Tolyporphins L-R: Unusual Tetrapyrroles from a Brasilonema sp. of Cyanobacterium.

Tolyporphins L-R (2-8) have been isolated from a mixed cyanobacterium-microbial culture. The structures of tolyporphins L and M have been revised to four constitutional isomers, isolated as two mixtures of dioxobacteriochlorins (2/3 and 4/5). In contrast, tolyporphin P (6) is a fully oxidized tetrapyrrole, while tolyporphins Q and R (7 and 8) are oxochlorins. X-ray structures are reported for the first time for tolyporphins A (1), R (8), and E (9), revealing unexpected stereochemical variation within the series.

Crystal structure of penta-kis-(ethyl-enedi-amine-κ(2) N,N')lanthanum(III) trichloride-ethylene-diamine-dichloromethane (1/1/1).

We report here the crystal structure of a ten-coordinate lanthanum(III) metal coordinated by five bidentate ethyl-enedi-amine ligands, [La(C2H8N2)5]Cl3·C2H8N2·CH2Cl2. One free ethyl-enedi-amine mol-ecule and three Cl(-) anions are also located in the asymmetric unit. The overall structure is held together by an extensive hydrogen-bonding network between the Cl(-) anions and the NH groups on the metal-bound ethyl-enedi-amine ligands. The free ethyl-enedi-amine mol-ecule is held in an ordered position by additional hydrogen bonds involving both the chlorides and -NH groups on the metal-bound ligands. One highly disordered mol-ecule of di-chloro-methane is located on an inversion center; however, all attempts to model this disorder were unsuccessful. The electron density in this space was removed using the BYPASS procedure [van der Sluis & Spek (1990 ▶). Acta Cryst. A46, 194-201].