3,5-Di-tert-butyl-o-benzoquinone complexes of lanthanides

Cooperative reduction by Ln2+ and Cp*− ions: synthesis and properties of Sm, Eu, and Yb complexes with 3,6-di-tert-butyl-o-benzoquinone

“…The characteristic lengths of C-O and C-C bonds suggest that the quinone ligand acquires the catecholate (2−) state. 17,34,35 The IR spectra of 1 and 2 are nearly identical, in accordance with the same coordination environment of the complexes (Fig. S1, ESI †).…”

“…3). Unlike compounds 1 and 2, the Mg atoms are not bearing Cp* ligands, so the quinone ligands are present in the catecholate state, in agreement with the C-O and C1-C2 bond lengths, 17,34,35 the IR spectral data, 37 as well as its colourless appearance. The Mg 2 O 2 ring is not flat (the angle between two Mg 2 O planes is 133.65(8)°), and both dbcat ligands are turned to the same side of the Mg 2 O 2 butterfly, as opposed to the dimeric molecules of 1 and 2.…”

“…[4][5][6]15,16 A few complexes of Ln(II) with sq and cat ligands are known; to the best of our knowledge, the only examples are homoleptic [Ln(dbcat)] (Ln = Sm, Eu) and heteroleptic [EuLi 4 (dbsq) 2 (dbcat) 2 (LiI) 2 (thf ) 6 ] complexes obtained by Bochkarev and co-workers in the reaction of EuI 2 or Ln(N(SiMe 3 ) 2 with 3,5-di-tert-butyl-o-benzoquinone (3,5-dbbq). 17 Lately, a ligand containing 3,6-di-tert-butyl-o-benzoquinone (3,6-dbbq) coupled with tetrathiafulvalene was employed for syntheses of bridged dimeric Ln complexes (Ln = Dy, Er, Yb); in the case of dysprosium, each Dy 3+ ion was seen to behave as an independent single-ion magnet. 18,19 The possibility of tuning the redox properties of a ligand by changing its substituents or by using iminoquinone derivatives 14 can be used to enhance the magnetic interactions between the Ln ion and the ligand in its radical-ion form.…”

Structural Diversity of Calcium, Strontium, and Barium Complexes with Reduced Forms of the 3,6‐Di‐tert‐butyl‐o‐benzoquinone Ligand

“…[14a], [16a] Salt metathesis reactions between dehydrated halogenides and an alkali metal catecholate/semiquinolate in organic medium are driven by insolubility of alkali halogenides, and assume removal of the latter (Scheme b) . Action of catechol as an acid to complexes with weaker acid anions, such as amides or alkyls, can provide rather a convenient way in case the amines or alkanes formed are volatile and easily removable (Scheme c) . Finally, complexes with ligands possessing reducing properties can be used as a source of metal.…”

“…Notably, polynuclear complexes with bridging semiquinonate ligands are not known for Ae metal and barely known for Ln cations. For the latter, according to the best of our knowledge, only two examples have been described: dinuclear [Gd 2 (HBPz 3 ) 2 (3,5‐SQ) 4 ][9c] and trinuclear [Tm 3 (3,5‐SQ) 4 (3,5‐Cat) 2 (3,5‐CatH)(dme) 2 ] (dme = 1,2‐dimetoxyethane) complexes . The thulium complex is structurally similar to the trinuclear complexes 1 , 2 , and 5 , for it also contains two µ 3 ‐catecholates joining all three metal atoms, and semiquinolate ligands, both bridging and terminal.…”