RESUMO
Two conformationally different [26]rubyrin(1.1.0.1.1.0) macrocycles with varying heteroatoms (S/O) and their bis-BODIPYs are reported. The solid-state structure confirms O2N4 with fairly planar pyrrole-inverted conformation, whereas a thiophene-inverted structure for S2N4 is observed. Such conformational differences can also be clearly realized from their spectral and optical features. Upon BF2 complexation, both rubyrins led to their respective bis-BODIPYs where S2N4-BOD displayed a perfectly planar conformation as evident from its X-ray structure.
RESUMO
1,4-Phenylene-linked cyclotrimer (3T) and cyclotetramer (4T) have been synthesized via Lewis acid-catalyzed self-condensation of appropriate precursors. Structural and Density Functional Theory (DFT) studies reveal the disruption of annulenic conjugation in both 3T and 4T by linking phenylene rings prevented them from global antiaromaticity. The single crystal X-ray structure of 4T reveals all the nitrogens are pointing toward the macrocyclic core with near-planar and square-shaped geometry, thus in sharp contrast to the ring-strained conformation of 3T.
RESUMO
Acid-catalyzed condensation of a newly prepared di-m-benzipentapyrrane with appropriate mono- and diheterocyclic dialcohols selectively produced stable di-m-benzihexaphyrins and di-m-benziheptaphyrins with only two meso-carbon bridges. Single-crystal X-ray diffraction analyses reveal planar conformation with slight distortion of bridged phenylene rings. Despite the presence of m-phenylene units interrupting the global delocalization, the presence of bithiophene units in di-m-benziheptaphyrins 3a-b exhibits altered optical features covering the entire visible region (ca. 250-720 nm), exhibiting a black dye property as a "metal-free" porphyrinoid.
