Palladium principal characteristics

Palladium chemistry of heterocycles has its idiosyncrasies stemming from their different structural properties from the corresponding carbocyclic aryl compounds. Even activated chloroheterocycles are sufficiently reactive to undergo Pd-catalyzed reactions. As a consequence of a and y activation of heteroaryl halides, Pd-catalyzed chemistry may take place regioselectively at the activated positions, a phenomenon rarely seen in carbocyclic aryl halides. In addition, another salient peculiarity in palladium chemistry of heterocycles is the so-called heteroaryl Heck reaction . For instance, while intermolecular palladium-catalyzed arylations of carbocyclic arenes are rare, palladium-catalyzed arylations of azoles and many other heterocycles readily take place. Therefore, the principal aim of this book is to highlight important palladium-mediated reactions of heterocycles with emphasis on the unique characteristics of individual heterocycles. 

The complexes of type 641 were obtained according to the same technique by interaction of ligands 640 with Co, Ni, Cu, Zn, and Cd acetates in methanol. In case of palladium acetate, acetone was used as solvent [95], The principal circumstance is the fact that, together with well-known and studied binuclear complexes 641 (X = Y = O) [92,93], a series of novel binuclear complexes (X = NTs, Y = 0, S) has been obtained and, in some cases, structurally characterized [94,96,98], They possess antiferromagnetic properties, which are especially characteristic for Cu, Ni, and Co complexes with M2S2bridge. Their magnetic moments at 78 K have considerably decreased magnitudes 1.45 B.M. (M = Co2+), 0.45 B.M. (M = Ni2+), and 0.41 B.M. (M = Cu2+) [95],... 

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