Structural and magnetic properties of cyclic tetranuclear or hexanuclear complexes synthesized with [PtCl2(NCtBu)2] and CuCl2 under basic conditions

Abstract

When cis- or trans-[PtCl2(NCtBu)2] was mixed with CuCl2 in MeOH under basic conditions, coordinated NCtBu was hydrolyzed to pivalamidate (piam) to capture Cu2+, accompanied by −OMe coordination and Cl− ion release. These mixing with cis-[PtCl2(NCtBu)2] and trans-[PtCl2(NCtBu)2] provided [{PtCu(piam)2}2(μ-OCH3)4] (1) and [{PtCu2(piam)2(OCH3)2}2(μ-OCH3)4] (2), which formed cyclic tetranuclear -Pt–Cu---Pt–Cu- and hexanuclear -Pt---Cu---Cu---Pt---Cu---Cu-, respectively. Several physical measurements revealed that the formal metal oxidation state in both 1 and 2 is +2, where the dx2–y2 unpaired electrons lie on the Cu2+ ions. Magnetic susceptibility measurements indicated that these unpaired electrons antiferromagnetically interact with neighboring electrons with 2J = −0.52 cm−1 for 1 and −26 cm−1 for 2.