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Title compound1Ni, [Ni(C₄₆H₃₂N₄O₂)], a secochlorin nickel complex, was prepared by diol cleavage of a precursortrans-dihydroxydimethylchlorin. Two crystallographically independent molecules in the structure are related by pseudo-A lattice centering, with molecules differing mainly by a rotation of one of the acetyls and an adjacent phenyl groups. The two molecules have virtually identical conformations characterized by noticeable in-plane deformation in the A_1gmode and a prominent out-of-plane deformation in the B_1u(ruffling) mode. Directional interactions between molecules are scarce, limited to just a few C—H...O contacts, and intermolecular interactions are mostly dispersive in nature. 

Abstract An intramolecular S_NAr displacement of oneo‐fluorine atom of ameso‐pentafluorophenyl‐substituted porphyrin metal complex by a neighboring β‐amino functionality generated the correspondingmeso‐fluorophenyl‐substituted metallo‐quinolino[2,3,4‐at]porphyrins that are not accessible using established quinoline‐annulation methodologies. The Cu(II), Ni(II), and Zn(II) complexes were thus prepared. The parent free base quinolino[2,3,4‐at]porphyrin is accessible only by demetallation of the copper or zinc complexes. A strong through‐space NMR‐spectroscopic coupling between the remainingo‐fluorine atoms on the annulatedmeso‐aryl group and the β‐hydrogen atom on the adjacent pyrrole moiety provide a clear spectroscopic signature for the annulation. Quinoline‐annulation alters the optical properties significantly. On account of the presence of the β‐amino functionality, all quinoline‐annulated porphyrins show strong halochromic responses with Brønsted acids and bases, the prerequisite for their potential use in chemosensing applications. 

The title morpholinochlorin, C 46 H 16 F 20 N 4 O 3 , was crystallized from hexane/methylene chloride as its 0.44 methylene chloride solvate, C 46 H 16 F 20 N 4 O 3 ·0.44CH 2 Cl 2 . The morpholinochlorin was synthesized by stepwise oxygen insertion into a porphyrin using a `breaking and mending strategy': NaIO 4 -induced diol cleavage of the corresponding 2,3-dihydroxychlorin with in situ methanol-induced, acid-catalyzed intramolecular ring closure of the intermediate secochlorins bisaldehyde. Formally, one of the pyrrolic building blocks was thus replaced by a 2,3-dimethoxymorpholine moiety. Like other morpholinochlorins, the macrocycle of the title compound adopts a ruffled conformation, and the modulation of the porphyrinic π-system chromophore induces a red-shift of its optical spectrum compared to its corresponding chlorin analog. Packing in the crystal is governed by interactions involving the fluorine atoms of the pentafluorophenyl substituents, dominated by C—H...F interactions, and augmented by short fluorine...fluorine contacts, C—F...π interactions, and one severely slipped π-stacking interaction between two pentafluorophenyl rings. The solvate methylene chloride molecule is disordered over two independent positions around an inversion center with occupancies of two × 0.241 (5) and two × 0.199 (4), for a total site occupancy of 88%. 

The title chlorin, 2 Ph H 2 , hydrogen-bonded to dimethylaminopyridine (DMAP), C 44 H 32 N 4 O 2 ·C 7 H 10 N 2 , and its corresponding zinc(II) complex, 2 Ph Zn , axially coordinated to ethylenediamine (EDA), [Zn(C 44 H 30 N 4 O 2 )]·C 2 H 8 N 2 , were isolated and crystallized by adventitious reduction of the corresponding osmate esters by DMAP and EDA, respectively. Known since 1996 and, inter alia , used for the preparation of a wide range of (planar and non-planar) chlorin analogues (so-called pyrrole-modified porphyrins), their conformational analyses in the solid state are important benchmarks. Both macrocycles are only modestly distorted from planarity and both are slightly more non-planar than the corresponding dimethoxy-derivative, but less planar than a free-base meso -pentafluorophenyl-based osmate ester. NSD analyses provide quantitative and qualitative analyses of the distortion modes. One origin of the non-planarity is presumably the avoidance of the eclipsed configuration of the two vic–cis diols on the pyrroline moiety; the resulting deformation of the pyrroline translates in some cases into the macrocycle. The structure of 2 Ph H 2 features voids making up ca 26% of the unit-cell volume filled with highly disordered solvate molecules (chloroform and hexanes). 2 Ph Zn crystallized with a 13.6 (4)% occupied solvate methanol molecule. 

Abstract To date, only two pigments have been identified in avian eggshells: rusty-brown protoporphyrin IX and blue-green biliverdin IXα. Most avian eggshell colours can be produced by a mixture of these two tetrapyrrolic pigments. However, tinamou (Tinamidae) eggshells display colours not easily rationalised by combination of these two pigments alone, suggesting the presence of other pigments. Here, through extraction, derivatization, spectroscopy, chromatography, and mass spectrometry, we identify two novel eggshell pigments: yellow–brown tetrapyrrolic bilirubin from the guacamole-green eggshells ofEudromia elegans,and red–orange tripyrrolic uroerythrin from the purplish-brown eggshells ofNothura maculosa. Both pigments are known porphyrin catabolites and are found in the eggshells in conjunction with biliverdin IXα. A colour mixing model using the new pigments and biliverdin reproduces the respective eggshell colours. These discoveries expand our understanding of how eggshell colour diversity is achieved. We suggest that the ability of these pigments to photo-degrade may have an adaptive value for the tinamous. 

Despite the formal presence of an acac-like moiety, β-oxo-meso-OH-porphyrins do not bind 3d and 4d metal ions at their periphery. This is attributed to the loss of macrocycle aromaticity upon expression of an acac-like chelate. 

meso-Tetrahexylporphyrin was converted to its corresponding 7,8-dihydroxychlorin using an osmium tetroxide-mediated dihydroxylation strategy. Its diol moiety was shown to be able to undergo a number of subsequent oxidation reactions to form a chlorin dione and porpholactone, the first meso-alkylporphyrin-based porphyrinoid containing a non-pyrrolic building block. Further, the diol chlorin was shown to be susceptible to dehydration, forming the porphyrin enol that is in equilibrium with its keto-chlorin form. The meso-hexylchlorin dione could be reduced and it underwent mono- and bis-methylation reactions using methyl-Grignard reagents, and trifluoromethylation using the Ruppert-Prakash reagent. The optical and spectroscopic properties of the products are discussed and contrasted to their corresponding meso-aryl derivatives (where known). This contribution establishes meso-tetrahexyl-7,8-dihydroxychlorins as a new and versatile class of chlorins that is susceptible to a broad range of conversions to generate functionalized chlorins and a pyrrole-modified chlorin analogue.