Synthesis and crystal structures of some bis(3‐methyl‐1 H ‐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‐1 H ‐indol‐2‐yl)methyl]‐6‐methylphenol, (II a ), 2‐[bis(3‐methyl‐1 H ‐indol‐2‐yl)methyl]‐4,6‐dichlorophenol, (II b ), 2‐[bis(3‐methyl‐1 H ‐indol‐2‐yl)methyl]‐4‐nitrophenol, (II c ), and 2‐[bis(3‐methyl‐1 H ‐indol‐2‐yl)methyl]‐4,6‐di‐ tert ‐butylphenol, (II d ). BIMs (II a ) and (II b ) were characterized crystallographically as the dimethyl sulfoxide (DMSO) disolvates, i.e. C 26 H 24 N 2 O·2C 2 H 6 OS and C 25 H 20 Cl 2 N 2 O·2C 2 H 6 OS, respectively. Both form strikingly similar one‐dimensional hydrogen‐bonding chain motifs with the DMSO solvent molecules. BIM (II a ) packs into double layers of chains whose orientations alternate every double layer, while (II b ) forms more simply packed chains along the a axis. BIM (II a ) has a remarkably long c axis.