Bismuth Polycations Research Articles

Bismuth Infrared Star: being at a glance.

Bismuth polycations have garnered significant attention from researchers due to their extraordinary and counter-intuitive structures and stoichiometries. Despite extensive experimental and theoretical investigations, our understanding of the bonding in such clusters remains insufficient. In this study, we conducted an AdNDP bonding analysis to elucidate the bonding characteristics using both homoatomic and heteroatomic bismuth clusters with various stoichiometries. By analyzing the calculated nucleus-independent chemical shift data, we confirmed the aromatic nature of these species. We identified some universal bonding patterns that can be applied to a range of homoatomic and heteroatomic bismuth clusters. Additionally, we performed calculations of absorbance and fluorescence spectra to gain insights into the near-infrared emission and establish a potential correlation between absorbance and the identified bonding patterns.

Bismuth Polycations Revisited: Alternative Synthesis and Electronic Structure of Bi6Br7, and Bonding in Main-Group Polyatomic Ions from a Direct Space Perspective

A bismuth subbromide, Bi6Br7, was synthesized in the form of single crystals using the reaction between Bi and Hg2Br2 in a gradient furnace. Its crystal structure was reinvestigated by low-temperature single-crystal X-ray diffraction (Pnnm, a = 15.4996(6) Å, b = 23.6435(7) Å, c = 9.0231(2) Å, Z = 8, R1 = 0.041, wRall = 0.087). Based on the diffraction data, the structure description was revised as containing Bi95+ cluster polycations and 1∞[Bi3Br145−] ladder-like anions. DFT calculations of band structure showed the compound to be a narrow-gap semiconductor with a band gap of ca. 1.3 eV, with the nature of the compound as ionic salt confirmed by charge density analysis. Direct-space bonding analysis based on the ELF topology and QTAIM partitioning, performed for all known homoatomic bismuth polycations, as well as isoelectronic main-group metal ions, shows patterns of localized pairwise and three-center bonding forming the frameworks of the clusters. In addition to obtaining new data, the use of highly augmented basis sets allowed us to revise and amend several previously made conclusions regarding bonding in such species.

ChemInform Abstract: Polyhedral Bismuth Polycations Coordinating Gold(I) with Varied Hapticity in a Homoleptic Heavy‐Metal Cluster.

AbstractSingle crystals of [Au(Bi8)2](AlCl4)5 are obtained from the reaction of AuCl, BiCl3, and Bi in the ionic liquid [bmim]Cl·4AlCl3 (evacuated silica tubes, 180 °C, 16 h).

Polyhedral Bismuth Polycations Coordinating Gold(I) with Varied Hapticity in a Homoleptic Heavy‐Metal Cluster

Shiny black, air‐sensitive crystals of [Au(Bi8)2](AlCl4)5 were obtained from the reaction of AuCl, BiCl3, and bismuth in the ionic liquid [BMIm]Cl·4AlCl3 (BMIm = 1‐n‐butyl‐3‐methylimidazolium) at 180 °C. [Au(Bi8)2](AlCl4)5 crystallizes in the monoclinic space group P21/n. In the heavy‐metal cluster [Au(Bi8)2]5+, two square‐antiprismatic Bi82+ polycations coordinate the gold(I) atom in η2‐ and η4‐mode, respectively. Quantum chemical calculations demonstrate that both Bi82+ polycations involve skeletal electrons for the donor bonding, which causes a widening of Bi–Bi distances compared with those in free Bi82+.

ChemInform Abstract: [Ru(Bi8)2]6+ — A Cluster in a Highly Disordered Crystal Structure Is the Key to the Understanding of the Coordination Chemistry of Bismuth Polycations.

AbstractBlack platelets of Bi39.67Ru2Br35.0 are crystallized from a melt of Bi, BiBr3, and Ru (evacuated silica tube, 450 °C, 8 h).

Ru(Bi8)2]6+– A Cluster in a Highly Disordered Crystal ­Structure is the Key to the Understanding of the Coordination Chemistry of Bismuth Polycations

AbstractBlack platelets of Bi39.67(7)Ru2Br35.0(2)were crystallized from a melt of Bi, BiBr3, and Ru. In the tetragonal crystal structure [P4/mbm,a= 1311.92(6) pm,c= 3018.2(4) pm at 155(5) K], cluster cations [(Bi82+)Ru2+(Bi82+)] are embedded in a matrix of disordered bromido‐bismuthate(III) groups. A thorough analysis of the disorder in the anionic part enabled the unambiguous assignment of the cluster charge. The η4‐coordination of the two Bi82+square antiprisms to the RuIIatom in the sandwich complex resembles the bonding of Bi5+and Bi82+in the clusters [(Bi5+)Ru+(Bi4Br4)Ru+(Bi5+)] and [(Bi82+)Ru+(Bi4Br4)Ru+(Bi5+)] as well as of Bi42–in$\rm^{1}_{\infty}$[(Bi42–)Ru+(Bi4Br4)Ru+]. By combining crystal chemical considerations for all mentioned compounds and using quantum chemical calculations, a common bonding scheme for the coordination compounds of bismuth polycations and polyanions was established. The η4‐coordinating bismuth polycations and polyanions act as six electron donors, comparable tonido‐carborane ligands, Zintl anionsE94–andE56–(E= Si to Pb), cyclopentadienyl ligands, or the cyclobutadiene dianion. The electron count for the transition metal is 18 in all finite clusters.

Bi65Cu13Ge41O6Br122, a Low‐Valent Compound of High Structural Complexity Featuring the Trigonal Anion [O(GeIIBr2)3]2–with an sp2‐Hybridized μ3‐Oxide Ion

AbstractThiny black air‐sensitive crystals of Bi65Cu13Ge41O6Br122= (Bi5)2(Bi9)6[O(GeBr2)3]6[Cu6Ge5Br20][BiCu7Ge18Br66] were obtained by very slow cooling of a melt of bismuth, bismuth tribromide, copper, and partly oxidized germanium. The crystal structure was described in the hexagonal space groupP63(no. 173) witha= 2584.2(4) pm andc= 1277.4(3) pm at 296(1) K. The polarity of the structure is subtle; large parts of the structure show a pseudo mirror plane. The highly diversified structure comprises five distinct structural fragments. For the first time, two polyhedral bismuth polycations, Bi53+(trigonal bipyramid,D3h) and Bi95+(tricapped trigonal prism,D3h), occur in one and the same chemical compound. A hitherto unknown group is theC3h‐symmetric μ3‐oxido‐tris[dibromidogermanate(II)] anion [O(GeBr2)3]2–, in which the germanium atoms of three GeIIBr2units bind to a central oxide ion with sp2hybridization. Density‐functional‐theory‐based calculations on an isolated [O(GeBr2)3]2–anion confirm the stability of the group and its shape. Real‐space chemical bonding analysis supports the polar nature of the Ge–O and Ge–Br bonds as well as the assigned oxidation states. The [O(GeBr2)3]2–anion and the bismuth polycations are embedded between two kinds of one‐dimensional networks, which are running parallel to thecaxis, a bromido‐cuprate(I)‐germanate(II) network1∞[Cu6Ge5Br20]4–and a bromido‐bismuthate(III)‐cuprate(I)‐germanate(II) network1∞[BiCu7Ge18Br66]20–. The latter features pentacoordinate germanium(II) atoms with bond angles close to 90°. The solution of the crystal structure from X‐ray diffraction data was hampered not only by severe pseudo‐symmetry and the similar scattering power of copper, germanium, and bromine atoms, but also by substantial atomic disorder and orientational disorder of the Bi53+polycation. Bi65Cu13Ge41O6Br122may be seen as a link between low‐valent germanium compounds and low‐valent bismuth compounds.

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

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.

Experimental and theoretical studies of photoluminescence from Bi82+ and Bi53+ stabilized by [AlCl4]− in molecular crystals

The photophysical properties of Bi82+ and Bi53+ polycations stabilized by [AlCl4]- have been studied experimentally and theoretically. The obtained product was thoroughly evaluated by powder X-ray diffraction and photoluminescence spectroscopy, making it clear that both Bi82+ and Bi53+ contribute to the observed broad near-infrared emission. Furthermore, it was revealed that Bi82+ polycation mainly results in the emission peaking at ca. 1180 nm, while Bi53+ the longer-wavelength emission. The following quantum chemistry calculation on Bi82+ polycation helps us attribute some observed excitation bands in the visible spectral range to specific electronic transitions of bismuth polycations. It is believed that systematical investigation of structural and luminescent properties as well as detailed quantum chemistry calculation of molecular crystals containing such kinds of bismuth units allows us to obtain a clearer picture on bismuth-related photophysical behaviors, which not only serve to solve the confusions on the luminescence origin of bismuth in other material systems such as bulk glasses, glass fibers and conventional crystals, but also is helpful to develop novel applicable broadband tunable laser mediums.

Room‐Temperature Synthesis of Bismuth Clusters in Ionic Liquids and Crystal Growth of Bi5(AlCl4)3

AbstractThe viability of Lewis‐acid ionic liquids for the synthesis of low‐valent bismuth compounds is demonstrated. At room temperature, elemental bismuth and bismuth(III) cations synproportionate in the ionic liquid [BMIM]Cl/AlCl3 ([BMIM]+: 1‐n‐butyl‐3‐methylimidazolium) within minutes. The existence of bismuth polycations in the dark colored solution was proven by Raman spectroscopy. Dark‐red crystals of Bi5(AlCl4)3 were isolated from the ionic liquid and characterized by Raman spectroscopy and X‐ray crystallography (rhombohedral space‐group $R{\bar 3}c$, a = 1187.1(2) pm, c = 3012.0(3) pm). The method allows the synthesis of bismuth cluster compounds under milder conditions than in high‐temperature melts and more conveniently and environmental friendly than in liquid SO2 with strongly oxidizing, toxic agents like SbF5 or AsF5.

Improvements of and Insights into the Isolation of Bismuth Polycations from Benzene Solution — Single‐Crystal Structure Determinations of Bi8[GaCl4]2 and Bi5[GaCl4]3.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Tetratellurium bis[heptachlorodigallate(III)], Te4[Ga2Cl7]2

Compounds containing main-group clusters, with focus on bismuth polycations, have been synthesized and characterized using X-ray diffraction and spectroscopic methods. Six new compounds have been isolated from synthesis in GaX3-arene media; Bi8[GaCl4]2, Bi8 [GaBr4]2, Sb8[GaCl4]2, Sb8[GaBr4]2, Te4[Ga2Cl7]2 and Te4[Ga2Br7]2. Sb2+ 8 is the first homopolyatomic antimony cation to be isolated. The cation forms a square antiprism, in correlation with Wade’s rules, and displays a significant difference in length between the inter-square and intra-square Sb–Sb distances. The geometries of the Sb2+ 8 cations in Sb8[GaCl4]2 and Sb8[GaBr4]2 are in excellent agreement; the average intra-square and intersquare Sb–Sb distances are 2.87 A and 2.97 A, respectively. A very strong Raman band attributed to Sb2+8 is found at 180 cm-1. The Bi2+8 (square antiprismatic) and Te2+4 (squareplanar) polycations are known from earlier compounds. The Bi–Bi distances in Bi8[GaCl4]2 (3.07–3.12 A) are in general agreement with previous structures, while the Bi–Bi distances of Bi8[GaBr4]2 (2.92–3.18 A) display a wider distrubution than previously observed. The Te–Te distances of the cations of Te4[Ga2Cl7]2 and Te4[Ga2Br7]2 are 2.66 and 2.67 A, respectively. Quantum chemical calculations on bismuth polycations show that all species predicted byWade’s rules are local minima on a potential energy surface. The cation–anion interactions have been considered for salts containing bismuth polycations and it has been confirmed that such interactions have a major influence on the polycation stability. The new compound Bi16I4 has been isolated from molten Bil3. The structure consists of polymerized Bi16I4 molecules forming infinite ribbons and is very similar to the structure of the known metal-rich bismuth iodides, Bi14I4 and Bi18I4. DFT calculations predict all three compounds to be metallic conductors, while Bi4I4 is a semiconductor.

Ab initio calculations on bismuth cluster polycations.

Ab initio calculations on bismuth polycationic species of the types Bi(n(n-2))+, Bi(n(n-4))+, and Bi(n(n-6))+ (n = 3 - 12) were performed at the Hartree-Fock and density functional theory levels in order to investigate their general properties and the applicability of Wade's rules on bismuth polycations. Some exceptions to Wade's rules were encountered, and, moreover, several predicted and calculated minima show only meta-stable behavior. The bonding in bismuth polycations is characterized by a high degree of electron delocalization and "three-dimensional aromaticity".