Assembly of Mn(III) Schiff Base Complexes with Heptacyanorhenate (IV)

A pioneering research on a self-assembly of the magneto-anisotropic module [Re(CN)7] with the Mn(III) complexes involving Salen type (N,N′-ethylenebis(salicylideneiminate)) Schiff base (SB) ligands was performed using the known [Mn(Salen)(H2O)2]2(ClO4)2·H2O (1) and the firstly synthesized [Mn2(Salen)2OAc]PF6 (2). In the case of 1, a slow diffusion of the component solutions led to the ionic compound Ph4P[Mn(Salen)(H2O)2]2[Re(CN)7]·6H2O (3). The direct mixing of the same solutions has resulted in the microcrystalline nearly insoluble solid [Mn(Salen)(H2O))4Re(CN)7]ClO4·1.5MeCN·6.5H2O, which is likely to comprise the pentanuclear clusters [(Mn(SB)(H2O))4Re(CN)7]. The use of 2 resulted in a 2D-network assembly of octanuclear clusters, [{(Mn(Salen))6(H2O)2Re(CN)7}2Re(CN)7]Cl2(PF6)·H2O (4), incorporating one Re-center in a pentagonal bipyramid coordination environment, while another has strongly distorted capped trigonal prism as a coordination polyhedron. The latter was observed for the first time for Re(IV) complexes. A synthetic challenge to obtain the 0D assemblies with Re:Mn ≥ 3 has yielded a hexanuclear complex [Mn(Salen)H2O(i-PrOH)] [(Mn(Salen))5H2O(i-PrOH)2Re(CN)7](PF6)2(OAc)·2i-PrOH (5) being 1D chain via a bridging phenoxyl group. Owing to a low solubility of the final product, an addition of a bulk anion Ph4B to the MeCN/MeOH solution of [Re(CN)7]and 1 in ratio 1:6 resulted in rhenium-free matter [Mn(Salen)(H2O)2][Mn(Salen)(H2O)MeCN](Ph4B)2·5MeCN (6).