In the title mol-ecule, C(20)H(26)O(3), a clerodane diterpenoid isolated from Dodonaea viscosa-, the trans-fused six-membered rings of the deca-line system display chair conformations. The five-membered lactone ring adopts an envelope conformation and the five-membered furan ring is essentially planar with a maximum deviation of 0.0052 (12) Å.

The imino-carbon double bond in the title Schiff base, C(26)H(24)N(4)O, has an E configuration. The 13-membered carbazolyl fused-ring (r.m.s. deviation = 0.056 Å) is nearly coplanar with five-membered pyrazole ring (r.m.s. deviation = 0.036 Å) [dihedral angle between the two systems = 10.4 (1)°]; the phenyl substituent is twisted by 51.1 (1)° with respect to the five-membered ring.

The title compound, C28H24O5, consists of a fused tricyclic system containing two five-membered rings and one six-membered ring. The five-membered rings both exhibit an envelope conformation with the O atom at the flap, whereas the six-membered ring adopts a boat conformation. The dihedral angle between the 4-methyl-phenyl rings at the 1,8-positions is 76.4 (1)°. In the crystal, mol-ecules are ...

In the title solvate, C(30)H(39)NO(5)·CH(4)O {systematic name: 21-acet-oxy-18,21-dihy-droxy-5,6,16,18-tetra-methyl-10-phenyl-6,7-ep-oxy-[11]cytochalasa-13,19-dien-1-one methanol solvate}, the organic mol-ecule exhibits the tetra-cyclic terpenoid skeleton of cytochalasin, consisting of fused five-, six-, three- and 11-membered rings. The five-membered ring adopts an envelope conformation, while ...

The title compound, C(16)H(23)Cl(2)NO, was synthesised from β-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzocyclo-heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The mol-ecule contains a seven membered ring, which is fused to a five- and a three-membered ring. The five-membered ring has a twisted conformation, whereas the seven-memb...

It is shown that the resonance Kondo tunneling through a double quantum dot ~DQD! with even occupation and singlet ground state may arise at a strong bias, which compensates the energy of singlet/triplet excitation. Using the renormalization group technique we derive scaling equations and calculate the differential conductance as a function of an auxiliary dc bias for parallel DQD described by ...

Isotenulin, C17H22O5, is a sesquiterpene lactone isolated from sneezeweed Helenium amarum. It crystallizes with two independent mol-ecules in the asymmetric unit. In each mol-ecule, two five-membered rings (cyclo-pentenone and lactone) are trans-fused to the central seven-membered ring. The five-membered rings each adopt envelope conformations. The seven-membered ring adopts a twist-chair confo...

Spectroscopic manifestations of protonation of the trimethylated pyrichrominium ion studied previously experimentally [1] are investigated using a semiempirical IN DO /S Cl method. Singlet and triplet energy levels of the free ion and several protonated species are calculated, and transition energies and oscillator strengths are compared with experimental spectra. Calculated charge densities on...

The biradicaloid character of the ground-state structures of N2P2 rings is studied by using the high-level ab initio multiconfigurational CASPT2/CASSCF method. In order to obtain accurate descriptors, we combine two criteria: 1) singlet-triplet energy gaps and 2) relative values of the occupation numbers for bonding and antibonding orbitals associated with the radical sites. The singlet-triplet...