title: Charge and spin transport in an organic molecular square.
abstract: Understanding electronic communication among multiple chromophoric and redox units requires construction of well-defined molecular architectures. Herein, we report the modular synthesis of a shape-persistent chiral organic square composed of four naphthalene-1,8:4,5-bis(dicarboximide) (NDI) sides and four trans-1,2-cyclohexanediamine corners. Single crystal X-ray diffraction reveals some distortion of the cyclohexane chair conformation in the solid state. Analysis of the packing of the molecular squares reveals the formation of highly ordered, one-dimensional tubular superstructures, held together by means of multiple [CH⋅⋅⋅OC] hydrogen-bonding interactions. Steady-state and time-resolved electronic spectroscopies show strong excited-state interactions in both the singlet and triplet manifolds. Electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) spectroscopies on the monoreduced state reveal electron sharing between all four NDI subunits comprising the molecular square.
authors: Argonne-Northwestern Solar Energy Research (ANSER) Center and Center for the Chemistry of Integrated Systems (CCIS), Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (USA).
authors: Yilei
authors: Y
authors: Wu
authors: Argonne-Northwestern Solar Energy Research (ANSER) Center and Center for the Chemistry of Integrated Systems (CCIS), Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (USA).
authors: Siva Krishna Mohan
authors: SK
authors: Nalluri
authors: Argonne-Northwestern Solar Energy Research (ANSER) Center and Center for the Chemistry of Integrated Systems (CCIS), Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (USA).
authors: Ryan M
authors: RM
authors: Young
authors: Argonne-Northwestern Solar Energy Research (ANSER) Center and Center for the Chemistry of Integrated Systems (CCIS), Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (USA).
authors: Matthew D
authors: MD
authors: Krzyaniak
authors: Argonne-Northwestern Solar Energy Research (ANSER) Center and Center for the Chemistry of Integrated Systems (CCIS), Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (USA).
authors: Eric A
authors: EA
authors: Margulies
authors: Argonne-Northwestern Solar Energy Research (ANSER) Center and Center for the Chemistry of Integrated Systems (CCIS), Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (USA). stoddart@northwestern.edu.
authors: J Fraser
authors: JF
authors: Stoddart
authors: Argonne-Northwestern Solar Energy Research (ANSER) Center and Center for the Chemistry of Integrated Systems (CCIS), Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (USA). m-wasielewski@northwestern.edu.
authors: Michael R
authors: MR
authors: Wasielewski
keywords: electron transport; hydrogen bonding; molecular electronics; molecular squares; organic semiconductors