Titanium complexes of dialkanolamine ligands: Synthesis and structure

Synthesis of the title compounds, viz. [RN(CH₂CH₂O)(CHR¹CR²R³O)]Ti(OiPr)₂ (13–15) and [RN(CH₂CH₂O)(CHR¹CR²R³O)]₂Ti (18–28), by the reaction of one ortwo equivalents of the corresponding dialkanolamines RN(CH₂CH₂OH)(CHR¹CR²R³OH) (1–12) with Ti(OiPr)₄ is reported. Other routes to [RN(CH₂CH₂O)(CHR¹CR²R³O)]₂Ti, such as the reaction of Ti(CH₂Ph)₄ with dialkanolamine and the reaction of TiCl₄(THF)₂ with dialkanolamine/Et₃N were also tested. Dimeric titanocane 16, [PhCH₂N(CH₂CH₂O)₂Ti(OMe)₂]₂, was obtained from the reaction of one equivalentof dialkanolamine 3 with CpTi(OMe)₃. PhCH₂N(CH₂CH₂O)₂Ti(OMenth)₂ (17) was prepared from the transalkoxylation reaction of 15 with two equivalents of menthol. The composition and structures of all novel compounds were established by ¹H and ¹³C NMR spectroscopy as well as elemental analysis data. The possible solution structure features of 13–28 are discussed. The single‐crystal X‐ray diffraction study oftitanocane 16 clearly indicates a dimeric structure for this compound in the solid state. According to X‐ray data, compounds [PhCH₂N(CH₂CH₂O)₂]₂Ti (19), [MeN(CH₂CH₂O)(CH₂CHPhO)]₂Ti (20), [MeN(CH₂CH₂O)(CH₂CPh₂O)]₂Ti (23), erythro‐[MeN(CH₂CH₂O)(CHPhCHPhO)]₂Ti (24), threo‐[MeN(CH₂CH₂O)(CHPhCHPhO)]₂Ti (25), and {MeN(CH₂CH₂O)[CH(CH₂)₄CHO]}₂Ti (27) possess a monomeric structure with a hexacoordinate titanium atom in the solid state. Among them complexes 19, 20, 23, 25, and 27 are characterized by a cis disposition of the nitrogen atoms in the coordination environment of the Ti atom, while nitrogen atoms in 24 occupy trans positions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)