Correction for ‘Synthesis, cytotoxic and hydrolytic studies of titanium complexes anchored by a tripodal diamine bis(phenolate) ligand’ by Sónia Barroso et al., Dalton Trans., 2014, 43, 17422–17433.

The reactivity, cytotoxic studies and hydrolytic behaviour of diamine bis(phenolate) titanium complexes are reported. The reactions of [Ti(tBu2O2NN′)Cl]2(μ-O) (1) with LiOiPr or HOiPr in the presence of NEt3, aiming at the synthesis of the alkoxido derivative of 1 led to no reaction or to the synthesis of the monomeric complex [Ti(tBu2O2NN′)(OiPr)2] (3), respectively. A small amount of the alkoxidotitanium dimer [Ti(tBu2O2NN′)(OiPr)]2(μ-O) (2) crystallized out of a solution of 3 and DFT calculations showed that the transformation of 1 into 3 is a thermodynamically favorable process in the presence of a base (NEt3) (ΔG = −14.7 kcal mol−1). 2 was quantitatively obtained through the direct reaction of the ligand precursor H2(tBu2O2NN′) with titanium tetra(isopropoxido). Further reaction of 2 with an excess of TMSCl was revealed to be the most suitable method for the preparation of [Ti(tBu2O2NN′)Cl2] (4). 1 and 3 disclosed cytotoxic activity towards HeLa, Fem-x, MDA-MB-361 and K562 cells and 1 exhibited moderate binding affinity to FS-DNA. 1H NMR hydrolysis studies attested the fast decomposition of 4 in the presence of D2O. The hydrolysis of 3 is slower and proceeds through the formation of [Ti(tBu2O2NN′)(OH)]2(μ-O) (5) that was crystallographically characterized. Upon D2O addition 1 immediately forms complex new species, stable in solution for long periods (weeks).