A series of alternating Na+/M3+ (M = Mn, Fe) covalent and ionic chains

Abstract

We report the synthesis and full characterisation of a family of chains each exhibiting an alternating [M–Na–M–]_n (M = Mn³⁺ or Fe³⁺) 1-D topology linked via the 2,2′-biphenol ligand along with various N-donor co-ligands such as pyridine, 3-picoline and 2,2-bipyridine. The chains [Na₂Mn₂(biphen)₄(py)₃(EtOH)₂]_n (1), [Na₂Mn₂(biphen)₄(3-cnp)₂(EtOH)₃]_n (5), [{Na₂Mn₂(biphen)₄(4-Et-py)₃(EtOH)₂}·EtOH]_n (6) and [NaFe(biphen)₂(2,2-bipy)(EtOH)₂] (8) are connected into 1-D arrays via predominantly covalent bonds while their siblings [Na(BiphenH₂)(EtOH)_x(H₂O)_y][M(biphen)₂(L)₂]_n (M = Mn³⁺, L = 3-picoline, x = 3, y = 0 (2); M = Fe³⁺ L = 3-picoline, x = 3, y = 0 (3) and M = Mn³⁺, L = 4-cyanopyridine, x = 2, y = 1 (4)) are linked via ionic bonds along with strong hydrogen bonding interactions.