Synthesis of functional derivatives of the [3,3′-Co(1,2-C2B9H11)2] anion

A series of various functional derivatives of the cobalt bis(1,2-dicarbollide) anion [8-XCH₂CH₂OCH₂CH₂O-3,3′-Co(1,2-C₂B₉H₁₀)(1′,2′-C₂B₉H₁₁)]⁻ (X=OH, NH₂, and CH(NH₂)COOH) were prepared by the ring-opening reactions of [8-O(CH₂CH₂)₂O-3,3′-Co(1,2-C₂B₉H₁₀)(1′,2′-C₂B₉H₁₁)] with different nucleophiles followed by functional group interconversion reactions. Acidic hydrolysis of [8-NCCH₂CH₂OCH₂CH₂O-3,3′-Co(1,2-C₂B₉H₁₀)(1′,2′-C₂B₉H₁₁)]⁻ resulted in the shorter-chain alcohol [8-HOCH₂CH₂O-3,3′-Co(1,2-C₂B₉H₁₀)(1′,2′-C₂B₉H₁₁)]⁻. Structures of (Bu₄N)[8-AcNHC(COOEt)₂CH₂CH₂OCH₂CH₂O-3,3′-Co(1,2-C₂B₉H₁₀)(1′,2′-C₂B₉H₁₁)] and [8-(1-C₅H₅N)CH₂CH₂OCH₂CH₂O-3,3′-Co(1,2-C₂B₉H₁₀)(1′,2′-C₂B₉H₁₁)] were determined by the single crystal X-ray diffraction method. Perspectives of application of functionalized cobalt bis(1,2-dicarbolide) derivatives in nuclear medicine are discussed.     

Synthesis of hetero-substituted derivatives of cobalt bis(1,2-dicarbollide)

A new approach to synthesis of hetero-substituted derivatives of cobalt bis(1,2-dicarbollide) was proposed. The approach involves stepwise introduction of functional groups into different dicarbollide ligands. Halogenation of the monohydroxy derivative [8-OH-3,3??-Co-(1,2-C₂B₉H₁₀)(1??,2??-C₂B₉H₁₁)]^? gave the corresponding halogen hydroxy derivatives [8-OH-8??-X-3,3??-Co(1,2-C₂B₉H₁₀)₂]^? (X = Cl, Br, and I). Reactions of 8,8??-??-iodonium-3-commo-cobaltbis(1,2-dicarba-closo-dodecaborate) [8,8??-I-3,3??-Co(1,2-C₂B₉H₁₀)₂] with chloroform and 1,2-dibromoethane yielded the mixed halides [8-Y-8??-I-3,3??-Co(1,2-C₂B₉H₁₀)₂]^? (Y = Cl and Br).     

Beiträge zur chemie des iodpentafluorids teil III. Chelatisierung und strukturisomerie bei α,β-methylierten IOD(V)-α,β-ethandiolat-fluoriden

We report metathetical reactions of IF₅ with series of α,β-trimethylsilylated ethanediolates with increasing numbers of CH₃-groups in α- and β-positions. Short lived intermediates IF₄[OC₂H_4?n(CH₃)_nO]X with X = Si(CH₃)₃ or IF₄ and stable chelates IF₃[OC₂H_4?n(CH₃)_nO] and IF[OC₂H_4?n(CH₃)_nO]₂ (n = 0–4) are observed and characterized. Time and temperature dependence of ¹⁹F-NMR-spectra in relation to degree of methylation, arrangement and stereo-chemistry are discussed referring to previously published mono- and polynuclear I(V)-compounds containing a series of monodentate alcoholates CH_3?n(CH₃)_nO^? and (CH₃)₃CCH₂O^? (n = 0,2,3) [1,2] and of bidentate alcoholates ^?O(CH₂)_nO^? (n = 2,3,4,5,6,12) [1]. In contrast to aliphatic α,β-diolates the aromatic diolates 1,2-C₆H₄(O^?)₂, 1,2-C₆Cl₄(O^?)₂ rapidly undergo redox reactions even at low temperatures.     

N-arylammonio- and N-pyridinium-substituted derivatives of dodecahydro-closo-dodecaborate(2-)

We report two methods for preparing N-arylammonio, N-pyridyl and N-arylamino dodecaborates: heating of the tetrabutylammonium salt of dodecahydro-closo-dodecaborate(2-) with aryl and pyridyl amines, or nucleophilic attack of [closo-B₁₂H₁₁NH₂]²⁻ on a strongly deactivated aromatic system. With aryl amines we obtained [1-closo-B₁₂H₁₁N(R¹)₂C₆H₅]⁻ (R¹ = H, CH₃). With 4-(dimethylamino)pyridine, [1-closo-(B₁₂H₁₁NC₅H₄)-4-N(CH₃)₂]⁻, with a bond between the boron and the pyridinium nitrogen, was obtained. A presumable mechanism for this kind of reactions is reported. By nucleophilic substitution, two products, [1-closo-(B₁₂H₁₁NHC₆H₃)-3,4-(CN)₂]²⁻ and [1-closo-(B₁₂H₁₁NHC₆H₂)-2-(NO₂)-4,5-(CN)₂]²⁻, were formed with 4-nitrophthalonitrile and 1-chloro-2,4-dinitrobenzene gave [1-closo-(B₁₂H₁₁NHC₆H₃)-2,4-(NO₂)₂]²⁻. For [1-closo-B₁₂H₁₁N(CH₃)₂C₆H₅]⁻ and [1-closo-(B₁₂H₁₁NHC₆H₃)-2,4-(NO₂)₂]²⁻ single crystal X-ray structures were obtained.     

8-Dioxane ferra(III) bis(dicarbollide): A paramagnetic functional molecule as versatile building block for introduction of a Fe(III) centre into organic molecules

The synthesis of a new, paramagnetic closo-[(8-(-CH₂CH₂O)₂-1,2-C₂B₉H₁₀)(1′,2′-C₂B₉H₁₁)-3,3′-Fe]⁰ (3) is reported. This compound can serve as a versatile building block for construction of both anionic and zwitterionic derivatives, as exemplified by the synthesis of a series of compounds of general formula closo-[(8-X-(CH₂CH₂O)₂-1,2-C₂B₉H₁₀)(1′,2′-C₂B₉H₁₁)-3,3′-Fe], bearing organic end groups (X = NC₅H₅ (4), (C₆H₅)₃P (5), OH (6), and 2-O(1-CH₃O-C₆H₄) (7)) attached to the cluster by a diethyleneglycol spacer. Molecular structures of 3, 4, 5 and 7 were determined by single-crystal X-ray diffraction analysis and by the long-time neglected method of paramagnetic, high field NMR (¹H, ¹³C and ¹¹B) spectroscopy.     

Schiff base derivatives of lanthanons

Bifunctional tridentate Schiff bases such as, $$\begin{gathered} HOC_6 H_4 C(CH_3 ) : NCH_2 CH_2 OH, \hfill \\ HOC_6 H_4 C(CH_3 ) : NCH_2 CH_2 (OH)CH_3 , \hfill \\ HOC_6 H_4 C(H) : NCH_2 CH_2 OH \hfill \\ \end{gathered} $$ and HOC₆H₄C(H)∶NCH₂CH(OH)CH₃ react with La(III), Pr(III) and Nd(III) isopropoxides to 1∶1 and 2∶3 derivatives of the type,Ln(O?i-C₃H₇)(OC₆H₄C[R]∶NR′O) andLn ₂(OC₆H₄C[R]∶ NR′O)₃ [where,Ln=La(III), Pr(III) or Nd(III); R=CH₃ or H and R′=CH₂?CH₂ or CH₂CHCH₃] in dry benzene. The labile nature of the isopropoxy groups in the 1∶1 derivatives has been shown by exchange reactions with an excess oft-butyl alcohol leading to the formation ofLn(O?t-C₄H₉)(OC₆H₄C[R]∶NR′O); (where R=CH₃ and R′=CH₂CHCH₃) type derivatives in almost quantitative yield. The IR spectra of the resulting derivatives have been recorded in the range of 4000–400 cm^?1, ν C=N frequency bands appear at ≈ 1620 cm^?1 and almost no change has been noted in their positions on complexation. Some new peaks are, however, observed in the range of 700–600 cm^?1 and these may be ascribed to the ring deformation coupled with both theLn?O stretching and C?CH₃ stretching modes.     

Syntheses of C-substituted icosahedral dicarbaboranes bearing the 8-dioxane-cobalt bisdicarbollide moiety

The treatment of 1,2-, 1,7- and 1,12-carbaborane lithiated isomers with [3,3′-Co-8-(CH₂CH₂O)₂-(1,2-C₂B₉H₁₀)-(1′,2′-C₂B₉H₁₁)] (1) at molar ratios 1:1 or 1:2 at room temperature in THF leads generally to the formation of a series of orange double-cluster mono and dianions. These were characterized by NMR and MS methods as [1′′-X-1′′,2′′-closo-C₂B₁₀H₁₁]⁻, [2]⁻; [1′′-X-1′′,7′′-closo-C₂B₁₀H₁₁]⁻, [3]⁻ and [1′′-X-1′′,12′′-closo-C₂B₁₀H₁₁], [4]⁻ for the monoanions, whereas [1′′,2′′-X₂-1′′,2′′-closo-C₂B₁₀H₁₀]²⁻, [2]²⁻; [1′′,7′′-X₂-1′′,7′′-closo-C₂B₁₀H₁₀]²⁻, [3]²⁻; and [1′′,12′′-X₂-1′′,12′′-closo-C₂B₁₀H₁₀]²⁻, [4]²⁻ for the dianions (where X = 3,3′-Co-8-(CH₂CH₂O)₂-(1,2-C₂B₉H₁₀)-1′,2′-(C₂B₉H₁₁)). Moreover, these borane-cage subunits can be easily modified via attaching variable substituents onto cage carbon and boron vertices, which makes these compounds structurally flexible potential candidates for BNCT of cancer and HIV-PR inhibition.     

Ruthenium carborane complexes: a relationship between the structure, electrochemical properties, and reactivity in catalysis of polymerization processes

The ruthenacarborane complexes of the exo-nido- and closo-structure, namely, diamagnetic exo-nido-5,6,10-[RuCl(PPh₃)₂]-5,6,10-(μ-H)₃-10-H-7,8-(CH₃)₂-7,8-C₂B₉H₆, 3,3-[Ph₂P(CH₂) _n PPh₂]-3-H-3-Cl-closo-3,1,2-RuC₂B₉H₁₁ (n = 4, 5), paramagnetic 3,3-[Ph₂P(CH₂) _n PPh₂]-3-Cl-closo-3,1,2-RuC₂B₉H₁₁ (n = 2–5), and their some ortho-phenylenecycloboronated derivatives, were studied by cyclic voltammetry. All chelate closo-complexes are characterized by reversible redox transitions, while the exo-nido-complex is liable to irreversible oxidation. Shortening of the methylene link in the diphosphine ligand of closo-ruthenacarboranes and/or the introduction of ortho-phenylenecycloboronated moieties and methyl substituents to the carbon atoms of the {C₂B₉} ligand lead to a decrease in the redox potential and electron density redistribution to the metal atom. A comparison of the experimental results on methyl methacrylate polymerization in the presence of the catalytic systems based on the studied metallacarboranes with the data on their electrochemical characteristics suggests that the efficiency of using the ruthenium complexes as catalysts is mainly determined by steric factors.     

Protonation of the Dodecahydro-<Emphasis Type="Italic">closo</Emphasis>-Dodecaborate Anion in CH<Subscript>3</Subscript>CN/CF<Subscript>3</Subscript>COOH

The behavior of the [B₁₂H₁₂]^2– anion in CH₃CN, CF₃COOH, and the CH₃CN/CF₃COOH system is studied by IR spectroscopy. Based on the IR spectroscopy data correlated with the data obtained when studying the protonation processes of boron cluster anions [B₆H₆]^2– and [B₁₀H₁₀]^2–, the possibility to prepare the protonated form of the closo-dodecaborate anion, namely monoanion [B₁₂H₁₃]^–, is concluded in CF₃COOH and the CH₃CN/CF₃COOH system. In the IR spectra of salts of the protonated forms of anions [B_nH_n]^2– (n = 6, 10, 12) in solutions and Nujol mulls, a high-frequency shift of the ν(BH) absorption bands is observed as compared with the spectra of salts of non-protonated anions Cat₂[B_nH_n] (Δν = 70–100 cm^–1).     

Practical synthesis of 1,4-dioxane derivative of the closo-dodecaborate anion and its ring opening with acetylenic alkoxides

Practical method of synthesis of the 1,4-dioxane derivative of the closo-dodecaborate anion was developed. The cleavage of the dioxonium ring in [B₁₂H₁₁O(CH₂CH₂)₂O]⁻ with acetylenic alcohols gave rise to the preparation of closo-dodecaborate derivatives with terminal acetylene group. These compounds can be introduced into click reactions with phenylazide leading to the corresponding triazoles. The structures of (Bu₄N)[B₁₂H₁₁O(CH₂CH₂)₂O] and (Bu₄N)₂[B₁₂H₁₁(OCH₂CH₂)₂OCH₂CCH] · 0.5HOCH₂CCH were determined by single-crystal X-ray diffraction.     

Group 12 metal complexes of tetradentate N2O2–Schiff-base ligands incorporating pyrazole: Synthesis,characterisation and reactivity toward S-donors,N-donors,copper and tin acceptors

New [M(Q)₂(X)] derivatives (where M=Zn, Cd or Hg; Q=1-phenyl-3-methyl-4-R(C=O)-pyrazolon-5-ato; in detail: Q_L, R=C₆H₅; Q_B, R=CH₂C(CH₃)₃; Q_S, R=CH(C₆H₅)₂; X=EtOH or H₂O) have been synthesised and characterised. These compounds undergo a condensation reaction with the appropriate diamine in ethanol, affording novel Schiff-base metal derivatives [M(diaquo)bis(1-phenyl-3methyl-4-R(C=N)-pyrazolone)(CH₂)_ndiimmine] (LⁿH₂, R=C₆H₅, n=2, 3 or 4; BⁿH₂, R=CH₂C(CH₃)₃, n=2, 3 or 4; SⁿH₂, R=CH(C₆H₅)₂, n=2 or 3; M=Zn, Cd or Hg). These compounds possess a six-coordinate metal environment. A ¹¹³Cd NMR study has been carried out on cadmium derivatives. The derivative [Zn(L²)(H₂O)₂] reacted with CuCl₂ and with Cu(ClO₄)₂ affording [Cu(Q_L)₂] and [Cu(en)₂](ClO₄)₂ (en=ethylendiamine), respectively, upon breaking of the C=N bond in the Schiff-base donor. In addition [Zn(L²)(H₂O)₂] reacted with 1,10-phenanthroline (phen), yielding the derivative [Zn(Q_L)₂(phen)]. Whereas when [Zn(L²)(H₂O)₂] reacted with CdCl₂, formation of [Cd(L²)(H₂O)₂] due to exchange of the metal centre was observed. Finally the derivative [Zn(L²)(Hmimt)], likely containing a five-coordinate ZnN₂O₂S central core, has been obtained from the exchange reaction between [Zn(L²)(H₂O)₂] and 1-methylimidazolin-2-thione (Hmimt).     

First example of the ribbed-functionalized iron(ii) clathrochelate with six pendante closo-borate substituents

The nucleophilic substitution of the reactive chlorine atoms of the n-butylboron-capped hexachlorine-containing clathrochelate precursor with the thiol-terminated closo-decaborate (PPh₄)₂[B₁₀H₉OCH₂CH₂OCH₂CH₂SH] in the presence of triethylamine afforded the closo-decaborate-containing clathrochelate dodecaanion [Fe{[(B₁₀H₉OCH₂CH₂OCH₂CH₂S)₂Gm]₃-(BBuⁿ)₂}]^12?, which was isolated in the form of its tetraphenylphosphonium and sodium salts. The complexes obtained were characterized using elemental analysis, UV-VIS, ¹H, ¹¹B, and ¹³C{¹H} NMR, and IR spectroscopies.     

Synthesis of 12-vertex mixed ligand closo-cobaltacarborane complexes and molecular structure of [3,3-(Ph2P(CH2)2PPh2)-3-Cl-closo-3,1,2-CoC2B9H11]

A reaction of complexes CoCl₂(dppe) (dppe is the 1,2-bis(diphenylphosphino)ethane) or CoCl₂(dppp) (dppp is the 1,3-bis(diphenylphosphino)propane) with [K][7,8-nido-C₂B₉H₁₂] upon reflux in benzene led to the mixed ligand closo-cobaltacarboranes [3,3-(Ph₂P(CH₂) _n PPh₂)-3-Cl-closo-3,1,2-Co^IIIC₂B₉H₁₁] (n = 2 and 3, respectively) in moderate yields (34 and 16%). The structure of the 18-electron complexes in solution and the solid state was studied by NMR and IR spectroscopy, the structure in the case of the closo-complex with dppe-ligand was confirmed by X-ray crystallography.     

Synthesis of hetero-binuclear derivatives of the tetrathiolato complexes [Mo(η-C5H5CH2SR)2)], R = Prn and Ph,with platinum,palladium, and rhodium

The compound Mo(η-C₅H₄(CH₂)₂SPrⁿ)₂(SPrⁿ)₂ acts as a bidentate ligand giving the heteronuclear bi-metallic compounds [Mo(η-C₅H₄CH₂CH₂SPrⁿ)₂-(SPrⁿ)₂(PtCl₂)],[Mo(η-C₅H₄CH₂CH₂SPrⁿ)₂(SPrⁿ)₂(PdCl₂)₂], [Mo(η-C₅C₄CH₂CH₂SPrⁿ)₂(SPrⁿ)₂(RhCl₃)₂], [Mo(η-C₅H₄CH₂CH2SPrⁿ)₂(μ-SPrⁿ)₂Rh(dppe)]BF₄, [Mo(η-C₅H₄CH₂CH₂SPrⁿ)₂(μ-SPrⁿ)₂(COD)Rh]Cl, [Mo(η-C₅H₄CH₂CH₂SPrⁿ)₂-(μ-SPrⁿ)₂Pt(PPh₃)₂](PF₆)₂, and the compound [Mo(η-C₅H₄(CH₂)₂-μ-SPh)₂Cl₂Rh(COD)]Cl bonds via the ring-sulphur substituents giving [Mo(η-C₅H₄(CH₂)₂-μ-SPh)₂-Cl₂Rh(COD)]Cl.     

Reactions of dodecahydro-closo-dodecaboric acid with chitosan

A donor-acceptor interaction between H⁺-cations of dodecahydro-closo-dodecaboric acid and the amine group of chitosan results in the generation of chitosanium dodecahydro-closo-dodecaborate, (C₆O₄H₉NH₃)₂B₁₂H₁₂ — water-insoluble salt. The presence of four pairs of donor oxygen atoms in its composition makes for the existence of (C₆O₄H₉NH₃)₂B₁₂H₁₂× nH₂B₁₂H₁₂ (0 < n ≤ 4) compounds. When treating the latter with gaseos ammonia, the compounds of (C₆O₄H₉NH₃)₂B₁₂H₁₂×n(NH₄)₂B₁₂H₁₂ (0 < n ≤ 4) composition are formed. The individuality of the compounds was confirmed by IR and X-ray PE spectral studies, chemical and X-ray phase analyses, and thermogravimetry.     

Why Are B ions stable species in peptide spectra?

Protonated amino acids and derivatives RCH(NH₂)C(+O)X · H⁺ (X = OH, NH₂, OCH₃) do not form stable acylium ions on loss of HX, but rather the acylium ion eliminates CO to form the immonium ion RCH = NH ₂ ⁺ . By contrast, protonated dipeptide derivatives H₂NCH(R)C(+O)NHCH(R′)C(+O)X · H⁺ [X = OH, OCH₃, NH₂, NHCH(R″)COOH] form stable B₂ ions by elimination of HX. These B₂ ions fragment on the metastable ion time scale by elimination of CO with substantial kinetic energy release (T _1/2 = 0.3–0.5 eV). Similarly, protonated N-acetyl amino acid derivatives CH₃C(+O)NHCH(R′)C(+O)X · H⁺ [X = OH, OCH₃, NH₂, NHCH(R″)COOH] form stable B ions by loss of HX. These B ions also fragment unimolecularly by loss of CO with T _1/2 values of ～ 0.5 eV. These large kinetic energy releases indicate that a stable configuration of the B ions fragments by way of activation to a reacting configuration that is higher in energy than the products, and some of the fragmentation exothermicity of the final step is partitioned into kinetic energy of the separating fragments. We conclude that the stable configuration is a protonated oxazolone, which is formed by interaction of the developing charge (as HX is lost) with the N-terminus carbonyl group and that the reacting configuration is the acyclic acylium ion. This conclusion is supported by the similar fragmentation behavior of protonated 2-phenyl-5-oxazolone and the B ion derived by loss of H-Gly-OH from protonated C₆H₅C(+O)-Gly-Gly-OH. In addition, ab initio calculations on the simplest B ion, nominally HC(+O)NHCH₂CO⁺, show that the lowest energy structure is the protonated oxazolone. The acyclic acylium isomer is 1.49 eV higher in energy than the protonated oxazolone and 0.88 eV higher in energy than the fragmentation products, HC(+O)N⁺H = CH₂ + CO, which is consistent with the kinetic energy releases measured.     

C2-Bridged sandwich and half-sandwich entities with Ti(IV) and Cr(0) centers

The intense purple colored bi- and trimetallic complexes {Ti}(CH₂SiMe₃)[CC(η⁶-C₆H₅)Cr(CO)₃] (3) ({Ti}=(η⁵-C₅H₅)₂Ti) and [Ti][CC(η⁶-C₆H₅)Cr(CO)₃]₂ (5) {[Ti]=(η⁵-C₅H₄SiMe₃)₂Ti}, in which next to a Ti(IV) center a Cr(0) atom is present, are accessible by the reaction of Li[CC(η⁶-C₆H₅)Cr(CO)₃] (2) with {Ti}(CH₂SiMe₃)Cl (1) or [Ti]Cl₂ (4) in a 1:1 or 2:1 molar ratio. The chemical and electrochemical properties of 3, 5, {Ti}(CH₂SiMe₃)(CCFc) [Fc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄)] and [Ti][(CC)_nMc][(CC)_mM′c] [n, m=1, 2; n=m; n≠m; Mc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄); M′c=(η⁵-C₅H₅)Ru(η⁵-C₅H₄); Mc=M′c; Mc≠M′c] will be comparatively discussed.     

Two inclusion compounds of guanylthiourea and 1,3,5-thiadiazole-5-amido-2-carbamate

In the crystal structure of [(n-C₄H₉)₄N]⁺·[NH₂(C₂N₂S)NHCOO^?]·NH₂CSNC(NH₂)₂ (1), guanylthiourea molecules and 1,3,5-thiadiazole-5-amido-2-carbamate ions are joined together by intermolecular N–H…O, N–H…N, and weak N–H…S hydrogen bonds to generate stacked host layers corresponding to the (110) family of planes, between which the tetra-n-butylammonium guest cations are orderly arranged in a sandwich-like manner. In the crystal structure of [(n-C₃H₇)₄N]⁺·[NH₂(C₂N₂S)NHCOO^?]·NH₂CSNC(NH₂)₂·H₂O (2), the tetrapropyl ammonium cations are stacked within channels each composed of hydrogen bonded ribbons of guanylthiourea molecules, 1,3,5-thiadiazole-5-amido-2-carbamate ions and water molecules.     

Darstellung und Charakterisierung von kationischen η2-1-Buten- und Acetonitrilkomplexen

Preparation and Characterization of Cationic η²-1-Butene and Acetonitrile Complexes The reaction of the species η⁵-C₅H₅M(CO)_n-σ-C₄H₇ (M = Fe, Mo, W; n = 2, 3) with (C₆H₅)₃CBF₄ yielded – instead of the expected cationic butadiene complexes of the type [η⁵-CpM(CO)_n?1-η⁴-C₄H₆][BF₄], which would have been formed in case of hydride cleavage – compounds of the type [η⁵-CpM(CO)_n η²-C₄H₈][BF₄], which were formed by protonation of the σ-C₄H₇ ligands. The reaction proceeded quantitatively. The BF₄^? anion can be substituted by other anions, such as ClO₄^?, B(C₆H₅)₄^?, PF₄^?, and [Cr(SCN)₄(NH₃)₂]^? in the complexes obtained. The mechanism of the reaction leading to the η²-bonded 1-butene complexes was determined by isotope experiments. In trying to recrystallize the butene complexes from acetonitrile the cationic complexes [η⁵-C₅H₅ Fe(CO)₂CH₃CN]BF₄ and [η⁵-C₅H₅ M(CO)₃CH₃CN]BF₄ were observed; the X-ray structure analysis of the former is reported.     

1D and 2D supramolecular structures of silver carborane dicyclohexylphosphine complexes constructed by C-H?H-B dihydrogen bonding interactions

Five new carborane dicyclohexylphosphine complexes, [Ag₂(μ-I)₂{1,2-(P Cy₂)₂-1,2-C₂B₁₀H₁₀}₂] (1), [Ag₂(SCN)₂{1,2-(PCy₂)₂-1,2-C₂B₁₀H₁₀}₂]_n·CH₂Cl₂ (2), [Ag(ClO₄){1,2-(PCy₂)₂-1,2-C₂B₁₀H₁₀}]·CH₂Cl₂ (3), [Ag₂(μ-NO₃)₂{1,2-(PCy₂)₂-1,2-C₂B₁₀H₁₀}₂]·CH₂Cl₂ (4) and [Ag(SC₆H₄COOH){1,2-(PCy₂)₂-1,2-C₂B₁₀H₁₀}₂]·CH₂Cl₂ (5), have been synthesized by the reactions of 1,2-bis(dicyclohexylphosphino)-1,2-dicarba-closo-dodecaborane with AgX (X = I, SCN, ClO_4, NO₃ and SC₆H₄COOH) in CH₂Cl₂. The structures of the five complexes were characterized by elemental analysis, FT-IR, ¹H, ¹³C, ¹¹B and ³¹P NMR spectroscopy. X-ray structure analysis revealed that the structures of the complexes can be classified into three types. Complexes 1 and 4 are di-μ-X-bridged structures and complexes 3 and 5 are mononuclear structures, while complex 2 is a chain-like polymer. Complexes 1 and 2 form 2D supramolecular networks and complexes 3, 4 and 5 form 1D chains via C-H?H-B dihydrogen bonding interactions.