Structural characterization and photochromic behaviour of a novel compound based on a π-acidic naphthalene diimide derivative and a double hydroxide-bridged dinuclear Al^III aqua ion cluster

Abstract

Noncovalent interactions, such asstacking interactions, C-HÁ Á Á interactions and hydrogen bonding, are important driving forces for self-assembly in the construction of functional supermolecules and materials, especially in multicomponent supramolecular systems. Herein, a novel compound based on a -acidic naphthalene diimide derivative and a double hydroxide-bridged dinuclear Al 3+ aqua ion cluster, namely bis[N,N 0 -bis(2-sulfonatoethyl)-1,4,5,8naphthalene diimide] di--hydroxido-bis[tetraaquaaluminium(III)] tetrahydrate, (C 18 H 12 N 2 O 10 S 2 ) 2 [Al 2 (OH) 2 (H 2 O) 8 ]Á4H 2 O, was obtained using the above-mentioned common noncovalent interactions, as well as uncommon lonepair-interactions. Functional molecular modules were connected by these noncovalent interactions to generate obvious photochromic properties. The compound was prepared by the self-assembly of N,N 0 -bis(2-sulfoethyl)-1,4,5,8naphthalene diimide and Al(NO 3 ) 3 Á9H 2 O under mixed solvothermal conditions, and was characterized in detail by single-crystal X-ray diffraction, powder X-ray diffraction and FT-IR spectroscopy. The thermal stability and photochromic properties were also investigated; furthermore, in-situ solid-state UV-Vis absorption spectroscopy and electron spin resonance (ESR) were used to clarify the photochromic mechanism.research papers

Condensed π-molecular arrangement for –C2H4SO3− armed naphthalenediimide

“…The crystal structures of salts 1Á4.0(H 2 O) and 3 have been reported previously. [71][72][73][74][75] However, there is no evaluation of the dimensionality of the electronic structure and electron transport properties. No systematic changes in the molecular arrangement have been reported when cations are increased in size from Na + , K + , Rb + , to Cs + .…”

“…In the previous BSNDI 2À salts, only rotational degree of freedom around the N-C 4 H 4 SO 3 À bond is allowed, whereas in ESNDI 2À , the conformational freedom of the ethyl sulfonate group is enhanced and the various molecular arrangement of the NDI p-core is observed. Although the crystal structure and carrier generation by photoirradiation of the ESNDI 2À molecule combined with M + = Na + , K + , Rb + , Mg 2+ , and Al 3+ salts have been reported, [71][72][73][74][75] there has been no comparative study on the molecular arrangements, formation of condensed p-packing structures, and electron transport properties when the size of M + is systematically changed. We focused on (M + ) 2 (ESNDI 2À ) salts with M + = Na + , K + , Rb + , and Cs + and attempted to investigate changes in the molecular arrangement and electron transport properties in a series of crystals in terms of the appearance of condensed p-molecular arrangements.…”