Time-dependent Self-assembly of 31-epimerically Pure and Mixed Zinc Methyl Bacteriopheophorbides-d in an Aqueous THF Solution

Abstract

The self-aggregation process of 3(1)-epimerically pure and mixed zinc methyl bacteriopheophorbides-d (ZMBPhes-d) was examined by stopped-flow technique. A 33(v/v)% tetrahydrofuran (THF) - water solution of ZMBPhe-d was rapidly mixed with a 7(v/v)% THF - water solution to form a chlorosome-type aggregate with a red-shifted Qy band around 700 nm. We observed a rapid autocatalytic aggregation in a subsecond time scale. Aggregates of the 3(1)R epimer increased with a change in the Qy absorption maximum from 698 to 705 nm, suggesting that small aggregates formed as intermediate species. In addition, the rate of aggregation was dependent on the stereochemistry at the 3(1)-position of ZMBPhe-d; the 3(1)R epimer self-aggregated more rapidly than the 3(1)S epimer.

Stereoselective Self‐Aggregation of 31‐Epimerically Pure Amino Analogs of Zinc Bacteriochlorophyll‐d in an Aqueous Micelle Solution

“…It was previously reported that zinc methyl bacteriopheophorbide‐ d epimers 5 R/S stereoselectively self‐aggregated in 1% CH 2 Cl 2 and (cyclo)hexane as well as in an aqueous solution containing THF or α ‐lecithin to form supramolecular structures dependent on the 3 1 ‐chirality . In an aqueous TX‐100 micelle solution, (3 1 R ) ‐ epimer 5 R afforded broadened and redshifted electronic absorption bands at 708 and 434 nm, compared with the monomeric bands (648 and 422 nm in THF), where large exciton‐coupled CD couplets were observed (red line of Fig.…”

“…700 nm (1% CH 2 Cl 2 −cyclohexane) . In addition, its self‐aggregation has been studied in an aqueous solution containing THF, α ‐lecithin or Triton X‐100 (TX‐100) . Its 3 1 ‐epimerically pure 5 R and 5 S showed different self‐aggregation behavior in these solutions.…”

Crystal structure and solvent-dependent behaviours of 3-amino-1,6-diethyl-2,5,7-trimethyl-4,4-diphenyl-3a,4a-diaza-4-bora-s-indacene

“…On the other hand, time-dependent spectroscopic changes, in emission intensity, shift of maximal emission wavelength, or absorbance, have been observed for compounds that undergo self-assembly in solution (Gassensmith et al, 2007;Miyatake et al, 2005). Taken together, these observations suggest that BODIPY 2b shows a tendency to form assembled structures in The molecular structure of the title compound, with displacement ellipsoids drawn at the 30% probabilty level.…”

Self-Aggregation of Synthetic Bacteriochlorophyll-dAnalogues Possessing a B-Ring Reduced Chlorin π-System

“…Diastereomeric control by the 3 1 -epimers in 1 R and 1 S has been well studied: the stereochemical difference at the 3 1 -chiral center in 1 greatly influenced their self-aggregation behaviors (Figure S3, Supporting Information). ,, We examined self-aggregation of 3 R and 3 S and found a similar diastereomeric control by the 3 1 -configuration (Figure S3, Supporting Information). A common feature in 1 and 3 was that the UV−vis spectrum of each 3 1 R form in the self-aggregates was similar to that of the corresponding diastereomeric mixture (Figure ).…”