework of the quantum Atoms in Molecules theory have recently been used to analyze the electron-pair structure of closed-shell molecules. Here we report calculations of localization and delocalization indices for open-shell molecules at the Hartree-Fock (HF) level. Several simple doublet and triplet radical molecules are studied. In gene...

The geometries, electronic and magnetic properties of neutral and negatively charged Mn(coronene)m (M = V and Ti; n, m = 1, 2) complexes were investigated using density functional theory. The results show that one V or Ti atom prefers to occupy the η(6)-site in M(coronene)(0/-) complexes and to be sandwiched between the two coronene molecules in M(coronene)2(0/-) complexes. Two metal atoms alwa...