Synthesis and crystal structure of a heterobimetallic nickel-manganese 12-metallacrown-4 methanol disolvate monohydrate compound.

Abigail J Hall,Curtis M Zaleski,Matthias Zeller

doi:10.1107/s205698902001316x

Abstract

The synthesis and crystal structure of the title compound [systematic name: di-μ-acetato-tetra-kis-(μ4-N,2-dioxido-benzene-1-carboximidato)hexa-methano-ltetra-manganese(III)nickel(II) methanol disolvate monohydrate], [Mn4Ni(C7H4NO3)4(C2H3O2)2(CH4O)6]·2CH4O·H2O or Ni(OAc)2[12-MCMn(III)N(shi)-4](CH3OH)6·2CH3OH·H2O, where MC is metallacrown, -OAc is acetate, and shi3- is salicyl-hydroximate, are reported. The macrocyclic metallacrown is positioned on an inversion center located on the NiII ion that resides in the central MC cavity. The macrocycle consists of an MnIII-N-O repeat unit that recurs four times to generate an overall square-shaped mol-ecule. Both the NiII and MnIII ions are six-coordinate with an octa-hedral geometry. In addition, the MnIII ions possess an elongated Jahn-Teller distortion along the z-axis of the coordination environment. The inter-stitial water mol-ecule is slightly offset from and disordered about an inversion center.

Highlights

-acetato-tetrakis(4-N,2-dioxidobenzene-1-carboximidato)hexamethanoltetramanganese(III)nickel(II) methanol disolvate monohydrate], [Mn4Ni(C7H4NO3)4(C2H3O2)2(CH4O)6]Á2CH4OÁH2O or Ni(OAc)2[12-MCMn(III)N(shi)-4](CH3OH)6Á2CH3OHÁH2O, where MC is metallacrown, ÀOAc is acetate, and shi3À is salicylhydroximate, are reported
The macrocyclic metallacrown is positioned on an inversion center located on the NiII ion that resides in the central MC cavity
While several examples of heterobimetallic 3d ‘collapsed’ metallacrowns, species without a central MC cavity and no central metal ion (Psomas et al, 2001; Gole et al, 2010), and inverse metallacrowns, species that bind a non-metal atom in the central MC cavity to the ring metal ions (Szyrwiel et al, 2013; Shiga et al, 2014; Zhang et al, 2014; Nesterova et al, 2015), have been reported, only two heterobimetallic 3d archetypal 12-MC-4 compounds have been described to date

Summary

Chemical context

Since their recognition in 1989 by Pecoraro, metallacrowns (MC) have proven to be a versatile class of metallamacrocycles with applications such as single-molecule magnets, magnetorefrigerants and optical imaging agents (Mezei et al, 2007; Nguyen & Pecoraro, 2017; Lutter et al, 2018). Homometallic compounds were produced; heterobimetallic systems were soon generated that typically contained transition-metal ions in the ring metal position and either alkali or lanthanide ions captured in the central cavity of the MC (Pecoraro et al, 1997; Mezei et al, 2007). We report a third heterobimetallic 3d archetypal 12MC-4 compound: NiII(OAc)2[12-MCMn(III)N(shi)-4](CH3OH)6Á2CH3OHÁH2O, 1, that contains ring MnIII ions and a NiII ion captured in the central MC cavity. The acetate binding motif is different than the analogous homometallic MnII(OAc)2[12MCMn(III)N(shi)-4](DMF)6Á2DMF, where the acetate anions bind on the same face of the MC and the central MnII ion exhibits a geometry that is best described as a trigonal prism (Lah & Pecoraro, 1989)

Structural commentary

Supramolecular features

Database survey

Synthesis and crystallization

Findings

Refinement