ESCA, SOLID-STATE NMR, AND X-RAY-DIFFRACTION STUDIES OF PERISUBSTITUTED NAPHTHALENE DERIVATIVES

We correlate ESCA, NMR, and X-ray diffraction measurements for 1,8-din itro-2,7-dimethoxynaphthalene (DNMN), 1,8-diaminonaphthalene (DAN), 1, 8-bis(4-toluenesulfonamido)naphthalene (PSAN), 1,8-bis(dimethylamino)- 4-nitronaphthalene (NDMAN); 4-picryl-1,8-bis(dimethylamino)naphthalene (PDMAN), and complexes of 1,8-bis(dimethylamino)naphthalene (DMAN) wi th HBF4, 1,2-dichloromaleic acid, and HNCS. The strong ionic [N-H ... N](+) hydrogen bonds influence the binding energies of the core electr ons of the donor and acceptor atoms. The substituent effect of the NO2 groups in DNMN increases the ipso angle at C(1) and C(8) and shortens the C(1)-C(2) bonds. In PDMAN, the electron-releasing substituent eff ect of the -NMe(2) groups results in the shortening of the C-N bonds. The geometry of the N-H ... N bond in PSAN affects the C-N bond length s and ipso angles. We assign the H-1 and C-13 NMR resonances in all co mpounds, the latter by examining the dipolar-dephased and short-contac t-time spectra. There are well-defined trends in the chemical shifts o f the nuclei at the different sites, and we rationalize their dependen ce on the density of valence electrons. In DMANH(+)BF(4)(-), DMANH(+)C lMH(-) and DMANH(+)NCS(-) the N(1s) ESCA peaks from the donor and acce ptor atoms are shifted toward higher binding energies. We propose the difference between the binding energies of the donor and the acceptor as a measure of the strength and asymmetry of strong hydrogen bonds.