Synthesis and crystal structures of some bis(3-methyl-1H-indol-2-yl)(salicyl)methanes.

Four 2,2'-bisindolylmethanes (BIMs), a useful class of polyindolyl species joined to a central carbon, were synthesized using salicylaldehyde derivatives and simple acid catalysis; these are 2-[bis(3-methyl-1H-indol-2-yl)methyl]-6-methylphenol, (IIa), 2-[bis(3-methyl-1H-indol-2-yl)methyl]-4,6-dichlorophenol, (IIb), 2-[bis(3-methyl-1H-indol-2-yl)methyl]-4-nitrophenol, (IIc), and 2-[bis(3-methyl-1H-indol-2-yl)methyl]-4,6-di-tert-butylphenol, (IId). BIMs (IIa) and (IIb) were characterized crystallographically as the dimethyl sulfoxide (DMSO) disolvates, i.e. C26H24N2O·2C2H6OS and C25H20Cl2N2O·2C2H6OS, respectively. Both form strikingly similar one-dimensional hydrogen-bonding chain motifs with the DMSO solvent molecules. BIM (IIa) packs into double layers of chains whose orientations alternate every double layer, while (IIb) forms more simply packed chains along the a axis. BIM (IIa) has a remarkably long c axis.

{2-[Bis(3-methyl-1H-indol-2-yl)meth-yl]phenolato-κO}dimeth-yl(tetra-hydro-furan-κO)aluminium(III).

The title compound, [Al(CH(3))(2)(C(25)H(21)N(2)O)(C(4)H(8)O)], was isolated as a minor component from a reaction mixture of the parent indolyl ligand and trimethyl-aluminum in tetra-hydro-furan. The ligands adopt a distorted tetra-hedral geometry around aluminium. Obvious hydrogen-bonding interactions are not present.