Darstellung von aliphatisch und cycloaliphatisch verbrückten Porphyrin‐Chinonen als Modellverbindungen zur Untersuchung der lichtinduzierten Ladungstrennung in der Photosynthese

Synthesis of Porphyrin Quinones with Aliphatic and Cycloaliphatic Bridges as Model Compounds for Studying the Light‐Induced Charge Separation in Photosynthesis Covalently linked porphyrin quinones (P–Qs) are well‐suited as biomimetic model compounds in studying the light‐induced charge separation occuring in primary processes of photosynthesis. We report on a synthetic strategy which leads to P–Qs with the porphyrin donor covalently linked to the quinone acceptor via aliphatic and cycloaliphatic spacers. Preparation of two diastereomeric cyclohexylene‐bridged P–Qs 1 and 2 and of 3 bearing a butylene spacer is described. Structures, including the spatial arrangements of the donor, bridge and acceptor, are determined by various NMR techniques. These data are compared with those deduced from simple force‐field calculations using the molecular modelling program ALCHEMY II (Tripos Associates) and MNDO (MOPAC‐6) calculations.