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Chiral and Extended π‐Conjugated Bis(2‐pyridyl)phospholes as Assembling N,P,N Pincers for Coordination‐Driven Synthesis of Supramolecular [2,2]Paracyclophane Analogues
Author(s) -
Aranda Perez Ana Isabel,
Biet Thomas,
Graule Sébastien,
Agou Tomohiro,
Lescop Christophe,
Branda Neil R.,
Crassous Jeanne,
Réau Régis
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201001862
Subject(s) - phosphole , helicene , supramolecular chemistry , chemistry , circular dichroism , stereochemistry , conjugated system , stacking , crystallography , supramolecular chirality , crystal structure , molecule , polymer , organic chemistry
Chiral, π‐conjugated 3,4‐butano‐1‐phenyl‐2,5‐bis(2‐pyridyl)phosphole derivatives 1 a 2,2′ and 1 a 3 with chiral trans ‐1,2‐diol moieties and fused pinene derivatives, respectively, were prepared from the corresponding chiral diynes by using the Fagan–Nugent method. Their UV/Vis absorption and chiroptical properties (optical rotation and circular dichroism) were studied. Their behavior as N,P,N chelates towards coordination of Cu I and formation of chiral supramolecular assemblies with π‐conjugated ditopic dicyano ligands was investigated. Chiral C 2 ‐symmetric rectangles that are [2,2]paracyclophane analogues were obtained, as demonstrated by X‐ray crystallography. During the course of this study, the first stable water‐soluble phosphole derivative ( 1 a 2 ⋅ 2 HCl) was prepared. Furthermore, achiral 3,4‐butano‐1‐phenyl‐2,5‐bis(aza[4]helicene)phosphole 1 a 4 was synthesized and displays extended π conjugation. A supramolecular rectangle was obtained by coordination to Cu I and assembly with a dicyano stilbene. This coordination‐driven supramolecular assembly contains a total of four aza[4]helicene moieties and displays two types of π–π stacking interactions in the solid state, that is, between two helicene moieties and between one helicene and a bridging dicyano ligand. All the supramolecular arrangements are discussed by comparing them with previous work on the parent 3,4‐butano‐1‐phenyl‐2,5‐bis(2‐pyridyl)phosphole.