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Two rhenium complexes, namely, fac‐tricarbonyl(triphenylphosphane‐κP)(tropolonato‐κ2O,O′)rhenium(I), [Re(C7H5O2)(C18H15P)(CO)3] or fac‐[Re(Trop)(PPh3)(CO)3] (1), and fac‐tricarbonyl(3,5,7‐tribromotropolonato‐κ2O,O′)(triphenylphosphane‐κP)rhenium(I), [Re(C7H2Br3O2)(C18H15P)(CO)3] or fac‐[Re(TropBr3)(PPh3)(CO)3] (2) (TropH is tropolone and and TropBr3H is tribromotropolone), were synthesized and their crystal and molecular structures confirmed by single‐crystal X‐ray diffraction. Both crystallized in the space group P and display an array of inter‐ and intramolecular interactions which were confirmed by solid‐state 13C NMR spectroscopy using cross polarization magic angle spinning (CPMAS) techniques, as well as Hirshfeld surface analysis. The slightly longer Re—P distance of 1 [2.4987 (5) versus 2.4799 (11) Å for 1 and 2, respectively] suggests stronger back donation from the carbonyl groups in the former case, possibly due to the stronger electron‐donating ability of the unsubstituted tropolonate ring system. However, this is not supported in the Re—CO bond distances of 1 and 2. [ABSTRACT FROM AUTHOR]

The synthesis and crystal structures of two new rhenium(I) complexes obtained utilizing benzhydroxamic acid (BHAH) and 3‐hydroxyflavone (2‐phenylchromen‐4‐one, FlavH) as bidentate ligands, namely tetraethylammonium fac‐(benzhydroxamato‐κ2O,O′)bromidotricarbonylrhenate(I), (C8H20N)[ReBr(C7H6NO2)(CO)3], 1, and fac‐aquatricarbonyl(4‐oxo‐2‐phenylchromen‐3‐olato‐κ2O,O′)rhenium(I)–3‐hydroxyflavone (1/1), [Re(C15H9O3)(CO)3(H2O)]·C15H10O3, 3, are reported. Furthermore, the crystal structure of free 3‐hydroxyflavone, C15H10O3, 4, was redetermined at 100 K in order to compare the packing trends and solid‐state NMR spectroscopy with that of the solvate flavone molecule in 3. The compounds were characterized in solution by 1H and 13C NMR spectroscopy, and in the solid state by 13C NMR spectroscopy using the cross‐polarization magic angle spinning (CP/MAS) technique. Compounds 1 and 3 both crystallize in the triclinic space group P with one molecule in the asymmetric unit, while 4 crystallizes in the orthorhombic space group P212121. Molecules of 1 and 3 generate one‐dimensional chains formed through intermolecular interactions. A comparison of the coordinated 3‐hydroxyflavone ligand with the uncoordinated solvate molecule and free molecule 4 shows that the last two are virtually completely planar due to hydrogen‐bonding interactions, as opposed to the former, which is able to rotate more freely. The differences between the solid‐ and solution‐state 13C NMR spectra of 3 and 4 are ascribed to inter‐ and intramolecular interactions. The study also investigated the potential labelling of both bidentate ligands with the corresponding fac‐99mTc‐tricarbonyl synthon. All attempts were unsuccessful and reasons for this are provided. The synthesis and crystal structures of two new rhenium(I) complexes, obtained utilizing benzhydroxamic acid and 3‐hydroxyflavone as bidentate ligands, are reported. Furthermore, the crystal structure of free 3‐hydroxyflavone was redetermined at 100 K in order to compare the packing trends and solid‐state NMR spectroscopy with those of the solvate flavone molecule. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of two dinuclear complexes, namely fac‐hexacarbonyl‐1κ3C,2κ3C‐(pyridine‐1κN)[μ‐2,2′‐sulfanediyldi(ethanethiolato)‐1κ2S1,S3:2κ3S1,S2,S3]dirhenium(I), [Re2(C4H8S3)(C5H5N)(CO)6], (1), and tetraethylammonium fac‐tris(μ‐2‐methoxybenzenethiolato‐κ2S:S)bis[tricarbonylrhenium(I)], (C8H20N)[Re2(C7H7OS)3(CO)6], (2), together with two mononuclear complexes, namely (2,2′‐bithiophene‐5‐carboxylic acid‐κ2S,S′)bromidotricarbonylrhenium(I), (3), and bromidotricarbonyl(methyl benzo[b]thiophene‐2‐carboxylate‐κ2O,S)rhenium(I), (4), are reported. Crystals of (1) and (2) were characterized by X‐ray diffraction. The crystal structure of (1) revealed two Re—S—Re bridges. The thioether S atom only bonds to one of the ReI metal centres, while the geometry of the second ReI metal centre is completed by a pyridine ligand. The structure of (2) is characterized by three S‐atom bridges and an Re…Re nonbonding distance of 3.4879 (5) Å, which is shorter than the distance found for (1) [3.7996 (6)/3.7963 (6) Å], but still clearly a nonbonding distance. Complex (1) is stabilized by six intermolecular hydrogen‐bond interactions and an O…O interaction, while (2) is stabilized by two intermolecular hydrogen‐bond interactions and two O…π interactions. [ABSTRACT FROM AUTHOR]