Design, Synthesis, Characterization And Photo-electric Properties Of Novel Multi-ferrocenyl Pyridinium Salts

In this dissertation, a series of novel multi-ferrocenyl pyridinium salts, with pyridinium cation as electron acceptor and ferrocenyl as electron donor, were designed and synthesized for generating materials possessing interesting optical and electrochemical properties. Main contents are as follows.1. Seven new compounds were designed and synthesized by inserting different conjugated bridge, including vinyl, ethynyl, phenyl or chloroethenyl, between pyridinium cation and ferrocenyl, 2,6-bis [4- ferrocenyl -(1E,3E)-1,3-butadienyl] -N- methylpyridinium iodide (36), 2,4,6-tris [4- ferrocenyl-(1E,3E)-1 ,3-butadienyl] -N- methylpyridinium iodide (37), 2,6- bis [(4-ferrocenyl)phenyl-2-(E)-vinyl]-N-methylpyridinium iodide (38), 2,4,6-tris [(4-ferrocenyI)phenyl-2-(E)-vinyI]-N-methylpyridinium iodide (39), 2,6-bis[4- ferrocenyl-(1E,3Z)-4-chloro-1,3-butadienyl]-N-methylpyridinium iodide (40), 2,4,6-tris[4-ferrocenyl-(1E,3Z)-4-chloro-1,3-butadienyl]-N-methylpyridmium iodide (41), 2,6-bis [4-ferrocenyl-(1E)-buten-3-yne]-N-methylpyridinium iodide (42). The structures of these compounds were characterized with MS, ¹H NMR, ¹³C NMR, and elementary analysis.Reasonable synthetic route was suggested and some reactions were improved. For example, a practical procedure for preparation of (E)-3-ferrocenyl-2-propenal, as an important intermediate, was developed from ferrocene carboxaldehyde with Nagata's reagent in high yield (83%) under mild conditions. This process was unsensitive to moisture and oxygen, and the purification was convenient.2. One of important ways for improving nonlinear optical and electrochemical properties of pyridinium salts is change of anion. In this dissertation, two salts 2, 6-bis (ferrocenylvinyl)-N-methylpyridinium idodide and 2, 4, 6-tris (ferrocenylvinyl)-N-methylpyridinium iodide were used as model compounds, and I" was replaced with Br^-, Cl^-, ClO₄^-, and NO₃^-, respectively. Eight new compounds of 2, 6-bis(ferrocenylvinyl)-N-methylpyridinium and 2, 4, 6-tris (ferrocenylvinyl) - N-methyl pyridinium salts with different anions were obtained.It is difficult to achieve the above-mentioned salts by directly anion transformation for all of the salts are insoluble in water. However, quaternary ammonium hydroxide could be easily quantitatively prepared by reaction of 2, 6-dimethyl-N-methylpyridinium iodide or 2, 4, 6-trimethyl-N-methylpyridinium iodide with fresh prepared silver oxide, and then treated with strong-basic ion-exchange resin. Reaction of this quaternary ammonium hydroxide with different acids, including HCl, HBr, HNO₃ or HClO₄, gave the corresponding salts of 2, 6-dimethyl-N-methylpyridinium or 2, 4, 6-trimethyl-N-methylpyridinium with Cl^-, Br^-, NO₃^-, or ClO₄^- as anion. At last the condensation of ferrocene carboxaldehyde with these salts gave the eight new compounds with satisfactory yields (Cl^-, 91 %; Br^-, 87%; NO₃^-, 86%; ClO₄^-, 82% for 2,6-bis(ferrocenylvinyl)-N-methylpyridinium salts; Cl^-, 85%; Br^-, 80%; NO₃^-, 76%; ClO₄^-, 71% for 2,4,6-tris(ferrocenylvinyl) -N-methyl pyridinium salts).3. The above-mentioned salts were modified on nitrogen atom by introducing different alkyl groups to give series of different N-alkyl pyridinium salts.2,6-dimethyl-N-alkylpyridinium or 2,4,6-trimethyl-N-alkylpyridinium iodide was prepared with the method similar to 2,6-dimethyl-N-methylpyridinium or 2,4,6-trimethyl-N-methylpyridinium iodide by replacing of iodomethane with ethyl iodide, n-propyl iodide, n-butyl iodide, and n-pentyl iodide, respectively. 2,6-Bis(ferrocenylvinyl)-N-ethylpyridinium iodide (76), 2,6-bis(ferrocenylvinyl)-N-propylpyridinium iodide(77), 2,6-bis(ferrocenylvinyl)-N-butylpyridinium iodide(78), and 2,6-bis(ferrocenylvinyl)-N-pentyl pyridinium iodide (79) were synthesized under the optimized condition. Similarly, 2, 4, 6- tris (ferrocenylvinyl)-N-ethylpyridinium iodide (80), 2,4,6-tris(ferrocenylvinyl) -N-propyl yridinium iodide (81), 2,4,6-tris(ferrocenyl- vinyl)-N-butylpyridinium iodide (82) were prepare...