Readily water-soluble photosensitive e.g. for photolysis in water - based on ruthenium complex contg. new poly:ethoxy-di:pyridazine cpd. ligand

摘要

Photosensitisers are based on Ru(II) complexes (I) contg. a complex cation of the formula Ru(LaLbLc(2+; La, Lb and Lc = substd. dipyridazine ligands of formula (II). New 6,6'-bis(omega-hydroxy-polyethoxy) -3,3'-dipyridazines and their symmetrical and asymmetrical ethers and esters are of formula (II); n and m = 1-10; R1-2 = H, 1-20C alkyl or acyl, opt. with halogen substit(s)., or 6-22C aryl, aralkyl or aracyl, opt. with halogen or alkoxy substit(s).; each R1 and/or R2 of the ligands may form a bridge linking the ligands. The prepn. of (I), which includes the prepn. of (II), is claimed. Pref., R1 and/or R2 = 2-20C alkyl, acyl, aryl or aracyl forming bridges between the substd. bipyridazine units. In particular, R1 = benzyl; the 3 R2 together = a benzene-1,3,5-tricarbonyl gp. (derived from trimesic acid); n = 1; m = 2. USE/ADVANTAGE - (I) have excellent photophysical properties, esp. high photostability, high quantum yield and long lifetime in the excited state. The hydrophilic substits. impart excellent solubility in water, which is necessary for significant technical processes. They can be synthesised easily in excellent yields. Photosensitisers of this type are useful in light-induced electron transfer reactions, e.g., the photochemical formation of CH4 from CO2 and esp. photolysis of H2O to H2 and O2.