Rhenium Complexes Based on an N₂O Tridentate Click Scaffold: From Synthesis, Structural and Theoretical Characterization to a Radiolabelling Study

Abstract

International audienceA general synthetic approach to a novel range of semirigid bifunctional chelating agents (BCAs) that include an aromatic ring and a triazolyl moiety in the chelating unit has been investigated for the fac-[M(CO)3]+ core (M = 185/187Re or 188Re). The strategy includes the facile preparation of these N2O ligands bearing various functionalized arms (carboxylate, terminal alkyne, aromatic amine). The reaction of commercial [Re(CO)5Cl] ₒr a freshly prepared [Re(OH2)3(CO)3]+ precursor_ with our BCAs in methanol led to the formation of stable neutral tricarbonylrhenium complexes of general formula [Re(CO)3(L)] (LH = 5, 10, 11) in high yields. These compounds were characterized by IR and NMR spectroscopy, mass spectrometry, electrochemistry, and X-ray crystallography for [Re(CO)3(5–H)] and [Re(CO)3(11–H)] as well as by DFT calculations. The analogous rhenium-188 complexes [188Re(CO)3(5)] and [188Re(CO)3(11–H)] were also prepared, in acceptable to excellent yields, by the reaction of 5 or 11 with the fac-[188Re(OH2)3(CO)3]+ precursor in methanol at 80 °C. The structural identities of the radioactive complexes were assessed by HPLC studies. The good affinity of these click ligands for the ReI core combined with the ease of their derivatization make this chelating system promising for the conception of target-specific radiopharmaceuticals for therapeutic purposes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Phenyl-pyta-tricarbonylrhenium(i) complexes: combining a simplified structure and steric hindrance to modulate the photoluminescence properties

“…The former process can be mainly assigned to an irreversible Re(I) oxidation process. 23 This process presents some slightly reversible character when increasing the scan rate around 50 V/s for complexes 2 and 3 (See ESI). Considering the OSWV cathodic part, as for RePBO, a clear reduction process was observed for all the new complexes around 1.30 V. 13 It can be attributed to the reduction process of the substituted triazole ring whose value may substantially decrease by complexation as observed in related compounds.…”

Novel Re(I) tricarbonyl coordination compounds based on 2-pyridyl-1,2,3-triazole derivatives bearing a 4-amino-substituted benzenesulfonamide arm: synthesis, crystal structure, computational studies and inhibitory activity against carbonic anhydrase I, II, and IX isoforms†

“…These features make them interesting tools for numerous potential practical applications, such as photo sensitisers in solar cells 1 , CO 2 reduction catalysts 2 , organic light-emitting devices (OLEDs) 3 , luminescence sensors 4 , and CO-releasing moieties (CORMs) 5 . Additionally, radioactive fac -[ 188 Re(CO) 3 ] + complexes have recently drawn the attention of several research groups for their use as therapeutic radiopharmaceuticals 6 .…”

Synthesis of (−)-6,7-Dideoxysqualestatin H5 by Carbonyl Ylide Cycloaddition–Rearrangement and Cross-electrophile Coupling

“…Under optimized conditions (solvent, ratio of reactants, concentration, and additives were examined on model systems), a 1:1 mixture of hydroxy iodide 25 and alkenyl iodide 4 in DMF (0.8 M) gave alkene 26 in 66% yield with complete stereoretention. Desilylation using TBAF was accompanied by hydrolysis of the C-3 ester to give the known diester 27 in 67% yield. Finally, hydrolysis of the remaining more-hindered esters using anhydrous KOH gave (−)-6,7-dideoxysqualestatin H5 2 possessing spectral data in complete agreement with that previously reported …”