Apically homoleptic octahedral rhenium cluster complexes with 3-methylpyrazole

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

“…Various neutral and anionic ligands have been introduced at the six terminal positions of sulfide-capped octahedral hexanuclear rhenium(III) complexes by thermal substitution reactions of the terminal halides or hydroxides in [Re 6 (μ 3 -S) 8 X 6 ] 4– (X = Cl, Br, I, OH) in solution or under melt conditions (see refs ( 16 , 35 , 37 , 39 , 44 , 45 , 47 − 49 , 52 − 54 , 56 − 58 , 61 , 63 , 65 − 67 , 70 , 71 , 75 , 76 , 83 − 88 )). To our knowledge, several reports have been published on photosubstitution reactions of octahedral hexanuclear metal complexes.…”

“…Various neutral and anionic ligands have been introduced at the six terminal positions of sulfide-capped octahedral hexanuclear rhenium­(III) complexes by thermal substitution reactions of the terminal halides or hydroxides in [Re 6 (μ 3 -S) 8 X 6 ] 4– (X = Cl, Br, I, OH) in solution or under melt conditions (see refs , , , , , , − , − , − , , , − , , , , , − ). To our knowledge, several reports have been published on photosubstitution reactions of octahedral hexanuclear metal complexes. ,,− Gray et al reported that the emission lifetime (τ em ) and quantum yield (Φ em ) of a hexanuclear rhenium complex with terminal iodides or solvent molecules in dichloromethane increase in the presence of an added iodide ion or neat solvent molecules [i.e., dimethyl sulfoxide (DMSO)], suggesting the labile nature of the terminal halides in the excited state. , Zheng et al reported that UV irradiation of [Re 6 (μ 3 -Se) 8 (PEt 3 ) 5 {HNC­(OCH 3 ) (CH 3 )}] 2+ in acetonitrile produces [Re 6 (μ 3 -Se) 8 (CH 3 CN) (PEt 3 ) 5 ] 2+ and that of a dichloromethane solution of [Re 6 (μ 3 -Se) 8 (CO)­(PEt 3 ) 5 ] 2+ affords a 23e complex, [Re 6 (μ 3 -Se) 8 Cl­(PEt 3 ) 5 ] 2+ , in which the coordinating chloride ion originates from dichloromethane. , Szczepura et al reported oxazoline and oxazine ligand removal reactions on [Re 6 (μ 3 -Se 8 ) (PEt 3 ) 5 (L)] 2+ (L = 2-methyloxazoline, 2-phenyloxazoline, and 2-methyloxazine) by UV irradiation .…”

“…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) .…”

“…Sulfide-capped octahedral hexanuclear rhenium­(III) complexes exhibit photoluminescence in the solid state and in solution. ,− ,− ,,,− ,− ,,,,− ,− , The photoemissive excited triplet states of these complexes can be classified into two types: cluster core-centered ( 3 CC) and cluster core-to-L charge-transfer [more generally metal-to-ligand charge-transfer ( 3 MLCT)] states. Most octahedral hexanuclear complexes generate the relevant 3 CC states upon photoexcitation.…”

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 .…”