Cross polarization/magic angle spinning (CP/MAS)(13)C (solid state high resolution) NMR spectra were observed for chlorosomes and BChlc aggregates. Similarity of both kinds of spectra (except for some signals assignable to proteins and lipids in chlorosomes) indicates that BChlc's in chlorosomes are present just as in synthetic BChlc aggregates. Chemical shifts for C13(1) carbonyl and C3(1) hydroxylethyl carbons indicate hydrogen bonding between them. Comparison of solution and solid state(13)C NMR chemical shifts shows the five coordinated nature of BChlc aggregates. Some chemical shift differences were attributable to ring currents shifts. Their comparisons with calculated ring current shift values predicted structures for the aggregates. Cross polarization dynamics of the CP/MAS(13)C NMR signals explored dynamic and structural nature of the BChlc aggregates.

A new thermophilic bacterium Chlorobium tepidum contains two major bacteriochlorophyll c components whose periphery substituents at 4-position are either an ethyl or a propyl group. Both components possess ethyl groups at 5-position, and the ester alkyl groups at 7-position are farnesyl groups. As an aggregate structure in CDCl3 a piggy-back type dimer was suggested on the basis of variations of 1H NMR chemical shifts accompanied with the aggregate formation and of values of calculated ring current shifts. Bacteriochlorophyll c (BChl c) aggregates with absorption maxima around 677, 705, and 740 nm showed stepwise interchanges in hexane-dichloromethane with variations in BChl c concentrations and in solvent compositions. Exciton theoretical analysis of the stepwise spectral shifts predicted high ordered organization of BChl c, implying a model for rod-elements in chlorosomes.

High resolution solid state 13C NMR signals of bacteriochlorophyll (BChl) c were obtained for chlorosomes from Chlorobium tepidum. Observed BChl c signals which resembled those from oligomeric BChl c afforded ring current shift from which an aggregation structure was proposed.

Six bacteriochlorophyll (BChl) d homologues were isolated from Chlorobium limicola. The absorption spectral profiles in hexane–dichloromethane and the solvent effects indicate that the aggregation property of the BChl d’s strongly depend on the nature of the peripheral substituents.

A new thermophilic bacterium Chlorobium tepidum contained two major bacteriochlorophyll c components whose periphery substituent at 4-position was either an ethyl or a propyl group. Both components possessed ethyl groups at 5-position and the ester alkyl groups at 7-position were farnesyl groups.