Guest‐Induced Unidirectional Dual Rotary and Twisting Motions of a Spiroborate‐Based Double‐Stranded Helicate Containing a Bisporphyrin Unit

Abstract

Einflussreiche Gäste: Die Interkalation eines elektronenarmen aromatischen Gastes (rot) zwischen zwei Porphyrinringe eines optisch aktiven, porphyrinverknüpften doppelsträngigen Spiroborat‐Helikats induzierte eine Rotationsbewegung der Porphyrinringe und damit eine unidirektionale Verdrehung der Spiroborat‐Helix. Das System könnte für die Entwicklung chiralitätresponsiver molekularer Funktionseinheiten geeignet sein.

Tautomerism and Atropisomerism in Free‐Base (meso)‐Strapped Porphyrins: Static and Dynamic Aspects

“…Besides their exceptional optical, photophysical and electrochemical properties extensively exploited for decades in donor-acceptor systems [1] and molecular photovoltaics, [2][3][4] porphyrins (Pors) have also proved to be extraordinary supramolecular scaffolds in the design of sophisticated 1D-, 2D-and 3D-dimensional architectures, [5][6][7][8][9] covalently or self-assembled, [10][11][12][13][14] including chiral materials [15][16][17] or sensors, [18] molecular cages, [19][20][21][22][23] turnstiles, [24] tweezers [25,26] and dendrimer cores. [9] Since the first reported example in 1969, [27] atropisomerism in porphyrins has been a concept widely exploited in these kinds of architectures (and, in particular, in tetra-meso-arylporphyrins).…”

Silver‐Mediated Formation of a Cofacial Porphyrin Dimer with the Ability to Intercalate Aromatic Molecules

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Porphyrins are widely used for functional molecular systems based on their excellent photophysical and redox properties. [2,3] Cofacial porphyrin dimers can be readily constructed by linking two porphyrin rings by covalent, [4][5][6][7][8][9][10][11][12] hydrogen, [13] or coordination bonds. [2,3] Cofacial porphyrin dimers can be readily constructed by linking two porphyrin rings by covalent, [4][5][6][7][8][9][10][11][12] hydrogen, [13] or coordination bonds.

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“…For example, a fullerene molecule is captured by p-p interactions, [6,9,15] or various ligand molecules bind to the axial site of the central metals from inside. Many cofacial dimers of porphyrins [8,[10][11][12]18] and other aromatic compounds [18,[20][21][22][23] have been developed for their recognition of aromatic guests. Many cofacial dimers of porphyrins [8,[10][11][12]18] and other aromatic compounds [18,[20][21][22][23] have been developed for their recognition of aromatic guests.…”

“…[1] In particular, multiple porphyrins arranged in a well-ordered manner show unique functions such as photoelectron conversion, catalysis, and molecular recognition, all of which cannot be achieved by a monomeric porphyrin analogue. [2,3] Cofacial porphyrin dimers can be readily constructed by linking two porphyrin rings by covalent, [4][5][6][7][8][9][10][11][12] hydrogen, [13] or coordination bonds. [14][15][16][17][18][19] So far, a great number of porphyrin dimers have been reported as host molecules for guest recognition.…”

“…[5,13,16,17,19] When two aromatic rings are positioned parallel to each other at a distance of about 6-7 , the dimer can be a good receptor for intercalating guest molecules through p-p interactions. Many cofacial dimers of porphyrins [8,[10][11][12]18] and other aromatic compounds [18,[20][21][22][23] have been developed for their recognition of aromatic guests. However, many aromatic-dimer host molecules either have low-binding ability because of the structural flexibility (e.g., rotation of aromatic moieties) or are difficult to synthesize (e.g., inefficient linking or cyclization).Coordination-driven self-assembly of organic ligands and metal ions is an efficient way to construct three-dimensional molecular architectures.…”