Helical chirality control in zinc bilinone dimers

Novel freebase and zinc bilinone dimers with optically active peripheral groups. Synthesis and application to chiral nematic induction in a nematic mesophase

“…3 are shown the high-energy region of the CD spectra of Fb-1-4 and Zn-1-4 in CH 2 Cl 2 at 288 K, where the CD intensities were normalized by the concentration of the bilinone unit. In general, the helicity-enriched bilinone derivatives show alternating signs of Cotton effects in the near-IR and visible-to-near-UV regions [20,[24][25][26]. In the case of M-helicity bilinones, the first negative and second positive Cotton effects are observed, whereas the opposite spectral pattern is obtained for P-helicity.…”

“…at ambient temperature [24,25]. Dimerization via chiral spacers is also a promising way to achieve effective helicity induction of ZnBL, leading to the enrichment of the homohelicity conformer [26,27]. Recently, we applied these helicity-enriched ZnBL derivatives to induce the helicity of a liquid crystal [28].…”

18 Supramolecular coordination chemistry

“…If the substituent R is aromatic, additional p-stacking interactions also in£uence the product distribution. 22 Reaction of the chiral bis-bidentate bridging L 21 ligand with Ag results in a polymeric double helix, arising from two intertwined single-helical strands [{Ag(L 21 )} n ] n connected only by van der Waals interactions with no inter-strand p stacking. 10 In the mononuclear complex [Zn (L 19 )] the ligand has a helical twist around the metal, whose sense is dictated by the chirality of the substituent R such that diastereomeric excesses of b95% are obtained (cf.…”

Conversion of Cobalt(II) Porphyrin into a Helical Cobalt(III) Complex of Acyclic Pentapyrrole

“…[4][5][6][7][8][9][10] Biliverdin-type ligands are nonplanar tetrapyrrole derivatives and have been utilized for the syntheses of metal complexes with helical structures that are easily racemized, owing to its low steric hindrance for interconversion. [11][12][13][14][15][16] In contrast, metal complexes bearing acyclic polypyrroles constructed of more than five pyrroles are still rare because of the limited availability of synthetic routes to prepare them. [17][18][19][20][21][22] As an exceptional example, a new dicopper(II) complex bearing acyclic heptapyrrolic helices has been prepared from dicopper(II) heptaphyrin by reaction with O 2 .…”