Hetero[17]annulendioxide und ein [16]Annulendioxid — Synthese unter Verwendung von Furanbaugruppen

Das bekannte, äußerst reaktive [18]Annulen 1 und das hypothetische Isomer 2 sollten sich durch CH2‐ und CHCH‐Gruppen als innere bzw. äußere Brücken stabilisieren lassen. Die entsprechenden Kohlenwasserstoffe 3 bzw. 4 sind nicht bekannt, obwohl sie als Bindeglieder zwischen den nicht‐natürlichen Annulenen und dem Porphyrin 5 bzw. dem kürzlich erstmals synthetisierten Porphycen 6 von großem Interesse sind. Gelungen ist jetzt die Herstellung der Tetraoxa‐Analoga von 5 und 6, d. h. der Dikationen 7 bzw. 8. Sie konnten in beiden Fällen als Perchlorate isoliert und strukturell charakterisiert werden, wobei ihre Verwandtschaft mit 5 bzw. 6 offen zu Tage trat. Während bei der Synthese von 7 der entscheidende Schritt eine MacDonald‐Kondensation war, der direkt eine Oxidation folgte, führte der Weg zu 8 über eine McMurry‐Kupplung mit anschließender Oxidation. Die Umsetzung von 2,2′‐Difurylmethan mit Formaldehyd ergab in geringer Ausbeute Tetraoxaporphyrinogen, das sich mit Salpetersäure tatsächlich zum Tetraoxaporphyrin oxidieren ließ.

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Tetraoxaporphyrin‐Dikation

Vogel

Haas

Knipp

et al. 1988

Angewandte Chemie

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Tetraoxaporphyrin Dication

Vogel

Haas

Knipp

et al. 1988

Angew. Chem. Int. Ed. Engl.

150

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should be regarded as a binuclear sandwich complex having two four-electron donor p,q2-P2 ligands (i.e., 18 valence electrons (VE) per Rh atom), the bonding in the Co analogue 6 is more complicated. The X-ray structure analysis reveals two independent molecules per unit cell,1'21 each of whose Co-Co distances is ca. 3.1 A. In this case, the P,bridging ligand forms a "long" (similar to that of 2b) and a "short" (32-VE triple-decker with cyclo-P,?) rectangle, whose average P_P values correspond almost exactly to the distance of 2.38 A in the cubic (metallic) m~d i f i c a t i o n l '~~ of black phosphorus (z(P-P) = 2.45 A for 2b). The Rh-Rh' distance of 2b (3.324(1) A) is significantly longer than d ( M-M) for triple-decker complexes (2.63-2.73 A) containing a C~C I O -P~~~, middle deck and exhibiting metal-metal i n t e r a~t i o n ; [~.~] the average Rh-P value for 2b (2.416 A) is larger than that observed for 7 (2.335 A).[141 Experimental Procedure 2a.b: la (650mg, 2.2 mmol) [Isa] [lb (600 mg, 1.95 mmol) [I5b]] and P, (547 mg, 4.4 mmol) [483 mg, 3.9 mmol) were stirred in refluxing xylene (ca. 30 mL) for 8 h. The reaction solution (containing small amounts of insoluble components) was concentrated to 10 mL under oil-pump vacuum, treatedwith 3 g of AIZO3 (basic, activity II), and then dried under oil-pump vacuum to afford a freely flowing solid. Upon chromatography (column: 25 x 2.5 cm), excess P4 was eluted as a yellow forerun with pentane. Elution with pentane/toluene ( I : I ) then afforded Za,b as a yellow-orange fraction.After removal of the solvent under oil-pump vacuum, Za,b were obtained as spectroscopically pure, orange powders. Recrystallization from pentane (ca.-18°C) afforded Z a as needle-shaped and 2 b as cube-shaped, orange crystals. Yield Za: 207 mg (31Yo) [Zb: 190mg (3IYo)l.

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A Flexible Porphyrin–Annulene Hybrid: A Nonporphyrin Conformation formeso‐Tetraaryldivacataporphyrin

Pacholska‐Dudziak¹,

Szterenberg²,

Latos‐Grażyński³

2011

Chemistry A European J

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An annulene-porphyrin hybrid, the diaaza-deficient porphyrin 5,10,15,20-tetraaryl-21,23-divacataporphyrin, has been synthesized by an extrusion of tellurium atom(s) from 5,10,15,20-tetraaryl-21,23-ditelluraporphyrin under treatment with HCl. In addition, a monoaza-deficient 5,10,15,20-tetraaryl-21-tellura-23-vacataporphyrin was formed in the same reaction. The two new members of the vacataporphyrin family were characterized by X-ray crystallography, as well as UV/Vis and NMR spectroscopy. These aromatic molecules preserve the fundamental structural and spectroscopic features of the parent tetraarylporphyrin. The X-ray crystal structures of 21,23-divacataporphyrin and 21-tellura-23-vacataporphyrin show typical porphyrin patterns. The molecules are not strictly planar and show distortion of the annulene moieties. The N22⋅⋅⋅N24 distances (5.23 and 5.09 Å) are considerably longer than in regular porphyrins. For 21,23-divacataporphyrin, variable-temperature (1)H NMR spectroscopy data allowed the identification of divacataporphyrin stereoisomers differentiated by the geometry of the butadiene bridges. The forms remain in thermodynamic equilibrium.

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Hetero[17]annulendioxide und ein [16]Annulendioxid — Synthese unter Verwendung von Furanbaugruppen

Abstract: Das vollständige Manuskript dieser Zuschrift erscheint in: Angew. Chem. Suppl. 1983, 480. DOI: 10.1002/ange.198304800

Cited by 8 publications

References 8 publications

Tetraoxaporphyrin‐Dikation

Tetraoxaporphyrin‐Dikation

Tetraoxaporphyrin Dication

A Flexible Porphyrin–Annulene Hybrid: A Nonporphyrin Conformation formeso‐Tetraaryldivacataporphyrin

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