{CoII/III5} horseshoe and {NiII4} lacunary cubane coordination clusters: the isobutyrate/N-butyldiethanolamine reaction system

Abstract

The polynuclear coordination compounds [Co II 3 Co III 2 (Hbda) 2 (bda) 2 (ib) 6 ]$2MeCN (1) and [Ni II 4 (Hbda) 3 (ib) 5 (MeCN)] (2) (H 2 bda ¼ N-butyldiethanolamine, ib ¼ isobutyrate) are prepared under aerobic conditions using an identical synthetic protocol that solely differs in the employed transition metal (Co II vs. Ni II ). Whereas compound 1 displays a mixed-valent, pentanuclear, horseshoe-shaped structure with alternating Co(II) and Co(III) ions, compound 2 presents a tetrahedrally-shaped Ni(II) structural motif where four nickel centers are bridged by three O atoms to afford a lacunary Ni 4 O 3 cubane, a motif hitherto only observed as a substructure of higher-nuclearity coordination clusters and polyoxometalates. Both compounds are thermally surprisingly stable (>130 C). 1 exhibits weak antiferromagnetic exchange interactions; 2 shows a ferromagnetic coupled triangle of three Ni centers interacting antiferromagnetically with a single Ni apex. Fig. 4 Temperature dependence of c m T at 0.1 T of compound 2; inset: molar magnetization M m vs. B at 2.0 K: experimental data (open circles), least-squares fit (red solid lines).This journal is

Synthesis and crystal structure of a one-dimensional chain-like strontium(II) coordination polymer built of N-methyldiethanolamine and isobutyrate ligands

“…= 61.25%), and it yields SrCO 3 . Overall, the thermal stability of I up to 130 C in air is similar to that determined for isobutyrate diethanolamine complexes of cobalt (140 C) and nickel (130 C) (Schmitz et al, 2016).…”

“…(Parsons et al, 2000). The formation of these polynuclear homo-and heterometallic complexes was enabled by the introduction of flexible amino alcohol ligands into the reaction mixtures (Schmitz et al, 2016;Malaestean et al, 2010). We describe here the first example of a coordination polymer composed of monomeric Sr II units that are supported by both isobutyrate and amino alcohol ligands.…”

Conductive Self-Assembled Monolayers of Paramagnetic {CoIICo4III} and {Co4IICo2III} Coordination Clusters on Gold Surfaces

“…Compound 2 crystallizes in the orthorombic space group Pbca and represents an ionic compound consisting of the hexanuclear [Co 6 (N 3 ) 4 ( N - n -bda) 2 (bza·SMe) 5 (MeOH) 4 ] + complex charge-balanced by a Cl − ion (Figure 2). Five cobalt atoms exhibiting alternating oxidation states +II and +III [ Σ bv (Co II ) = 1.9–2.0, Σ bv (Co III ) = 3.1] form a semicircular or horseshoe-shaped metal core structure reminiscent of that previously described complex [Co3IICo2III( N - n -bda) 2 ( N - n -Hbda) 2 (ib) 6 ] (Schmitz et al, 2016a) (see Supporting Information for a comparative analysis). However, in 2 , this structural motif is complemented with a centrally accommodated, sixth cobalt(II) atom.…”

“…Each compound was dissolved in DMSO and the resulting green solutions were heated up to 100°C for 120 h in sealed autoclavable glass vials, followed by slow cooling to room temperature. Contrary to the reaction solution containing 1 yielding pink needle-shaped crystals of [Co10II(N 3 ) 2 ( N - n -bda) 6 (bza·SMe) 6 ] ( 3 ), that of compound 2 gave no crystalline product, although 2 can be strikingly compared to the previously synthesized coordination cluster [Co3IICo2III( N - n -bda) 2 ( N - n -Hbda) 2 (ib) 6 ] (ib − = isobutyrate) (Schmitz et al, 2016a). Interestingly, the latter complex acts as an indispensable precursor material for the preparation of the previously reported complex [Co10II(OH) 2 ( N - n -bda) 6 (ib) 6 ] (Schmitz et al, 2018b) that shows similarities to 3 (see Discussion of their molecular structures below).…”

“…Molecular structure of [Co4IICo2III(N 3 ) 4 ( N - n -bda) 2 (bza·SMe) 5 (MeOH) 4 ] + in 2 (A) and comparison to [Co3IICo2III( N - n -bda) 2 ( N - n -Hbda) 2 (ib) 6 ] (Schmitz et al, 2016a) (B) . Hydrogen atoms, Cl − counterion, and co-crystallized solvent molecules are omitted for clarity.…”