Octahedral chalcogenide rhenium cluster complexes with imidazole

Abstract

Reactions of [{Re6Q8}Br6] 4−/3− (Q = S, Se) with molten imidazole lead to the formation of two new neutral cluster complexes [{Re6Q8}(imzH)4(imz)2] (imzH = imidazole). The interaction of [{Re6Q8}(imzH)4(imz)2] with hydrohalic acids resulted in cationic complexes [{Re6Q8}(imzH)6]X2 (X = Cl, Br). All compounds were characterised by X-ray single-crystal and powder diffraction analyses, elemental analysis, energy dispersive X-ray and IR spectroscopies. The luminescence of the neutral compounds [{Re6Q8}(imzH)4(imz)2] was also studied.

Self-Assembled Microporous M-HOFs Based on an Octahedral Rhenium Cluster with Benzimidazole

“…During the reaction, the apical homoleptic cationic cluster [{Re 6 Se i 8 }­(bimzH) a 6 ] 2+ was formed, which once again proved the previously suggested theory . Briefly, using protic (i.e., possibility of self-ionization) proligands, to which the weak acid bimzH (p K a ∼ 12.8) belongs, allows one to obtain a hexasubstituted cluster, as was demonstrated in the case of imidazole, pyrazole, , 4-aminopyridine, etc. , The phase purity and composition of Re 6 -HOF-1 as and Re 6 -HOF-2 as were proven by elemental analysis, IR (Figures S1 and S2) and NMR spectroscopy, and PXRD analysis. Also, single crystals of Re 6 -HOF-1 as and Re 6 -HOF-2 as suitable for X-ray structural analysis (SCXRD) were obtained by slow cooling of the reaction mixture from 200 °C to room temperature at a rate of 7.5 °C h –1 .…”

“…All distances (Re–Re, Re–Se, and Re–N) in the [{Re 6 Se i 8 }­L a 6 ] 2+ cation are in good agreement with the literature data for other complexes with organic ligands (Table S2). ,, These building blocks are connected to each other via hydrogen bonds between each bimzH ligands and X anion (N–H···X), so that each X anion connects three cluster cations, with N–X distances of 3.068–3.080 and 3.220–3.278 Å for X = Cl and Br, respectively, forming infinite layers along a plane perpendicular to the crystallographic directions [1,1,1] (Figure b,c). On the other hand, stacking of the layers occurs because of parallel displaced π–π-stacking interactions (the average distances between centroids of the benzene rings are 3.730 and 3.686 Å for Re 6 -HOF-1 as and Re 6 -HOF-2 as , respectively) between three bimzH molecules in the fac positions of one cluster and the bimzH molecules of three other clusters of the adjacent layer (Figure S5).…”

Tuning the Ground- and Excited-State Redox Potentials of Octahedral Hexanuclear Rhenium(III) Complexes by the Combination of Terminal Halide and N-Heteroaromatic Ligands

“…The chemistry of chalcogenide-capped octahedral hexanuclear rhenium complexes with six terminal ligands has been well studied: − the complex has 24 d electrons (24e), and the oxidation state of each rhenium ion is +3. The complex unit is intriguing because it exhibits rich redox and photoluminescent properties. − ,− The terminal ligands on the complex are moderately inert to a substitution reaction, which results in stepwise ligand substitutions at the terminal positions. ,,, The complex unit undergoes one-electron oxidation, and the Re 6 (23e)/Re 6 (24e) process is dependent on the nature of the terminal ligands. ,,, The one-electron oxidation process of [Re 6 (μ 3 -S) 8 Cl 6 ] 4– (0.31 V vs Ag/AgCl) shifts positively upon substitution of the terminal chloride ligands with pyridine (py), leading to show at 0.77 V for trans -/ cis -[Re 6 (μ 3 -S) 8 Cl 4 (py) 2 ] 2– or 1.03 V for [Re 6 (μ 3 -S) 8 Cl 3 (py) 3 ] − . A trend similar to that mentioned above has also been observed for [Re 6 (μ 3 -S) 8 Cl 6– n (PEt 3 ) n ] n −4 (PEt 3 : triethylphosphine, n = 1–4) .…”

Supramolecular Frameworks Based on Rhenium Clusters Using the Synthons Approach

“…Most of these investigations have been carried out by using amines or amino groups as functional ligands, which leads to complexes or supramolecular networks. One can note, for instance, the functionalization by azides [ 21 , 22 ], azolates [ 23 , 24 , 25 , 26 , 27 ], pyridine, and its derivatives [ 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. When an additional cation, transition metal, or lanthanide is employed, then some extended coordination networks can be reached [ 35 , 36 ], as in the cases of phenantroline and Gd yielding a 2D framework [ 36 ], amines and Cu yielding a 2D framework [ 37 ], ethylenediamine and 3D transition metals yielding a 2D framework with resulting porosity [ 38 , 39 ], or salen salts [ 40 ].…”