A Tightly Stretched Ultralong Supramolecular Multiporphyrin Array Propagated by Double‐Strand Formation

Abstract

A shape-programmed linearity through supramolecular polymerization is demonstrated by a step-growth double-strand formation of a telechelic oligomeric porphyrin array in which two alternating pyridyl-porphyrin sequenced units are held together by self-complementary ligand-to-metal coordination. The stiff rod-like structure and sufficiently large binding constant of the double-strand unit considerably extended a supramolecular array in the one dimension, which produced a tightly stretched string with a length that exceeded several micrometers.

Coordination‐Driven Dimerization of Zinc Chlorophyll Derivatives Possessing a Dialkylamino Group

“…Figure 7 shows the temperature-dependent 1 HNMR spectra of Zn-1.A t 223 K, several sets of proton signals were observed. The protons ignals of 5-H and 3 1 -N(CH 3 ) 2 of Zn-2 and Zn-3 also shiftedt oh igh magnetic fields and broadened with ad ecrease in temperature (Figures S8 and S9), resulting in an open dimer which was also observed for Zn-1.T he meso-protons at the C5, C10, and C20 positions of Zn-2 at 263 Kand those of Zn-3 at 223 Kwere similar in shape to those of Zn-1 at 323 K. These observations were DOSY methods have been used for estimating molecular weights of polymers, [30][31][32][33] and has been recently applied to elucidatet he supramolecular structure of chlorophyll assemblies. [26][27][28][29] Since the shift values of 10-H and 20-H were smaller ( Figure 7, blue square), at low temperature, they were located at relativelyd istant positions from the other chlorin moiety in the resulting supramolecule.…”

“…The complexly split NMR peaks of Zn-1 at 223 Ks howeds everal conformers were present as closed dimers whose structures were not precisely determined. The protons ignals of 5-H and 3 1 -N(CH 3 ) 2 of Zn-2 and Zn-3 also shiftedt oh igh magnetic fields and broadened with ad ecrease in temperature (Figures S8 and S9), resulting in an open dimer which was also observed for Zn-1.T he meso-protons at the C5, C10, and C20 positions of Zn-2 at 263 Kand those of Zn-3 at 223 Kwere similar in shape to those of Zn-1 at 323 K. These observations were DOSY methods have been used for estimating molecular weights of polymers, [30][31][32][33] and has been recently applied to elucidatet he supramolecular structure of chlorophyll assemblies. The Wasielewski and Otsuki research groups described the formation of cyclic trimer and tetramero fc hlorophyll derivatives possessing ap yridinyl group in the substituents at the C20 and C3 positions in an organic solventb yD OSY procedures.…”

“…DOSY methods have been used for estimating molecular weights of polymers, and has been recently applied to elucidate the supramolecular structure of chlorophyll assemblies. The Wasielewski and Otsuki research groups described the formation of cyclic trimer and tetramer of chlorophyll derivatives possessing a pyridinyl group in the substituents at the C20 and C3 positions in an organic solvent by DOSY procedures .…”

Supramolecular Polymer of Near-Infrared Luminescent Porphyrin Glass

“…The current molecular design of supramolecular polymers introduces a slipped-cofacial stack of porphyrin planes by extracting the essential unit structure from natural photosynthetic light-harvesting antenna complexes, wherein circularly arranged bacteriochlorophyll pigments in a successive slipped-cofacial stack efficiently capture sunlight and transport excitons quantitatively to the neighboring subunit. − Aimed at supramolecular polymerization of porphyrin glass, the present molecular design employed self-complementary methodology; two zinc (2-pyridyl­ethynyl)­porphyrin planes are held together by self-complementary pyridyl-to-zinc coordination bonds to form a slipped-cofacial dimer. − Then, the ditopic zinc (2-pyridyl­ethynyl)­porphyrin 1 is extended to give a slipped-cofacial stack, which then forms a biomimetic successive π-stacked system through supramolecular polymerization (Scheme ), wherein the primary structural key to 1 was the use of meso -3,4,5-tri­(( S )-3,7-dimethyl­octyloxy)­phenyl groups to form amorphous molecular glass, the so-called porphyrin glass, under solvent-free conditions . As underpinned by Kasha’s molecular exciton theory, , the longitudinal displacement of cofacially stacked chromophores is seminal in producing the lowest optically allowed electronic transition for long-range exciton transport.…”

A Convenient Synthesis of Pentaporphyrins and Supramolecular Complexes with a Fulleropyrrolidine

“…Several synthetic strategies have been developed to produce multiporphyrin oligomers, including directly meso – meso -, meso – β - and β – β -linked multiporphyrin systems, oligoporphyrins with fused π-systems and arrays bearing rigid or flexible spacers. In this context, different types of covalent or supramolecular porphyrin arrays with a large structural diversity [19,20,21,22], including linear [23,24,25], zig-zag [26], and dendritic arrays [27,28], tapes [29,30,31], belts [32], barrels [33], rings [34,35,36,37,38,39,40,41,42,43,44] and boxes [45] and balls [46], have been synthesized.…”