Reaction of yttrium and lanthanum trichloride with 1 equiv of sodium or potassium hydrotris(3,5-dimethylpyrazolyl)borate and 1 equiv of 2,2'-bipyridine gives good yields of the complexes [MCl(2)(Tp(Me2))(C(10)H(8)N(2))] (M = Y (1), La (2)). The analogous compounds with 1,10-phenanthroline, [MCl(2)(Tp(Me2))(C(12)H(8)N(2))] (M = Y (3), La (4)), have been obtained by a similar procedure. The solid-state structures of 2-4 were determined by single-crystal X-ray diffraction and revealed that the compounds are all seven-coordinate with capped octahedral geometry. In contrast, reaction of yttrium trichloride with 1 equiv of sodium hydrotris(3,5-dimethylpyrazolyl)borate in the presence of 1 equiv of neocuproine affords [YCl(3)(Tp(Me2))][Na(neoc)(3))] (5). Compounds 1 and 2 provide an entry for the synthesis of complexes containing the bipyridyl ligand in a radical anionic form or in a dianionic form. Reaction of 1 and 2 with an excess of sodium amalgam gives [Y(Tp(Me2))(bipy)(THF)(2)] (6) and [La(Tp(Me2))(2)(bipy)] (7), respectively. The structures of both compounds have been determined by X-ray crystallography. Compound 7 can be oxidized with iodine to give [La(Tp(Me2))(2)(bipy)]I (8).

Reaction of yttrium and lanthanide trichlorides (Ln = La, Eu, Yb) with 1 equiv of the trisodium salt of 1,4,7-tris(dimethylsilylaniline)-1,4,7-triazacyclononane (Na(3)[(SiMe(2)NPh)(3)-tacn](THF)(2)) gives good yields of the compounds [M[(SiMe(2)NPh)(3)-tacn]] (M = Y (1), Eu (3), Yb (4)) and [La[(SiMe(2)NPh)(3)-tacn](THF)] (2). Reduction of 3 with Na/Hg followed by recrystallization in the presence of diglyme yielded crystals of [Eu[(SiMe(2)NPh)(3)-tacn]][Na(diglyme)(2)] (5). Synthesis of the uranium(III) complex [U[(SiMe(2)NPh)(3)-tacn]] (6) is achieved by reaction of 1 equiv of Na(3)[(SiMe(2)NPh)(3)-tacn](THF)(2) with uranium triiodide. The U(IV) complexes, [U[(SiMe(2)NPh)(3)-tacn]X] (X = Cl (7); I (8)), were prepared via oxidation of 6 with benzyl chloride or I(2), but salt metathesis from UCl(4) provided a higher yield route for 7. The solid-state structures of 1-7 were determined by single-crystal X-ray diffraction. The ligand [(SiMe(2)NPh)(3)-tacn] generates a trigonal prismatic coordination environment for the metal center in the neutral complexes 1, 3, 4, and 6 and the ionic 5. In 2 the six nitrogen atoms of the ligand are in a trigonal prismatic configuration with the oxygen atom of the THF capping one of the triangular faces of the trigonal prism. In 7 the coordination geometry around the uranium atom is best described as bicapped trigonal bipyramidal.

A new approach to design "antenna-ligands" to enhance the photoluminescence of lanthanide coordination compounds has been developed based on a π-type ligand-the polyphenyl-substituted cyclopentadienyl. The complexes of di-, tri-, and tetraphenyl cyclopentadienyl ligands with Tb and Gd have been synthesized and all the possible structural types from mononuclear to di- and tetranuclear complexes, as well as a coordination polymer were obtained. All types of the complexes have been studied by single-crystal X-ray diffraction and optical spectroscopy. All terbium complexes are luminescent at ambient temperature and two of them have relatively high quantum yields (50 and 60%). Analysis of energy transfer process has been performed and supported by quantum chemical calculations. The role of a low-lying intraligand charge transfer state formed by extra coordination with K in the Tb ion luminescence sensitization is discussed. New aspects for design of lanthanide complexes containing π-type ligands with desired luminescence properties have been proposed.

A new family of lanthanide complexes with di- and triphenylacetate ligands was prepared from LnCl3. Dimeric diphenylacetates were the only isolated products of the reaction between LnCl3 (Ln = La, Nd) and Ph2CHCOONa. The exchange reaction between LnCl3 and Ph3CCOONa led to the formation of three structurally different types of neodymium and lanthanum complexes under different reaction conditions. Various coordination modes of the carboxylate ligands were revealed, including κ2- and κ1-terminal coordination, μ2-κ1:κ1-bridging, and μ2-κ1:κ2-semibridging. The treatment of La and Nd tris-triphenylacetates with excess AlEt3 produces the dimeric tetraethylaluminates [Ln2((μ2-κ1:κ1-Ph3CCOO)4(AlEt4)2]. The structures of the key La and Nd triphenylacetates that were obtained from these reactions were verified by X-ray diffraction, and the complex [(THF)4Nd2(Ph2CHCOO)2(μ2-κ1:κ2-Ph2CHCOO)2(μ2- κ1:κ1-Ph2CHCOO)2] was studied by high-resolution X-ray diffraction. Neodymium di- and triphenylacetate complexes can serve as precursors of catalysts for butadiene and isoprene stereospecific 1,4-cis polymerization.

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Yttrium trichloride reacts with both Na 2 [Ph 2 CCPh 2 ] and K 2 [Ph 2 CCPh 2 ], made from Ph 2 CdCPh 2 and sodium and potassium mirrors, respectively, to form complexes of general formulaComplex 2 undergoes cation exchange with NaBPh 4 in THF to form crystals of [Na(THF) 6 ][Y(Ph 2 CCPh 2 ) 2 ](THF) 2 , 3, suitable for X-ray diffraction. The anionic unit in 3, [Y(Ph 2 CCPh 2 ) 2 ] -, has a sandwich-like structure in which each (Ph 2 CCPh 2 ) 2dianion has six carbon atoms oriented toward the metal center with Y-C distances ranging from 2.518(6) to 2.689(7) Å.

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