Homoleptic Complexes of 2,2-Bipyridine

The majority of reports dealing with Group IA complexes of 2,2 -bipyridine are concerned with the species (M(bpy) . The lithium complexes Li2(bpy) and Li(bpy) have been used (primarily by Herzog and 

There have been remarkably few studies of the homoleptic alkaline earth complexes of 2,2 -bipyridine. The complex Be(bpy)2 is formed by the direct reaction of 2,2 -bipyridine with beryllium (975). The complex is paramagnetic (/Xeff 1.80-2.23 /xb over the temperature range 79.9-383.1 K), and it is likely that the compound is of the type Be + — (bpy )2) (975). The reaction of Be(bpy)2 with lithium metal in THF, followed by treatment with dioxane, yields a diamagnetic material formulated Li2[Be(bpy)2] (356). 

The complex Mg(bpy)2-3THF can be prepared by the direct reaction of magnesium with 2,2 -bipyridine in THF and is presumably of the 

A number of compounds of the stoichiometry [M(bpy)4] have been reported. The complex [La(bpy)4] (fx ff 1.8 BM) is prepared by the reaction of LaBrs with Li2(bpy) in the presence of bpy (257, 360). Similar routes have been used for the synthesis of the extremely air-sensitive compounds [Ce(bpy)4] (p,eff 2.85 (jlb) (370). [Nd(bpy)4] (fXect 3.62 (ib) (370), and [Tb(bpy)4] (715). The reaction of bpy with the blue solutions of ytterbium or europium in liquid ammonia are reported to yield [M(bpy)3] or [M(bpy)4] species, depending on the precise conditions (246, 715). In solution, [Yb(bpy)4] exhibits a normal magnetic moment (fXeff 2.79 BM) whereas [Eu(bpy)4] exhibits a novel form of temperature dependency that is attributed to an antiferromagnetic interaction between the metal center and the ligands (246). 

The compounds [M(bpy)3][SeCN]3 (M = Ce, Pr, Nd, Tb, Dy, Ho, or Er) have been prepared by the reaction of M(SeCN)3 with bpy (307, 849). Conductivity studies of solutions of the compounds, together with infrared and crystallographic studies of the solids, suggested that a 6-coordinate formulation was appropriate. The ground-state magnetic properties and photophysical properties of the triplet excited states of [M(bipy) ] + complexes (M = Pr, Nd, Tb, Dy, or Er n = 3 or 4) have been reported (872). The complexes are prepared by the reaction of the appropriae metal perchlorates with bpy in ethanol. 

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Homoleptic complexes of 2,2 -bipyridine. Adv. Inorg. Chem. Radioehem. 34, 1 (1989). 

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