New Titanium Imido Synthons: Syntheses and Supramolecular Structures

Reactions of Ti(NMe2)2Cl2 with a wide range of primary alkyl and arylamines RNH2 afforded the corresponding
5-coordinate imido titanium compounds Ti(NR)Cl2(NHMe2)2 (R = tBu (1), iPr (2), CH2Ph (3), Ph (4), 2,6-C6H3Me2
(5), 2,6-C6H3iPr2 (6), 2,4,6-C6H2F3 (7), 2,3,5,6-C6HF4 (8), C6F5 (9), 4-C6H4Cl (10), 2,3,5,6-C6HCl4 (11), 2-C6H4CF3
(12), 2-C6H4tBu (13)). The compounds 1−13 are monomeric in solution but in the solid state form either N−H···Cl
hydrogen bonded dimers or chains or perfluorophenyl π-stacked chains, depending on the imido R-group. The
compound 13 was also prepared in a “one-pot” synthesis from RNH2 and Ti(NMe2)4 and Me3SiCl. Reaction of
certain Ti(NR)Cl2(NHMe2)2 compounds with an excess of pyridine afforded the corresponding bis- or tris-pyridine
analogues [Ti(NR)Cl2(py)x]y (x = 3, y = 1; x = y = 2), and the structure of Ti2(NC6F5)2Cl2(μ-Cl)2(py)4 shows
π-stacking of perfluorophenyl rings. Reaction of Ti(NMe2)2Cl2 with cross-linked aminomethyl polystyrene gave
quantitative conversion to the corresponding solid-supported titanium imido complex. This paper represents the
first detailed study of how supramolecular structures of imido compounds may be influenced by simple variation of
the imido ligand N-substituent.