Synthesis, characterization and structural computational investigation of novel Zn(II) phthalocyanines containing peripheral anthracene moieties

New zinc(II) phthalocyanines (ZnPc-I and ZnPc-II) containing four peripheral anthracene pendant groups were synthesized by cyclotetramerization of (E)-4-(3-(4-((anthracen-9-yl-methylene)amino)phenoxy)propoxy)phthalonitrile and 4-(3-(4-((anthracen-9-ylmethyl)amino)phenoxy)propoxy)phthalonitrile. All compounds were characterized using a combination of analytical and spectroscopic techniques such 1H, [Formula: see text]C NMR, FT-IR, UV-vis and MS spectral data. The molecular geometry and gauge including atomic orbital (GIAO) 1H and [Formula: see text]C chemical shift values of the compounds in the ground state have also been calculated using B3LYP with the 6–31G([Formula: see text] basis set. The chemical shift of the optimized molecular structure is compared with the experimental chemical shift values.

A permutation approach to the assignment of the configuration to diastereomeric tetrads by comparison of experimental and ab initio calculated differences in NMR data

Scoring permutations of experimental chemical shift deviations and DFT/GIAO calculated deviations of isotropic shieldings for sets of four diastereomers can help to assign their relative configurations. This method was exercised on a set of diastereomeric Cinchona alkaloid derivatives, where 13C NMR data always identified the proper configuration. The presented approach is also an attempt to quantify the assignment by exclusion.

Modeling Substituent-Dependence of the Twist and Shielding in a Series of 4-Substituted N-(4-Nitrobenzylidene)anilines

A series of 15 4-substituted N-(4-nitrobenzylidene)anilines was synthesized and studied by 1H NMR spectroscopy. Their ab initio calculated geometries and the shielding as expressed by aromatic ring currents were used in correlation analysis. The geometries were fully optimized using density functional theory B3LYP/6-311G** approaches. For the determination of the ring current contribution to the shielding of azomethine hydrogens Hα was used direct ab initio calculation of the chemical shielding in a model system. Experimental chemical shift values free of these contributions were successfully correlated with increments ap of chemical shift for monosubstituted benzenes. In the same manner, the contribution of the anisotropy of C=N double bond to Hm hydrogen were calculated and values of the Hm chemical shift free of this contribution were successfully correlated with increments of chemical shift am.

Spectroscopic Studies with N-Chloroarylsulphonamides: IR and 1H, 13C and 23Na Nmr Spectra of Sodium Salts of N-Chloro-Mono- and Di-Substituted-Benzenesulphonamides, 4-X-C6H4SO2NANCl (X = H; CH3; C2H5; F; Cl; Br; I or NO2) and i-X, j-YC6H3SO2NANCl (i-X, j-Y = 2,3-(CH3)2; 2,4-(CH3)2; 2,5-(CH3)2; 2-CH3, 4-Cl; 2-CH3, 5-Cl; 3-CH3, 4-Cl; 2,4-Cl2 or 3,4-Cl2)

In an effort to introduce N-chloroarylsulphonamides of different oxydising strengths, sixteen sodium salts of N-chloro-mono- and di-substituted benzenesulphonamides of the configuration, 4- X-C6H4SO2NaNCl (where X = H; CH3; C2H5; F; Cl; Br; I or NO2) and i-X, j-YC6H3SO2NaNCl (where i-X, j-Y = 2,3-(CH3)2; 2,4-(CH3)2; 2,5-(CH3)2; 2-CH3,4-Cl; 2-CH3,5-Cl; 3-CH3,4-Cl; 2,4- Cl2 or 3,4-Cl2) are prepared, characterized through their infrared spectra in the solid state and NMR spectra in solution. The υN-Cl frequencies vary in the range 950 - 927 cm−1. Effects of substitution in the benzene ring in terms of electron donating and electron withdrawing groups have been considered, and conclusions drawn. The chemical shifts of aromatic protons and carbon-13 in all the N-chloroarylsulphonamides have been calculated by adding substituent contributions to the shift of benzene. Considering the approximation employed the agreement between the calculated and experimental chemical shift values for different protons or carbon-13 is quite good. Effects of phenyl ring substitution on chemical shift values of both 1H and 13C are also graphically represented in terms of line diagrams.

Infrared and NMR Spectra of Arylsulphonamides, 4-X-C6H4SO2NH2 and i-X, j-YC6H3SO2NH2 (X=H; CH3; C2H5; F; Cl; Br; I or NO2 and i-X, j-Y=2,3-(CH3)2; 2,4-(CH3)2; 2,5- (CH3)2; 2-CH3, 4-Cl; 2-CH3, 5-Cl; 3-CH3, 4-Cl; 2,4-Cl2 or 3,4-Cl2)

Several arylsulphonamides of the configuration, 4-X-C6H4SO2NH2 (where X= H; CH3; C2H5;F; Cl; Br; I or NO2) and i-X, j-YC6H3SO2NH2 (where i-X, j-Y=2,3-(CH3)2; 2,4-(CH3)2; 2,5-(CH3)2;2-CH3,4-Cl; 2-CH3,5-Cl; 3-CH3,4-Cl; 2,4-Cl2 or 3,4-Cl2) were prepared, and their infrared spectra were measured in the solid state. The NMR spectra were recorded in solution. N-H asymmetric and symmetric stretching vibrations absorb in the ranges, 3390 - 3323 cm-1 and 3279 - 3229 cm-1,respectively. Asymmetric and symmetric SO2 stretching vibrations appear as strong absorption lines in the ranges, 1344 - 1317 cm-1 and 1187 - 1147 cm-1, respectively. Sulphonamides exhibit S-N stretching vibrational absorptions in the range, 924 - 906 cm-1. The effect of substitution inthe phenyl ring in terms of electron withdrawing and electron donating groups could not be generalised, as the effect is non-systematic. The chemical shift is highly dependent on the electron density around the nucleus or associated with the atom to which it is bonded. Hence empiricalcorrelations relating the chemical shifts to the structures have been discussed. The chemical shifts of aromatic protons and carbons in all the arylsulphonamides have been calculated by adding substituent contributions to the shift of benzene, the principle of substituent addition. Considering the approximation made, the agreement between the calculated and experimental chemical shift values is reasonably good. Generally, electron-withdrawing groups shows high chemicalshifts compared to electron-donating groups.

Experimental chemical shift correlation maps from heteronuclear two-dimensional nuclear magnetic resonance spectroscopy. II: Carbon-13 and proton chemical shifts of a-D-glucopyranose oligomers

Double Fourier transform ("2D") nmr methods allow the simultaneous measurement of proton and carbon-13 chemical shifts for each directly bonded carbon–proton pair in a molecule. As well as greatly increasing the number of different resonances that may be distinguished in the spectra of complex systems, the measurement of correlated proton and carbon-13 shifts allows the otherwise inaccessible proton shifts to be determined, and facilitates the assignment of conventional proton and carbon-13 spectra. Results are presented for glucose, maltose, maltotriose, α-cyclodextrin, β-cyclodextrin, and dextran T-10; reassignments are proposed for the carbon-13 spectra of maltose and maltotriose.