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'Porphyrins' in keywords Facet   section ZfN Section B  [X]
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1Author    Requires cookie*
 Title    Metallkomplexe mit Tetrapyrrol-Liganden, XIV1 * Eisenporphodimethene: Sterisch und elektronisch modifizierte Häme und Hämine  
 Abstract    M etal Complexes of T etrapyrrole Ligands, X IV 1 Iro n P o rp h o d im eth en es: Sterically and E lectronically Modified H em es an d H em ins J o h a n n W. B u c h l e r u n d K . L am L a y Iron An air-stable porphodimethene, namely a, y-dimethyl-a, y-dihydrooctaethylporphyrin [H 2(OÄPMe2)*; (1)] is metalated with Fe(CO)5/I2 in toluene to yield an air-stable binuclear iron(III) porphodimethene, /i-oxobis(a, y-dimethyl-a, 
  Reference    (Z. Naturforsch. 30b, 385—392 [1975]; eingegangen am 27. Februar 1975) 
  Published    1975 
  Keywords    Porphyrins, Iron Porphodimethenes, Hemes, Hemins 
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 TEI-XML for    default:Reihe_B/30/ZNB-1975-30b-0385.pdf 
 Identifier    ZNB-1975-30b-0385 
 Volume    30 
2Author    Steffen Runge, M. Athias, O. SengeRequires cookie*
 Title    Electron Donor-Acceptor Compounds. Synthesis and Structure of 5-(l,4-Benzoquinone-2-yl)-10,15,20-trialkylporphyrins  
 Abstract    A series of 5-(benzoquinone)-10,15,20-trialkylporphyrins was synthesized via cross conden­ sation of the respective aldehydes, 2,5-dimethoxybenzaldehyde and pyrrole followed by de-methylation with BBr3 and oxidation with P b 0 2. This method worked reasonably well for compounds bearing the benzoquinone substituent and butyl, isopropyl, 1 -methylpropyl and 2-ethylpropyl residues (2a-d). The free base porphyrin quinones were converted into the zinc(II) complexes (3a-d) all of which showed remarkable stability for porphyrin quinones. The zinc(II) complex 3c bearing isopropyl residues was investigated by X-ray crystallography and showed a supramolecular structure consisting of polymeric chains facilitated by coordina­ tion of a benzoquinone oxygen to a neighboring zinc(II) center. Attempts to synthesize a 5-(benzoquinone)-10,15,20-tris(terr-butylporphyrin) resulted in the formation of a yellow por-phomethene (4), which could not be oxidized further. A crystal structure analysis of 4, the first for a free base porphomethene, shows an extremely twisted conformation with syn-orientation of the three rm-butyl groups. The results indicate that new methods will have to be developed for the synthesis of nonplanar porphyrin quinones. 
  Reference    Z. Naturforsch. 53b, 1021—1030 (1998); received June 15 1998 
  Published    1998 
  Keywords    Porphyrins, Quinones, Electron Transfer Compounds, Crystal Structure, Conformation 
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 TEI-XML for    default:Reihe_B/53/ZNB-1998-53b-1021.pdf 
 Identifier    ZNB-1998-53b-1021 
 Volume    53 
3Author    Steffen Runge3, MathiasO. Senge3, Karin Ruhlandt-SengebRequires cookie*
 Title    5,10,15,20-Tetrakis(diphenylmethyl)porphyrin -A Nonplanar Porphyrin with Intermediate Degree of Ruffling  
 Abstract    The title compound was prepared by condensation of pyrrole and diphenylacetaldehyde in 16% yield. Based on spectroscopic data, the free base porphyrin exhibits a nonplanar macrocycle in solution with a degree of distortion between that of 5,10,15,20-tetracyclohexyl-porphyrin and 5,10,15,20-tetra(r-butyl)porphyrin. A crystal structure determination of the cobalt(II) complex reveals a ruffled macrocycle conformation with an average out-of-plane displacement of the m eso carbon atoms by 0.55 A. 
  Reference    Z. Naturforsch. 54b, 662 (1999); received February 17 1999 
  Published    1999 
  Keywords    Porphyrins, Steric Strain, Cobalt Porphyrins, Crystal Structure, Conformation 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0662.pdf 
 Identifier    ZNB-1999-54b-0662 
 Volume    54 
4Author    M. Athias, O. SengeRequires cookie*
 Title    Fixation o f Neutral M olecules in the Binding Cavity of Nonplanar Porphyrins -A Third Dodeca- phenylporphyrin Modification with NH -Solvent Hydrogen Bonding  
 Abstract    Reprint requests to Priv.-Doz. Dr. M. O. Senge. Fax: 0 3 0 -8 3 8 -4 2 4 8 . E-mail: mosenge@chemie.fu-berlin.de A third crystalline modification of dodecaphe-nylporphyrin is described in which the pyrrole ni­ trogen atoms are hydrogen-bonded to two etha­ nol molecules. This is the first crystallographic proof for the accessibility of nitrogen atoms in saddle-distorted free base porphyrins for hy­ drogen bonding. N o such coordination is possible in either planar or ruffled porphyrins. Thus, the possibility exists to utilize conformationally dis­ torted porphyrins for the binding of neutral m ole­ cules. 
  Reference    Z. Naturforsch. 54b, 821 (1999); received March 2 1999 
  Published    1999 
  Keywords    Porphyrins, Steric Strain, Conformational Flexi­ bility, Crystal Structure, Hydrogen Bonding 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0821_n.pdf 
 Identifier    ZNB-1999-54b-0821_n 
 Volume    54 
5Author    M. Athias, O. Senge, W. Erner, W. KalischRequires cookie*
 Title    Structure and Conformation of Tetra-meso-, O c t a -ß and Dodecasubstituted 22,24-Dihydroporphyrins (Porphyrin Dications)  
 Abstract    A comparative crystallographic analysis of the conformation of porphyrin diacids with various substituent types reveals considerable differences in the degree of nonplanarity and distortion modes. Diacids of 5,10,15,20-tetraarylporphyrins generally exhibit typical saddle-distorted macrocycles with displacements of the Cb positions in the range of 0.7-1.0 A. Adding peripheral substituents, i.e., using dodecasubstituted porphyrins for the diacid forma­ tion yields similar distortion types albeit with larger out-of-plane displacements. As a result of the combined effect of both peripheral (interaction between the Cb and Cm substituents) and core (interaction between the four inner hydrogen atoms) steric strain the maximum Cb displacements reach 1.3-1.5 A. Quite a different situation is observed for the diacids of 2,3,7,8,12,13,17,18-octaalkylporphyrins. Here, macrocycles with pair-wise displacement of neighboring pyrrole rings and significant NH pyramidalization and those with classic saddle distortion are found. Generally, octa-/?-substituted porphyrin diacids show smaller degrees of nonplanarity; Cb displacements ranged from 0.06 to 0.72 A. On the basis of the overall degree of conformational distortion (ZI24 = average deviation of the 24 macrocycles atoms from the mean plane), the three different types of porphyrin macrocycles studied differ considerably in their degree of conformational flexibility. For several porphyrin crystal structures with different counterions and/or solvate molecules were obtained. Taking into account results from the literature 2,3,7,8,12,13,17,18-octaethyl-22,24-dihydro-5,10,15.,20-tetraphenylporphy-rin (13) shows the smallest degree of flexibility (ZI24 = 0.61-0.63 A; four different X-ray structures),o while 22,24-dihydro-5,10,15,20-tetraphenylporphyrin (1) is more flexible (ZI24 = 0.42-0.52 A; four structures). The largest flexibility is observed for 2,3,7,8,12,13,18-octaethyl-22,24-dihydroporphyrin (7) (A24 = 0.02-0.33 A; four structures). 
  Reference    Z. Naturforsch. 54b, 943—959 (1999); received May 4 1999 
  Published    1999 
  Keywords    Porphyrins, Steric Strain, Porphyrin Dications, Crystal Structure, 22, 24-Dihydroporphyrins 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0943.pdf 
 Identifier    ZNB-1999-54b-0943 
 Volume    54 
6Author    M. Ath, O. S. EngeRequires cookie*
 Title    A Conformational Study of 5,10,15,20-Tetraalkyl-22//+,24//+-porphyrindiium Salts (Dication Salts)  
 Abstract    N-protonation of 5,10,15,20-tetraalkylporphyrins with n-butyl, isobutyl, isopropyl, 1-ethyl-propyl or ferf-butyl substituents yields the respective 22,24-dihydroporphyrins (22//+,24//+-porphyrindiium salts) that exhibit highly nonplanar conformations. Depending on the steric demand of the meso substituents, the free base porphyrins have planar to moderately ruffled macrocycles (primary or secondary alkyl residues) or are severely ruffled (tertiary alkyl resi­ dues). X-ray crystallographic studies show that protonation of porphyrins with «-Bu (2), i-Pr (3) or EtPr (4) substituents leads to steric congestion of the core resulting in symmetric, saddle distorted macrocycles as evidenced by average displacements of the Cb positions from the mean plane ranging from 0.79 to 1.01 A. The structures observed for these porphyrin diacids are very similar in distortion mode and degree of nonplanarity to 5,10,15,20-tetraaryl-22f/+,24//+-porphyrindiium salts and to 2,3,7,8,12,13,17,18-octaalkyl-5,10,15,20-tetraaryl-porphyrins. In contrast, protonation of the highly ruffled 5,10,15,20-tetrakis(teA-r-butyl)porph-yrin results in a switch of the conformational distortion mode. The dication 6 shows both saddle distortion (Cb displacements -1.3 A) and ruffling of the macrocycle (Cm displacements of approx. 0.48 A). Thus, the need to accomodate four N-H units in the porphyrin core with its associated out-of-plane tilting of the pyrrole rings and the steric strain induced at the meso carbon atoms results in a highly nonplanar porphyrin with mixed distortion modes. 
  Reference    Z. Naturforsch. 55b, 336—344 (2000); received January 20 2000 
  Published    2000 
  Keywords    Porphyrins, Steric Strain, Porphyrin Dications, Crystal Structure, Conformational Analysis, 22, 24-Dihydroporphyrins 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0336.pdf 
 Identifier    ZNB-2000-55b-0336 
 Volume    55