Ab-initio simulations with the quantum chemistry code DMOL have been performed to investigate the adsorption behaviour of two possible titanium precursors for SrTiO3 deposition, TiO(thd)(2) (titanyl-bis-[tetramethyl-heptan-dionato]) and TTIP (titan-tetraisopropoxy). We have developed a cluster representation of 3 x 3 elementary cells which proved to be a model system for the adsorption at a 2-D (100) SrO terminated surface. Moder calculations for TiO2 and CH4 adsorption at this and a variety of modified clusters allowed an estimation of the errors introduced by the use of a finite cluster instead of the infinite surface. Our calculations show that the TTIP precursor has a much higher energy of adsorption, a closer distance of the adsorbed state to the surface as well as a higher dissociation energy than the TiO(thd)(2) molecule. From these results it is rather straightforward to expect a higher sticking probability and a lower surface mobility for TTIP than for TiO(thd)(2). This is in good agreement with experimental results on edge coverage of BST films deposited by the MOCVD method from the respective Ti precursors.