A New Transition Metal Tetracyanidoborate: Synthesis, Structure and Properties of Co[B(CN)₄]₂·2H₂O

Abstract

The reaction of tetracyanidoboronic acid, H[B(CN)4], with CoCO3 or Co(OH)2 in aqueous solution leads after slow evaporation of water to single crystals of Co[B(CN)4]2·2H2O. The compound has been characterized by single crystal X‐ray diffraction ($I {\bar 4} \mathit{2}d$, a = 12.2922(9), c = 9.2235(7) Å, Z = 4). The Co2+ ion is octahedrally coordinated by four nitrogen atoms of four different tetracyanidoborate CN groups occupying the four equatorial positions and two molecules of water occupying the remaining corners of the octahedron. The single crystal X‐ray structure, the vibrational spectra, and the thermal properties are compared with other known tetracyanidoborates with divalent cations.

Tetracyanidoborates with Sterically Demanding Phosphonium Cations – Thermally Resistant lonic Liquids

“…Compared to tetracyanidoborates with metal cations, e.g. Co[B(CN) 4 ] · 2H 2 O {(ν CN , Raman) = 2270 cm –1 and (ν CN , IR) = 2275 cm –1 30}, the bands of the CN stretching mode are not shifted to higher wavelengths, which indicates that only weak interionic contacts exist between the cations and the anions.…”

Homoleptic Luminescent Lanthanide Frameworks with the Tricyanohydridoborate Anion

“…as components in ionic liquids (ILs) such as [EMIM][B(CN) 4 ] (EMIM + = 1-ethyl-3-methylimidazolium), with low melting points as well as low viscosities, [1] making them potential and promising electrolytes for solar cells. [2] Cyanoborate anions are also utilized as building blocks for manifold coordination compounds, comprising salts, molecular complexes and coordination polymers, which have mostly been obtained with the tetracyanoborate anion [B(CN) 4 ] -. [3][4][5][6] There are far less examples for related compounds that contain anions in which cyano groups are substituted with other groups, such as in the tricyanofluoroborate anion [BF(CN) 3 ] -.…”

“…[2] Cyanoborate anions are also utilized as building blocks for manifold coordination compounds, comprising salts, molecular complexes and coordination polymers, which have mostly been obtained with the tetracyanoborate anion [B(CN) 4 ] -. [3][4][5][6] There are far less examples for related compounds that contain anions in which cyano groups are substituted with other groups, such as in the tricyanofluoroborate anion [BF(CN) 3 ] -. [7] Anhydrous, homoleptic frameworks 3 ∞ [Ln{C 2 F 5 B(CN) 3 } 3 ] (Ln = La, Eu, Ho) [8] could be obtained using (H 3 O)[C 2 F 5 B(CN) 3 ] and by an ionothermal approach.…”

Conductivity, Structures, Spectra, and Thermal Properties of Lithium and Sodium Tetracyanidoborates with Crown Ether Encapsulated Cations: Isolated Ions in [AI(12‐crown‐4)2][B(CN)4] and 1D Chains in [AI (15‐crown‐5)][B(CN)4] (AI = Li, Na)

“…[2] Since then, a more efficient synthetic procedure has been developed in 2003, [3] and this class of materials has become a subject of intensive research. [4][5][6][7][8] Compounds are known that contain solvent molecules, for example, K[B(CN) 4 ]·THF [6,9] or [NH 4 ][B(CN) 4 ]·CH 3 CN, [6,9] and, furthermore, there are established tetracyanidoborate alkali cations complexed by macrocyclic polyether molecules, which show an unusual network of low-dimensional salt chains with different coordination behavior between the encapsulated alkali metal cations and the multifunctional [B(CN) 4 ]units. [4][5][6][7][8] Compounds are known that contain solvent molecules, for example, K[B(CN) 4 ]·THF [6,9] or [NH 4 ][B(CN) 4 ]·CH 3 CN, [6,9] and, furthermore, there are established tetracyanidoborate alkali cations complexed by macrocyclic polyether molecules, which show an unusual network of low-dimensional salt chains with different coordination behavior between the encapsulated alkali metal cations and the multifunctional [B(CN) 4 ]units.…”

“…Therefore, tetracyanidoborates became a useful starting material for unusual anions such as [B(CF 3 ) 4 ]or [B{CN·B(C 6 F 5 ) 3 } 4 ] -, [4,[11][12][13][14][15][16][17][18][19][20] which are able to stabilize highly reactive cations. [23][24][25] In this paper, we report the syntheses, structures, and some properties of four new tetracyanidoborates, [Li(C 8 [18,21,22] The addition of a macrocyclic polyether to lithium salts increases their conductivity.…”