Intense Ground‐State Charge‐Transfer Interactions in Low‐Bandgap, Panchromatic Phthalocyanine–Tetracyanobuta‐1, 3‐diene Conjugates. Issue 18 (24th March 2016)

• Record Type: Journal Article
• Authors: Sekita, Michael; Ballesteros, Beatriz; Diederich, François; Guldi, Dirk M.; Bottari, Giovanni; Torres, Tomás
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 18(2016)
• Page Start: 5560
• Page End: 5564
• Publication Date: 2016-03-24
• Subjects: charge transfer -- donor–acceptor systems -- photophysics -- phthalocyanines -- tetracyanobutadienes; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201601258
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: A cycloaddition–retroelectrocyclization reaction between tetracyanoethylene and two zinc phthalocyanines (Zn II Pcs) bearing one or four anilino‐substituted alkynes has been used to install a strong, electron‐accepting tetracyanobuta‐1, 3‐diene (TCBD) between the electron‐rich Zn II Pc and aniline moieties. A combination of photophysical, electrochemical, and spectroelectrochemical investigations with the Zn II Pc‐TCBD‐aniline conjugates, which present panchromatic absorptions in the visible region extending all the way to the near infrared, show that the formal replacement of the triple bond by TCBD has a dramatic effect on their ground‐ and excited‐state features. In particular, the formation of extremely intense, ground‐state charge‐transfer interactions between Zn II Pc and the electron‐accepting TCBD were observed, something unprecedented not only in Pc chemistry but also in TCBD‐based porphyrinoid systems. Abstract : Two Pc‐TCBD‐aniline conjugates (phthalocyanine–tetracyanobutadiene–aniline conjugates) have been prepared. The intense ground‐state charge transfer between Pc and TCBD, the panchromatic absorption of these derivatives in the visible and near‐infrared regions, the low HOMO–LUMO gaps, and the photo‐induced electron‐transfer behavior upon photoexcitation render these systems promising materials for applications in molecular photovoltaics.