Ti, Zr Hf and La precursors for use in MOCVD techniques have a ligand of the general formula OCR.sup.1(R.sup.2)CH.sub.2X, wherein R.sup.1 is H or an alkyl group, R.sup.2 is an optionally substituted alkyl group and X is selected from OR and NR.sub.2, wherein R is an alkyl group or a substituted alkyl group.