Jay R. Stork

Preparation and characterization of asymmetric α-alkoxy dipyrrin ligands and their metal complexes

Asymmetric α-substituted dipyrrins have been synthesized and characterized. The compounds were formed by a metal mediated reaction involving a single alkoxy group substituted into the α-position of an α,β-unsubstituted dipyrrin. An α-methoxy dipyrrin, 5-(4-cyanophenyl)-1-methoxydipyrrin (α-OMe-4-cydpm), was prepared from 5-(4-cyanophenyl)-4,6-dipyrromethane. Methoxy, ethoxy, and propoxy derivatives (α-OMe-4-mecdpm, α-OEt-4-mecdpm, α-OPr-4-mecdpm) of 5-(4-methoxycarbonylphenyl)-4,6-dipyrromethane have also been prepared. A homoleptic, bis(1-methoxy)dipyrrinato zinc(II) complex, [Zn(α-OMe-4-mecdpm)2], has been synthesized, as has a heteroleptic cobalt(III) complex with one α-OMe-4-cydpm ligand and two unsubstituted 5-(4-cyanophenyl)dipyrrin (4-cydpm) ligands ([Co(α-OMe-4-cydpm)(4-cydpm)2]). The rotational barrier of the meso-aryl substituent of [Zn(α-OMe-4-mecdpm)2] was found to be 17.3 kcal mol−1 by variable-temperature NMR spectroscopy. The compounds α-OMe-4-cydpm and [Zn(α-OMe-4-mecdpm)2] have also been characterized by X-ray diffraction. The formation of the new dipyrrin derivatives is shown to be general and can be performed on dipyrrins with various meso-aryl substitutents, with a variety of alcohols, and can be promoted by several metal salts.

Enantiopure vs. racemic metalloligands: impact on metal–organic framework structure and synthesis

Carboxylate-decorated tris(dipyrrinato) cobalt(III) complexes have been used to construct 2-D and 3-D metal-organic frameworks with infinite and trinuclear zinc secondary-building units.

Variation in crystallization conditions allows the isolation of trimeric as well as dimeric and monomeric forms of [(alkyl isocyanide)4RhI]+

Trimeric green [(i-PrNC)12Rh(I)3]Cl3.4.5H2O, monomeric [(C6H11NC)4Rh(I)](BPh4) and [(i-PrNC)4Rh(I)](BPh4) (both yellow), and red, dimeric [(C6H11NC)8Rh(I)2]Cl2.0.5C6H6.2H2O have been crystallized.