Controllable Self-assembly of Sandwich-type Mixed (phthalocyaninato)(porphyrinato) Rare Earth Triple-Decker Complexes

Two novel sandwich-type mixed (phthalocyaninato)(porphyrinato) rare earth complexes Tb2[TClPP]2Pc (1) and Tb2[TClPP] Pc2 (2) [Pc = phthalocyaninate, TClPP = meso-tetrakis (4-chlorophenyl) porphyrinate] have been fabricated into nanostructures by a solution-based method. Their self-assembly properties have been comparatively studied by electronic absorption spectroscopy, transmission electron microscope (TEM), X-ray diffraction (XRD) techniques and current–voltage (I–V) measurements. Due to the different number of porphyrin and phthalocyanine ligands interference, the self-assembly of the two molecules results in totally different morphologies in aggregate: one-dimensional (1D) nanoribbon from 1 vs. two-dimensional (2D) nanosheet from 2. The electronic absorption measurements indicated that J-type aggregates have been formed with the increasing red-shifted degree from nanoribbons to nanosheets depending on the competition and cooperation between the inter-molecular π–π interaction and van der Waals for different compounds. Examination by XRD revealed that in the nanostructures of 1 and 2, a dimeric supramolecular structure was formed through an intermolecular π–π interaction and van der Waals between two sandwich-type molecules, which as the building block self-assembles into the target nanostructures. In addition, the nanosheets from 2 were revealed to show excellent semiconducting properties with the conductivity of 3.0 × 10−3 S m−1 in air due to readily π-stacks with adjacent planar molecules enhanced by higher ordered crystalline molecular arrangement.