Bis-Arene Complexes [Re(η-arene)] as Highly Stable Bioorganometallic Scaffolds.

The synthesis of mono- and difunctionalized [Re(η-CHR)(η-CHR)] (n = 0, 1; R = COOH, Br) complexes starting from [Re(η-benzene)] is described. The lithiation of [Re(η-benzene)] with n-BuLi leads preferentially to the neutral, alkylated product [Re(η-CH)(η-CH-Bu)] but not to the expected deprotonation of the arene ring. Deprotonation/lithiation with LDA gave the mono- and the dilithiated products in situ.

From Tc to Tc; facile syntheses of bis-arene complexes [Tc(arene)] from pertechnetate.

Bis-arene complexes of technetium represent a fundamental class of organometallic compounds. Due to complex synthetic routes, no detailed insights into their properties have been reported so far. Reacting [TcO] with arenes in the exclusive presence of AlCl gives highly stable [Tc(arene)] in good yields.

[(Cp-R)M(CO)3] (M = Re or 99mTc) conjugates for theranostic receptor targeting.

Cyclopentadienyl complexes of 99mTc became accessible via a retro Diels-Alder synthetic approach of dimerized cyclopentadiene derivatives. So far, this approach was limited to derivatives comprising a carboxylic acid group, directly conjugated to the Cp-ring, leading to complexes [(C5H5COOH)99mTc(CO)3] and [(C5H5CONH-R)99mTc(CO)3], respectively. The introduction of an -NCO group via Curtius rearrangement and subsequent in situ reactions with alcohols or amines gave [(C5H5NHCO-OR)2] and [(C5H5NHCO-NHR)2].

Orthogonally protected artificial amino acid as tripod ligand for automated peptide synthesis and labeling with [(99m)Tc(OH(2))(3)(CO)(3)](+).

1,2-Diamino-propionic acid (Dap) is a very strong chelator for the [(99m)Tc(CO)(3)](+) core, yielding small and hydrophilic complexes. We prepared the lysine based Dap derivative l-Lys(Dap) in which the ε-NH(2) group was replaced by the tripod through conjugation to its α-carbon. The synthetic strategy produced an orthogonally protected bifunctional chelator (BFC).

The [(Cp)M(CO)(3)] (M=Re, (99m)Tc) building block for imaging agents and bioinorganic probes: perspectives and limitations.

Starting from asymmetric Thiele's acid derivatives, two different imaging probes [(99m)Tc(CO)(3)(CpR)] (R=potential targeting vector) are generated simultaneously in one-pot and from one substrate. This extends the previously introduced labeling strategy of metal-mediated retro-Diels-Alder reaction with HCp-R dimers. We demonstrate that chemically active functionalities such as hydroxamic acids are not following this labeling strategy.

[(Cp-R)M(CO)3] (M=Re or 99mTc) Arylsulfonamide, arylsulfamide, and arylsulfamate conjugates for selective targeting of human carbonic anhydrase IX.

Enhanced receptor selectivity: carbonic anhydrase inhibitors are relevant for both cancer diagnosis and therapy. Combining non-radioactive Re compounds with their radioactive (99m)Tc homologs enables the use of identical molecules for therapy and imaging (theragnostic). The syntheses and in vitro evaluation of [(Cp-R)M(CO)(3)] (Cp=cyclopentadienyl, M=Re, (99m)Tc) with R being a highly potent carbonic-anhydrase-targeting vector is reported.

Preparation and biological evaluation of cyclopentadienyl-based 99mTc-complexes [(Cp-R)99mTc(CO)3] mimicking benzamides for malignant melanoma targeting.

The biological evaluation of half-sandwich (99m)Tc-complexes that surrogate iodobenzamide with a high affinity for melanin tumor tissue is described. We have synthesized via retro Diels-Alder reaction two models of (99m)Tc complexes which possess the piano stool [Cp(99m)Tc(CO)(3)] motif instead of a phenyl ring as in the original iodobenzamide (123)I-N-(N-benzylpiperidin-4-yl)-2-iodobenzamide (2-IBP) and N-(2-diethylaminoethyl)-4-iodobenzamide (BZA). Diels-Alder products 2a-b (HCp-CONHR)(2) (2a, R=2-diethylaminoethyl; 2b, R=benzylpiperidin-4-yl) were prepared and reacted with fac-[(99m)Tc(H(2)O)(3)(CO)(3))](+) 1 in water to produce the corresponding (99m)Tc complexes [(2a)(99m)Tc(CO)(3))] 4a and [(2b)(99m)Tc(CO)(3))] 4b.

Amino acids labeled with [99mTc(CO)3]+ and recognized by the L-type amino acid transporter LAT1.

We have synthesized amino acids conjugated at the alpha-carbon through an alkyl spacer to a small tripod ligand. The tripod coordinates to the fac-[M(CO)3]+ moiety (M = Re, 99mTc). Depending on the lengths of the spacers, these metal complexes with pendent alpha-amino acids are recognized and transported by the l-type amino acid transporter LAT1.

Stable isotope analysis reveals differential effects of soil nitrogen and nitrogen dioxide on the water use efficiency in hybrid poplar leaves.

•  The effects of nitrogen dioxide (NO ) exposure are reported on the physiology, morphology and carbon partitioning of hybrid poplar clone cuttings (Populus ×euramericana) grown under high and low soil nitrogen supply. •  Plants were exposed to filtered air or NO -enriched air (80-135 nl l ) over 12 wk growth in phytotrons. Stable isotope analysis, combined with CO and H O gas exchange measurements, biomass analysis and morphological development, was used to assess the integrated long-term effects of NO .