[Ru₂Bi₁₄Br₄](AlCl₄)₄by Mobilization and Reorganization of Complex Clusters in Ionic Liquids

Abstract

Two polymorphs of the new cluster compound [Ru(2)Bi(14)Br(4)](AlCl(4))(4) have been synthesized from Bi(24)Ru(3)Br(20) in the Lewis acidic ionic liquid [BMIM]Cl/AlCl(3) ([BMIM](+) : 1-n-butyl-3-methylimidazolium) at 140 °C. A large fragment of the precursor's structure, namely the [(Bi(8))Ru(Bi(4)Br(4))Ru(Bi(5))](5+) cluster, dissolved as a whole and transformed into a closely related symmetrical [(Bi(5))Ru(Bi(4)Br(4))Ru(Bi(5))](4+) cluster through structural conversion of a coordinating Bi(8)(2+) to a Bi(5)(+) polycation, while the remainder was left intact. Both modifications have monoclinic unit cells that comprise two formula units (α form: P2(1)/n, a=982.8(2), b=1793.2(4), c=1472.0(3) pm, β=109.05(3)°; β form: P2(1)/n, a=1163.8(2), b=1442.7(3), c=1500.7(3), β=97.73(3)°). The [Ru(2)Bi(14)Br(4)](4+) cluster can be regarded as a binuclear inorganic complex of two ruthenium(I) cations that are coordinated by terminal Bi(5)(+) square pyramids and a central Bi(4)Br(4) ring. The presence of a covalent Ru-Ru bond was established by molecular quantum chemical calculations utilizing real-space bonding indicator ELI-D. Structural similarity of the new and parent cluster suggests a structural reorganization or an exchange of the bismuth polycations as mechanisms of cluster formation. In this top-down approach a complex-structured unit formed at high temperature was made available for low-temperature use.

The Intermetalloid Cluster Cation (CuBi8)3+

“…To day at otal of seven different polycations [10,17] and four polyanions [18] [11] [Ru(Bi 8 ) 2 ] 6 + , [12] [(Bi 5 )Ru(Bi 4 Br 4 )Ru(Bi 5 )] 4 + , [21] [(Bi 8 )Ru(Bi 4 Br 4 )Ru(Bi 5 )] 4 + , [22] and [(Bi 10 )(AuSbBi 3 Br 9 ) 2 ] [23] are examples of such complexes ( Figure 3). The calculated molecular orbital schemes corroborated the applicabilityo f1 8-electron counting rule and consequently the role of the polycations as six-electron donors (h 4 [11,12] Therefore, bismuth polycations act similart ok nown coordinating clusters or molecules such as nido-carboranes, [24] Zintl ions, [25] and arenes, [26] whereas bismuth polyanions tend to form heteroatomic clusters.…”

Controlled Synthesis of Polyions of Heavy Main-Group Elements in Ionic Liquids

“…Lewis-acidic ILs feature a remarkable solubility for metalloids and their halides, which extends to ternary compounds [29,107] with heavy transition metal elements like Bi 16 PdCl 22 = [Pd@Bi 10 ]Bi 6 Cl 22 [108]. The dissolution of Bi 16 PdCl 22 in the Lewis-acidic IL [BMIm]Br·4.1AlBr 3 yields [Pd@Bi 10 ](AlBr 4 ) 2 (Al 2 Br 7 ) 2 or [Pd@Bi 10 ](AlBr 4 ) 4 depending on temperature and/or AlBr 3 to [Pd@Bi 10 ] 4+ ratio [107,109].…”

“…Owing to the distinctive physicochemical properties of ILs (wide liquidus range, high redox and thermal stability, negligible vapor pressure, and tunable polarity) and their advantages over organic solvents, classic melts, or solid state reactions, their applications include separation techniques [7,8,9], lubrication [10], electrodeposition [11], acting as electrolytes in photovoltaic devices (e.g., solar cells) [12,13,14], catalysis for clean technology [15,16,17,18], polymerization processes [19], crystal engineering of a wide range of inorganic substances [20,21,22,23,24,25], and syntheses of new inorganic materials in general [23,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51]. Recently, several comprehensive reviews on syntheses of inorganic compounds in ILs have been published by Taubert [52], Feldmann [28], Dehnen [51], Janiak [42,53], Scrosati and Passerini [48], Morris [54], Mudring [55], Prechtl [56], Zhu [57], Dai [58], and Ruck [23,27,59] among others.…”

Reprint of “Coordination chemistry of homoatomic ligands of bismuth, selenium and tellurium”

“…The Bi 8 2+ polycation (as well as the E 9 4− polyanions) can be correlated to nido-carboranes ligands, such as the dicarbollide anion [77,78] The same coordination mode holds for the terminal Bi 5 + cation in the cluster [Ru 2 Bi 14 Br 4 ] 4+ = [(Bi 5 + )Ru + (Bi 4 Br 4 )Ru + (Bi 5 + )] (Fig. 2i), which has been crystallised as two modifications of its tetrachloridoaluminate salt [30]. Following the covalent approach, each of the bismuth atoms in the formally uncharged equatorial Bi 4 Br 4 ring contributes with one of its 6p electrons to the almost linear 3c4e bonds of the square ring.…”