Two dinuclear EuIII complexes have been synthesized by employing β-diketones and 2,2Ј-bipyrimidine (bpm) as sensitizing ligands for the Eu ion and a bridging ligand, respectively, and characterized by various means including single-crystal X-ray crystallography. The use of dibenzoylmethane (dbm) and trifluorothenoylacetone (tta) as β-diketones gave [Eu 2 (dbm) 6 (bpm)] (1) and [Eu 2 (tta) 6 (bpm)] (2). Both show strong intermolecular π-π interactions that may be responsible for their high melting points. The analysis of the absorption, excitation, and emission spectra of the dinuclear com-

[reaction: see text] It has been demonstrated for the first time that conjugated enynes can be employed as a facile substrate in olefin metathesis with the use of a bispyridine-substituted ruthenium benzylidene catalyst. Cross-metathesis of the enynes with alkenes turns out to proceed with preferential formation of (Z)-isomers over (E)-isomers up to >25:1 in moderate to good yields. The intramolecular version of conjugated enynes affords novel butadienyl cycloalkenes, which are a highly useful synthetic building blocks, in acceptable yields.

Novel C 1 -symmetric group 4 ansa-metallocene complexes Me 2 Si(C 5 Me 4 )(2-R-Ind)MCl 2 (R ) H, M ) Ti (5a), Zr (5b); R ) Me, M ) Ti (6a), Zr (6b)) were prepared from the reaction of dilithium salt of the corresponding ligands Me 2 Si(C 5 Me 4 H)(2-R-IndH) (R ) H, Me) with appropriate group 4 metal halides. Crystal structures of 5a, 6a, and 6b determined by X-ray diffraction studies reveal chiral C 1 -symmetric nature irrespective of the type of metal and ligand. The complexes 5a, 5b, 6a, and 6b were tested for the polymerization of propylene in the presence of methylaluminoxane (MAO) at various temperatures. All of them exhibit good activity and afford moderate to high isotactic polypropylenes. In the case of titanocenes (5a and 6a), polymerization activity, molecular weight, and isotacticity of polypropylene sharply increase as the polymerization temperature decreases, while the increase of polymerization activity and the decrease of isotacticity and molecular weight of polypropylene were observed upon increasing the polymerization temperature in the case of zirconocenes (5b and 6b). The effect of a 2-Me substituent at the indenyl ring on propylene polymerization was apparent in terms of polymerization activity and molecular weight of polypropylene, especially for zirconocenes, but was minor for titanocenes.

Cyano-bridged homometallic complex [Ni(baepn)(CN)](n)(ClO(4))(n)(1) and bimetallic complex [Ni(baepn)](2)(n)[Fe(CN)(6)](n)(H(2)O)(8)(n)(2) [baepn = N,N'-bis(2-aminoethyl)-1,3-propanediamine] were synthesized and characterized. 1 crystallizes in the monoclinic space group P2(1)/n with a = 9.560(3) A, b = 10.700(3) A, c = 14.138(9) A, beta = 90.18(6) degrees, and Z = 4; 2 crystallizes in the monoclinic space group P2(1)/c with a = 8.951(2) A, b = 13.672(3) A, c = 14.392(3) A, beta = 98.906(4) degrees, and Z = 4. The complex 1 has one-dimensional structure whose chain vector runs along the b axis with baepn ligands and perchlorate anions alternately arranged up and down in the c direction. The antiferromagnetic nature of 1 was explained in terms of the infinite chain model and Haldane gap, giving g = 2.33, J = -29.4 cm(-1), and the magnitude of Haldane gap E(g) = 5.22 K. The complex 2 that constitutes the first example of 2-D bimetallic assembly of Ni(II) ion and ferrocyanide anion is composed of the neutral layers based on the [Ni(4)Fe(4)] square grid spanning in the bc plane. For 2, the analysis with the Curie-Weiss law in 2-300 K range results in THETA = 0.200 K and the magnetism was explained in terms of the ability of ferrocyanide in the -Ni-NC-Fe-CN-Ni unit to promote ferromagnetic Ni-Ni interaction.