The stereospecific synthesis of Λ-α-{dipyrido[3,2-a:2′3′-c]-(6,7,8,9-tetrahydro)phenazine[N,N′-di(2-picolyl)-2,5-dimethyl-2S,5S-diaminocyclohexane]ruthenium(II)} and related β-isomers

The conglomerate, Delta,Lambda-alpha-[Ru(picchxnMe(2))(dpqC)](ClO4)(2).0.5H(2)O and Delta-alpha-[Ru(S,S-picchxnMe(2))(dpqC)](ClO4)(2).0.5H(2)O (where picchxnMe(2) = N,N'-dimethyl-1,2-di(2'-picolyl)-S,S-diaminocyclohexane and dpqC = dipyrido[3,2-a:2'3'-c](6,7,8,9-tetrahydro) phenazine) have been isolated. Single crystal X-ray structures have been determined, although it was discovered only after initial data had been collected that the, Delta,Lambda-alpha-[Ru(picchxnMe(2))(dpqC)](ClO4)(2).0.5H(2)O species was in fact a conglomerate. Lambda-alpha-[Ru(S,S-picchxnMe(2))(dpqC)](ClO4)(2).0.5H(2)O crystallises in the orthorhombic space group C222(1) with a = 15.127(2), b = 22.976(4), c = 25.561(7) Angstrom, (alternatively a = 15.187( 3), b = 23.003(6), c = 25. 685(7) Angstrom, for the separate determination of a crystal of the conglomerate), Z = 8, and the Lambda-alpha structure was refined to an R value of 0.059. This structure enables, for the first time, the correlation of the absolute configurations for Ru(II) complexes of the N-4 tetradentate with their CD spectra. We also report here a procedure to synthesise and isolate enantiomerically pure isomers of tetradentate metal complexes of the types alpha- and beta-[Ru(R*, R*-picchxnMe(2))(dpqC)](2+).