A systematic structural study of halogen bonding versus hydrogen bonding within competitive supramolecular systems

An extensive structural study on hydrogen and halogen bonding in co-crystals has helped clarify the competition and balance between them in a practical supramolecular synthesis.


S2. Melting Point Information
Melting point data was recorded on a Gallenkamp melting point apparatus, and results were noncorrected.

Figure S1
Melting point data shown graphically. It is noticeable that the melting point of most cocrystals falls between its donor and acceptor's melting points, but the melting point of the phenolic-ligand co-crystal are significantly higher than their components.

Figure S2
Melting point data for phenolic-donor ligand co-crystals.  Supporting information, sup-5

S3. Crystallographic Information
Samples were analyzed with either a Bruker Kappa APEX II system using CuK radiation (BrF 4 -OX--14, BrF 4 -OH--11) or a Bruker APEX II system using MoK radiation (all others). Data collection was carried out using APEX2 software. i Initial cell constants were found by small widely separated "matrix" runs. Data collection strategies were determined using COSMO. ii Scan speed and scan widths were chosen based on scattering power and peak rocking curves. All datasets were collected at -153°C using an Oxford Croystream low-temperature device.
Unit cell constants and orientation matrix were improved by least-squares refinement of reflections thresholded from the entire dataset. Integration was performed with SAINT, iii using this improved unit cell as a starting point. Precise unit cell constants were calculated in SAINT from the final merged dataset. Lorenz and polarization corrections were applied. Multi-scan absorption corrections were performed with TWINABS iv for the two non-merohedral twins in this set (I-COOH--11and Br-COOH--12), and SADABS v for the remainder.
Data were reduced with SHELXTL. vi The structures were solved in all cases by direct methods without incident. Except as noted below, hydrogen atoms were located in idealized positions and were treated with a riding model. All non-hydrogen atoms were assigned anisotropic thermal parameters. Refinements continued to convergence, using the recommended weighting schemes.

IF 4 -OX--3
The asymmetric unit contains two oxime / amine pairs, which were grouped into two RESIdues.

Br-OX--5
The asymmetric unit contains a single oxime / amine pair. The pyrrolidine moiety was disordered at the ethylene bridge, with the population of the two PARTs being set by a free variable.
Thermal parameters of the disordered fragment were pairwise constrained with EADP commands.
Coordinates of the oxime hydrogen H17 were allowed to refine.

Br-COOH--5
The asymmetric unit contains two carboxylic acids and a single amine. The pyrrolidine moiety was disordered at the ethylene bridge, with the population of the two PARTs being set by a free variable. DFIX commands were used to idealize the geometry of the disordered ethylene bridge, and thermal parameters of the disordered fragment were pairwise constrained with EADP commands. Proton transfer from a carboxylic acid to the amine was clearly observed. Coordinates for the remaining carboxylic acid proton and the ammonium proton were allowed to refine.

Br-COOH--3
The asymmetric unit contains a single carboxylic acid / amine pair. Proton transfer from carboxylic acid to amine was clearly observed. Coordinates of the ammonium proton were allowed to refine.

IF 4 -COOH--4
The asymmetric unit contains a single carboxylic acid and two amines. The iodo acid was disordered in a head-to-tail fashion, with the population of the two PARTs being set by a free variable. A