Triply Stacked Heterogeneous Array of Porphyrins and Phthalocyanine through Stepwise Formation of a Fourfold Rotaxane and an Ionic Complex

Abstract

We report the preparation and crystal structure of a triply stacked metal complex array in which a Cu-phthalocyanine is sandwiched between different Cu-porphyrins. The discrete heterogeneous assembly was prepared through formation of a fourfold rotaxane from a tetradactyl porphyrin with alkylammonium moieties and a phthalocyanine bearing four crown ethers and the subsequent formation of an ionic complex between the fourfold rotaxane and a tetraanionic porphyrin. The tetraanionic porphyrin, Cu-TPPS(4-), is selectively bound to the fourfold rotaxane through cooperative π-π and ionic interactions. The crystal structure revealed the columnar stacked array of the three planar building components in a precise order and spatial arrangement that promote intermolecular electronic communication.

Assembly of Multi‐Phthalocyanines on a Porphyrin Template by Fourfold Rotaxane Formation

“…This implies significant electronic interaction between the transition dipole moments of the two Cu II phthalocyanine units due to the closely stacked structure. In Cu3−ST 8+ ⋅ 8 Cl − , ammonium ions in the sidechains are connected through C6 alkyl chains whose extended length is approximately 8 Å, which is much longer than the stacking distance between porphyrin and phthalocyanines or between two phthalocyanines (approximately 3–4 Å) ,. We considered that the alkylammonium sidechains may be bent or twisted along the stacking axis, so that two phthalocyanines are stacked closely.…”

Site‐Selective Supramolecular Complexation Activates Catalytic Ethane Oxidation by a Nitrido‐Bridged Iron Porphyrinoid Dimer

“…CCDC 944188c ontain the supplementary crystallographic dataf or 1 4 + -Cu II -TPPS 4À .These data are provided free of charge by The Cambridge Crystallographic Data Centre). [8] b) Schematic representation of the concept of this work.T he catalytico xidationo f ethanew as enhanced by the complexationwith M-TPPS 4À . distribution patterns correspondingt o3 5 + ·5Cl À agreed with calculated values, as shown in Figure 2b.T he sharps ignals, assigned to one-quarterp art of 3 5 + that were observed in the 1 HNMR spectrum from 0t o9ppm (Figure 2c), suggest diamagnetic nature.I nt he literature, an itrido-bridged iron tetraphenylporphyrin dimer having two Fe 3.5 + ions that exchange rapidly was reported to exhibit significant broadening of 1 HNMR signals due to the paramagnetic effect, [11] whereas one-electron-oxidized species including two Fe 4 + centers showeds harp 1 HNMR signals.…”

“…[7] Moreover,i tw as found that tetraanionic porphyrin Cu II -TPPS 4À [TPPS 4À = 5,10,15,porphyrin copper(II)] strongly and selectively stacks above the phthalocyanine unit of 1 4 + through quadruple ionic interaction with four peripheral ammonium ions and p-p stacking to afford extended stacked assembly 1 4 + -Cu II -TPPS 4À , as confirmed by single-crystal X-ray structural analysis. [8] This supramolecular complexations ignificantly changed the redox potentialo f1 4 + to ad egree that could be tuned by changing the metal ion introduced in the centero fT PPS 4À . [9] Therefore, we hypothesized that am etal complex of TPPS 4À (M-TPPS 4À ) could act as an effector molecule to control the catalytic activity of an itrido-bridged iron porphyrinoid dimer based on the fourfold rotaxane heterodimer through post-synthetic electronic perturbation (Figure 1b).…”

An Introduction to the Mechanical Bond

“…Tris-and tetra-macrocyclic 'platforms', which are triply or quadruply interlocked with tripodal or tetrapodal 'rigs', respectively, have been described as mechanically interlocked 'bundles', 296 and 'molecular elevators', 178 the latter case pertaining to situations where a platform can be translocated under the influence of external stimuli-see Section 6.13.1.3. A triply interlocked bundle 296 is illustrated in Figure 1.28g, while the solid-state structure of a fourfold interlocked molecular elevator 297,298 is represented in Figure 1.29d. A suitane (Section 4.3.5) is a molecule that has been named 8,299 to reflect a molecular 'suit' which mechanically envelops a multi-limbed molecular 'body' (a suit[n]ane has n 'limbs').…”