[Synthesis and spectral characterization of novel chiral macrocyclic dioxopolyamines].

Two novel chiral macrocyclic dioxopolyamines, which can be used as NMR chiral solvating agents (CSAs) for chiral carboxylic acids, were synthesized from L-proline through esterification, bridging and ring-closing reaction. With the aid of orthogonal experiments the optimum reaction conditions were determined: for (8S, 18S)-1, 4, 10, 13, 16-pentaaza-tricyclo [16.3. 0.04(4,8)] heneicosane-9,17-dione(2-a), reaction temperature 50 degrees C, reaction time 10 d, in nitrogen atmosphere, absolute MeOH, yield 34.9%, and m. p. 278-280 degrees C; for 13-phenyl-(8S, 18S)-1, 4, 10, 13,16-pentaaza-tricyclo [16.3. 0.0(4,8)] heneicosane-9,17-dione (2-b), reaction temperature at reflux, reaction time 20 d, in nitrogen atmosphere, absolute MeOH, yield 2.6%, and m. p. 243-245 degrees C. Their molecular structures were characterized by elemental analysis (EA), mass spectroscopy (MS), infrared spectroscopy (IR), and 1D and 2D nuclear magnetic resonance spectrometry (NMR). The main infrared absorption peaks and nuclear magnetic spectral bands of the compounds were assigned. The spectroscopic analytical result provides useful information for further study of the mechanism of host-guest interaction and for preparing new and effective CSAs.

DFT/TDDFT studies of the geometry, electronic structure and spectra of (12S)-1,4,7,10-tetraazadicyclo[10,3,0]-pentadecane-3,11-dione and its derivatives.

The FT-Raman and UV-visible spectra of (12S)-1,4,7,10-tetraazadicyclo[10,3,0]-pentadecane-3,11-dione and its derivatives were obtained and discussed. The harmonic vibrational wavenumbers and the corresponding Raman scattering activities in their electronic ground-states were calculated at the DFT-B3LYP/6-31G(d) level of theory. The calculated wavenumbers were then scaled and compared with the experimental values. The 7-(2,4-dinitrophenyl)-(12S)-1,4,7,10-tetrazadicyclo[10,3,0]-pentadecane-3,11-dione derivative has mainly an amide (II) character, while the others have an amide (I) character. Moreover, the different substituents do not cause a significant shift of the vibrational mode of the macrocyclic plane. The electronic vertical excitation energy and the oscillator strength were determined with the help of TDDFT calculations and by employing pure (BLYP) and hybrid (B3LYP, B3P86, and mPW1PW91) functionals together with the 6-31G(d) basis set. The BLYP functional reproduces the UV-vis absorption spectra better than the B3LYP, B3P86, or mPW1PW91 hybrid functionals. A dimolecular model, which considers hydrogen-bonded structures, proved that strong inter- and intramolecular hydrogen bonds are present in these compounds. Due to the transannular effect, the UV-vis absorption spectrum of macrocyclic dioxotetraamines is completely different from that of single amide compounds.