SYNTHESIS AND CHARACTERIZATION OF THE FIRST GROUP 2 MIXED BETA-DIKETONATE ALKOXIDE COMPLEXES - X-RAY CRYSTAL-STRUCTURES OF A-4(TMHD)(4)(OET)(4)(ETOH)(4)],[CA-4(TMHD)(6)(OCH2 CH(2)NME(2))(2)], AND [H2BA4(TMHD)(6)(OCH2CH2OPRI)(4)]

The reaction of the ethanol-solvated metal ethoxides [M(OEt)(2)(EtOH)( 4)](infinity) (M = Ca, Sr, Ba) in n-hexane suspensions/solutions with 1 equiv of a beta-diketone, H-tmhd {H-tmhd is Bu(t)COCH(2)COBu(t)}, yi elds the compounds [Ca-4-(tmhd)(4)(OEt)(4)(EtoH)(4)] (1), [Sr(tmhd)(OE t)(EtOH)(0.66)](n) (2), and [Ba(tmhd)(1.5)(OEt)(0.5)(EtOH)(0.33)](n), (3); further reaction of these complexes with a bifunctional alcohol y ields the complexes [Ca-4(tmhd)(6)(OCH(2)CH(2)NMe(2))(2)] (4), [Ca(tmh d)(1.5)(OCH2CH2OPri)(0.5)](n) (5), [Sr(tmhd)(OCH(2)CH(2)NMe(2))](n) (6 ), [H0.5Sr(tmhd)(1.5)(OCH(2)CH(2)OMe)](n) (7), [H-2- Ba-4(tmhd)(6)(OCH 2CH2OPri)(4)] (8), and [H0.5Ba(tmhd)(1.5)(OCH(2)CH(2)OMe)](n), (9) {th e values of n are as yet unknown}. 1, 4, and 8 have also been characte rized by X-ray crystallography. Crystal data: for 1, monoclinic space group P2(1)/c, a = 14.781(2) Angstrom, b = 26.959(7) Angstrom, c = 20. 443(2) Angstrom, beta = 110.60(2)degrees, Z = 4; for 4, monoclinic spa ce group P2(1)/n, a = 14.1803(7) Angstrom, b = 12.047(3) Angstrom, c = 25.114(5) Angstrom, beta = 100.64(1)degrees, Z = 2; for 8, monoclinic space group C2/c, a = 30.899(7) Angstrom, b = 11.395(2) Angstrom, c = 29.782(5) Angstrom, beta = 103.08(1)degrees, Z = 4. Complexes 1, 4, a nd 8 are all tetrameric with a M(4)O(4) structural motif; 1 has a cuba ne type structure while 4 and 8 are built from a ladder-like framework . All Ca atoms in 1 have very similar six-coordinate octahedral symmet ry. The two unique Ca atoms in 4, which is centrosymmetric, are also s ix-coordinate, but one is octahedral and the other is trigonal prismat ic. In complex 8, which is also centrosymmetric, the environments of t he two unique Ba atoms are again different, one showing an eight-coord inate, bicapped trigonal prismatic and the other a nine-coordinate, mo nocapped square prismatic geometry. Compounds 1-9 may have properties pertinent for application as sol-gel precursors.