EFFECT OF PROTONATION ON THE STRUCTURE OF 1,3,6,8-TETRAAZATRICYCLO[4.4.1.13,8]DODECANE (TATD) ADAMANZANE: CRYSTAL STRUCTURE AND DFT ANALYSIS OF 3,6,8-TRIAZA-1-AZONIATRICYCLO[4.4.1.13,8]DODECANE 4-NITROPHENOLATE 4-NITROPHENOL
A. Rivera1, J.M. Uribe1, J. Rios-Motta1, M. Bolte2
1Universidad Nacional de Colombia, Bogota, Colombia
2Institut fur Anorganische Chemie, Frankfurt Main, Germany
Keywords: 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane, adamanzane, crystal structure, proton transfer, hydrogen bond, aminal cage, DFT calculations
Abstract
The reaction between 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD) and 4-nitrophenol (4-NP) under solvent-free conditions results in the formation of a proton transfer (PT) complex, (TATD)+(4-NP)-x4-NP, (3). This is the first crystal structure of a PT complex of TATD, whose structure is stabilized by N+-H⋯O and O-⋯H-O hydrogen bonds. The characterization was performed using FTIR and 1H NMR spectroscopy, and X-ray crystallography. From X-ray diffraction data collected at 173(2) K, it is concluded that it crystallizes in the monoclinic system (C2/c space group) containing one 4-nitrophenolate anion and one neutral 4-nitrophenol molecule. The stoichiometry of the proton transfer species in DMSO- d 6 solution is in agreement with the structural data. A combined theoretical and experimental correlation of the structural parameters of free and protonated TATD are in good agreement. The discrepancies in the C-C bond distances between the experimental and calculated results can be attributed to hyper-conjugative interactions and electron delocalization.
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