Conversion of carbon dioxide to oxalate by α-ketocarboxylatocopper(II) complexes.

The α-ketocarboxylatocopper(II) complex [{Cu(L1)}{O2CC(O)CH(CH3)2}] can be spontaneously converted into the binuclear oxalatocopper(II) complex [{Cu(L1)}2(µ-C2O4)] upon exposure to O2/CO2 gas. (13)C-labeling experiments revealed that oxalate ions partially incorporated (13)CO2 molecules. Furthermore, the bicarbonatocopper(I) complex (NEt4)[Cu(L1){O2C(OH)}] in an Ar atmosphere and the α-ketocarboxylatocopper(I) complex Na[Cu(L1){O2CC(O)CH(CH3)2}] in an O2 atmosphere were also transformed spontaneously into the oxalato complex [{Cu(L1)}2(µ-C2O4)].

{Tris[3-(adamantan-1-yl)-5-isopropylpyrazol-1-yl-κN(2)]hydroborato}thallium(I): the scorpionate with the most bulk?

In the thallium(I) complex, [Tl(C48H70BN6)], of tris[3-(adamantan-1-yl)-5-isopropylpyrazol-1-yl]hydroborate, the most hindered scorpionate ligand, the Tl(I) ion is coordinated by three N atoms from the anionic tridentate chelating ligand [average Tl-N bond length = 2.522 (4) Å] in a distorted trigonal-pyramidal environment [average N-Tl-N angle around the Tl(I) ion = 76.4 (1)°]. This coordination geometry is compared with that of the reported Tl(I) complex of the super-hindered tris(7-tert-butylindazol-2-yl)hydroborate ligand.