Coordination versatility of 1,5-bis(salicylidene)carbohydrazide in Ni(II) complexes

A propeller-shaped μ4-carbonate hexanuclear dysprosium complex with a high energetic barrier to magnetisation relaxation

“…The three ligands possess central C-O distances of: d C10-O2 = 1.28(2) Å, d C29-O5 = 1.25(2) Å, and d C48-O8 = 1.26(2) Å, thus confirming that they are in the keto form, as the ligand has been reported in its enol form with a comparatively longer d C-O = 1.33(2) Å. 32 This is surprising as there are only a few examples of carbohydrazide derived Schiff base complexes which have been structurally characterized and found to exhibit the keto over the enol form. 32,33 The three dinuclear units are linked through three CO 3 2− anions, μ 4 -η 1 :η 2 :η 2 coordinated, which are attributed to CO 2 fixation from the atmosphere under basic conditions, in this case in the presence of KOH (Fig.…”

“…32 This is surprising as there are only a few examples of carbohydrazide derived Schiff base complexes which have been structurally characterized and found to exhibit the keto over the enol form. 32,33 The three dinuclear units are linked through three CO 3 2− anions, μ 4 -η 1 :η 2 :η 2 coordinated, which are attributed to CO 2 fixation from the atmosphere under basic conditions, in this case in the presence of KOH (Fig. 2, see the ESI † for synthetic details).…”

Vanadium(V) Complexes with Substituted 1,5-bis(2-hydroxybenzaldehyde)carbohydrazones and Their Use As Catalyst Precursors in Oxidation of Cyclohexane

“…Ditopic ligands based on the carbohydrazide fragment linked with pyridine, carboxylate, and oxime functional groups display coordination versatility and lead to various structural motifs. − The polydentate Schiff base ligand 1,5-bis­(salicylidene)­carbohydrazide (H 4 L) that resulted from a condensation reaction between 2-hydroxybenzaldehyde and carbohydrazide provides two different binding sites, ONN and ONO, to accommodate metal ions. Thus, dioxidomolybdenum­(VI), diorganotin­(IV), nickel­(II), and copper­(II) complexes have been reported. − In all of these compounds, the ligand acts as a trianion, in contrast to its thioanalogue, which also can be stabilized in metal complexes as a tetraanion …”

A new cyclic binuclear Ni(II) complex as a catalyst towards nitroaldol (Henry) reaction

“…Ni(II) complexes play an important role in various homogeneous catalytic reactions, such as, tetralin oxidation [17], asymmetric aldol reaction [18], Mannich-type and Michael reactions [19] and alkene epoxidation [20], and can also exhibit interesting magnetic properties [21,22]. Some nickel compounds can also act as catalysts towards the Henry reaction under different conditions, namely in homogeneous systems [23], under solvent free microwave conditions [16] or in ionic liquids [24], and high activities (more than 90% yields) are found in a few cases [16,24].…”