Monodisperse gold nanoparticles (AuNPs) were obtained by hydrolytic decomposition of a new molecular precursor, tetramethylammonium bis(trifluoromethyl)aurate(I), [NMe4][Au(CF3)2], which has been characterised by spectroscopic and single‐crystal X‐ray diffraction analyses. On account of the simple and high‐yield synthesis, the title compound represents a versatile synthon and an alternative to the commonly used chloroauric acid (HAuCl4).

Fully green and facile redox chemistry involving reduction of colloidal iron hydroxide (Fe(OH)3) through green tea (GT) polyphenols produced water-soluble Fe3O4 nanocrystals coated with GT extracts namely epigallocatechin gallate (EGCG) and epicatechin (EC). Electron donating polyphenols stoichiometrically reduced Fe(3+) ions into Fe(2+) ions resulting in the formation of magnetite (Fe3O4) nanoparticles and corresponding oxidized products (semiquinones and quinones) that simultaneously served as efficient surface chelators for the Fe3O4 nanoparticles making them dispersible and stable in water, PBS, and cell culture medium for extended time periods. As-formed iron oxide nanoparticles (2.5-6 nm) displayed high crystallinity and saturation magnetization as well as high relaxivity ratios manifested in strong contrast enhancement observed in T2-weighted images. Potential of green tea-coated superparamagnetic iron oxide nanocrystals (SPIONs) as superior negative contrast agents was confirmed by in vitro and in vivo experiments. Primary human macrophages (J774A.1) and colon cancer cells (CT26) were chosen to assess cytotoxicity and cellular uptake of GT-, EGCGq-, and ECq-coated Fe3O4 nanoparticles, which showed high uptake efficiencies by J774A.1 and CT26 cells without any additional transfection agent. Furthermore, the in vivo accumulation characteristics of GT-coated Fe3O4 nanoparticles were similar to those observed in clinical studies of SPIONs with comparable accumulation in epidermoid cancer-xenograft bearing mice. Given their promising transport and uptake characteristics and new surface chemistry, GT-SPIONs conjugates can be applied for multimodal imaging and therapeutic applications by anchoring further functionalities.

Exchange Coupling in Tris(p-hydroxo) bis[ (1,4,7-trimethyl-1,4,7-triazacyclononane)chromium( 111)] Triper c hlora t e T r i hydra t eMagnetic susceptibility data have been collected in the temperature range 1.7-336 K for the tris(r-hydroxo)-bridged bimetallic chromium complex [LCr(OH)3CrL](C104)3.3Hz0. The magnetic susceptibility data reflect antiferromagnetic exchange coupling interactions and may be fit with the assumption of bilinear and biquadratic exchange of the form -WS1.S2j(S1.S2)* with the Van Vleck equation. The best fit of the experimental data yields J = -64 (1) cm-I, j = 1.8 (2) cm-I, and g = 1.98 ( 1 ) with an estimated impurity percentage of 0.84 (1). The large value of the bilinear exchange coupling constant reflects the number of bridging hydroxo groups as well as structural features of the superexchange pathway. EPR spectra collected as a function of temperature at X-and Q-band have been theoretically simulated with the spin Hamiltonian parameters D = f0.34 cm-I, 0, = *0.18 cm-I, and g = 1.98, with AHpp = 150 G .A flow type cryostat with an internal helium reservoir was used for the measurements between 336 and 1.7 K. The temperature was measured with a calibrated Au (0.3% Fe)/chromel thermocouple, and Veal, J. T.; Jeter, D. Y.; Hempel, J. C.; Eckberg, R. P.; Hatfield, W. E.: Hodson. D. J. Inorp. Chem. 1973. 12. 2928. Engel, Py; Gidel, H. U."Inorg. Chem. 1977, 16, 1589. Urishiyama, A.; Nomura, T.; Nakahara, M. Bull. Chem. SOC. Jpn. 1970, 43, 3971. Yevitz, M.; Stanko, J. A. J. Am. Chem. SOC. 1971, 93, 1512.

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MeTeR f (R f = CF 3 , C 2 F 5 ) can easily be prepared via the reactions of methyl iodide and the corresponding tetramethylammonium perfluoroalkyltellurates(0), [NMe 4 ]TeR f (R f = CF 3 , C 2 F 5 ). Both compounds are easily oxidized by xenon difluoride and the heavier halogens to yield the corresponding dihalides, MeTe(R f )X

[NMe(4)][R(f)Te(SC(S)NR(2))(2)] derivatives are selectively formed by the oxidation of [NMe(4)]TeR(f) (R(f) = CF(3), C(2)F(5)) with [R(2)NC(S)S](2) (NR(2) = NEt(2), NBz(2), N(CH(2))(4)) in almost quantitative yields. An alternative route to obtain the dithiocarbamato complex anions offer reactions of Te[SC(S)NR(2)](2) (NR(2) = NEt(2), NBz(2)) with equimolar amounts of Me(3)SiR(f) and [NMe(4)]F. Some of the derivatives were recrystallized with bulky cations in order to determine the crystal structures. Structural elucidation by diffraction methods exhibit the structural feature of a distorted pentagonal planar environment (resembling "butterflies") around the tellurium centres. The carbamato tellurates can be transferred easily into the neutral derivatives, R(f)TeSC(S)NR(2), upon treatment with Ag[BF(4)]. In solution they equilibrate with Te(2)(R(f))(2) and [R(2)NC(S)S](2) and finally are transformed into Te(R(f))(2), Te[SC(S)NR(2)](2), and Te[SC(S)NR(2)](4), respectively. All compounds are fully characterized by NMR spectroscopic methods ((1)H, (13)C, (19)F, (125)Te). Additionally, synthesis and characterization of the hitherto unknown derivative [NMe(4)]TeC(2)F(5) are described.

Abstract. Attempted syntheses of AgR f ·DMAP were performed using the established route starting from AgF and Me 3 SiR f (R f = CF 3 , C 2 F 5 , C 6 F 5 ) followed by the addition of DMAP. Unexpectedly, reactions with perfluoroalkylsilver(I) derivatives yielded products, which underwent known equilibria, while exclusively the pentafluorophenyl derivative exhibits its zwitterionic nature in solution and in the solid state. Moreover, both perfluoroalkyl derivatives investigated decomposed slowly

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