Cyclotetrapeptide Complexes of Nickel(II) and Palladium(II) by Template Synthesis from Dipeptide Esters with Functionalized Side Chains-Crystal Structure of [(cyclo-Gly-beta-Ala-Gly-beta-Ala-4H~+)Cu](PPN)_2

摘要

The cyclocondensations ofdipeptide esters[Gly-L-Asp-(OMe)_2,Gly-L-Glu(OMe)_2,L-AspOMe-beta-AlaOMe,beta-Ala-L-Lys(omega-N-Boc,OMe),beta-Ala-L-Orn(omega-N-Boc,OMe)] at nickel(II),palladium(II),and copper(II) templates give dianionic square-planar complexes of deprotonated cyclotetrapeptides that contain funcional groups in the side chains.The complexes with 14- or 16-membered rings were isolated as [Ph_3PNPPh_3]~+ salts.Hydrolysis of {[cyclo-Gly-Asp(OMe)-Gly-Asp(OMe)-4H~+]Pd}~2- affords the tetraanionic complex [{cyclo-Gly-Asp(O~-)-Gly-Asp(O~-)-4H~+}Pd]~4-(Li~+)_2(PNP~+)_2.the crystal structure of [(cyclo-Gly-bta-Ala-Gly-beta-Ala-4H~+)Cu](PPN)_2 is also reported.