Molecular and electronic structure of the dithiooxalato radical ligand stabilised by rare earth coordination

Abstract

Coordinating rare earth ions to bis(dithiooxalato)nickel produces the first structurally characterised complexes possessing the elusive dithiooxalato radical ligand.

Bulky countercation effects on the crystal packing of anionic dithiooxalato-containing Ni(ii), Pd(ii) and Pt(ii) complexes: spectroscopic–redox correlations

“…38 In contrast, the low-energy UV-vis band is likely attributed to metal-to-ligand charge transfer (MLCT) and n d– n d ( n = 3–5) transitions between the four filled d( z 2 )/d( xz )/d( yz )/d( x 2 – y 2 ) and the empty d( xy ) metal orbitals. 39 Interestingly, this broad absorption band shows a significant hypsochromic shift to a shorter wavelength for the [M II (dto) 2 ] 2− complexes following the trend Ni > Pt > Pd, which is eventually responsible for the colour change from red (Ni) to orange (Pt) and yellow (Pd) (inset of Fig. 10).…”

“…6 This ligand reduction is favoured upon coordination of the free carbonyl groups to rare earth metal ions, like in the dithioxalato-bridged trinuclear lanthanide( iii )-nickel( ii ) complexes of general formula {Ni II (dto) 2 [Ln III {HB(pz) 3 } 2 ] 2 } [Ln = Y and Gd; HB(pz) 3 − = hydrotris(pyrazol-1-yl)borate]. 39…”

“…6 This ligand reduction is favoured upon coordination of the free carbonyl groups to rare earth metal ions, like in the dithioxalato-bridged trinuclear lanthanide(III)-nickel(II) complexes of general formula {Ni II (dto) 2 [Ln III {HB(pz) 3 } 2 ] 2 } [Ln = Y and Gd; HB(pz) 3 − = hydrotris(pyrazol-1-yl)borate]. 39 The formal potential for the M III /M II redox couple of 4-6 increases in the order Ni < Pt < Pd, a trend that does not correspond at all with the decrease found for the third ionization energy of the atomic ions in the gas phase as one moves down the group in the periodic table [IE 3 = 3395 (Ni) > 3177 (Pd) > 2800 kJ mol −1 (Pt)]. Nevertheless, both formal potential for the M III /M II redox couple and energy of the near UV-vis absorption maxima of the [M II (dto) 2 ] 2− complexes in solution increase in the order Ni < Pt < Pd, being almost linearly correlated (inset of Fig.…”

Influence of a Lanthanide Ion on the Ni Site of a Heterobimetallic 3d–4f Mabiq Complex

“…[34][35][36] Despite the number of reports with either 3d or 4f centers in combination with redox-active ligands, complexes comprising all three groups are surprisingly limited. [37][38][39][40] Given the evidence for improved magnetic properties in systems with two paramagnetic centers, synthesizing 3d-4f systems comprising redox-active ligands -in which a ligand radical can exist alongside a paramagnetic lanthanide -offers further opportunities to modulate and exploit exchange interactions. An example is the study by Goudy et.…”

“…Recently, several of these mixed-metal systems have also incorporated redox-active ligands, which offers further potential for both catalysis and magnetism. − In the field of transition metal chemistrythrough their ability to participate in redox transformationsthese ligands act as “electron storage sites”, thereby opening up the reactive possibilities of the complex as a whole. − Ligand-based reactivity has not been robustly developed within lanthanide chemistry. However, investigations into 4f complexes with, for example, redox-active Schiff bases and aminophenolate ligands have shown how these ligands can support the formation of reduced lanthanide ions. − Despite the number of reports with either 3d or 4f centers in combination with redox-active ligands, complexes comprising all three groups are surprisingly limited. − Given the evidence for improved magnetic properties in systems with two paramagnetic centers, synthesizing 3d–4f systems comprising redox-active ligandsin which a ligand radical can exist alongside a paramagnetic lanthanideoffers further opportunities to modulate and exploit exchange interactions. An example is the study by Goudy et al concerning the [(Cp*) 2 Yb­(L)­PdMe 2 ] complexes (L = bipyrimidine (bipym) or 4,5,9,10-tetraaza­phenanthrene (taphen)) .…”