title: Synthesis and Spectroscopic Characterization of Novel Heterotermetallic Isopropoxides: X-ray Crystal Structures of ICd{M(2)(OPr(i))(9)} and [{Cd(OPr(i))(3)}Ba{M(2)(OPr(i))(9)}](2) (M = Ti, Hf).
abstract: Metathesis reactions between CdI(2) and KM(2)(OPr(i))(9) (M = Ti, Hf) in toluene produce monomeric iodo-heterobimetallic isopropoxides ICdM(2)(OPr(i))(9) (1, M = Ti; 2, M = Hf) which have been characterized by solution ((1)H, (13)C, and (113)Cd) and solid state ((13)C and (113)Cd) CP MAS NMR spectroscopy, microanalysis, cryoscopic molecular weight determination, and single crystal X-ray diffraction study. Both 1 and 2 in the solid state represent the first structurally characterized examples of halide heterobimetallic alkoxides based on {Ti(2)(OPr(i))(9)}(-) and {Hf(2)(OPr(i))(9)}(-) bioctahedral subunits, respectively. The overall molecular geometry of 1 and 2 can be viewed formally as an interaction of the CdI(+) fragment with {M(2)(OPr(i))(9)}(-) substructures via two terminal and two bridging (&mgr;(2)-) isopropoxy groups. Reaction of 1 and 2 with equimolar KBa(OPr(i))(3) in toluene afforded novel heterotermetallic isopropoxides [{Cd(OPr(i))(3)}Ba{M(2)(OPr(i))(9)}](2) (3, M = Ti; 4, M = Hf). Formation of heterotermetallic frameworks involves an interesting rearrangement of the central metal atoms between the two precursor molecules, which is probably commanded by the tendency of barium to achieve higher coordination numbers. The dimeric forms of 3 and 4 as shown by cryoscopy and (113)Cd solution and solid state CP MAS NMR studies are confirmed by crystallography. The X-ray crystal structures of 3 and 4 reveal, as a common feature, a central Ba(&mgr;(2)-OPr(i))(2)Cd(&mgr;(2)-OPr(i))(2)Cd(&mgr;(2)-OPr(i))(2)Ba unit formed by a spirocyclic linking of two LBa(OPr(i))(2) (3, L = Ti(2)(OPr(i))(9); 4, L = Hf(2)(OPr(i))(9)) units to a four membered, Cd(2)(OPr(i))(2), ring. Crystal data: for 1, monoclinic, space group P2(1)/m, a = 11.71(2) Å, b = 15.78(3) Å, c = 12.16(2) Å, beta = 116.69(14) degrees, Z = 2; for 2, triclinic, space group P&onemacr;, a = 9.825(2) Å, b = 11.428 Å, c = 20.619 Å, alpha = 95.619(12) degrees, beta = 99.915(11) degrees, gamma = 111.347(11) degrees, Z = 2; for 3, monoclinic, space group P2(1)/c, a = 22.68(2) Å, b = 12.603(11) Å, c = 19.00(2) Å, beta = 96.83(8) degrees, Z = 2; for 4, monoclinic, space group P2(1)/c, a = 23.197(5) Å, b = 12.886(3) Å, c = 19.378(4) Å, beta = 97.18(3) degrees, Z = 2.
authors.affiliation: Institute of Inorganic Chemistry, University of Saarland, P.O. 151150, D-66041 Saarbrücken, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Veith
authors.forename: Sanjay
authors.initials: S
authors.lastname: Mathur
authors.forename: Volker
authors.initials: V
authors.lastname: Huch