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Temperature-Dependent Order-Disorder Phenomena in Crystal Structures Containing Dimers of Carboxylic Acids: The Crystal and Molecular Structure of 3,5-Dinitrobenzoic Acid at Room and Liquid Nitrogen Temperature and Statistics of the Geometries of Hydrogen-Bonded Carboxyl Groups

Jan A. Ranters ; Bijvoet Center for Biomolecular Research, Laboratory for Crystal and Structural Chemistry, Rijksuniversiteit Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands
Jan Kroon ; Bijvoet Center for Biomolecular Research, Laboratory for Crystal and Structural Chemistry, Rijksuniversiteit Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands
Rob Hooft ; Bijvoet Center for Biomolecular Research, Laboratory for Crystal and Structural Chemistry, Rijksuniversiteit Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands
Arie Schouten ; Bijvoet Center for Biomolecular Research, Laboratory for Crystal and Structural Chemistry, Rijksuniversiteit Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands
Jack A. M. van Schijndel ; Bijvoet Center for Biomolecular Research, Laboratory for Crystal and Structural Chemistry, Rijksuniversiteit Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands
Jeroen Brandsen ; Bijvoet Center for Biomolecular Research, Laboratory for Crystal and Structural Chemistry, Rijksuniversiteit Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands

Sažetak

3,5-dinitrobenzoic acid crystallizes in space group P2i/c with four molecules in the unit cell. At room temperature (RT), the cell dimensions are a = 10.0237(4), b = 8.8728(3), c = 9.5090(4) A, = 95.68(1)° and V = 841.56(6) A3 and at liquid nitrogen temperature (LNT) a = 9.761(2), b = 8.9192(4), c = 9.444(2) A, /S = 97.55(1)° and V = 815.1(2) A3. At both temperatures, the crystals contain the common centrosymmetric carboxylic acid dimers. At RT the carboxyl groups are partially disordered, as indicated by the C=0 [1.249(3)] and C-0 [1.276(2)A] distances, C-C = 0 [118.4(2)1 and C-C-0 [116.4(2)°] angles and by the presence of disordered H atoms with occupancy factors of 0.63 and 0.37 in the O—O hydrogen bond.
At LNT, the acidic proton is ordered with a distance of 0.96(2) A from the donor hydroxyl O atom and the carboxyl group geometry is normal, with C=0 1.232(2) and C-0 1.305(2) A and C-C = 0 120.6(1) and C-C-O 114.4(1)°.
The differences Ar distances and A of the C-C-O angles are 0.027 A and 2.0°, respectively, at RT and 0.073 A and 6.2°, respectively, at LNT, which indicates an increase of ordering with decreasing temperature. The mechanism of disordering most probably invokes a temperature-dependent concerted two-proton jump across the dimer hydrogen bonds. To test the relationship between Ar and A, a statistical analysis is performed on the C-0 distances and C-C-O angles of RT and LNT dimer and non-dimer structures retrieved from the Cambridge Structural Database. The analysis indicates that disorder in RT dimers is more frequent than in RT non-dimers and also that ordering is pronounced in both LT dimer and non-dimer structures.

Ključne riječi

Hrčak ID:

137308

URI

https://hrcak.srce.hr/137308

Datum izdavanja:

31.12.1991.

Posjeta: 1.023 *