Crystallographic characterization of rare-earth cyanotriphenylborate complexes and the cyanoborates [NCBPh3]1−, [NCBPh2Me]1−, and [NCBPh2(μ-O)BPh2]1−

The investigation of the coordination chemistry of rare-earth metal complexes with cyanide ligands led to the isolation and crystallographic characterization of the Ln III cyanotriphenylborate complexes dichlorido(cyanotriphenylborato-κN)tetrakis(tetrahydrofuran-κO)lanthanide(III), [LnCl2(C19H15BN)(C4H8O)4] [lanthanide (Ln) = dysprosium (Dy) and yttrium Y)] from reactions of LnCl3, KCN, and NaBPh4. Attempts to independently synthesize the tetraethylammonium salt of (NCBPh3)− from BPh3 and [NEt4][CN] in THF yielded crystals of the phenyl-substituted cyclic borate, tetraethylazanium 2,2,4,6-tetraphenyl-1,3,5,2λ4,4,6-trioxatriborinan-2-ide, C8H20N+·C24H20B3O3 − or [NEt4][B3(μ-O)3(C6H5)4]. The mechanochemical reaction of BPh3 and [NEt4][CN] without solvent produced crystals of tetraethylazanium cyanodiphenyl-λ4-boranyl diphenylborinate, C8H20N+·C25H20B2NO− or [NEt4][NCBPh2(μ-O)BPh2]. Reaction of BPh3 and KCN in THF in the presence of 2.2.2-cryptand (crypt) led to a crystal of bis[(2.2.2-cryptand)potassium] 2,2,4,6-tetraphenyl-1,3,5,2λ4,4,6-trioxatriborinan-2-ide cyanomethyldiphenylborate tetrahydrofuran disolvate, 2C18H36KN2O6 +·C24H20B3O3 −·C14H13BN−·2C4H8O or [K(crypt)]2[B3(μ-O)3(C6H5)4][NCBPh2Me]·2THF. The [NCBPh2(μ-O)BPh2]1− and (NCBPh2Me)1− anions have not been structurally characterized previously. The structure of 1-Y was refined as a two-component twin with occupancy factors 0.513 (1) and 0.487 (1). In 4, one solvent molecule was disordered and included using multiple components with partial site-occupancy factors.

Transition-metal complexes of group 12 with 1,1′-bis(phosphanyl)ferrocene ligands

The syntheses of four new cadmium and zinc complexes with 1,1′-bis(phosphanyl)ferrocene ligands and their phosphine chalcogenide derivatives are reported. The complexes were characterized by elemental analyses and IR, 1H NMR, 31P NMR and electronic absorption spectroscopy. The crystal structures of dichlorido[1-diphenylphosphinoyl-1′-(di-tert-butylphosphanyl)ferrocene-κ2 O,P]cadmium(II), [CdCl2{(C17H14OP)(C13H22P)Fe}] or CdCl2(κ2 P,O-dppOdtbpf) (1), bis[μ-(tert-butyl)(1′-diphenylphosphinoylferrocen-1-yl)phosphinato-κ3 O,O′:O′′]bis[chloridozinc(II)], [Zn2{(C9H13O2P)(C17H14OP)Fe}2Cl2] or [ZnOCl{κ2 O,O′-Ph2POFcPO2(t-Bu)}]2 (2), 1,1′-bis(di-tert-butylthiophosphinoyl)ferrocene, [Fe(C13H22PS)2] or dtbpfS2 (3), and [1,1′-bis(dicyclohexylphosphanyl)ferrocene-κ2 P,P′][chlorido/cyanido(0.25/1.75)]zinc(II), [Zn(CN)1.75Cl0.25{(C17H26P)2Fe}] or Zn(CN)2(κ2-dcpf) (4), were determined crystallographically. Compound 1 has tetrahedral geometry in which the CdII centre is coordinated by one dppOdtbpf ligand in a κ2-manner and by two Cl atoms, while compound 2 displays a centrosymmetric dimeric unit in which two oxide atoms bridge the two Zn atoms to generate an eight-membered ring. Compound 3 revealed a sandwich structure with both phosphane groups sulfurized. In compound 4, the ZnII atom adopts a tetrahedral geometry by coordinating to the 1,1′-bis(dicyclohexylphosphanyl)ferrocene ligand in a κ2-manner and to two cyanide ligands.

Synthesis, decomposition studies and crystal structure of a three-dimensional CuCN network structure with protonated N-methylethanolamine as the guest cation

The compound poly[2-hydroxy-N-methylethan-1-aminium [μ3-cyanido-κ3 C:C:N-di-μ-cyanido-κ4 C:N-dicuprate(I)]], {(C3H10NO)[Cu2(CN)3]} n or [meoenH]Cu2(CN)3, crystallizes in the tetragonal space group P43. The structure consists of a three-dimensional (3D) anionic CuICN network with noncoordinated protonated N-methylethanolamine cations providing charge neutrality. Pairs of cuprophilic Cu atoms are bridged by the C atoms of μ3-cyanide ligands, which link these units into a 43 spiral along the c axis. The spirals are linked together into a 3D anionic network by the two other cyanide groups. The cationic moieties are linked into their own 43 spiral via N—H...O and O—H...O hydrogen bonds, and the cations interact with the 3D network via an unusual pair of N—H...N hydrogen bonds to one of the μ2-cyanide groups. Thermogravimetric analysis indicates an initial loss of the base cation and one cyanide as HCN at temperatures in the range 130–250 °C to form CuCN. We show how loss of a specific cyanide group from the 3D CuCN structure could form the linear CuCN structure. Further heating leaves a residue of elemental copper, isolated as the oxide.

The versatility of lithium cation coordination modes in salts with [W(CN)6(bpy)]2− anions

Effect of the cation size (compared to Cs+) in Li2[W(CN)6(bpy)] salts on the nature of the interaction with cyanide ligands and on the crystal structure is discussed, unusual decrease of the W–W distance and increase of cell volume are observed.

Crystal structure of catena-poly[[[(2-ethoxypyrazine-κN)copper(I)]-di-μ2-cyanido] [copper(I)-μ2-cyanido]]

In the asymmetric unit of the title coordination compound, {[Cu(CN)(C4H3OC2H5N2)][Cu(CN)]} n , there are two Cu atoms with different coordination environments. One CuI ion is coordinated in a triangular coordination geometry by the N atom of the 2-ethoxypyrazine molecule and by two bridging cyanide ligands, equally disordered over two sites exchanging C and N atoms, thus forming polymeric chains parallel to the c axis. The other Cu atom is connected to two bridging cyanide groups disordered over two sites with an occupancy of 0.5 for each C and N atom, and forming an almost linear polymeric chain parallel to the b axis. In the crystal, the two types of chain, which are orthogonal to each other, are connected by cuprophilic Cu...Cu interactions [2.7958 (13) Å], forming two-dimensional metal–organic coordination layers parallel to the bc plane. The coordination framework is further stabilized by weak long-range (electrostatic type) C—H...π interactions between cyano groups and 2-ethoxypyrazine rings.

A novel three-dimensional copper(I) cyanide coordination polymer constructed from various bridging ligands: synthesis, crystal structure and characterization

The cyanide ligand can act as a strong σ-donor and an effective π-electron acceptor that exhibits versatile bridging abilities, such as terminal, μ2-C:N, μ3-C:C:N and μ4-C:C:N:N modes. These ligands play a key role in the formation of various copper(I) cyanide systems, including one-dimensional (1D) chains, two-dimensional (2D) layers and three-dimensional (3D) frameworks. According to the literature, numerous coordination polymers based on terminal, μ2-C:N and μ3-C,C,N bridging modes have been documented so far. However, systems based on the μ4-C:C:N:N bridging mode are relatively rare. In this work, a novel cyanide-bridged 3D CuI coordination framework, namely poly[(μ2-2,2′-biimidazole-κ2 N 3:N 3′)(μ4-cyanido-κ4 C:C:N:N)(μ2-cyanido-κ2 C:N)dicopper(I)], [Cu2(CN)2(C6H6N4)] n , (I), was synthesized hydrothermally by reaction of environmentally friendly K3[Fe(CN)6], CuCl2·2H2O and 2,2′-biimidazole (H2biim). It should be noted that cyanide ligands may act as reducing agents to reduce CuII to CuI under hydrothermal conditions. Compound (I) contains diverse types of bridging ligands, such as μ4-C:C:N:N-cyanide, μ2-C:N-cyanide and μ2-biimidazole. Interestingly, the [Cu2] dimers are bridged by rare μ4-C:C:N:N-mode cyanide ligands giving rise to the first example of a 1D dimeric {[Cu2(μ4-C:C:N:N)] n+} n infinite chain. Furthermore, adjacent dimer-based chains are linked by μ2-C:N bridging cyanide ligands, generating a neutral 2D wave-like (4,4) layer structure. Finally, the 2D layers are joined together via bidentate bridging H2biim to create a 3D cuprous cyanide network. This arrangement leads to a systematic variation in dimensionality from 1D chain→2D sheet→3D framework by different types of bridging ligands. Compound (I) was further characterized by thermal analysis, solid-state UV–Vis diffuse-reflectance and photoluminescence studies. The solid-state UV–Vis diffuse-reflectance spectra show that compound (I) is a wide-gap semiconductor with band gaps of 3.18 eV. The photoluminescence study shows a strong blue–green photoluminescence at room temperature, which may be associated with metal-to-ligand charge transfer.

Functionalization of [Re6Q8(CN)6]4− clusters by methylation of cyanide ligands

Methylation of anionic cluster complexes [Re6Q8(CN)6]4− with ((CH3)3O)BF4 or CF3SO3CH3 afforded homoleptic isonitrile cluster complexes [Re6Q8(CH3NC)6]2+ (Q = S, Se, Te).

Synthesis and crystal structures of bis(imidazolidine-2-thione-κS)bis(thiocyanato-κS)mercury(II) and bis(cyanido)bis(μ2-imidazolidine-2-thione-κS)mercury(II).Hg(CN)2

Two mercury(II) complexes containing imidazolidine-2-thione (Imt) and thiocyanate or cyanide ligands, [Hg(Imt)2(SCN)2] (1) and [Hg(Imt)2(CN)2].Hg(CN)2(2), have been prepared and characterized by IR and NMR spectroscopy and X-ray crystallography. In compound1, the mercury atom is located on a two-fold rotation axis and is coordinated to two thione sulfur atoms of imidazolidine-2-thione (Imt) and to two sulfur atoms of thiocyanate in a distorted tetrahedral mode with the S-Hg-S bond angles in the range of 98.96(3)–148.65(6)°. In2, the mercury atom is hexa-coordinated having a distorted octahedral geometry composed of two cyanide C atoms [Hg-C=2.055(5) Å] and four weakly bound thione S atoms of imidazolidine-2-thione (Imt) [Hg-S=3.1301(13) and 3.1280(13) Å]. One free Hg(CN)2molecule is also present in the crystal. In both complexes, the molecular structure is stabilized by N-H…N and N-H…S hydrogen bonding interactions.