Photoswitchable Heterotrimetallic Chain Based on Octacyanomolybdate, Copper, and Nickel: Synthesis, Characterization, and Photomagnetic Properties

Abstract

Taking into account the general interest in photoswitchable nanomagnets, we present an original synthetic route to well-defined photoswitchable heterotrimetallic complexes. Our strategy demonstrates the feasibility of using a "molybdenum-copper" switchable complex with terminal cyanide ligands as relevant synthons for the rational design and synthesis of heterotrimetallic photoswitchable molecular architectures. Starting from a pentanuclear compound based on an octacyanometalated precursor, [MoIV(CN)4(CNCuII(Me2en)2)4]4+, and a [NiII(cyclam)]2+ assembling building block, we succeeded in synthesizing a photoswitchable heterotrimetallic chain, denoted as {NiMo2Cu7}n. The compound has been characterized by single-crystal X-ray diffraction, UV-vis and IR spectroscopies, and powder magnetic and photomagnetic susceptibility measurements. Before irradiation, the compound behaves as a paramagnet with eight independent spin carriers (CuII d9, S = 1/2, and NiII d8, S = 1). After irradiation, a long-lived metastable state persists until relatively high temperature (120 K) and is thermally reversible.