Donor–acceptor perylenediimide–ferrocene conjugates: synthesis, photophysical, and electrochemical properties Bhausaheb Dhokale, Prabhat Gautam, Rajneesh Misra ⇑ Department of Chemistry, Indian Institute of Technology Indore, Indore 452 017, India article info Article history: Received 25 January 2012 Revised 22 February 2012 Accepted 25 February 2012 Available online 5 March 2012 Keywords: Perylenediimide Ferrocene Donor–acceptor Electrochemical Photophysical abstract Donor–acceptor, perylenediimide–ferrocene conjugates have been synthesized by Suzuki, and Sonogashira coupling reactions. The photophysical and electrochemical properties of these conjugates are discussed. It has been shown that fluorescence as well as the electron affinity of the perylenediimide can be tuned by attaching the appropriate ferrocenyl derivatives. Ó 2012 Elsevier Ltd. All rights reserved. In recent years significant progress has been made in the design and synthesis of multi-photon absorbing materials with large cross sections. 1,2 These investigations established the main molecular scaffolds to be considered, D-p-A, D-p-D, D–A–D, and A–D–A; where D, and A are electron donors and acceptors, respectively, and p is a conjugated bridge. 3 Perylene dyes continue to emerge as archetypal component in a vast variety of photo-functional materials due to their unique thermal stability, chemical persis- tency, light harvesting, and redox properties. 4 Among the perylene dyes, the perylenediimide (PDI) seems to be the best fit for light based applications, because of its excellent photophysical properties. 5 The PDI dyes have strong absorption, with high molar absorp- tion coefficient, and long fluorescence life time. PDIs with their low reduction potential are convenient electron acceptors. 6 The photophysical properties of PDI can be tuned by substitution at bay position as well as, at the N atom of the carboxydiimide (peri-position). 7,8 However substitution at former position, per- turbs the electronic properties more effectively than at latter position. 9 Therefore substituting the donor groups, at the bay position of perylenediimide will result in donor–acceptor system. There are several reports, where the donor is substituted on both sides of the perylenediimide moiety resulting in D–A–D system. 10 We were interested in substituting the donor, on one side of the bay posi- tion, which will result in D–A system. Ferrocene is the most widely studied donor. The ferrocene derivatives are thermally, and photochemically stable, and show large nonlinear optical effect. 11 To the best of our knowledge, there 0040-4039/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.tetlet.2012.02.107 ⇑ Corresponding author. Tel.: +91 731 2438710; fax: +91 731 2361482. E-mail address: rajneeshmisra@iiti.ac.in (R. Misra). ——— N O O O O R N O O N O N 2 B HO HO CsF, Ag 2 O, Pd(PPh 3 ) 4 , THF, 80°C, 24Hr, O Fe R= H 1 R= Br 1' Fe Scheme 1. Synthesis of 2. Tetrahedron Letters 53 (2012) 2352–2354 Contents lists available at SciVerse ScienceDirect Tetrahedron Letters journal homepage: www.elsevier.com/locate/tetlet