Хлорофилл b

Description

Chlorophyll b is a photosynthetic pigment of plants and green algae, a magnesium complex of a porphyrin (forbin) framework with a phytol side chain. CAS 519-62-0, chemical formula C55H70MgN4O6. One of the two main chlorophylls of higher plants, along with chlorophyll a, is distinguished by the presence of a formyl group instead of a methyl group at the 7th carbon atom of the porphyrin ring.

Basic Attributes

• CAS No.: 519-62-0
• Chemical formula: C55H70MgN4O6
• Molecular weight: 907.47
• Exact weight: 906.514587
• EU number: 208-272-4
• HS code: 29339900
• PSA specifications: 121.32
• XLogP3: 9.1335

Physico-chemical characteristics

• Melting point: 183–185 °C
• Boiling point: 1071.6 °C at 760 mm Hg. Art.
• Flash point: 601.9 °C
• Storage conditions: 2–8 °C
• Specific rotation: D20 -267° (acetone-methanol)

Class of substance and role in photosynthesis

Chlorophyll b is an auxiliary pigment of the light-harvesting antenna complexes (LHC) of plant photosystems. The absorption spectrum of chlorophyll b (maximum around 460 nm) complements that of chlorophyll a, expanding the range of light captured. The pigment is necessary for stabilizing the main light-harvesting chlorophyll-binding antenna proteins, although it itself is not necessary for primary photochemistry - this function is performed by chlorophyll a in the reaction center of the photosystem. The energy of the light absorbed by chlorophyll b is transferred along the chain of pigments to the chlorophyll a molecule of the reaction center.

Scope of application

• biochemical standard for analytical methods for the quantitative determination of photosynthetic pigments
• object of research on the structure and function of light-harvesting complexes of plants and algae
• natural green dye and component of plant extracts
• raw materials for the production of semi-synthetic derivatives, including chlorophyllin

Safety Information

• Transport codes: NONH for all modes of transport
• WGK Germany: 3
• Safety instructions: 22-24/25

Storage and transportation conditions

Store at 2–8 °C in an airtight container, protected from light - like all chlorophylls, the compound is sensitive to photo-oxidation and degradation at room temperature. The storage area is dry, away from heat sources and direct sunlight.

Synonyms

The nomenclature includes “β-chlorophyll”, “magnesium, [3,7,11,15-tetramethyl-2-hexadecenyl...forbinpropanoato]-”, reflecting the full systematic name of the forbin derivative.

Comparison with chlorophyll a

It differs from chlorophyll a in the presence of a formyl group (-CHO) instead of a methyl group at the 7th carbon atom of the porphyrin ring, which shifts the absorption spectrum and gives chlorophyll b a characteristic blue-green rather than bright green hue.

Extraction and purification

Isolated from plant materials by extraction with organic solvents followed by chromatographic purification from accompanying pigments - chlorophyll a, carotenoids and xanthophylls.