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Two kit preparations of the organometallic precursor [ 188 Re(H 2 O) 3 (CO) 3 ] + in aqueous media are presented. Method A uses gaseous carbon monoxide and amine borane (BH 3 ‚NH 3 ) as the reducing agent. In method B CO(g) is replaced by K 2 [H 3 BCO 2 ] that releases carbon monoxide during hydrolysis. Both procedures afford the desired precursor in yields >85% after 10 min at 60 °C. HPLC and TLC analyses revealed 7 ( 3% of unreacted 188 ReO 4and <5% of colloidal 188 ReO 2 . Solutions of up to 14 GBq/mL Re-188 have been successfully carbonylated with these two methods. The syntheses of two tailor-made bifunctional ligand systems for the precursor [ 188 Re(H 2 O) 3 (CO) 3 ] + are presented. The tridentate chelates consist of a bis[imidazol-2-yl]methylamine or an iminodiacetic acid moiety, respectively. Both types of ligand systems have been prepared with alkyl spacers of different length and a pendent primary amino or carboxylic acid functionality, enabling the amidic linkage to biomolecules. The tridentate coordination of the ligands to the rhenium-tricarbonyl core could be elucidated on the macroscopic level by X-ray structure analyses and 1D and 2D NMR experiments of two representative model complexes. On the nca level, the ligands allow labeling yields >95% with [ 188 Re(H 2 O) 3 (CO) 3 ] + under mild reaction conditions (PBS buffer, 60 °C, 60 min) at ligand concentrations between 5 × 10 -4 M and 5 × 10 -5 M. Thus, specific activities of 22-220 GBq per µmol of ligand could be achieved. Incubation of the corresponding Re-188 complexes in human serum at 37 °C revealed stabilities between 80 ( 4% and 45 ( 10% at 24 h, respectively, and 63 ( 3% and 34 ( 3% at 48 h postincubation in human serum depending on the chelating system. Decomposition product was mainly 188 ReO 4 -. The routine kit-preparation of the precursor [ 188 Re(H 2 O) 3 (CO) 3 ] + in combination with tailormade ligand systems enables the organometallic labeling of biomolecules with unprecedented high specific activities.

In analogy to the [M II (bpy) 3 ] 2+ cations, where M II is a divalent transition-metal and bpy is 2,2′-bipyridine, the tris-chelated [M III (bpy)

Bimetallic, oxalate-bridged compounds with bi- and trivalent transition metals comprise a class of layered materials which express a large variety in their molecular-based magnetic behavior. Because of this, the availability of the corresponding single-crystal structural data is essential to the successful interpretation of the experimental magnetic results. We report in this paper the crystal structure and magnetic properties of the ferromagnetic compound {[N(n-C(3)H(7))(4)][Mn(II)Cr(III)(C(2)O(4))(3)]}(n)() (1), the crystal structure of the antiferromagnetic compound {[N(n-C(4)H(9))(4)][Mn(II)Fe(III)(C(2)O(4))(3)]}(n)() (2), and the results of a neutron diffraction study of a polycrystalline sample of the ferromagnetic compound {[P(C(6)D(5))(4)][Mn(II)Cr(III)(C(2)O(4))(3)]}(n)() (3). Crystal data: 1, rhombohedral, R3c, a = 9.363(3) Å, c = 49.207(27) Å, Z = 6; 2, hexagonal, P6(3), a = 9.482(2) Å, c = 17.827(8) Å, Z = 2. The structures consist of anionic, two-dimensional, honeycomb networks formed by the oxalate-bridged metal ions, interleaved by the templating cations. Single-crystal field dependent magnetization measurements as well as elastic neutron scattering experiments on the manganese(II)-chromium(III) samples show the existence of long-range ferromagnetic ordering behavior below T(c) = 6 K. The magnetic structure corresponds to an alignment of the spins perpendicular to the network layers. In contrast, the manganese(II)-iron(III) compound expresses a two-dimensional antiferromagnetic ordering.

Building blocks for conducting polymers or NLO materials are the linear, unsaturated carbon chain bridged manganese complexes 1(n+) (n=0-2). All oxidation states were investigated spectroscopically and by X-ray structure determinations. The analytical data confirm a communication of the electrons over the C(4) chain-a prerequisite for electrical conductivity and NLO properties of oligo- or polymeric materials.

The structures of single crystals of [bipyH]+ [Fen,(ox)2(H20)2]-iH20 (1) and of a photoreaction product of 1, namely of single crystals of a 3-dimensional polymeric compound [FeII(bipy)3]2+"[FeII2(ox)3]"* 12"-(2), where ox is oxalate and bipy is 2,2'-bipyridine, have been determined by X-ray diffraction. Crystal data: 1, monoclinic, /lei, a = 7.302(2) A, b = 23.046(3) A, c = 10.361(2) A, ß = 91.12(2)°, Z = 4, R(F0) = 0.040 for 3273 independent data [/ > 3 (/); 2, cubic, P4332, a = 15.392(2) A, Z = 4, R(F0) = 0.050 for 1594 independent data [/ > 3 (/)].[Fen(ox)3/2]-units in 2 build a 3-dimensional anionic network. It can be described as a 3-connected net consisting of 10-gons, wherein the [Fe(bipy)3]2+ cations occupy the vacancies in an elaborate manner. There exist very few examples as yet of inorganic compounds with structures based on 3-dimensional 3-connected nets.

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