Interplay between lead carboxylate and Ti or Zr isopropoxides in solution routes to perovskites: synthesis, molecular structures and reactivity of single source non-oxo Pb–Zr and Pb–Ti carboxylatoalkoxides supported by 2-ethylhexanoate ligands

Abstract

The reactions between Ti(O(i)Pr)(4) and Zr(2)(O(i)Pr)(8)(HO(i)Pr)(2), respectively, and lead 2-ethylhexanoate Pb(O(2)CC(7)H(15))(2) have been investigated at rt and by heating. The initial mixed-metal species, characterized by single-crystal X-Ray diffraction, were adducts namely Pb(4)Zr(4)(mu-O(2)CR')(8)(mu-OR)(6)(mu(3)-OR)(2)(OR)(8)(OHR)(2) and Pb(2)Ti(4)(mu-O(2)CR')(4)(mu-OR)(6)(mu(3)-OR)(2)(OR)(8) (R' = CHCH(Et)C(2)H(4)Me, R = (i)Pr) independently of the stoichiometry used. They are the first Pb-Ti and Pb-Zr non-oxo carboxylatoalkoxides reported. is also the first Pb-Zr species based on an alkoxide-carboxylate ligand set matching the PbZrO(3) stoichiometry. Both structures are centrosymmetric with six-coordinate transition metals, as required for the perovskite, and are based on triangular M(2)Pb cores (M = Zr, Ti). The lead centers display quite high coordination numbers, six and seven. The thermal and hydrolytic condensation reactions of and were investigated. Heat treatment of and elimination of the volatiles under vacuum afforded Pb(2)Ti(3)(mu(4)-O)(mu(3)-O)(mu-O(2)CC(7)H(15))(2)(mu-O(i)Pr)(6)(O(i)Pr)(4) resulting from extrusion of Ti(O(i)Pr)(4) and scrambling of carboxylate ligands. Characterization of the various compounds was achieved by elemental analysis, FT-IR, (1)H and (207)Pb NMR.

The Added Value of Solid‐State Pb NMR Spectroscopy to Understand the 3D Structures of Pb Amino Acid Complexes

“…On the other hand, regarding the “activity” of the lone pair formally present in the valence shell of Pb II ,15 an intermediate situation is also observed for the well‐characterized [PbO 7 ] complexes. Two complexes display holodirected coordination18,19 spheres, while three are hemidirected 20–22. Complex 1 is hemidirected, a large void being located almost trans to atom O11 belonging to the monodentate Hile ligand (Figure 1).…”

Metal 2-ethylhexanoates and related compounds as useful precursors in materials science

“…Recently, the first heterometal alkoxide-alkanoate species involving 2-ethylhexanoate ligands were reported from our laboratory. 8,9 Unlike mixed metal Pb-Ti and Pb-Zr acetatealkoxides, [4][5][6] these 2-ethylhexanoate-isopropoxide derivatives Pb 4 Zr 4 (m-O 2 CCHEtC 4 H 9 ) 4 (m-OPr i ) 6 (m 3 -OPr i ) 2 (OPr i ) 8 (Pr i OH) 2 and Pb 2 Ti 4 (m-O 2 CCHEtC 4 H 9 ) 4 (m-OPr i ) 6 (m 3 -OPr i ) 2 (OPr i ) 8 show absence of oxo ligands, formulae that correspond to simple adducts and, as required for PZ ceramics, a 1 : 1 ratio of lead and zirconium for Pb-Zr derivative.…”

Lead-rich carboxylate-substituted titanium–lead oxo clusters

“…The polynuclear compounds Pb 2 Ti 4 (OR) 16 (OOCR′) 4 [6, 8] (without oxo groups, with different R and R′) have similar structures to that of Pb2Ti4 .…”

“…The (chain-like) structures of the carboxylate-substituted oxo clusters with a Pb:Ti ratio of 2:2–4, Pb 2 Ti 2 O(O i Pr) 8 (OAc) 2 ( Pb2Ti2 ) [ 5 ], Pb 2 Ti 3 O 2 (O i Pr) 12 (OOCC 7 H 15 ) 2 ( Pb2Ti3 ) [ 6 ], and Pb 2 Ti 4 O 2 (OEt) 14 (OAc) 2 ( Pb2Ti4 ) [ 7 ], are based on Ti 2 (OR) x (μ-OOCR) y building blocks. The polynuclear compounds Pb 2 Ti 4 (OR) 16 (OOCR′) 4 [ 6 , 8 ] (without oxo groups, with different R and R′) have similar structures to that of Pb2Ti4 .…”