Bipyridyl diamine

Various efforts >22,23 have been made to overcome the difficulties associated with the above synthesis. One approach is to modify the polymer structure to increase the solubility of the polyamic acid, for example, introducing some methylene groups via the use of an aliphatic diamine together with the aromatic diamine or the use of bipyridyl diamines. The other approach has been to use a different reaction to form the imide linkage. It is now known that polyimides can be formed from tetraacids and their dianhydride by condensation with diisocyanates with subsequent loss of CO2 and H2O [5].24-27... 

Numerous diamines and aromatic dianhydrides have been investigated. WhoUy aromatic Pis have been stmctiirally modified by incorporating various functional groups, such as ether, carbonyl, sulfide, sulfone, methylene, isopropjlidene, perfluoroisopropyUdene, bipyridyls, sdoxane, methyl phosphine oxide, or various combinations of these, into the polymer backbone to achieve improved properties. The chemistry and apphcations of Pis have been described in several review articles (4). 

Infrared spectral studies have been made for a large number of octahedral metal-carbonyl systems of the types LM(CO)5 (L = pyridine and quinoline), L2M(CO)4 [L2 = ethylene diamine, (pyridine)2, and bipyridyl], [LM(CO)4]2 (L = dimethylarsine or dimethylphosphine M = Cr, Mo, and W), and [LFe(CO)3]2 (L = SMe, PMe2) before and after electrochemical reduction. The force constants for the carbonyl groups... 

Modification of the [Co(CN)5]3 catalyst by addition of diamines has been reported to lead to higher catalytic activity in diene hydrogenation and a predominant 1,2-addition of hydrogen. Such systems are thought to contain the species [CoH(CN)3(diamine)]. Ethylenediamine, 2,2 -bipyridyl and 1,10-phenanthroline were the diamines used.57 58... 

Substitution at [CoCmnOaCPPhg)]" by the bidentate ligands ethylene-diamine, 2,2 -bipyridyl, 1,10-phenanthroline, and maleonitriledithiolate, and by the monodentate ligand triphenyl phosphite, takes place by two parallel paths. In the first, equilibrium loss of triphenylphosphine is followed by attack of the incoming ligand at the square-planar intermediate... 

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