High-resolution structure and conformational dynamics of rigid, cofacially aligned porphyrin-bridge-quinone systems as determined by NMR spectroscopy and ab initio simulated annealing calculations.

The high-resolution solution structure and dynamics of a cofacially aligned porphyrin--phenylene--quinone compound have been determined using (1)H NMR spectroscopy and simulated annealing calculations. Members of this class of pi-stacked assemblies feature a 1,8-naphthyl pillaring motif that enforces sub van der Waals interplanar separations between juxtaposed porphyryl, aromatic bridge, and quinonyl components of the donor--spacer--acceptor compound; this structural motif gives rise to a comprehensive set of structurally significant NOE signatures that can be used as constraints in quantitative structural calculations. Examination of such data using ab initio simulated annealing analytical methods shows that 5-[8'-(4' '-[8' "-(2' " ',5' "-benzoquinonyl)-1' "-naphthyl]-1' '-phenyl)-1'-naphthyl]-10,20-diphenylporphyrin displays an unusual degree of conformational homogeneity in the condensed phase, and represents a rare example where such an analysis determines unequivocally a single unique structure in solution.

Highly selective synthesis of heterosubstituted aromatic sulfamides.

The sulfamide functional group is increasingly relevant in both medicinal and supramolecular chemistry, yet few selective synthetic steps are available for its elaboration. We report here a mild, general, and efficient method for the selective differentiation of N-atom substituents of aromatic sulfamides. [reaction: see text]