Investigation of New 2,5‐Dimethylpyrrolyl Titanium Alkylamide and Alkoxide Complexes as Precursors for the Liquid Injection MOCVD of TiO₂

Abstract

The new titanium 2,5‐dimethylpyrrolyl complexes [(Me2C4H2N)Ti(NMe2)3] and [(Me2C4H2N)Ti(µ2‐OiPr)(OiPr)2]2 and the previously reported titanium pyrrolyl complex [(C4H4N)Ti(µ2‐OiPr)(OiPr)2]2 are synthesized and chemically and structurally characterized. Single‐crystal X‐ray diffraction (XRD) data show that [(Me2C4H2N)Ti(NMe2)3] is monomeric with a pseudo‐tetrahedral geometry and contains an N‐σ bonded 2,5‐dimethylpyrrolyl ligand. The complexes [(Me2C4H2N)Ti (µ2‐OiPr)(OiPr)2]2 and [(C4H4N)Ti(µ2‐OiPr)(OiPr)2]2 are dimeric and contain two terminal and two bridging isopropoxy groups and terminal N‐σ‐bonded pyrrolyl ligands. The complexes [(Me2C4H2N)Ti(NMe2)3] and [(Me2C4H2N)Ti (µ2‐OiPr)(OiPr)2]2 are investigated as precursors for the deposition of TiO2 by liquid injection metal‐organic (MO)CVD. Titanium oxide films deposited at 450 °C from [(Me2C4H2N)Ti(NMe2)3] contain significantly more carbon impurities (C = 12.7 at.‐%) than those grown from [(Me2C4H2N)Ti(µ2‐OiPr)(OiPr)2]2 (C = 6.1 at.‐%). XRD analysis shows that the titanium oxide films deposited at 450 °C are amorphous.

MOCVD of TiO2 Thin Films using a Heteroleptic Titanium Complex: Precursor Evaluation and Investigation of Optical, Photoelectrochemical and Electrical Properties

“…[Ti{( i PrN) 2 C(NMe 2 )}(NMe 2 ) 3 ] was particularly used to deposit nitrogen–doped TiO 2 thin films for photocatalysis . In certain cases, mixed O,N–coordinated complexes derived from alkoxides have yielded non–stoichiometric TiO 2 films under liquid injection‐based processes, however no such reports are available on the stabilization of amide complexes by introducing ligands with a mixed donor center. The reactivity of the amides could be altered by introduction of the chelating ligands, i.e., by introducing two oxygen‐donating sites on the ligand to maintain a balance between stability and reactivity.…”

Crystal structure of {2-[2-(1H-inden-3-yl)-2-phenylethyl]-1H-imidazolylκN1}- tris[N,N-diethylamido-kN]ti ta nium(IV), C32H47N5Ti

“…Analysis of the Cambridge Structural Database (CSD; version 5.32, release February 2011 [1])reveals only 5entries (5 fragments) for the Group 4transition metal complexes in which the tetrahedral central atom is linked to threea liphatic ando ne hetaryl-type amido-groups (for threeT i complexes, see [2][3][4]; for two Zr complexes, see [2]). In complex (I), theTi1-N1 [2.0682(17) Å] and Ti1-N3 to Ti1-N5 distances [1.8773(16) SAINT [6], SADABS [7], SHELX [8], OLEX2 [9] pp-dp donation from each NEt 2 group towards the metal centre and, thus, of the 14e -nature of the complex (or of its 16e -nature, if an analogous additional donation from the imidazolido-group to the Ti-atom is considered; for the discussion of related cases, see [5] …”

Novel properties and potential applications of functional ligand-modified polyoxotitanate cages

“…41 However, so far only mono-and di-nuclear titanium complexes have been reported as CVD precursors and the use of cages with higher nuclearity remains largely unexplored. 42,43 More interestingly, self-assembled TiO 2 @C core-shell nanoparticles can be produced simply by heating the mononuclear complex [Ti(OEt) 3 (bdmap)] (Hbdmap = 1,3-bis-(dimethylamino)propanol) (2) in a N 2 -filled Swagelock cell at 700 1C. 43 Hence, organic ligands do not always act as sources of detrimental carbon impurities for TiO 2 crystallization, but instead can be employed to produce novel hybrid titania materials.…”