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New amphiphilic and spin-labile MnIIIcomplexes based on dianionic N4O2-hexadentate sal2trien or sal2bapen ligands, which contain OC6H13, OC12H25, or OC18H37alkoxy substituents at different positions of the salicylidene unit were prepared (H2sal2trien = N,N′′′-bis(salicylidene)-1,4,7,10-tetraazadecane, H2sal2bapen = N,N′′′-bis(salicylidene)-1,5,8,12-tetraazadodecane). According to electrochemical measurements, these complexes undergo two (quasi)reversible redox processes. Temperature-dependent magnetic measurements revealed a high-spin configuration for all sal2trien complexes (S= 2) and gradual spin crossover for sal2bapen complexes from high to low spin (S= 1). The chain length strongly influences the spin crossover, as C18-functionalization stabilizes the low spin state at much higher temperatures than shorter alkyl chains. Moreover, long alkyl chains allow for spontaneous self-assembly of the molecules, which was investigated in single crystals and in Langmuir-films at the air–water interface. Long alkyl chains (C12or C18) as well as a mutual syn-orientation of these molecular recognition sites were required for the Langmuir monolayers to be stable. [ABSTRACT FROM AUTHOR]

New sal2(trien) ligands that contain alkoxy substituents of various length in metaposition of the phenolate entities were coordinated to electronically and magnetically active iron(III) and cobalt(iii) centers. The electrochemical and spectroscopic properties of these amphiphilic complexes are virtually unaffected upon alteration of the alkoxy substituents, thus providing a system in which the physical behavior and the metal-centered chemical activity can be tailored independently. The amphiphilic character has been exploited for preparing Langmuir monolayers at the air–water interface and for constructing Langmuir–Blodgett films, hence allowing for hierarchical assembling of electronically and magnetically active systems. While Langmuir films were stable, transfer onto solid supports was limited, which restricted the magnetic analysis of the Langmuir–Blodgett assemblies. [ABSTRACT FROM AUTHOR]