X-ray Diffraction, FT-IR, and <sup>13</sup>C CP/MAS NMR Structural Studies of Solvated and Desolvated C-Methylcalix[4]resorcinarene
Rafal Kuzmicz
Violetta Kowalska
Sławomir Domagała
Marcin Stachowicz
Krzysztof Woźniak
Waclaw Kolodziejski
10.1021/jp1015565.s001
https://acs.figshare.com/articles/journal_contribution/X_ray_Diffraction_FT_IR_and_sup_13_sup_C_CP_MAS_NMR_Structural_Studies_of_Solvated_and_Desolvated_C_Methylcalix_4_resorcinarene/2741374
Solid C-methylcalix[4]resorcinarene solvated by acetonitrile and water (CAL-Me) and then modified by slow solvent evaporation (CAL-Me*) was studied using single-crystal and powder X-ray diffraction, FT-IR, and <sup>13</sup>C CP/MAS NMR. The CAL-Me solvate crystallizes in the monoclinic <i>P</i>2<sub>1</sub>/<i>n</i> space group with three CH<sub>3</sub>CN and two H<sub>2</sub>O molecules in the asymmetric part of the unit cell. The CAL-Me molecules adopt a typical crown conformation with all of the hydroxyl groups of the aryl rings oriented up and all of the methyl groups disposed down (the <i>rccc</i> isomeric form). The crystalline network is formed by resorcinarene, CH<sub>3</sub>CN, and H<sub>2</sub>O molecules and assembled by intermolecular hydrogen bonds and weak C−H···A or C−H···π interactions. The desolvated CAL-Me* loses its crystalline character and becomes partly amorphous. It is devoid of CH<sub>3</sub>CN and deficient in water. However, the resorcinarene molecules still remain in the crown conformation supported by intramolecular hydrogen bonds, while intermolecular hydrogen bonds are considerably disintegrated. The work directs general attention to the problem of stability and polymorphism of resorcinarene solvates. It shows that the joint use of diffractometric and spectroscopic methods is advantageous in the structural studies of complex crystalline macromolecular systems. On the other hand, the solid-state IR and NMR spectroscopic analyses applied in tandem have been found highly beneficial to elucidate the disordered structure of poorly crystalline, desolvated resorcinarene.
2010-08-19 00:00:00
crown conformation
H 2O molecules
resorcinarene
intramolecular hydrogen bonds
hydrogen bonds
desolvated
CP
NMR spectroscopic analyses
solvate
CH 3CN
rccc isomeric form
IR