Synthesis of zinc bacteriochlorophyll-d analogues with various 17-substituents and their chlorosomal self-aggregates in non-polar organic solvents

Abstract

Zinc 3(1)-demethyl-bacteriopheophorbides-d possessing various 17-propionate residue (17(2)-COOCH2-) were prepared as models of light-harvesting pigments in major photosynthetic antennae of green bacteria. The synthetic compounds were monomeric in polar organic solvents to give the same visible absorption spectra, but self-aggregated in non-polar organic solvents to afford large oligomers with broadened and red-shifted absorption bands. The peak positions were identical for all the self-aggregates but the widths of the redmost (Qy) bands were dependent upon the substituents. More hydrophobic and less sterically hindered hydrocarbon moieties as the esterifying group sharpened oligomeric Qy bands, giving less inhomogeneous supramolecular structures due to stabilization of the self-aggregates. In the reverse esters (17(2)-CH2OCO-) structurally isomeric to the above compounds, the same optical behavior was observed. Movement of the oxo group from the 17(3)- to 17(5)-position (17(2)-COOCH2--->17(2)-CH2OCO-) slightly increased the widths of self-aggregated Qy bands without change of the peak positions, where minor less self-aggregated components would enhance in the solution due to a little more stabilization of such species by the 17(4)-carbonyl group.

Chlorophyll-aDerivatives with Various Hydrocarbon Ester Groups for Efficient Dye-Sensitized Solar Cells: Static and Ultrafast Evaluations on Electron Injection and Charge Collection Processes

“…Chlorin-1, methyl pyropheophorbide- d , methyl pyropheophorbide- a (chlorin-R1), and chlorin-R2 were prepared according to reported procedures. Chlorins-2−5 were synthesized by transesterification of methyl ester of methyl pyropheophorbide- d with ROH, followed by Wittig reaction of the 3-formyl group with Ph 3 PCHCOOC(CH 3 ) 3 , and acidic cleavage of the resulting tert -butyl ester. Their synthtetic route is shown in the Supporting Information, Figure S6.…”

Synthesis, Spectroscopic, and in Vitro Photosensitizing Efficacy of Ketobacteriochlorins Derived from Ring-B and Ring-D Reduced Chlorins via Pinacol–Pinacolone Rearrangement

“…These chromophores exhibit long-wavelength absorption in the range of 720–800 nm depending on the nature of substituents present at the peripheral positions of the molecules. In recent years, enormous interest has been generated due to the utility of bacteriochlorins in the bacterial photosynthetic reaction center and in the treatment of cancer by PDT. There are several bacteriochlorophyll-a analogues, which are currently under advanced human clinical trials (e.g., Tookad) or at the advanced preclinical studies (bacteriopurpurinimides) for the treatment of cancer .…”

Trifunctional (Pyropheophorbide a – Steroid – Hexadecyl Chain) Conjugates: Synthesis, Solubilization, Interaction with Cultured Cells

“…On the contrary, spectra 1 -pl and 2 -pl even at a ratio conjugate/pluronic 1:50 were insufficiently resolved (Figure 4); the Soret bands were broad; the long wave maxima had additional shoulder near 710 mn, that indicated association of macrocycle chromophores with formation of stacked Trifunctional (Pyropheophorbide a -Steroid -Hexadecyl Chain) Conjugates structures. [24,25] The related spectra 1 -pl and 2 -pl at a ratio conjugate/pluronic 1:10 were resemble to those presented in Figure 4, but displayed certain turbidity and poor resolution. In comparison with conjugate -PC micelles, conjugate -pluronic micelles were larger in size and less stable.…”