A Family of Octahedral Rhenium Cluster Complexes [Re₆Q₈(H₂O)_n(OH)_6 - n]^n - 4 (Q = S, Se; n = 0−6):  Structural and pH−Dependent Spectroscopic Studies

Abstract

The conversions of hexahydroxo rhenium cluster complexes [Re6Q8(OH)6]4- (Q=S, Se) in aqueous solutions in a wide pH range were investigated by chemical methods and spectroscopic measurements. Dependences of the spectroscopic and excited-state properties of the solutions on pH have been studied in detail. It has been found that a pH decrease of aqueous solutions of the potassium salts K4[Re6Q8(OH)6].8H2O (Q=S, Se) results in the formation of aquahydroxo and hexaaqua cluster complexes with the general formula [Re6Q8(H2O)n(OH)6-n]n-4 that could be considered as a result of the protonation of the terminal OH- ligands in the hexahydroxo complexes. The compounds K2[Re6S8(H2O)2(OH)4].2H2O (1), [Re6S8(H2O)4(OH)2].12H2O (2), [Re6S8(H2O)6][Re6S6Br8].10H2O (3), and [Re6Se8(H2O)4(OH)2] (4) have been isolated and characterized by X-ray single-crystal diffraction and elemental analyses and infrared (IR) spectroscopy. In crystal structures of the aquahydroxo complexes, the cluster units are connected to each other by an extensive system of very strong hydrogen bonds between terminal ligands.

Novel supramolecular compounds based on Cucurbit[6]uril, 1,8-diaminooctane and octahedral thiohydroxo anions with cluster core [Re6S8]

“…The Re-Re and Re-S bond lengths have the respective ranges for compounds 1 and 2: 2.5710 (8) (19) Å. These bond lengths are similar to the distances in the starting potassium salt and other related compounds [12,[16][17][18].…”

Supramolecular Frameworks Built up from Red‐Phosphor­escent trans‐Re6 Cluster Building Blocks: One Pot Synthesis, Crystal Structures, and DFT Investigations

“…[61] Indeed, the resulting architecture is primarily governed by π stacking of coordinated and non-coordinated linkers, which allows the formation of infinite layers in the bc plane. The interaction of OH -groups from the cluster units with two water molecules incorporated in the voids of the crystal lattice establishes H 3 O 2 units [62][63][64][65][66] along the a axis ( Figure S1 adjacent layers by two shared water molecules (O4) has previously been reported by Gao, [64] Prasad, [67] and co-workers. The combination of supramolecular interactions (i.e.…”

Photoinduced Electron Transfer Reactions of Hexarhenium(III) Cluster: Oxidative Quenching of [Re6S8Cl6]4− Emission by Electron Acceptors

“…We reported previously, on the other hand, that hexarhenium(III) clusters, [Re 6 (l 3 -S) 8 X 6 ] 4-(X = Cl -, Br -, I -, and so forth), showed relatively intense room temperature emission in the visible * near infrared region (600-1,000 nm) with the emission lifetime (s) and quantum yield (U) in acetonitrile being s = 4-11 ls and U = 0.015-0.056, respectively [8] [15], N-heteroaromatics [16][17][18][19][20][21], phosphine derivatives [17,18,22,23], HCOO [24], CH3COO [25], and N 3 [26] [8,29]. Acetonitrile (Wako Pure Chemicals Co. Ltd.) as a medium throughout the study was purified by distillation over CaH 2 .…”