Reaction of Tetra(tert-Butoxy)Tin or -Zirconium with Hydroxylated Titanium in Ultrahigh Vacuum:  Contrasting Reactivity with Hydroxylated Aluminum Substrate

Topological surface states of Bi2Te2Se are robust against surface chemical modification

“…Growing a thin layer of TiO 2 on either 1 or 2 is a two‐step process, consisting of vapor deposition of volatile tetra( tert ‐butoxy)titanium ( 6 ) onto the surface at reduced pressure and low temperature followed by thermal treatment, which cleaves tert ‐butoxy ligands by loss of iso butylene to yield the cross‐linked oxide . Under mild thermolysis (50 °C), some tert ‐butoxy groups remain bonded to the distal surface of the TiO 2 layer; at higher temperatures (>120 °C), most residual tert ‐butoxy groups are cleaved.…”

“…Key to film growth is the initial interaction between 6 and substrate surface coordination sites. This process was originally developed for substrate surfaces replete with oxygen‐based coordination sites as are present in 2 . Here we describe the first illustration of this method of thin‐film formation applied to a Te‐terminated substrate ( 1 ) in which each step is characterized by XPS and AFM analysis and in which Te atoms serve as ligation sites.…”

“…We attribute this shoulder to Ti directly bonded to Te at the TiO 2 ‐BTS interface. Carbon species were also present that are attributed to residual tert ‐butoxy groups on the TiO 2 surface (for C 1s, BE = 286.2 eV and 288.7 eV ). Further heating to 120 °C under argon resulted in reduction of the carbon peaks with no discernible change in the Ti spectrum.…”

Enhanced Bonding of Organometallics to Titanium via a Titanium(III) Phosphate Interface

“…The hydroxyl groups of 1/Ti can also serve as reactive sites for covalent attachment of protolytically labile reagents, such as Zr 12,25 or Si 14,15 alkoxides; surface loadings of these organometallics are far higher than those obtained on the native oxide of Ti in which only about 15% of surface oxygen is derived from hydroxyl groups. 10 For example, deposition of 3 onto the Ti native oxide surface 25 gives [Ti]-[O]-Zr(t-OBu) 3 which has a characteristic peak (∆R/R ≈ 0.75%) at 2977 cm -1 in the IR (ν CH3 antisym ). In comparison, reaction of 3 with 1/Ti also gives product with a peak at 2977 cm -1 , but which is about 10-fold stronger (∆R/R ≈ 10%).…”

“…In comparison, reaction of 3 with 1/Ti also gives product with a peak at 2977 cm -1 , but which is about 10-fold stronger (∆R/R ≈ 10%). Since it has been established 25 that 3 reacts with hydroxylated surfaces by proton transfer, this increase in peak intensity is consistent with an increase in the surface content of reactive OH sites for 1/Ti versus the Ti native oxide [Figure 3]. Surface-bound [Ti]-[O]-Zr(t-OBu) 3 has been shown to be an effective interface between alkanephosphonic acids and the Ti native oxide surface, for example, by ligand exchange with 4 to give [Ti]-[O]-Zr(t-OBu)(O 3 PC 18 H 37 ) 2 12 which has a characteristic IR peak at 2923 cm -1 (ν asymCH2 , ∆R/R ≈ 0.4%).…”