Reactions of bis(2-pyridyl)amine and its deprotonated anion with ruthenium and osmium carbonyl complexes

The reactions and coordination geometry of bis(2-pyridyl)amine (Hdpa) and its deprotonated anion (dpa) can be effectively modified by the reaction conditions. Depending on the solvent system, the reaction of multinuclear ruthenium carbonyls such as Ru-3(CO)(12) and [Ru(CO)(3)Cl-2](2) with Hdpa at moderate reaction temperatures lead to low yields of a monomeric cis(CO), cis(Cl)-Ru(Hdpa)(CO)(2)Cl-2 or a dimeric metal-metalbonded [Ru(dpa)(2)(CO)(2)](2)- In organic solvents high temperatures favor the formation of [Ru(dpa)(2)(CO)(2)](2) from clustered Ru-3(CO)(12) and Hdpa. The high-temperature reactions in HCl solution can, in turn, be used for selective synthesis of cis(CO),cis(Cl)-Ru(HdPa)(CO)(2)Cl-2. dpa (deprotonated with CH3Li) readily reacts with [Ru(CO)(3)Cl-2](2), Ru-3(CO)(12), or H4Ru4(CO)(12) in organic solvents, leading to [Ru(dpa)(2)(CO)(2)](2)- Under the corresponding conditions Os carbonyls produce a new type of dpa-bridged dimer compound without a direct metal-metal bond, [Os(dpa)(CO)(2)(CH3)](2), in addition to the ruthenium dimer equivalent [Os(dpa)(2)(CO)(2)](2).