Crystal and Molecular Structures of Some Metal Tetraphenylporphines

Fleischer, Everly B.; Miller, C.; Webb, Lawrence E.

doi:10.1021/ja01066a009

Cited by 313 publications

(198 citation statements)

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“…[28][29][30] The main non-planar deformations are the ruffling, a twisting around the M-N p bond, such as in CuTPP and PdTPP, [31] the saddling, i.e the displacement of the pyrrole rings alternately above and below the mean porphyrin plane, for example in CuT4, [32] the doming often observed in five-coordinate complexes, due to the axial ligand such as in MImCoTPP, [33] and the waving, where one pair of opposing pyrrole rings is displaced up and down, while the other pair is twisted in the same direction along their M-N p bond, such as in NiTMeP. [34] Several parameters influence the porphyrin assembling.…”

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“…The starting setup for structural analysis of the template-imprinted sample were available data (experimental CuT 4 and theoretical H 2 TTPS) on corresponding homo-aggregates. [31,32,37,38] No data are available, in fact, for hetero-aggregates. The theoretical structural analysis has shown that an increasing molecular tilting decreases the intensity of the main peak.…”

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Supramolecular Structure of Extrinsically Chiral Porphyrin Hetero‐Assemblies and Achiral Analogues

et al. 2007

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Nature uses chiral information to achieve the excellent degree of selection and efficiency peculiar to all living systems. But chirality is also receiving growing interest for the possible technological applications that span from chiroptical devices [1] to asymmetric catalysis, [2] memory systems, [3,4] and others.[5]The transfer of chiral information to achiral molecules through non-covalent interactions, expressed at a supramolecular level, has, in particular, gained great consideration. [6,7] In fact, non-covalent synthesis, especially when molecular recognition and self-assembly processes are involved, [8] presents many advantages: i) it is not time consuming, ii) it does not lead to side products, and iii) it dose not require an external energy source for reaction. When a chiral structure is imprinted onto an assembly of symmetric molecules by a chiral template or by macroscopic forces (i.e. mechanical effects), [9,10] through mere non-covalent interactions, the resulting supramolecular chiral system may experience two different fates following the template chiral structure modification or removal: i) if the species is under thermodynamic control, it loses the imprinted chiral properties but, ii) if the species is kinetically inert, then it can preserve the imprinted chiral properties for hours, months or even longer. The last case is defined as "memory" effect. [11][12][13] The chiral memory phenomenon is of particular interest because, used in combination with the non-covalent strategy, permits to assembly supramolecular species able to perform predetermined functions coupled with chiral discrimination. [14,15] With these premises, it is clear that understanding the forces involved and the mechanism accompanying induction, modulation and memory of supramolecular chirality could allow for the rational design and assembly of chiral supramolecular systems. Taking advantage of the chiral memory approach, we have recently published the non-covalent synthesis of chiral porphyrin hetero-aggregates, templated by polypeptides or aminoacids. [16][17][18] These aggregates keep memory of the imprinted chirality that is maintained, even after removing the chiral template. Furthermore, their interactions in the absence of chiral templates leads to achiral species.Here, we present the first structural determination of a porphyrin (chiral) hetero-aggregate through energy dispersive X-ray diffraction analysis (EDXD) because of the poor crystalline character of the aggregates. The achiral components are represented by meso-tetrakis(N-Methylpyridium-4-yl)porphinato-copper(II) (CuT4-cationic) and meso-tetrakis-(4-sulfonatophenyl)porphyrin (H 2 TTPS-anionic), while L-phenilalanine is used as chiral mould. Also, a comparison is reported with the amorphous hetero-aggregate structure that the same porphyrins form in the absence of the chiral template. The aggregation process may involve one type of porphyrin only, the homo-assemblies or homo-aggregates, [19,20] or more porphyrins of different type, [21][22][23] the hetero-assem...

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Supramolecular Structure of Extrinsically Chiral Porphyrin Hetero‐Assemblies and Achiral Analogues

et al. 2007

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“…The zinc center is tetracoordinated with an average Zn-N bond length of 2.047(2) Å similar to that of Zn(II)6f 2.043(5) Å. 18 The molecular packing (Fig. 5) is characterized by the formation of standard head-to-tail dimeric aggregates.…”

Section: Manuscript For Tetrahedronmentioning

confidence: 99%

Conformational and structural studies of meso monosubstituted metalloporphyrins—Edge-on molecular interactions of porphyrins in crystals

et al. 2016

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Leave this area blank for abstract info.Senge, M. O.; Flanagan, K. J.; Ryan, A. A.; Donath, M.; Twamley, B. (2016):Conformational and Structural Studies of meso Monosubstituted Metalloporphyrins -Edge-on molecular interactions of porphyrins in crystals. Tetrahedron 72, 105-115. doi: 10.1016Tetrahedron 72, 105-115. doi: 10. /j.tet.2015 Manuscript A series of meso monosubstituted metalloporphyrins were synthesized to assess the structural chemistry of porphyrins with only one substituent. The structures of four nickel(II) and zinc(II) complexes with either alkyl or aryl residues indicate primarily planar macrocycles. This gives rise to a different type of -interactions in the crystal and the formation of dimeric, trimeric or tetrameric porphyrin units that function as building blocks for the overall crystal structure. Notably, some structures exhibit a unique edge-on packing of porphyrins, while the molecules of (5-n-butylporphyrinato)nickel(II) forms an unusual bilayer type structure where rows of two porphyrin macrocycles are separated by the alkyl residues arranged in a head-to-head fashion. This adds to the canon of intermolecular porphyrin packing arrangements and is of relevance for the preparation of ordered nanoscopic porphyrin devices.

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“…Whilst the aromatic π-system of porphyrins may at first imply planar compounds, it has long been known that the macrocycle possesses considerable conformational flexibility ( Figure 10) [61]. Indeed, extended aromatic systems such as those of Chl or BChl must be conformationally flexible and numerous structural and spectroscopic studies since have led to a deeper understanding of the importance of this phenomenon for the functional properties of porphyrins [62,63].…”

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confidence: 99%

Chlorophylls, Symmetry, Chirality, and Photosynthesis

et al. 2014

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Chlorophylls are a fundamental class of tetrapyrroles and function as the central reaction center, accessory and photoprotective pigments in photosynthesis. Their unique individual photochemical properties are a consequence of the tetrapyrrole macrocycle, the structural chemistry and coordination behavior of the phytochlorin system, and specific substituent pattern. They achieve their full potential in solar energy conversion by working in concert in highly complex, supramolecular structures such as the reaction centers and light-harvesting complexes of photobiology. The biochemical function of these structures depends on the controlled interplay of structural and functional principles of the apoprotein and pigment cofactors. Chlorophylls and bacteriochlorophylls are optically active molecules with several chiral centers, which are necessary for their natural biological function and the assembly of their supramolecular complexes. However, in many cases the exact role of chromophore stereochemistry in the biological context is unknown. This review gives an overview of chlorophyll research in terms of basic function, biosynthesis and their functional and structural role in photosynthesis. It highlights aspects of chirality and symmetry of chlorophylls to elicit further interest in their role in nature.

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Crystal and Molecular Structures of Some Metal Tetraphenylporphines

Cited by 313 publications

References 3 publications

Supramolecular Structure of Extrinsically Chiral Porphyrin Hetero‐Assemblies and Achiral Analogues

Supramolecular Structure of Extrinsically Chiral Porphyrin Hetero‐Assemblies and Achiral Analogues

Conformational and structural studies of meso monosubstituted metalloporphyrins—Edge-on molecular interactions of porphyrins in crystals

Chlorophylls, Symmetry, Chirality, and Photosynthesis

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