Benziporphyrin, a Benzene‐Containing, Nonaromatic Porphyrin Analogue

Abstract

6] S. Pasynkiewicz, Po/i./idron 1990. 9. 429. 171 Crystal data of [3(thf),] 6 T H F M = 1986.46, rhomhohedral, space group R k . [I = h = 2353.6(3). c = 3133.0(6) pm. Y = 15.030(4) nm'. Z = 6. pL,,,Cd = 1.317 Mgm-3. F(000) = 6264. ; . =71.073 pm, T = -120 C . p(MoK,) = 1.651 mni-'. crystal dimensions: 0.7 x0.5 xO.5 mm, 6 5 2 0 < 40 ; of the 6127 collected reflections, 2440 are independent, and these were used for the refinement of 164 parameters with the help of 198 restraints: maximal residual electron density: 899 enin-'. R I ( F > 4 o ( F ) ) = 0.069 and wR2 = 0.199 (all data) with R1 = X l l F , l ~ ~k :~~, I~F o \ and PIRZ = (Zii,F~:-Ff)*:Zii.(F3)l)il '.The data here collected on a Stoe-Huher diffractometer. Intensities of 3 rapidlq cooled crgstiil in a n oil drop [XI Mere collected by 2 0 :~ method. Semiempirical absorption corrections were carried out on all data. The structure was solved hg direct methods (SHELXS-90) [9] and refined by least squares on F' [lo]. The disorders of the T H F solvent molecules were refined with dictance restraints. The refinement of the inversion twinning paramter 11 I ] ( \ = 0.00 (4) for .r = 0 for the correct absolute structure and i = + 1 for the inverted structure) confirmed the absolute structure of3. The solution of the structure and the refinement in the space group R5c were unsuccessful. The structure could he solved in the space group C<,, but a refinement was also here unsuccessful. Further details of the crystal structure investigation may he obtained from the Director of the Cambridge Crystallographic Data Centre. 12 Union Road, GB-Cambridge CB2 IEZ. on quoting the full journal citation. 1i5. 4971. An,qew. Chon. Inr. E d Engl. 1994, 33. No. 12 VCH Yerluxsgrsellschufr mhH, 0-69451 Weinherni, 1994 0570-0833,'94!1212-1?47 J 10.00 + .2SW

Pyrrole‐Appended Derivatives of O‐Confused Oxaporphyrins and Their Complexes with Nickel(II), Palladium(II), and Silver(III)

“…Originally the benzene ring was embedded in an octaalkylporphyrin-like environment to give 8,19-dimethyl-9,13,14,18-tetraethyl-mbenziporphyrin. [26] The related macrocycle 6,11,16,21-tetraphenylbenziporphyrin ((TPmBPH)H) can give organometallic complexes with palladium(ii) and platinum(ii), [(TPmBP)Pd II ] and [(TPmBP)Pt II ]. [22] The metal ion is bound in the macrocyclic cavity by three pyrrolic nitrogen atoms and a trigonal carbon atom of the benzene ring.…”

Metalation of Carbaporphyrinoid Systems

“…However, in other cases the carbocyclic unit is crossconjugated and the macrocycle becomes less aromatic or nonaromatic. Reaction of isophthalaldehyde ( 11a) with tripyrrane 10 gives the nonaromatic benziporphyrin 3a, [20][21][22] while related dimethoxybenzenedialdehydes 11b and 11c give dimethoxybenziporphyrins 3b and 3c, respectively. [32] Similarly, 2-hydroxy-5-methyl-1,3-benzenedicarbaldehyde (12) reacts with 10 to afford the hydroxybenziporphyrin 13, and the internal hydroxyl substituents does not appear to significantly inhibit macrocycle formation.…”

“…These variables allow for greater differences in both reactivity and spectroscopic properties, and the element of symmetry present in many of these structures also allows for a simplification in the characterization of these systems as well as facilitating greater regiochemical selectivity. Although the first synthesis of a benziporphyrin 3 ( Figure 1) was reported in the same year that the earliest papers on NCPs were published, [20][21][22] and syntheses of oxybenziporphyrins 4, [21,22] carbaporphyrins ( e.g. 5), [23,24] azuliporphyrins 6, [25] carbachlorins 7 [26] and tropiporphyrins 8 [27] were reported over the next three years, until recently studies on these carbaporphyrinoid systems have fallen under the shadow of the NCPs.…”

Porphyrins: Syntheses and Reactions

“…Tropiporphyrin (20) is one successful example synthesized by Lash and Chaney. After the initial attempts of Breitmaier and coworkers [48], they were able to synthesize aromatic tropiporphyrin (20) with modified reaction conditions in 23% yield (Scheme 26.15) [26]. Unlike benziporphyrin, interestingly, the meta link of cycloheptatriene-1,6-dicarboxaldehyde is attuned to accommodation into the 18p conjugated network of the macrocycle.…”

“…In this process, many aromatic units like pyridine, benzene, azulene and similar such units have successfully replaced one or more pyrrolic units in the macrocycle. Earlier attempts by Breitmaier and coworkers [48] yielded only the non-aromatic form of a benziporphyrin. This was attributed to the fact that the thermodynamically more stable 6p aromaticity of benzene could not be disrupted to be part of an 18p system.…”