E. A. Malinina

Specific interactions in metal salts and complexes with cluster boron anions BnHn2− (n = 6, 10, 12)

Specific interactions that appear in metal salts and complexes with cluster boron anions BnHn2− (n = 6, 10, 12) have been discussed. These interactions, as well as chemical bonds, involve vertices, edges, or faces of boron polyhedra. Specific interactions have a considerable effect on the structure of compounds, making a significant contribution to the formation of the unit cell and forming supramolecular assemblies. Compounds containing BnHn2− cluster anions shed new light onto the nature of specific interactions owing to their many-center character and great variety.

Coordination compounds of electron-deficient boron cluster anions BnHn2− (n = 6, 10, 12)

This survey concerns the coordination ability of BnHn2− (n = 6, 10, 12) boron cluster anions and their derivatives in complex formation. Boron cluster anions form four types of compounds: salts of organic cations and alkali-metal cations, including Cat2BnHn, where specific interactions can be observed between a cation Cat and a boron cluster anion; salts of protonated anions CatB6H7 and CatB10H11, analogues of Cat[MBnHn] complexes, where an extra hydrogen atom appears bound with the BBB face of a boron polyhedron and performs as a hard acceptor; metal complexes with outer-sphere boron cluster anions where specific ligand-ligand interactions may be observed between a boron cluster anion and an inner-sphere ligand; and true metal complexes with boron cluster anions that enter the inner coordination sphere. The last case characterizes closo-hydroborate anions as polydentate ligands whose denticity can vary widely under the effect of substituents or other ligands in the complex.

Redox, complexation, and substitution reactions in [Cu2B10H10]-2,2′-bipyridylamine-CH3CN system

Reaction of [Cu2B10H10] with 2,2′-bipyridylamine (bpa) in acetonitrile was studied. A redox reaction was found to proceed in reaction solution at ambient temperature. Copper coordination compounds with the metal of different oxidation states—[Cu2I(bpa)2B10H10] · 2NCCH3, [Cu4II(bpa)4(OH)4][Cu2I(B10H10)3] · nNCCH3, [CuII(bpa)2(NCCH3)2](2-B10H9bpa)2 · 2H2O, [Cu2II(bpa)2(OH)2B10H10], and [(Cu2II(bpa)2(CO3)2] · H2O—were isolated under various reaction conditions. The compounds were characterized by IR spectroscopy, X-ray crystallography, and elemental analysis.

Tetranuclear hydroxo-bridged copper(II) cluster of the Z type: Preparation and structural and magnetic characterization of [(Cu 4 bipy 4 (OH) 4 (B 10 H 10 ) 2 (DMSO) 2 ]

(n = 6, 10, 12) has been isolated and character ized, namely, [(аguH)2]0.388[Cu(аgu)2]6.12(B12H12)] (agu is aminoguanidine, I) [5, 8]. According to X ray dif fraction data [8], compound I has a nontrivial struc ture consisting of polymeric chains composed of alter nating [Cu(agu)2B12H12] and (aguH)2B12H12 units. In the present paper, we propose a general proce dure for synthesizing Cu(II) complexes with the

Anionic silver(I) complexes with closo-dodecaborate anion

Silver(I) complex formation with closo-dodecaborate anion was studied systematically in various media: water, acetonitrile, and acetonitrile/trifluoroacetic acid (TFA). A possibility of formation of complexes Cat[AgB12H12] and [Ag2B12H12] was demonstrated. Synthesis parameters (reaction medium, reagent ratio, and cation size in precursor dodecaborate) were shown to affect the type of the resulting complex and the coordination sphere around the central atom.

anti-syn and anti-anti coordination of the bridging CO32− group in [Cu2(Phen)4(μ-CO3)]B10H10 binuclear complexes: Synthesis, structure, and magnetic properties

A redox reaction that occurs in the [Cu2B10H10]/Phen system in CH3CN/DMSO and CH3CN/DMF in air yields a Cu(II) binuclear complex, [(Phen)2Cu(CO3)Cu(Phen)2]2+. The [Cu2(Phen)4(μ-CO3)]B10H10 · 2.5DMSO · 2H2O (I) and [Cu2(Phen)4(μ-CO3)]B10H10 · 4DMF (II) compounds have been isolated and studied by X-ray crystallography at 150 K and EPR at 295 K. Their magnetic properties have been studied in the range 300–2 K. In the cations of both compounds, the bridging CO32− group is bidentately coordinated to two Cu atoms. The cations in I and II have different spatial orientations of the Cu-O bonds: anti-syn and anti-anti, respectively. Compound I has weak magnetic interactions caused by a short Cu…Cu distance (4.441 Å) in the dimer. No exchange coupling is observed in II.

Aminoguanidinium closo-Borates and Their Reactions with Copper(II) Salts in Aqueous Solutions

Aminoguanidinium hexa-, deca-, and dodecaborates of (AguH)2BnHn· xH2O (Agu = (CN4H6), n= 6, 10, 12; x= 1, 2) composition were synthesized and studied by elemental analysis, magnetic susceptibility, and IR spectroscopy methods. Their reactions with copper(II) salts in aqueous solutions were investigated. A cation–anion interaction was shown to occur in aminoguanidinium closo-borates and to increase in the series B12< B10< B6. Depending on the closo-anion (BnH2–n), the reactions of aminoguanidinium closo-borates with copper(II) salts in aqueous solutions yield either complex compounds (n= 10, 12) or metallic copper (n= 6).

Anionic Complexes of Cu(I) with the Closo-Decaborate Anion

General procedures for synthesis of anionic Cu(I) complexes with the closo-decaborate anion were worked out; they make it possible to prepare coordination compounds with a wide set of organic cations. The interaction of onium closo-decaborates with [Cu2B10H10] in acetonitrile acidified with anhydrous trifluoroacetic acid was found to be the most effective synthetic method that secures high yield and quality of the obtained products. The structure of (C2H5)3NH[CuB10H10] was determined by X-ray diffraction analysis.

Copper(I) coordination compounds with closo-dodecaborate anion

Copper(I) complexes with a closo-dodecaborate anion were synthesized: Cat[CuB12H12], where Cat = Cs+, Ph4P+, Ph4As+, or RxNH4−x+ (R = Me, Et, Pr, or Bu; x = 3 or 4). The complexes were synthesized from the copper(II)-closo-dodecaborate-sulfur dioxide (sodium sulfite) system. The structure of [Cu2(NCCH3)4B12H12] was determined using X-ray crystallography.

Interaction between a Decahydro-closo-Decaborate(2–) Anion and Aliphatic Carboxylic Acids

Interaction between a closo-decaborate anion B10H2–10and carboxylic acids RCOOH (R = H, CH3, C2H5, iso-C3H7, C4H9) is studied. The mono-, di- tri- and tetrasubstituted products B10H10 – n(OCOR)2–nare formed in sequence with the temperature growth. The reaction follows an essentially regioselective mechanism: only one of all possible isomers forms at every stage of the process. The respective hydroxy-closo-decaborates B10H10 – n(OH)2–nwere prepared by alkaline hydrolysis in aqueous and nonaqueous solutions. All the compounds were identified by chemical analysis and 11B NMR and IR spectroscopy. The crystal structure of [Pb(Bipy)(DMF)(B10H9OH)] · DMF was determined by X-ray diffraction.