Preparation and crystal structure of bis[(dibenzo-18-crown-6)potassium]bis(μ<Subscript>2</Subscript>-chloro)-tetrachlorodicuprate(II)

A new complex compound bis[(dibenzo-18-crown-6)potassium]bis(μ₂-chloro)-tetrachlorodicuprate( II), {[K(Db18c6)]₂Cu₂Cl₆} (I) was prepared and its crystal structure was investigated by XRD analysis. Complex molecule I consist of anion [Cu₂Cl₆]²⁻ located in a crystallographic center of inversion, and two centrosymmetrical to each other complex cations [K(Db18c6)]⁺ of “guest-host” type: the cation K⁺ is located in the cavity of the crown-ligand Db18c6 and is coordinated by all its six O atoms, and also by one Cl atom of anion [Cu₂Cl₆]²⁻. The coordination of this cation K⁺ is enlarged up to hexagonal-bipyramidal due to the formation of unusual coordination bond K⁺ → π(      

(18-Crown-6)potassium tetrachloroferrate(III), dibromodichloroferrate(III), and tetrabromoferrate(III): Synthesis and crystal structures

Three new crystalline complexes are synthesized: [K(18-crown-6)]⁺ · An, where An = [FeCl₄]^?(I), [FeBr₂Cl₂]^? (II), and [FeBr₄]^? (III). The crystals of compounds I–III are cubic and isomorphic, space group Fd $ \bar 3 Three new crystalline complexes are synthesized: [K(18-crown-6)]⁺ · An, where An = [FeCl₄]⁻(I), [FeBr₂Cl₂]⁻ (II), and [FeBr₄]⁻ (III). The crystals of compounds I–III are cubic and isomorphic, space group Fd (Z = 16): a = 20.770(2) ? for I, 20.844(3) ? for II, and 20.878(4) ? for III. Structures I–III are solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.047 (I), 0.059 (II), and 0.098 (III) for all 680 (I), 684 (II), and 686 (III) independent reflections. In two tetrahedral anions [Fe(1)X₄]⁻ and [Fe(2)X₄]⁻ in structures I–III, all halogen atoms (X = Cl and Br) are randomly disordered over three close positions relative to the crystallographic axes 3. Structures I–III contain the [K(18-crown-6)]⁺ host-quest complex cation. The K⁺ cation (CN = 8) resides in the cavity of the 18-crown-6 ligand and coordinated by its six O atoms and two disordered halogen X atoms. The coordination polyhedron of the K⁺ cation in complexes I–III is a distorted hexagonal bipyramid. Original Russian Text ? A.N. Chekhlov, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 9, pp. 1566–1570.     

Synthesis and crystal structure of hexakis(isothiocyanato)erbium(III) thiocyanate bis(18-crown-6)dipotassium bis[(18-crown-6)ethanolpotassium]

A new complex compound, [K₂(18-crown-6)₂[K(18-crown-6)(EtOH)]₂[Er(NCS)₆](SCN) (I), was synthesized and its crystal structure was studied by X-ray diffraction. In this work, the synthes and X-ray difraction stady of the crystals of a new complex, hexakis (isothiocyanato) erbiu(III) thiocyanate bis(18-crown-6) dipotassium bis(18-crown-6) ethanolpotassium], [K₂(18-crown-6)₂][K(18-crown-6)(ETON)]₂[Er(NCS)₆(SCN)(I)] are described. In crystal I, the alternating [Er(NCS)₆]^3? anions and binuclear complex cation [K(18-crown-6)₂]²⁺ from infinite chains via the F-S bonds, while two complex cations [K(18-crown-6)(ETON)]⁺ and the statistically disordered SCN^? anion between them are linked by the hydragen bonds O-H…S and O-H…N. Complex I contains the host-guest complex cations [K₂(18-crown-6)₂)]²⁺ and [K(18-crown-6)(ETON)]⁺ [1]. The alternating octabedral [Er(NCS)₆]^3? anions and binuclear complex cations [K₂(18-crown-6)₂]²⁺of crystal I form infinite chains via the K-S bonds, while two complex cations [K(18-crown-6)(EtOH)]⁺ and the statistically disordered SCN^? anion lying between them are linked by interionic hydrogen bonds O-H…S and O-H…N. Complex I contains the host-guest complex cations [K₂(18-crown-6)₂]²⁺ and [K(18-crown-6)(EtOH)]⁺ [1].     

(Mesitylene)ruthenium π-complexes with benzo-15-crown-5 and dibenzo-18-crown-6

The reactions of benzo-15-crown-5 and dibenzo-18-crown-6 with 1 equiv. of [(mes)Ru(MeNO₂)₃]²⁺ (mes = 1,3,5-C₆H₃Me₃) give the mononuclear complexes [(mes)Ru(η⁶-benzo-15-crown-5)]²⁺ (1) and [(mes)Ru(η⁶-dibenzo-18-crown-6)]²⁺ (2) in 50% yield. Similar reaction with 2 equiv. of [(mes)Ru(MeNO₂)₃]²⁺ produces the dinuclear complex [(μ-η⁶:η⁶-dibenzo-18-crown-6)Ru₂(mes)₂]⁴⁺ (3) in 96% yield as a 2:3 mixture of cis- and trans-isomers. Structures of 2(OTf)₂ and trans-3(OTf)₄ were confirmed by X-ray diffraction. The NMR titration showed that mononuclear dications 1 and 2 bind Na⁺ ion less effective (K_a = 600 and 250 M^-1) than free benzo-15-crown-5 and dibenzo-18-crown-6 (K_a = 2 × 10⁵ and 5 × 10⁶ M⁻¹). The dinuclear tetracation 3 does not bind Na⁺ within measurable limits of NMR titration method. The electrochemical behaviour of complexes 1-3 was studied in propylene carbonate solution. They exhibit a partially chemically reversible Ru(II)/Ru(I) reduction, which in the case of the dinuclear complex 3 proceeds through two slightly separated steps. The redox activity of the complexes is substantially unaffected by the presence of sodium ion.     

A molecule based on polyoxometalate acid and crown ether: synthesis and characterization of [(H3O)(C20H24O6)]2[HPMo12O40]·C20H24O6·3MeCN·H2O (C20H24O6=dibenzo-18-crown-6)

The new molecule based on 12-molybdophosphate acid and dibenzo-18-crown-6, [(H₃O)(C₂₀H₂₄O₆)]₂[HPMo₁₂O₄₀]·C₂₀H₂₄O₆·3MeCN·H₂O 1, was synthesized in acetonitrile and characterized by elemental analyses, IR, ¹H NMR, electrospray mass spectra and single crystal X-ray diffraction, indicating that it contains [(H₃O)(dibenzo-18-crown-6)]⁺ cations, where oxonium ions are out of the planes defined by crown ether oxygen atoms, and disordered PMo₁₂O₄₀³⁻ anions with α-Keggin structure where the crystal has high lattice energy so that it is difficult to dissolve it. The crystallographic disorder averages Mo-Mo distances and Mo-O_b/c-Mo angles between the M₃ triplets and within the M₃ triplet. The interactions between crown ether molecules and oxonium ions are hydrogen-bonding with the O(crown ether)-OH₃⁺ distances of 2.510(10)-2.783(7) Å. The interactions between [(H₃O)(dibenzo-18-crown-6)]⁺ cations and PMo₁₂O₄₀³⁻ anions are dominantly electrostatic. The electrical conductivity is <10⁻⁷ S.cm⁻¹.     

Yttrium thiocyanate-based supramolecular architectures: Synthesis, crystal structures, and thermal properties

The reaction of [Y(H₂O)₅(NCS)₃]·H₂O (1) with crown ether (18-crown-6) and KNCS in methanol afforded the complexes [Y(H₂O)₄(NCS)₃]·1.5(18-crown-6) (2) and [K(18-crown-6)(H₂O)_1.25]_2n{[K(18-crown-6)]₂[Y(NCS)₆]}_n·n(NCS) (3). In mononuclear complex 1, yttrium has a coordination number 8 and forms the coordination unit YO₅N₃. Complexes 1 are linked by hydrogen bonds to form a framework. The crystal structure of 2 contains the centrosymmetric ensembles [Y(H₂O)₄(NCS)₃]₂(18-crown-6)₃ formed via hydrogen bonds. In the crystal structure of 3, the [Y(NCS)₆]³⁻ anions and the [K(18-crown-6)]⁺ cations form one-dimensional polymeric chains (-Y-NCS-K-)_n. The thermal behavior of compounds 1 and 2 was investigated. It was shown that the supramolecular assembly has an effect on the temperature range for the removal of coordinated water molecules from the thiocyanate complex. The oxidative decomposition of the acido ligands in 1 and 2 occurs in a similar way to give Y₂O₂SO₄ as the final product (700 °С).     

Mono and dinuclear half-sandwich platinum group metal complexes bearing pyrazolyl-pyrimidine ligands: Syntheses and structural studies

Reactions of 0.5 eq. of the dinuclear complexes [(η⁶-arene)Ru(μ-Cl)Cl]₂ (arene = η⁶-C₆H₆, η⁶-p-ⁱPrC₆H₄Me) and [(Cp∗)M(μ-Cl)Cl]₂ (M = Rh, Ir; Cp∗ = η⁵-C₅Me₅) with 4,6-disubstituted pyrazolyl-pyrimidine ligands (L) viz. 4,6-bis(pyrazolyl)pyrimidine (L1), 4,6-bis(3-methyl-pyrazolyl)pyrimidine (L2), 4,6-bis(3,5-dimethyl-pyrazolyl)pyrimidine (L3) lead to the formation of the cationic mononuclear complexes [(η⁶-C₆H₆)Ru(L)Cl]⁺ (L = L1, 1; L2, 2; L3, 3), [(η⁶-p-ⁱPrC₆H₄Me)Ru(L)Cl]⁺ (L = L1, 4; L2, 5; L3, 6), [(Cp∗)Rh(L)Cl]⁺ (L = L1, 7; L2, 8; L3, 9) and [(Cp∗)Ir(L)Cl]⁺ (L = L1, 10; L2, 11; L3, 12), while reactions with 1.0 eq. of the dinuclear complexes [(η⁶-arene)Ru(μ-Cl)Cl]₂ and [(Cp∗)M(μ-Cl)Cl]₂ give rise to the dicationic dinuclear complexes [{(η⁶-C₆H₆)RuCl}₂(L)]²⁺ (L = L1, 13; L2, 14; L3, 15), [{(η⁶-p-ⁱPrC₆H₄Me)RuCl}₂(L)]²⁺ (L = L1, 16; L2, 17; L3, 18), [{(Cp∗)RhCl}₂(L)]²⁺ (L = L1, 19; L2, 20; L3, 21) and [{(Cp∗)IrCl}₂(L)]²⁺ (L = L1 22; L2, 23; L3 24). The molecular structures of [3]PF₆, [6]PF₆, [7]PF₆ and [18](PF₆)₂ have been established by single crystal X-ray structure analysis.     

Preparation and crystal structure of bis(dibenzo-18-crown-6)-(tetrachlorocuprato(II)-Cl,Cl′, Cl″, Cl‴)dipotassium diaqua(dibenzo-18-crown-6)potassium dichlorocuprate(I)-dibenzo-18-crown-6

New mixed complex compound bis(dibenzo-18-crown-6)(tetrachlorocuprato(II)-Cl, Cl′, Cl″, Cl?) dipotassium diaqua(dibenzo-18-crown-6)potassium dichlorocuprate(I)dibenzo-18-crown-6 [(CuCl₄)[K(Db18C6)]₂]·[K(Db18C6)(H₂O)₂]⁺·[CuCl₂]^?·Db18C6 was prepared and its structure was studied by the X-ray structural analysis. The structure was found to be disordered. The asymmetric part of its unit cell contains 1/4 of each of its four components. For a given [CuCl₄]^2? anion its Cu²⁺ cation is disordered over two equally probable positions and its independent Cl atom is disordered over three positions differing by occupancy. In this structure two [K(Db18C6)]⁺ fragment of the complex molecule and the complex cation [K(Db18C6)(H₂O)₂]⁺ are of guest-host type with K⁺ cation as the guest. In this structure the statistically disordered alternating cations and Db18C6 molecules form infinite chains. The statistically disordered [CuCl₂]^? anions also form infinite chains.     

New calсium β-diketonate complexes: The monomeric complexes [Ca(PhCOCHCOCF3)2(15-crown-5)], [Ca(AdCOCHCOCF3)2(15-crown-5)] and the binuclear hydrated complex [{Ca(adtfa)(18-crown-6)(H2O)}{Ca(adtfa)3(H2O)}(EtOH)]. Synthesis, characterization and crystal structure

The preparation of the Ca-β-diketonate complexes with crown-ethers, [Ca(btfa)₂(15-crown-5)] (1), [Ca(adtfa)₂(15-crown-5)] (2), [Ca(adtfa)₂(15-crown-5)](C₆H₅CH₃)_0.5 (3) and [{Ca(adtfa)(18-crown-6)(H₂O)}{Ca(adtfa)₃(H₂O)}(EtOH)] (4) (btfa = 1,1,1-trifluoro-4-phenyl-butanedionato-2,4; adtfa = 1,1,1-trifluoro-4-(1-adamantyl)butanedionato-2,4; 15-crown-5 = 1,4,7,10,13-pentaoxacyclopentadecane; 18-crown-6 = 1,4,7,10,13,16-hexaoxacyclooctadecane), is described. Complex 1 has been prepared from the reaction of metallic Ca with 2 eq. of Hbtfa and 1 eq. of 15-crown-5 in toluene; complex 2 has been prepared from the reaction of metallic Ca with 2 eq. of Hadtfa and 1 eq. of 15-crown-5 in ethanol. The solvated complex 3 was obtained by cooling of a toluene-hexane solution of 2. The hydrated complex 4 was prepared from the reaction of metallic Ca with 2 eq. of Hadtfa and 1 eq. of 18-crown-6, followed by addition of excess H₂O to the resulting reaction mixture. The all complexes were characterized by elemental analyses, IR-spectroscopy, NMR-spectroscopy, single-crystal X-ray diffraction methods, DSC and TGA. A single-crystal X-ray study of 1 and 3 has show that complexes 1 and 3 are monomeric and contain the calcium atom bonded with two β-diketonate ligands and one molecule of crown-ether. Complex 4, as shown by X-ray analyses, is an ion-paired solvated adduct, containing the cation {Ca(adtfa)(18-crown-6)(H₂O)}⁺ and the anion {Ca(adtfa)₃(H₂O)}⁻. The monomeric complexes 1-3 are volatile and thermally stable in the temperature range 100-260 °C. Complex 4 undergoes decomposition above 110 °C with consecutive loss of ethanol, H₂O, 18-crown-6 and some evaporization of 4.     

Synthesis and crystal structure of 18-crown-6 <Emphasis Type="Italic">E</Emphasis>-2-phenylethenylphosphonic acid diaqua(18-crown-6)sodium <Emphasis Type="Italic">E</Emphasis>-2-phenylethenylphosphonate

New complex compound, diaqua(18-crown-6)sodium E-2-phenylethenylphosphonate 18-crown-6 E-2-phenylethenylphosphonic acid, [Na(18-crown-6)(H₂O)₂]⁺·HO ₃ ^? PCH=CHPh·18-crown-6·H₂O₃PCH=CHPh, was obtained and its crystal and molecular structures were studied by the X-ray structural analysis. In this structure the complex cation [Na(18-crown-6)(H₂O)₂]⁺ is of guest-host type. The coordination polyhedron of its Na⁺ cation is a slightly screwed hexagonal bipyramid with the base consisting of all 6 O atoms of 18-crown-6 ligand and with two opposite apexes at two O atoms of two ligand water molecules. In the studied crystal structure the alternating complex cations and 18-crown-6 molecules as well as the molecules of acid and its anion HO ₃ ^? PCH=CHPh form by means of hydrogen bonds the infinite chains of two different types.     

Bimetallic ruthenium-tin chemistry: Synthesis and molecular structure of arene ruthenium complexes containing trichlorostannyl ligands

A series of neutral, anionic and cationic arene ruthenium complexes containing the trichlorostannyl ligand have been synthesised from SnCl₂ and the corresponding arene ruthenium dichloride dimers [(η⁶-arene)Ru(μ₂-Cl)Cl]₂ (arene = C₆H₆, PrⁱC₆H₄Me). While the reaction with triphenylphosphine and stannous chloride only gives the neutral mono(trichlorostannyl) complexes [(η⁶-C₆H₆)Ru(PPh₃)(SnCl₃)Cl] (1) and [(η⁶-PrⁱC₆H₄Me)Ru(PPh₃)(SnCl₃)Cl] (2), the neutral di(trichlorostannyl) complex [(η⁶-PrⁱC₆H₄Me)Ru(NCPh)(SnCl₃)₂] (3) could be obtained for the para-cymene derivative with benzonitrile as additional ligand. By contrast, the analogous reaction with the benzene derivative leads to a salt composed of the cationic mono(trichlorostannyl) complex [(η⁶-C₆H₆)Ru(NCPh)₂(SnCl₃)]⁺ (5) and of the anionic tris(trichlorostannyl) complex [(η⁶-C₆H₆)Ru(SnCl₃)₃]⁻ (6). On the other hand, [(η⁶-PrⁱC₆H₄Me)Ru(μ₂-Cl)Cl]₂ reacts with SnCl₂ and hexamethylenetetramine hydrochloride or 18-crown-6 to give the anionic di(trichlorostannyl) complex [(η⁶-PrⁱC₆H₄Me)Ru(SnCl₃)₂Cl]⁻ (4), isolated as the hexamethylenetetrammonium salt or the chloro-tin 18-crown-6 salt. The single-crystal X-ray structure analyses of 1, 2, [(CH₂)₆N₄H][4], [(18-crown-6)SnCl][4] and [5][6] reveal for all complexes a pseudo-tetrahedral piano-stool geometry with ruthenium-tin bonds ranging from 2.56 (anionic complexes) to 2.60 Å (cationic complex).     

On the protonation of dibenzo-18-crown-6

Abstract  The stability constant of the dibenzo-18-crown-6·H₃O⁺ cationic complex species dissolved in nitrobenzene saturated with water has been determined from extraction experiments in the two-phase water–nitrobenzene system and from γ-activity measurements. Various structures of protonated dibenzo-18-crown-6 are discussed. Graphical abstract        

Thermodynamics of Solvation of 18-Crown-6 and Its Alkali-Metal Complexes in Various Solvents

Heats of solution of 1,4,7,10,13,16-hexaoxacyclooctadecane (18-crown-6) in acetonitrile, 1,2-dichloroethane, N,N-dimethylformamide, dimethyl sulfoxide, nitromethane, propylene carbonate, pyridine and water were measured at 25 °C and the enthalpies of the transfer of 18-crown-6 from waterto the aprotic solvents were derived. The thermodynamic quantities, G₁°, H₁° and T S₁°, for the formation of the[M(18-crown-6)]⁺ (M⁺ = Na⁺, K⁺, Rb⁺, Cs⁺, NH₄ ⁺) complexeswere determined by titration calorimetry in dimethyl sulfoxide containing0.1 mol dm^-3 (C₂H₅)₄NClO₄ as a constant ionic medium at 25 °C. These thermodynamic quantities suggest that the complexationof 18-crown-6 with the alkali-metal ions mainly reflects the different solvationof 18-crown-6 and also the different degree of solvent structure.     

Cationic half-sandwich complexes (Rh, Ir, Ru) containing 2-substituted-1,8-naphthyridine chelating ligands: Syntheses, X-ray structure analyses and spectroscopic studies

Reactions of the dinuclear complexes [(η⁶-arene)Ru(μ-Cl)Cl]₂ (arene = C₆H₆, p-ⁱPrC₆H₄Me) and [(η⁵-C₅Me₅)M(μ-Cl)Cl]₂ (M = Rh, Ir) with 2-substituted-1,8-naphthyridine ligands, 2-(2-pyridyl)-1,8-naphthyridine (pyNp), 2-(2-thiazolyl)-1,8-naphthyridine (tzNp) and 2-(2-furyl)-1,8-naphthyridine (fuNp), lead to the formation of the mononuclear cationic complexes [(η⁶-C₆H₆)Ru(L)Cl]⁺ {L = pyNp (1); tzNp (2); fuNp (3)}, [(η⁶-p-ⁱPrC₆H₄Me)Ru(L)Cl]⁺ {L = pyNp (4); tzNp (5); fuNp (6)}, [(η⁵-C₅Me₅)Rh(L)Cl]⁺ {L = pyNp (7); tzNp (8); fuNp (9)} and [(η⁵-C₅Me₅)Ir(L)Cl]⁺ {L = pyNp (10); tzNp (11); fuNp (12)}. All these complexes are isolated as chloro or hexafluorophosphate salts and characterized by IR, NMR, mass spectrometry and UV/Vis spectroscopy. The molecular structures of [1]Cl, [2]PF₆, [4]PF₆, [5]PF₆ and [10]PF₆ have been established by single crystal X-ray structure analysis.     

The reaction of 2,5-diphenylphosphacymantrene with solid KOH in the presence of crown ethers: Synthesis of the anionic η-phosphoryl manganese complexes

2,5-Diphenylphosphacymantrene (1) reacts with solid KOH in the presence of crown ethers in C₆H₆ or CH₂Cl₂ at room temperature adding OH nucleophile to the phosphorus atom to afford anionic complexes [(CO)₃Mn-η⁴-2,5-Ph₂H₂C₄P(O)H]⁻ [K−Crown]⁺, where Crown = 18-crown-6 (2) or dicyclohexyl-18-crown-6 (3). Complexes 2 and 3 are characterized by ¹H, ³¹P, ¹³C NMR and IR-spectra. The structure of 2 is established by X-ray crystal structure data.     

Synthesis and crystal structure of aqua(dibenzo-18-crown-6)potassium (dibenzo-18-crown-6)-(tetrachlorocuprato(II)-Cl)potassium

New mixed complex compound aqua(dibenzo-18-crown-6)potassium (dibenzo-18-crown-6)(tetrachlorocuprato(II)-Cl)potassium, [K(CuCl₄)(Db18C6)]^? · [K(Db18C6)(H₂O)]⁺, is synthesized and its crystal structure is studied by the method of x-ray structural analysis. The structure includes two independent complex ions, both of guest-host type: two cations K⁺ are located in the respective cavities of the Db18C6 crown-ligand (one in each) and each is coordinated by all its six O atoms and one Cl atom of the anion-ligand [CuCl₄]^2? or O atom of the ligand water molecule. Coordination of these two K⁺ cations is completed to hexagonal pyramidal one by formation by each of unusually weak coordination bond K⁺ → π(\(C\dddot - C\)) with two C atoms of respective benzene ring in the neighboring Db18C6 ligand. In this crystal structure the complex anions and cations form dual infinite chains via these coordination bonds and interionic O-H?Cl hydrogen bonds.     

An <Emphasis Type="Italic">ab initio </Emphasis> Quantum-Chemical Study of C<Subscript>6</Subscript>H<Subscript>5</Subscript>S(O)CH<Subscript>3</Subscript> and C<Subscript>6</Subscript>H<Subscript>5</Subscript>S(O)CF<Subscript>3</Subscript>

The potential functions of internal rotation around the C -S bond in the C₆H₅S(O)CH₃ and C₆H₅S(O)CF₃ molecules were obtained by ab initio MP2(full)/6-31+G* calculations. The stationary points were identified by solving the vibrational problems. The structures in which the plane of the C -S-C bonds is approximately perpendicular to the benzene ring plane correspond to the energy minimum. The barriers to rotation around the C -S bond, corrected for the zero-point vibration energy, are 21.29 [C₆H₅S(O)CH₃] and 28.98 [C₆H₅S(O)CF₃] kJ mol⁻¹. The bond angles (deg) are as follows: 95.7 (CSC), 107.1 (C SO), 106.3 (C SO) in C₆H₅S(O)CH₃; 93.5 (CSC), 108.2 (C SO), 105.2 (C SO) in C₆H₅S(O)CF₃. The bond lengths are as follows (Å): 1.520 (S=O), 1.804 (C -S), 1.810 (C -S) in C₆H₅S(O)CH₃; 1.507 (S=O), 1.799 (C -S), 1.870 (C -S) in C₆H₅S(O)CF₃. According to the results of NBO calculations, the formally double S=O bond consists of a strongly polarized covalent σ bond (S→O) and an almost ionic bond. An increase in the S=O bond multiplicity relative to a single bond is mainly due to hyperconjugation by the mechanism n(O)→σ*(C -S) and n(O)→σ*(C -S) and, to a lesser extent, by interaction of the oxygen lone electron pairs with the Rydberg orbitals of the S atoms, characterized by a large contribution of the d component.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 1, 2005, pp. 96–104.Original Russian Text Copyright © 2005 by Bzhezovskii, Il’chenko, Chura, Gorb, Yagupol’skii.     

Synthesis and property of BrCCH- and BrCCBr-coordinated tetrairon clusters

The reaction of (η⁵-C₅H₄Me)₄Fe₄(HCCH)₂ (1) with 1 equiv. of N-bromosuccinimide (NBS) gives the one-electron oxidized form in 83% yield. Further treatment of [1]⁺ with NBS results in the stepwise bromination of four acetylenic protons to give [(η⁵-C₅H₄Me)₄Fe₄(HCCH)(HCCBr)]⁺ ([2]⁺), [(η⁵-C₅H₄Me)₄Fe₄(HCCBr)₂]⁺ ([3a]⁺), [(η⁵-C₅H₄Me)₄Fe₄(HCCBr)(BrCCBr)]⁺ ([4]⁺), and [(η⁵-C₅H₄Me)₄Fe₄(BrCCBr)₂]⁺ ([5]⁺) in moderate yields, with the isomer of [3a]⁺, [(η⁵-C₅H₄Me)₄Fe₄(HCCH)(BrCCBr)]⁺ ([3b]⁺), formed as a minor product. These compounds are characterized by analytical and spectroscopic techniques, and the molecular structures of [2](PF₆), [4](TFPB), and [5](TFPB) are established by X-ray diffraction analysis [TFPB = tetrakis{bis(3,5-trifluoromethyl)phenyl}borate]. The compounds are confirmed to retain the butterfly core of four iron atoms as in [1](TFPB). The bromoacetylene part in [2]⁺ exhibits high reactivity toward various nucleophiles: Cluster[2]⁺ is moisture-sensitive and is converted to a mixture of [(η⁵-C₅H₄Me)₄Fe₄(HCCH)(μ₃-CH)(μ₃-CO)]⁺ ([6]⁺) and [1]⁺. Reactions of [2]⁺ with ZnR₂ (R = Me, Et) give [(η⁵-C₅H₄Me)₄Fe₄(HCCH)(HCC-R)]⁺ in good yields (R = Me ([9]⁺, 88%), Et ([10]⁺, 91%)). Accordingly, treatment of [2]⁺ with HC CMgBr and LiS^pTol leads to the introduction of the ethynyl and thiolate groups to give [(η⁵-C₅H₄Me)₄Fe₄(HCCH)(HCC-CCH)]⁺ ([11]⁺, 95%) and [(η⁵-C₅H₄Me)₄Fe₄(HCCH)(HCC-S^pTol)]⁺ ([12]⁺, 78%), respectively. Substitution of the bromo group in [2]⁺ with pyridine affords [(η⁵-C₅H₄Me)₄Fe₄(HCCH)(HCC-Py)]²⁺ ([13]²⁺) in 90% yield. The reaction with 4,4′-bipyridyl (bpy) requires the severer conditions (70 °C, 2 days), probably due to the relative low basicity of bpy, giving [(η⁵-C₅H₄Me)₄Fe₄(HCCH)(HCC-bpy)]²⁺ ([14]²⁺) in 54% yield. The substitution reaction with 4,4′-bipyridyl is strongly accelerated by treatment with silver salt to give [14]²⁺ in 90% yield. The products derived from [2]⁺ and nucleophiles are unequivocally determined by elemental, spectroscopic, and X-ray diffraction analyses.     

Synthesis and crystal structure of triaqua[0.25(bromo)1.75(nitrato-O)]copper(II) 18-crown-6 hydrate (solvate)

A complex triaqua[0.25(bromo)1.75(nitrato-O)]copper(II) 18-crown-6 hydrate (solvate), [CuBr_0.25(NO₃)_1.75(H₂O)₃] · 18-crown-6 · 5H₂O, is synthesized, and its crystal structure is studied by X-ray diffraction analysis (space group Cmc2₁, a = 13.705, b = 14.583, c = 13.174 Å, Z = 4; direct method, full-matrix least-squares refinement in the anisotropic approximation to R = 0.069 for 2547 independent reflections; CAD-4 automated diffractometer, λMoK _α radiation). The mixed complex molecule is a randomly disordered mixture of [Cu(NO₃)₂(H₂O)₃] and [CuBr(NO₃)(H₂O)₃] molecules with site occupancies of 0.875 and 0.125, respectively. The mixed complex molecule and 18-crown-6 molecule lie on the m plane. In the main complex molecule [Cu(NO₃)₂(H₂O)₃], the coordination polyhedron of the Cu²⁺ cation is a slightly distorted square pyramid. The 18-crown-6 molecule has the conformation of a crown with the approximate symmetry D _3d .     

Tetrakis(isothiocyanato)manganese(II) bis[aqua(18-crown-6)potassium] (18-crown-6)(thiocyanato)potassium

A new complex compound, i.e., tetrakis(isothiocyanato)manganese(II) bis[aqua(18-crown-6)potassium] (18-crown-6)(thiocyanato)potassium, was synthesized and its crystal structure was studied by X-ray diffraction (space group P2₁/m, a = 13.377, b = 14.690, c = 17.499 Å, β = 108.96°, Z = 2) and refined by the least-squares method in anisotropic approximation to R = 0.060 for 4715 independent reflections (CAD-4 automated diffractometer, λMoK _α). In the crystal, infinite chains are formed through the coordination bonds between its components. The monomer fragment of a chain [Mn(NCS)₅K₃(18-crown-6)₃(H₂O)₂] lies in plane m; three of the five SCN^? ligands and one of the two water molecules behave as bridges. The [Mn(NCS)₄]^2? anion has the tetrahedral structure. The coordination polyhedron of each of the three K⁺ cations is a distorted hexagonal bipyramid with six O atom of the corresponding crown ligand in a base. Three 18-crown-6 ligands have standard crown conformation.