569-53-9

Basic information

• Product Name: bacteriopheophytin a
• CAS NO: 569-53-9
• Molecular Weight: 889.232
• Mol File: 569-53-9.mol

Chemical Properties

• CAS DataBase Reference: bacteriopheophytin a(CAS DataBase Reference)
• NIST Chemistry Reference: bacteriopheophytin a(569-53-9)
• EPA Substance Registry System: bacteriopheophytin a(569-53-9)

Safety Data

• Hazardous Substances Data: 569-53-9(Hazardous Substances Data)

Downstream Products

• 569-54-0 3¹-oxo-rhodobacteriochlorin 17³-methyl ester 

Relevant articles and documents

Production of bacteriopurpurin-18 phytyl ester from bacteriopheophytin a via allomerization by contact with titanium oxides in the presence of molecular oxygen

Incubation of bacteriopheophytin (BPhe) a, which was a demetalated pigment of bacteriochlorophyll a in photosynthetic bacteria, in CH2Cl2 in the presence of TiO2 particles with bubbling O2 in the dark produced a pigment absorbing 814 nm. Detailed characterization of the novel pigment isolated from the CH2Cl2 suspension revealed that bacteriopurpurin-18 phytyl ester possessing an anhydride-type six-membered exocyclic E-ring was majorly formed by the treatment with TiO2 particles under oxygenic conditions. Oxidation of the bacteriochlorin ring in BPhe a, namely formations of derivatives of 3-acetyl pheophytin a and 3-acetyl protopheophytin a, can barely be detected through the conversion processes.

High-pressure and theoretical studies reveal significant differences in the electronic structure and bonding of magnesium, zinc, and nickel ions in metalloporphyrinoids

High pressure in combination with optical spectroscopy was used to gain insights into the interactions between Mg2+, Zn2+, and Ni2+ ions and macrocyclic ligands of porphyrinoid type. In parallel, the central metal ion-macrocycle bonding was investigated using theoretical approaches. The symmetry properties of the orbitals participating in this bonding were analyzed, and pigment geometries and pressure/ligation effects were computed within DFT. Bacteriopheophytin a was applied as both a model chelator and a highly specific spectroscopic probe. The analysis of solvent and pressure effects on the spectral properties of the model Mg2+, Zn 2+, and Ni2+ complexes with bacteriopheophytin a shows that various chemical bonds are formed in the central pocket, depending on the valence configuration of the central metal ion. In addition, the character of this bonding depends on symmetry of the macrocyclic system. Since in most cases it is not coordinative bonding, these results challenge the conventional view of metal ion bonding in such complexes. In (labile) complexes with the main group metals, the metal ion-macrocycle interaction is mostly electrostatic. Significantly, water molecules are not preferred as a second axial ligand in such complexes, mainly due to the entropic constraints. The metal ions with a closed d shell may form (stable) complexes with the macrocycle via classical coordination bonds, engaging their p and s orbitals. Transition metals, due to the unfilled d shell, do form much more stable complexes, because of strong bonding via both coordination and covalent interactions. These conclusions are confirmed by DFT computations and theoretical considerations, which altogether provide the basis to propose a consistent and general mechanism of how the central metal ion and its interactions with the core nitrogens govern the physicochemical properties of metalloporphyrinoids.

Modulation of reactive oxygen species photogeneration of bacteriopheophorbide a derivatives by exocyclic E-ring opening and charge modifications

With the knowledge that the dominant photodynamic therapy (PDT) mechanism of 1a (WST09) switched from type 2 to type 1 for 1b (WST11) upon taurine-driven E-ring opening, we hypothesized that taurine-driven E-ring opening of bacteriochlorophyll derivatives and net-charge variations would modulate reactive oxygen species (ROS) photogeneration. Eight bacteriochlorophyll a derivatives were synthesized with varying charges that either contained the E ring (2a-5a) or were synthesized by taurine-driven E-ring opening (2b-5b). Time-dependent density functional theory (TDDFT) modeling showed that all derivatives would be type 2 PDT-active, and ROS-activated fluorescent probes were used to investigate the photogeneration of a combination of type 1 and type 2 PDT ROS in organic- and aqueous-based solutions. These investigations validated our predictive modeling calculations and showed that taurine-driven E-ring opening and increasing negative charge generally enhanced ROS photogeneration in aqueous solutions. We propose that these structure-activity relationships may provide simple strategies for designing bacteriochlorins that efficiently generate ROS upon photoirradiation.

Lessons from chlorophylls: Modifications of porphyrinoids towards optimized solar energy conversion

Practical applications of photosynthesis-inspired processes depend on a thorough understanding of the structures and physiochemical features of pigment molecules such as chlorophylls and bacteriochlorophylls. Consequently, the major structural features of these pigments have been systematically examined as to how they influence the S1 state energy, lifetimes, quantum yields, and pigment photostability. In particular, the effects of the macrocyclic φ-electron system, central metal ion (CMI), peripheral substituents, and pigment aggregation, on these critical parameters are discussed. The results obtained confirm that the φ-electron system of the chromophore has the greatest influence on the light energy conversion capacity of porphyrinoids. Its modifications lead to changes in molecular symmetry, which determine the energy levels of frontier orbitals and hence affect the S1 state properties. In the case of bacteriochlorophylls aggregation can also strongly decrease the S1 energy. The CMI may be considered as another influential structural feature which only moderately influences the ground-state properties of bacteriochlorophylls but strongly affects the singlet excitedstate. An introduction of CMIs heavier than Mg2+ significantly improves pigments' photostabilities, however, at the expense of S1 state lifetime. Modifications of the peripheral substituents may also influence the S1 energy, and pigments' redox potentials, which in turn influence their photostability.

Synthesis of 18O-labeled photosynthetically active chlorophylls at the 3- or 7-carbonyl group with high regioselectivity

The 3- and 7-formyl groups of chlorophyll-d (Chl-d) and bacteriochlorophyll-e (BChl-e), respectively, were regioselectively labeled with an isotopically stable oxygen-18 (18O) atom to give 31-18O-labeled Chl-d and 71-18O-labeled BChl-e (ca. 90% 18O) by exchanging the carbonyl oxygen atoms in the presence of acidic H218O (ca. 95% 18O). Another photosynthetically active chlorophyll, BChl-a possessing the 3-acetyl group was treated under similar acidic conditions to afford a trace amount of 31-18O-labeled BChl-a and further demetallated compound, the corresponding 31-18O-labeled bacteriopheophytin-a as the major product with 55% 18O-degree. The FT-IR spectra of 18O-(un)labeled chlorophylls in the solution and the solid states showed that the 3- and 7-carbonyl stretching vibration modes moved to about a 30-cm-1 lower wavenumber by 18O-labeling at the 31- and 71-oxo moieties. In artificial chlorosome-like self-aggregates of BChl-e, the 18O-labeled 7-carbonyl stretching mode was completely resolved from the specially hydrogen-bonded 13-C=O stretching mode, evidently indicating no interaction of the 7-CHO with other functional groups in the supramolecules.