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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. 

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. 

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. 

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.