The weak hydrogen-bonded complexes between proton donors and the pi-cloud of indole and 1-methylindole (MI) are investigated theoretically by three different methods: DFT/B3LYP, MPW1B95, and MP2. This study addresses the question as to whether the 1:1 complex can only form between the proton and the pi-cloud of the pyrrole part of indole or if there also exists a 1:1 complex between the proton and the pi-cloud of the phenyl ring. For the water-indole system, the more elaborate MP2 and MPW1B95 methods yield only one minimum with a hydrogen bond to the pyrrole part and weak secondary interactions to the phenyl ring, in agreement with a recent criticism by Van Mourik (Chem. Phys. 2004, 304, 317-319) that the B3LYP functional is unable to account for the dispersion interaction. However, for the 1:1 complexes between MI and 2-propanol, all three methods indicate that both the five-membered and the six-membered rings of the indole chromophore can form pi-complexes. For the MI-trifluoroethanol (TFE) system, it is shown that the ethanol conformation is specific for the interaction site: for the complex to the five-membered ring, TFE is in the cis-gauche conformation, while for the complex to the six-membered ring site, it is in the trans conformation. These results are discussed as a function of local interactions in the systems.

Oxo-titanium phthalocyanine (TiOPc) derivatives of catechin and hematoxylin (natural ortho-diol type chiral compounds) have been prepared and characterized by spectral and chromatographic techniques. It is demonstrated that the TiOPc unit is an excellent template for chiral recognition through its isolated Q-transitions. The formation of a helical dimeric complex with hematoxylin induces strong CD-activity in the Q-band region. Ab initio geometry optimizations were combined with a Kuhn-Kirkwood coupled-oscillator mechanism to obtain the absolute configuration of hematoxylin. In addition, it is shown that the described chiroptical recognition method is sensitive to slight conformational changes.

Under the assumptions that no two sp 3 carbon atoms are adjacent in the end product of bromination of a fullerene and that the residual π system is a closed shell, graph theory predicts maximum stoichiometries C 60 Br 24 , C 70 Br 26 , C 76 Br 28 , C 84 Br 32 and rules out all but 58 of the ~10 23 addition patterns conceivable for these molecules.

The paper presents a computational study of the ground and excited states of 3-methylindole. The ground-state geometry is optimized using the DFT B3LYP potential in conjunction with a 6-31+G(d) basis set. In addition the ground and first and second excited singlet states are optimized, for the first time, using the CASSCF method with an ANO−S basis set. The results are compared with experiment and with the experimental and theoretical literature data for the parent indole. The calculated excitations are in agreement with the absorption data. The comparison also shows that the 3-methylindole relaxation of the second excited-state terminates in an avoided crossing. The relaxed geometry of the second excited 3-methylindole state is therefore of mixed 1L a /L b nature. The interaction of 3-methylindole with water is also examined, revealing three stable chromophore−water complexes. The calculations are extended to the more stable chromophore−(water)2 complexes. The excitation energies of these complexes are calculated using the CASPT2 method (ANO−S type basis). Calculations using ESP-charges instead of water molecules demonstrate the usefulness of such approximation for the calculation of excitation energy shifts. Analogous results are obtained using Amber5.0 point charges.