エネルギーと光誘導による電子の移転は,車輪形の人工光合成アンテナ-反応センター複合体にある
Gerdenis Kodis1, Yuichi Terazono, Paul A Liddell
1Department of Chemistry and Biochemistry, Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, AZ 85287-1604, USA.
Journal of the American Chemical Society
|February 9, 2006
まとめ
研究者は,エネルギーと電荷を効率的に転送する人工光合成分子を作成しました. これらのシミュレータは,急速なエネルギー伝送と,自然光合成システムに近付く,電荷分離のための高い量子収量を達成します.
科学分野:
- 人工光合成による合成です.
- 超分子化学 超分子化学
- フォトケミストリー フォトケミストリー
背景:
- 自然光合成は,効率的な光収集と電荷分離のためにアンテナと反応センターの複合体を利用します.
- これらの機能を模倣する人工システムの開発は,再生可能エネルギーアプリケーションにとって極めて重要です.
- 以前の人工システムは,同様の効率と安定性を達成する上で課題に直面していた.
研究 の 目的:
- 光合成アンテナ反応センター複合体の新しい機能的模倣を合成し,特徴づけること.
- これらの人工システム内のエネルギーと電子転送プロセスの効率を調査する.
- これらのミミックの性能を自然の光合成システムと理論モデルと比較する.
主な方法:
- ビス (((フェニルエチニル) アントラセンのアンテナ部分とポルフィリン・フルレンの二酸化物を含む複雑な分子の合成.
- エネルギーと電子伝送のダイナミクスを分析するためのスペクトロスコピー研究.
- 分析のためにフォースター共振エネルギー伝送 (FRET) と電子交換メカニズムを使用した.
主要な成果:
- 合成された分子でシングレット・シングレットエネルギー伝送と光誘導電子伝送を成功裏に統合した.
- ピコ秒の時間スケールでアンテナからポルフィリンへのエネルギー転送で,単位に近い量子収量 (1.0) を達成した.
- チャージ分離のための高い量子収量 (80-96%) が示され,チャージ分離状態のナノ秒寿命があります.
結論:
- 設計された分子は,天然の光合成複合体の重要な機能を効果的に真似しています.
- フォースターメカニズムによって,自然のシステムに匹敵する急速なエネルギー転送が促進されます.
- 人工システムは,効率的で安定した電荷分離を示し,太陽エネルギー変換の有望性を示しています.
関連する概念動画
Photosystem II
The multi-protein complex photosystem II (PS II) harvests photons and transfers their energy through its bound pigments to its reaction center, and ultimately to photosystem I (PSI) through the electron transport chain. The pigments responsible for caputirng the light energy in photosystems include chlorophyll a, chlorophyll b, and carotenoids.
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
Photoelectric Effect
When light of a particular wavelength strikes a metal surface, electrons are emitted. This is called the photoelectric effect. The minimum frequency of light that can cause such emission of electrons is called the threshold frequency, which is specific to the metal. Light with a frequency lower than the threshold frequency, even if it is of high intensity, cannot initiate the emission of electrons. However, when the frequency is higher than the threshold value, the number of electrons ejected...
The Photochemical Reaction Center
Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center is a more appropriate term that describes these complexes. The Nobel laureates Robert Emerson and William Arnold provided the first experimental evidence of photochemical reaction centers by demonstrating the participation of nearly 2,500 chlorophyll molecules for the release of just one molecule of oxygen. Despite thousands of photosynthetic...
The Antenna Complex
Plants and other photosynthetic organisms comprise pigments capable of absorption of direct sunlight. These pigments are present in the reaction center - the main site of photochemical reactions as well as in the antenna complex. Under average light conditions, the rate at which reaction center pigments absorb light is far below the electron transport chain's capacity. As a result, the reaction center alone cannot provide enough energy to drive photosynthesis. The photosynthetic efficiency can...
Energy Transfer in Chemical Reactions
Chemical reactions require sufficient energy to cause the matter to collide with enough precision and force that old chemical bonds can be broken and new ones formed. In general, kinetic energy is the form of energy powering any type of matter in motion. Imagine a person building a brick wall. The energy it takes to lift and place one brick on top of another is the kinetic energy—the energy matter possesses because of its motion. Once the wall is in place, it stores potential energy. Potential...
Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...


