Three hydrogen atoms participate in the unusual hydrogen bond in complex 1, which is obtained when the rhenium compound is cocrystallized with indole from benzene. The structure of 1 was elucidated by means of neutron diffraction (HN …︁ HM distances of 1.75 and 2.25 Å). The energy of the hydrogen bond was determined by IR spectroscopy (ΔH° = 4.3 ± 0.5 kcal mol−1). All these values were also reproduced by theoretical calculations. Indole may be a useful additive for crystal growing in general.

A kinetic model is developed for the chemical vapor deposition of poly(para-xylylene), or parylene, thin polymer films. The growth process is modeled as a multistep process that includes physisorption of monomer on the surface and subsequent chemisorption. The chemisorption step is equivalent to a propagation reaction between the monomer and a radical chain end, and each chemisorption produces a new chemisorption site. The sticking coefficient of the monomer as a function of substrate temperature is extracted from the measured data using the model and is determined to be 2.0 × 10-5 at 60 °C, increasing to 1.4 × 10-3 at −60 °C. The heat of physisorption for the monomer is also extracted from the experiment, and the value found (75 kJ/mol) is reasonable when compared to those of other similar molecules. The model fits experimental kinetic data well for a large range of pressures and temperatures, and it should be appropriate for use with all parylene-family polymers.

The growth front roughness of linear poly( p-xylylene) films grown by vapor deposition polymerization has been investigated using atomic force microscopy. The interface width w increases as a power law of film thickness d, w approximately d(beta), with beta = 0. 25+/-0.03, and the lateral correlation length xi grows as xi approximately d(1/z), with 1/z = 0.31+/-0.02. This novel scaling behavior is interpreted as the result of monomer bulk diffusion, and belongs to a new universality class that has not been discussed previously.

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