Efficient synthesis of a new L-shaped dimer of naphthalene, and its analogs.

Efficient syntheses of 14H-dinaphtho[1,8-bc:1',8'-fg]oxocin-14-one (2), 14H-dinaphtho[1,8-bc:1',2'-f]oxepin-14-one (3), and 2,2'(2H,2'H)-spirobi[naphtho[1,8-bc]furan] (9) are described. The putative structure of 2 has been reported previously, but the synthetic route was not reproducible. 7H-Dibenzo[c,h]xanthen-7-one (4), a known compound, was obtained by a different method. Possible reaction mechanism are proposed.

Atomic interactions in ethylenebis(1-indenyl)zirconium dichloride as derived by experimental electron density analysis.

A topological analysis of the experimental electron density in racemic ethylenebis(1-indenyl)zirconium dichloride, C20H16Cl2Zr, measured at 100 (1) K, has been performed. The atomic charges calculated by the numerical integration of the electron density over the zero-flux atomic basins demonstrate the charge transfer of 2.25 e from the Zr atom to the two indenyl ligands (0.19 e to each) and two Cl atoms (0.93 e to each). All the atomic interactions were quantitatively characterized in terms of the electron density and the electronic energy-density features at the bond critical points. The Zr-C2 bond paths significantly curved towards the C1-C2 bond were found; no other bond paths connecting the Zr atom and indenyl ligand were located. At the same time, the pi-electrons of the C1-C2 bond are significantly involved in the metal-ligand interaction. The electron density features indicate that the indenyl coordination can be approximately described as eta1 with slippage towards eta2. The ;ligand-opposed' charge concentrations around the Zr atom were revealed using the Laplacian of the electron density and the one-particle potential; they were linked to the orbital representations. Bonds in the indenyl ligand were characterized using the Cioslowski-Mixon bond-order indices calculated directly from the experimental electron density.