Polynuclear Bismuth‐Oxo Clusters: Insight into the Formation Process of a Metal Oxide

Abstract

The reaction of the bismuth silanolates [Bi(OSiR2R')3] (R = R' = Me, Et, iPr; R = Me, R' = tBu) with water has been studied. Partial hydrolysis gave polynuclear bismuth-oxo clusters whereas amorphous bismuth-oxo(hydroxy) silanolates were obtained when an excess of water was used in the hydrolysis reaction. The metathesis reaction of BiCl3 with NaOSiMe3 provided mixtures of heterobimetallic silanolates. The molecular structures of [Bi18Na4O20(OSiMe3)18] (2), [Bi33NaO38(OSiMe3)24].3 C7H8 (3.3 C7H8), [Bi50Na2O64(OH)2(OSiMe3)22].2 C7H8.2H2O (4.2 C7H8.2 H2O), [Bi4O2(OSiEt3)8] (5), [Bi9O7(OSiMe3)13].0.5 C7H8 (6. 0.5C7H8), [Bi18O18(OSiMe3)18)].2C7H8 (7. 2C7H8) and [Bi20O18(OSiMe3)24].3C7H8 (8.3C7H8) are presented and compared with the solid-state structures of [Bi22O26(OSiMe2tBu)14] (9) and beta-Bi2O3. Compound 2 crystallises in the triclinic space group P1 with the lattice constants a = 17.0337(9), b = 19.5750(14), c = 26.6799(16) A, alpha = 72.691(4), beta = 73.113(4) and gamma = 70.985(4) degrees ; compound 3.3C7H8 crystallises in the monoclinic space group P2(1)/n with the lattice constants a = 20.488(4), b = 22.539(5), c = 26.154(5) A and beta = 100.79(3) degrees ; compound 4.2C7H82 H2O crystallises in the monoclinic space group P2(1)/n with the lattice constants a = 20.0518(12), b = 24.1010(15), c = 27.4976(14) A and beta = 103.973(3) degrees ; compound 5 crystallises in the monoclinic space group P2(1)/c with the lattice constants a = 25.256(5), b = 15.372(3), c = 21.306(4) A and beta = 113.96(3) degrees ; compound 6.0.5C7H8 crystallises in the triclinic space group P1 with the lattice constants a = 15.1916(9), b = 15.2439(13), c = 22.487(5) A, alpha = 79.686(3), beta = 74.540(5) and gamma = 66.020(4) degrees ; compound 7.2C7H8 crystallises in the triclinic space group P1 with the lattice constants a = 14.8295(12), b = 16.1523(13), c = 18.4166(17) A, alpha = 75.960(4), beta = 79.112(4) and gamma = 63.789(4) degrees ; and compound 8.3C7H8 crystallises in the triclinic space group P1 with the lattice constants a = 17.2915(14), b = 18.383(2), c = 18.4014(18) A, alpha = 95.120(5), beta = 115.995(5) and gamma = 106.813(5) degrees . The molecular structures of the bismuth-rich compounds are related to the CaF2-type structure. Formally, the hexanuclear [Bi6O8]2+ fragment might be described as the central building unit, which is composed of bismuth atoms placed at the vertices of an octahedron and oxygen atoms capping the trigonal faces. Depending on the reaction conditions and the identity of R, the thermal decomposition of the hydrolysis products [Bi(n)O(l)(OH)(m-)(OSiR3)(3n-(2l-m))] gives alpha-Bi2O3, beta-Bi2O3, Bi12SiO20 or Bi4Si3O12.

Molecular Structure and Theoretical Studies of (PPh4)2[Bi10Cu10(SPh)24]

“…This range of oxidation states is not unusual in bismuth chemistry; the formation of homonuclear polycations is characteristic for of bismuth in low oxidation states. In bismuth subhalides, for example, Bi 6 Cl 7 [22] and Bi 6 [25] Ga [26] ). The bonding within these ploycations can be rationalized by the Wade rules.…”

Towards a Structural Understanding of the Anti‐Ulcer and Anti‐Gastritis Drug Bismuth Subsalicylate

“…Mehring and co-workers have proposed a set of rules to describe the growth pattern of bismuth oxo clusters, including homometallic oxo clusters containing 4, 9, 18, 20, and 22 bismuth atoms, in addition to several larger heterobimetallic clusters incorporating sodium which were derived from partial hydrolysis of bismuth silanolates. [39] They deduced that the structural building block for the bismuth-rich clusters is the [Bi 6 O 8 ] 2+ polyhedron, which has six octahedral Bi atoms with the eight O atoms located over all of the triangular faces. The structures of both 1 and 2 appear to conform to this.…”

Synthesis and structural studies of the simplest bismuth(iii) oxo-salicylate complex: [Bi4(μ3-O)2(HO-2-C6H4CO2)8]·2Solv (Solv = MeCN or MeNO2)

“…The chemistry of these oxo clusters has been reviewed. 9,[11][12][13][14][15][16][17] Often when reacting bismuth halides with sodium salts of alkoxides or carboxylates, oxo-compounds are obtained. We discovered that protonolysis of BiPh 3 using acidic organic compounds can avoid the formation of oxo ligands and have applied this methodology to the production of [Bi(OC 6 F 5 ) 3 (toluene)] 2 , Bi(Hsal) 3 and various derivatives thereof.…”