Synthesis and Structural Characterization of Nonplanar Tetraphenylporphyrins and Their Metal Complexes with Graded Degrees of beta-Ethyl Substitution.

Different porphyrin conformations are believed to play a role in controlling the cofactor properties in natural tetrapyrrole-protein complexes. In order to study the correlation between macrocycle nonplanarity and physicochemical properties in detail, a series of six porphyrins with graded degrees of macrocycle distortion were synthesized via mixed condensation of pyrrole, diethylpyrrole, and benzaldehyde. The formal introduction of successively more beta-ethyl groups into the tetraphenylporphyrin parent macrocycle gave access to diethyltetraphenylporphyrin (H(2)DETPP), two regioisomers of tetraethyltetraphenylporphyrin (H(2)tTETPP, H(2)cTETPP), and hexaethyltetraphenylporphyrin (H(2)HETPP).

The reaction of porphyrins with organolithium reagents.

Porphyrins react readily with organolithium reagents, preferentially in the meso positions. The overall reaction is a nucleophilic substitution and proceeds via initial reaction of the organic nucleophile with a meso carbon yielding an anionic species which is hydrolyzed to a porphodimethene (5,15-dihydroporphyrin), formally constituting an addition reaction to two Cm positions. Subsequent oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) yields meso-substituted porphyrins.

Facile meso Functionalization of Porphyrins by Nucleophilic Substitution with Organolithium Reagents.

The ruffle of the porphyrin increases with the number of meso substituents. (Octaethylporphyrin)nickel(II) undergoes nucleophilic substitution reactions upon treatment with alkylating reagents such as butyllithium, hydrolysis with water, and oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone [DDQ; Eq. (a)].

Electron microscopic band-interband pattern of polytene chromosomes in Drosophila nasuta albomicans. 1. Salivary gland chromosome 2R.

The band-interband pattern of salivary gland chromosome 2R in Drosophila nasuta albomicans (division 53-83) was studied by light (LM) and electron microscopy (EM) using squash preparations and surface-spread polytene (SSP) chromosome preparations, respectively. LM and EM maps were compiled. Based on the digitized EM patterns of five homologous SSP chromosomes a computerized chromosome map was plotted.