C6 to C17 Organic Products from Artificial Photosynthesis Catalyzed by 2-Phenyl Indole (PI) Titanium Tetrachloride Complex (PI)2TiCl4: The Synergism of Hydroxyl Radicals

Abstract

The newly discovered artificial photosynthesis process catalyzed by 2-phenyl indole (PI) and TiCl₄ complexes, activated by visible light, produces long-chain oxygenated hydrocarbons up to C₁₇. This process begins with the formation of α-carboxylic acid-ω-aldehyde compounds (C₆ to C₉), arising from a cascade of autocatalytic organotitanium complexes derived from (PI)₂TiCl₄. These complexes are formed via hydrolysis through ambient air humidity and the direct atmospheric capture (DAC) of CO₂. Carbon chain growth utilizes system-generated formaldehyde as a feedstock. The initial C₆ to C₉ compounds can further couple into C₁₂ to C₁₇ derivatives through a radical mechanism initiated by hydroxyl radicals. A proposed mechanism explores the synergistic interaction between organotitanium catalysis and hydroxyl radicals. This development represents the only known heterogeneous catalytic system that autonomously captures CO₂ and humidity from the atmosphere to subsequently produce long-chain oxygenated hydrocarbons using solar energy.