Preparation of Heteroleptic Tin(IV) N,O‐β‐Heteroarylalkenolate Complexes and Their Properties as PI‐MOCVD Precursors for SnO 2 Deposition

We have successfully prepared and structurally characterized five novel tin(IV) heteroleptic N,O‐β‐heteroarylalkenolates containing –CF 3 groups. The synthetic route used reactions of Sn(O t Bu) 4 with 3,3,3‐trifluoro(pyridin‐2‐yl)propen‐2‐ol (PyTFPH), 3,3,3‐trifluoro(dimethyl‐1,3‐oxazol‐2‐yl)propen‐2‐ol (DMOTFPH), and 3,3,3‐trifluoro(1,3‐benzthiazol‐2‐yl)propen‐2‐ol (BTTFPH) in dry aprotic solvents leading to elimination of tert ‐butanol and formation of Sn(O t Bu) 2 (PyTFP) 2 ( 1 ), Sn(O t Bu) 2 (DMOTFP) 2 ( 2 ), and Sn(O t Bu) 2 (BTTFP) 2 ( 3 ). The chelating ligands employed a bidentate N∩O donor set. The reactivity of O t Bu groups in the obtained Sn(O t Bu) 2 (N∩O) 2 complexes was further investigated in reactions with fluorinated alcohols, 2,2,2‐trifluoroethanol (TFEH) and 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFPH). Two complexes Sn(TFE) 2 (DMOTFP) 2 ( 4 ) and Sn(HFP) 2 (PyTFP) 2 ( 5 ) were obtained and structurally characterized. Thermal behavior of complexes 1 – 5 was studied by thermogravimetry and differential scanning calorimetry (TG/DSC). The most volatile compounds Sn(O t Bu) 2 (PyTFP) 2 ( 1 ) and Sn(O t Bu) 2 (DMOTFP) 2 ( 2 ) were chosen and tested in a PI‐MOCVD process for the SnO2 growth on sapphire‐C substrates. Film growth rates at different temperatures (500–900 °C), crystalline quality, surface roughness, transparency in UV/Vis‐mid‐IR spectral ranges have been investigated. The results showed that these two compounds are suitable precursors for MOCVD deposition of high quality SnO 2 films. Fabricated films displayed good response to CO and NO 2 in chemo‐resistive gas sensing measurements.