Trivalent copper stabilised by acetylacetone dithiocarbazate Schiff base ligands: structural, spectroscopic and electrochemical properties

Abstract

The copper coordination chemistry of bis(dithiocarbazate) Schiff base ligands derived from acetylacetone yields a diversity of products depending on the reaction conditions and presence of oxygen. Both di- and trivalent copper complexes have been isolated and characterised.

Copper Complexes of Benzoylacetone Bis-Thiosemicarbazones: Metal and Ligand Based Redox Reactivity

“…This is in the same region as the [Cu II (acacR)]complexes. [4] Taken with the results from the dithiocarbazate Schiff base relatives [11,21] and spectroelectrochemistry results (below), this corresponds to the Cu III/II couple. Additional irreversible responses were found around þ200 mV (oxidation) and -1600 mV (reduction).…”

“…The Cu-N and Cu-S bond lengths of [(Cu III (banphe)) 2 ] are also consistent with trivalent copper in related dithiocarbazate Schiff base copper complexes. [11,21] In contrast, there are numerous examples of structurally comparable Cu II thiosemicarbazone complexes in the Cambridge Structural Database [22] and the average coordinate bonds in those compounds (from a Mogul search) are significantly longer: 2.00 Å (Cu-N, n ¼ 55) and 2.24 Å (Cu-S, n ¼ 186).…”

Diastereomeric dinickel(ii) complexes with non-innocent bis(octaazamacrocyclic) ligands: isomerization, spectroelectrochemistry, DFT calculations and use in catalytic oxidation of cyclohexane

“…1,3-diketone-β-diiminato rings leading to either C-C bond formation 14,[24][25][26][27][28][29][30][31][32][33] or the generation of new ketone products. [34][35][36] The incorporation of six-membered 1,3-diketone-diiminato moieties in monomacrocyclic metal complexes predetermined the formation of dimetallic species of two-fold or even higher molecular symmetry via C-C bond coupling.…”

“…One issue that remained unaddressed in the reported works is, whether these coordinated macrocycles can be joined into dimers via the C-C bond formation between the γ-carbon atoms of the former Hacac moieties, even though these are now constituent atoms of a seven-membered chelate ring (Ni1NCCCNN1, see Chart 1). All oxidative dehydrogenation reactions reported so far occurred at the central carbon atom of six-membered 1,3-diketone--diiminato rings leading to either C-C bond formation 14,24,25,26,27,28,29,30,31,32,33 or generation of new ketone products. 34,35,36 The incorporation of six-membered 1,3-diketone-diiminato moieties in monomacrocyclic metal complexes predetermined the formation of dimetallic species of two-fold or even higher molecular symmetry via C-C bond coupling.…”

Synthesis of Cu(II) complexes by N,O‐donor ligand transformation and their catalytic role in visible‐light‐driven alcohol oxidation

“…[ 1–6 ] It has been also noticed that in a sterically demanding situation or for the sake of less strainer chelating environment, certain ligands can decyclise or ring‐opening of the ligands can happen. [ 7–15 ] In point of view of the catalytic properties, in‐built flexibility of the associated ligands in terms of denticity, ability to engage in different noncovalent interactions with substrate, and providing an efficient and robust platform remain very crucial as per earlier reports. [ 16–21 ] Among various catalytic activities, aerobic oxidation of primary alcohol is an important subclass of catalytic reaction in terms of biological as well as industrial viewpoint.…”