Highly Ordered Monolayer Films of [22.3.3]Propellanes

Despite the unusual geometry of [22.3.3]propellanes with their two perpendicular molecular planes, we have succeeded in forming well-ordered, compressed monolayer films of these molecules at an air-water interface. We present amodel for the packing of these films. This model is based on crystallographic data from related [m.3.3]propellane dione and diol molecules (m = 4,10,12) and on pressure-area isotherm studies of the [22.3.3]propelIane dione, ketols, and diols. Propellane dione ([22.3.3] and [12.3.3]) monolayers over an aqueous subphase saturated with NaCl corroborate the suggested orientation of the propellanes within this packing arrangement.