Supramolecular organization of perfluorinated 1H-indazoles in the solid state using X-ray crystallography, SSNMR and sensitive (VCD) and non sensitive (MIR, FIR and Raman) to chirality vibrational spectroscopies

1H-Indazole derivatives exhibit a remarkable property since some of them form chiral supramolecular structures starting from achiral monomers. The present work deals with the study of three perfluorinated 1H-indazoles that resolve spontaneously as conglomerates. These conglomerates can contain either a pure enantiomer (one helix) or a mixture of both enantiomers (both helices) with an enantiomeric excess (e.e.) of one of them. The difficulty of the structural analysis of these types of compounds is thus clear. We outline a complete strategy to determine the structures and configurations (M or P helices) of the enantiomers (helices) forming the conglomerates of these perfluorinated 1H-indazoles based on X-ray crystallography, solid state NMR spectroscopy and different solid state vibrational spectroscopies that are either sensitive (VCD) or not (FarIR, IR and Raman) to chirality, together with quantum chemical calculations (DFT).
This work was carried out with financial support from the Ministerio de Economía y Competitividad (Project No. CTQ2014- 56833R and CTQ2015-63997-C2-2-P), CICE/Junta de Andalucía (P08-FQM-04096) and CICE/JA-FEDER-UJA: Plan de Fortalecimiento de las Capacidades de I+D+i/2014-15 (UJA2013/08/03) and Comunidad Autónoma de Madrid (Project FOTOCARBON, ref. S2013/MIT-2841). Computer, storage and other resources from the CTI (CSIC) are gratefully acknowledged. Authors thank the University of Jaén for continuing financial support, for bridge projects (UJA2015/08/07) and (UJA2016/08/15) and for Accion 2: Financiacion de Incentivos a la Excelencia de I+D+i de la UJA 2014-15 in 2014 and 2015 calls and to its CICT for instrumental facilities. Authors also thank the FQM-323 research group, especially Rafael Lopez Blanco, David Moreno Gonzalez and Jose Robles Molina, for their help in the laboratory. M. M. Q. M. thanks the University of Jaen for a pre-doctoral fellowship. The CNRS is acknowledged for support