Ruthenium-Containing Polydyes

Polymers were synthesized from the reaction of cis-dichloro-bis(2 2-bipyridine)-ruthenium II, Ru(bipy)2Cl2, with dyes which were suspended in an 80% by volume methanol aqueous solution. This mixture was reflexed on a steam bath for about six hom, after which the methanol allowed to evaporate. The reaction mixture was cooled over night. The solution was washed with benzene to remove unieacted diamine and washed with chloroform to remove unreacted Ru(bipy)2Cl2. The remaining Uquid was removed under vacuum giving the polymer as a soUd, generally in good yield. 

The polymer, 9, from Ru(bipy)2Cl2 and 6-butoxy-2,6-diamino-3,3 -azodipyridine, diazopy is produced in 89% yield. It is soluble in DMSO, methanol, ethanol, and slightly soluble in chloroform. It is insoluble in benzene, carbon tetrachloride, acetone. 

The type of bonding between the ruthenium and the amine dye is coordination. The UV-Vis results are an important aspect to light harvesting. Spectra were obtained in DMSO. 

The diazopy dye itself has two bands at 291 nm, and the absorption band is at 454 nm. The polymer product shows a number bands, with the bands appearing at 495,437,355,328,295,266, and 252nm. There is a broad band on the higher side of 500 nm that probably corresponds to the 557 nm band found in Ru(bipy)2Cl2. The 

The polymer from Ru(bipy)2Cl2 and diazopy has all the bands from the two reactants essentially the same except for the A, max band for the dye at 454 nm, which is missing. However, the bands are broader for die polymer and the 454 nm band is now probably lost within this broadening caused by the Ru(bipy)2 moiety. The product also contains a large peak at 295 nm. The 295 nm band is the A. max for the product, as is the 300nm for Ru(bipy)2Cl2. There are also broad peaks at 355 nm and 495 nm and a less intense peak at 252 nm. It is interesting, that the A. max for the dye itself at 454 nm now corresponds to a much smaller peak at 437 nm. 

---