Thallophilic interactions in aryloxide compounds: the [Tl2(mu2-OAr)4] structural motif in (TlOAr)4 and Tl2Cu(OAr)4 compounds

Two thallium aryloxide compounds TlOC6F5 (TlOAr(F)) and bis-3,5-TlOC6H3(CF3)2 (TlOAr') have been recrystallized from THF and crystallographically characterized in different isomeric forms. The latter compound forms a solvated tetrameric cubane, [TlOAr']4.THF, 1. The TlOAr(F) compound crystallized with a similar stoichiometry, [TlOAr(F)]4.2 THF, 2, but contains a [Tl2(mu2-OAr(F))4] unit that includes a thallophilic interaction at a distance of 3.5943(15) angstroms. Solution 205Tl and 203Tl NMR studies of 1 and 2 support the retention of a cubane structure for 1 in solution and suggest a similar structure for 2 with coupled thallium centers down to -90 degrees C. Fluorescence spectroscopy data for both compounds 1 and 2 in THF are consistent with LMCT. DFT calculations of 1, 2, and three models of the [Tl2(mu2-OAr(F))4] unit show a bonding overlap of the bridged thallium atoms in 2 and are also used to describe the bonding in 1. The structures of two heterobimetallic compounds, Tl2Cu(OAr(F))4, 4, and Tl2Cu(OAr')4, 5, with the [Tl2(mu2-OAr(F))4] structural motif and thallophilic contacts of 3.86(6) and 3.564(1) angstroms, respectively, are described. The crystal structures of the unsolvated of TlOAr(F), 2b, solvated heterobimetallic derivative Tl2Cu(OAr')4.2THF, 5b, and the monomeric (18-crown-6)TlOAr(F), 3, and 205Tl NMR spectra of TlOC6H5, 6, are also reported for comparison purposes.     

Synthesis with structural and electronic characterization of homoleptic Fe(II)- and Fe(III)-fluorinated phenolate complexes

Four Fe(III) compounds and one Fe(II) compound containing mononuclear, homoleptic, fluorinated phenolate anions of the form [Fe(OAr)(m)](n-) have been prepared in which Ar(F) = C(6)F(5) and Ar' = 3,5-C(6)(CF(3))(2)H(3): (Ph(4)P)(2)[Fe(OAr(F))(5)], 1, (Me(4)N)(2)[Fe(OAr(F))(5)], 2, {K(18-crown-6)}(2)[Fe(OAr(F))(5)], 3a, {K(18-crown-6)}(2)[Fe(OAr')(5)], 3b, and {K(18-crown-6)}(2)[Fe(OAr(F))(4)], 6. Two dinuclear Fe(III) compounds have also been prepared: {K(18-crown-6)}(2)[(OAr(F))(3)Fe(μ(2)-O)Fe(OAr(F))(3)], 4, and {K(18-crown-6)}(2)[(OAr(F))(3)Fe(μ(2)-OAr(F))(2)Fe(OAr(F))(3)], 5. These compounds have been characterized with UV-vis spectroscopy, elemental analysis, Evans method susceptibility, and X-ray crystallography. All-electron, geometry-optimized DFT calculations on four [Ti(IV)(OAr)(4)] and four [Fe(III)(OAr)(4)](-) species (Ar = 2,3,5,6-C(6)Me(4)H, C(6)H(5), 2,4,6-C(6)Cl(3)H(2), C(6)F(5)) with GGA-BP and hybrid B3LYP basis sets demonstrated that, under D(2d) symmetry, π donation from the O 2p orbitals is primarily into the d(xy) and d(z(2)) orbitals. The degree of donation is qualitatively consistent with expectations based on ligand Br?nsted basicity and supports the contention that fluorinated phenolate ligands facilitate isolation of nonbridged homoleptic complexes due to their reduced π basicity at oxygen.     

Tetracyanoborate salts M[b(CN)4] with M = singly charged cations: properties and structures

A series of tetracyanoborate salts M[B(CN)4] with the singly charged cations of Li+, Na+, Rb+, Cs+, [NH4]+, Tl+, and Cu+ as well as the THF solvate tetracyanoborates Na[B(CN)4] x THF and [NH4][B(CN)4] x THF were synthesized and their X-ray structures, vibrational spectra, solubilities in water, and thermal stabilities determined and compared with already known M[B(CN)4] salts. Crystallographic data for these compounds are as follows: Na[B(CN)4], cubic, Fd3m, a = 11.680(1) A, Z= 8; Li[B(CN)4], cubic, P43m, a = 5.4815(1) A, Z= 1; Cu[B(CN)4], cubic, P43m, a = 5.4314(7) A, Z= 1; Rb[B(CN)4], tetragonal, /4(1)/a, a = 7.1354(2) A, c= 14.8197(6) A, Z= 4; Cs[B(CN)4], tetragonal, /4(1)/a, a = 7.300(2) A, c = 15.340(5) A, Z= 4; [NH4][B(CN)4], tetragonal, /4(1)/a, a = 7.132(1) A, c = 14.745(4) A, Z= 4; Tl[B(CN)4], tetragonal, /4(1)/a, a = 7.0655(2) A, c = 14.6791(4) A, Z= 4; Na[B(CN)4] x THF, orthorhombic, Pnma, a = 13.908(3) A, b = 9.288(1) A, c = 8.738(1) A, Z= 4; [NH4][B(CN)4] x THF, orthorhombic, Pnma, a = 8.831(1) A, b = 9.366(2) A, c = 15.061(3) A, Z= 4. The cubic Li+, Na+, and Cu+ salts crystallize in a structure consisting of two interpenetrating independent tetrahedral networks of M cations and [B(CN)4]- ions. The compounds with the larger countercations (Rb+, Cs+, Tl+, and [NH4]+) crystallize as tetragonal, also with a network arrangement. The sodium and ammonium salts with the cocrystallized THF molecules are both orthorhombic but are not isostructural. In the vibrational spectra the two CN stretching modes A1 and T2 coincide in general and the band positions are a measure for the strength of the interionic interaction. An interesting feature in the Raman spectrum of the copper salt is the first appearance of two CN stretching modes.     

Synthesis and characterization of benzoxazine-functionalized amine bridged bis(phenolate) lanthanide complexes and their application in the ring-opening polymerization of cyclic esters

The synthesis and structures of lanthanide complexes supported by benzoxazine-functionalized amine bridged bis(phenolate) ligand 6,6'-(2-(8-tert-butyl-6-methyl-2H-benzo[e][1,3]oxazin-3(4H)-yl)ethylazanediyl)bis(methylene)bis(2-tert-butyl-4-methylphenolato) (L(2-)) are described. Salt metathesis reaction between lanthanide trichloride and 2 eq of LNa(2) in THF at room temperature afforded the corresponding "ate" complexes [L(2)LnNa(THF)(2)] (Ln[double bond, length as m-dash]Y (1), Nd (2), Er (3), Yb (4)). Further treatment of the product with 18-crown-6 afforded discrete ion-pair complexes [L(2)Ln][(18-crown-6)Na(THF)(2)] (Ln[double bond, length as m-dash]Y (5), Yb (6)). The single-crystal structural analyses of 1 and 3-6 revealed that the lanthanide cation and the sodium cation were bridged by two phenolate oxygen atoms in complexes 1, 3 and 4, while in complexes 5 and 6, the anion comprises a lanthanide cation coordinated by two L(2-) and the cation is comprised of a sodium cation surrounded by an 18-crown-6 and two THF molecules. These complexes were found to exhibit distinct activities towards the ring-opening polymerization of ε-caprolactone and l-lactide.     

Iodide, azide, and cyanide complexes of (N,C), (N,N), and (N,O) metallacycles of tetra- and pentavalent uranium

In contrast to the neutral macrocycle [UN*(2)(N,C)] (1) [N* = N(SiMe(3))(3); N,C = CH(2)SiMe(2)N(SiMe(3))] which was quite inert toward I(2), the anionic bismetallacycle [NaUN*(N,C)(2)] (2) was readily transformed into the enlarged monometallacycle [UN*(N,N)I] (4) [N,N = (Me(3)Si)NSiMe(2)CH(2)CH(2)SiMe(2)N(SiMe(3))] resulting from C-C coupling of the two CH(2) groups, and [NaUN*(N,O)(2)] (3) [N,O = OC(═CH(2))SiMe(2)N(SiMe(3))], which is devoid of any U-C bond, was oxidized into the U(V) bismetallacycle [Na{UN*(N,O)(2)}(2)(μ-I)] (5). Sodium amalgam reduction of 4 gave the U(III) compound [UN*(N,N)] (6). Addition of MN(3) or MCN to the (N,C), (N,N), and (N,O) metallacycles 1, 4, and 5 led to the formation of the anionic azide or cyanide derivatives M[UN*(2)(N,C)(N(3))] [M = Na, 7a or Na(15-crown-5), 7b], M[UN*(2)(N,C)(CN)] [M = NEt(4), 8a or Na(15-crown-5), 8b or K(18-crown-6), 8c], M[UN*(N,N)(N(3))(2)] [M = Na, 9a or Na(THF)(4), 9b], [NEt(4)][UN*(N,N)(CN)(2)] (10), M[UN*(N,O)(2)(N(3))] [M = Na, 11a or Na(15-crown-5), 11b], M[UN*(N,O)(2)(CN)] [M = NEt(4), 12a or Na(15-crown-5), 12b]. In the presence of excess iodine in THF, the cyanide 12a was converted back into the iodide 5, while the azide 11a was transformed into the neutral U(V) complex [U(N{SiMe(3)}SiMe(2)C{CHI}O)(2)I(THF)] (13). The X-ray crystal structures of 4, 7b, 8a-c, 9b, 10, 12b, and 13 were determined.     

Coordination chemistry of novel scorpionate ligands based on 3-cyclohexylpyrazole and 3-cyclohexyl-4-bromopyrazole

The ligands [hydrotris(3-cyclohexylpyrazol-1-yl)borate, [Tp(Cy)](-), tetrakis(3-cyclohexylpyrazol-1-yl)borate, [pz(o)Tp(Cy)](-), and hydrotris(3-cyclohexyl-4-bromopyrazol-1-yl)borate, [Tp(Cy,4Br)](-) were synthesized and characterized as their Tl(I) derivatives. They were converted to a variety of tetrahedral LMX and octahedral LML' complexes, as well as to the dinuclear nickel carbonate complex [Ni(Tp(Cy))](2)(CO(3)), 4, and the compound Ni[Tp(Cy,4Br)][pz(Cy,4Br)](3)(H)(2), 5. The structures of Co[Tp(Cy)]Cl, 1, Co[Tp(Cy,4Br)]Cl, 2, Co[Tp(Cy,4Br)]NCS, 3, [Ni(Tp(Cy))](2)(CO(3)), 4, Ni[Tp(Cy,4Br)][pz(Cy,4Br)](3)(H)(2), 5, and Mo[Tp(Cy)](CO)(2)(eta(3)-methallyl), 6, were determined by X-ray crystallography. The structures of paramagnetic heteroleptic complexes Co[Tp(Cy)][Tp], Co[Tp(Cy)][Tp], Co[Tp(Cy,4Br)][Tp], and Co[Tp(Cy,4Br)][Tp] were established by NMR. The homoleptic compounds Co[Tp(Cy)](2) and Co[Tp(Cy,4Br)](2) rearrange thermally to Co[Tp(Cy)](2) and to Co[Tp((Cy,4Br))](2), respectively, containing one 5-cyclohexyl group/ligand.     

Synthesis, characterization, and chiral properties of CoIII2AgI3 pentanuclear, CoIII4ZnII4 octanuclear, and CoIII mononuclear complexes with aza-capped hexadentate-N3S3 thiolate ligands: crystal structures of

The reaction of an S-bridged Co2(III)Ag3(I) pentanuclear complex, [Ag3[Co(aet)3]2][BF4]3 (aet = NH2CH2CH2S-), with paraformaldehyde in basic acetonitrile, followed by adding aqueous ammonia, produced an aza-capped Co2(III)-Ag3(I) complex, [Ag3[Co(L)]2]3+ ([1]3+) (L = N(CH2NHCH2CH2S-)3). The crystal structure of [1]3+ was determined by X-ray crystallography. [1][PF6]3 x H2O, empirical formula C18H44Ag3Co2F18N8OP3S6, crystallizes in the tetragonal space group 142m with a = 13.012(1) A, c = 24.707(2) A, and Z = 4. In [1]3+ the two aza-capped [Co(L)] units are linked by three Ag(I) atoms, such that the two Co(III) atoms are encapsulated in a macrobicyclic metallocage, [Ag3(I)(L)2]3-. [1]3+ was converted to an aza-capped Co4(III)Zn4(II) octanuclear complex, [Zn4O[Co(L)]4]6+ ([2]6+), by reaction with I- in the presence of Zn2+ and ZnO in water. The crystal structure of [2]6+ was also determined by X-ray crystallography. [2][PF6]6 x 8H2O, empirical formula C36H100Co4F36N16O9P6S12Zn4, crystallizes in the monoclinic space group P2(1/n) with a = 14.33(7) A, b = 25.67(10) A, c = 24.83(6) A, beta = 101.3(3) degrees , and Z = 4. In [2]6+ each of four [Co(L)] units is bound to each trigonal Zn3(II) face of the tetrahedral [Zn4(II)O]6+ core, such that each Co(III) atom is encapsulated in a macrobicyclic [Zn4(II)O(L)] fragment. Treatment of [2]6+ with a basic aqueous solution resulted in a cleavage of the Zn-S bonds to produce an aza-capped Co(III) mononuclear complex, [Co(L)] ([3]), from which [1]3+ is readily reproduced by the reaction with Ag+ in water. All the reactions were found to proceed with retention of the absolute configuration (delta or lambda) of the Co(III) chiral centers; deltadelta-[1]3+, deltadeltadeltadelta-[2]6+, and A-[3] were derived from deltadelta-[Ag3[Co(aet)3]2]3+. The contributions to circular dichroism (CD) from the triple helicity in [1]3+, besides from the asymmetric N and S donor atoms and the Co(III) chiral centers in [1]3+ and [2]6+, were estimated by comparing the CD spectra of deltadelta-[1]3+, deltadeltadeltadelta-[2]6+, and delta-[3].     

Thallium(I) sandwich, multidecker, and ether complexes stabilized by weakly-coordinating anions: a spectroscopic, structural, and theoretical investigation

The reaction of thallium ethoxide with [H(OEt2)2][H2N{B(C6F5)3}2] in diethyl ether afforded [Tl(OEt2)3][H2N{B(C6F5)3}2] (2a), [Tl(OEt2)4][H2N{B(C6F5)3}2] (2b), or [Tl(OEt2)2][H2N{B(C6F5)3}2].CH2Cl2 (2c), depending on the reaction conditions. The dication in the hydrolysis product [Tl4(mu3-OH)2][H2N{B(C6F5)3}2]2.4CH2Cl2 consists of two bridging and two terminal Tl+ ions bound to triply bridging hydroxides. Heating Et2O complexes in toluene afforded [Tl(eta6-toluene)n][H2N{B(C6F5)3}2] (4, n = 2, 3), while C6Me6 addition gave the first thallium-C6Me6 adduct, [Tl(eta6-C6Me6)2][H2N{B(C6F5)3}2].1.5CH2Cl2 (5a), a bent sandwich complex with very short Tl...centroid distances. These arene complexes show no close contacts between cations and anions. Displacement of toluene ligands by ferrocene gave [Tl2(FeCp2)3][H2N{B(C6F5)3}2]2.5CH2Cl2 (6) which contains the multidecker cations [Tl(FeCp2)]+ and [Tl(FeCp2)2]+ in a 1:1 ratio. By contrast, decamethylferrocene leads to electron transfer; the isolable thallium-ferrocene complexes may therefore be viewed as precursor complexes for this redox step. With 18-crown-6 the complexes [Tl(18-crown-6)2][H2N{B(C6F5)3}2] (11a) and [Tl(18-crown-6)][H2N{B(C6F5)3}2].2CH2Cl2 (11b) were isolated. The structure of the latter shows an eight-coordinate thallium ion, where the coordination to the six oxygen donors in equatorial positions is completed by axial contacts to two F atoms of the counter anions. The bonding between thallium(I) and arenes was explored by density-functional theory (DFT) calculations. The optimized geometry of [Tl(tol)3]+ converged to a structure very similar to that obtained experimentally. Calculations on [Tl(C6Me6)2]+ (5b) to establish whether a linear or bent geometry is the most stable revealed a very flat potential-energy surface for distortions of the Ctr(3)-Tl-Ctr(4) angle. Overall, there is very little energetic preference for one particular geometry over another above about 140 degrees , in good agreement with the crystallographic geometry. The calculated Tl-arene interaction energies increase from 73.7 kJ mol-1 for toluene to 121.7 kJ mol-1 for C6Me6.     

Heteroleptic bis(phthalocyaninato) europium(III) complexes fused with different numbers of 15-crown-5 moieties. Synthesis, spectroscopy, electrochemistry, and supramolecular structure

A series of heteroleptic bis(phthalocyaninato) europium(III) complexes, namely, Eu(Pc)[Pc(15C5)] (2), Eu(Pc)[Pc(opp-15C5)2] (3), Eu(Pc)[Pc(adj-15C5)2] (4), Eu(Pc)[Pc(15C5)3] (5), and Eu(Pc)[Pc(15C5)4] (6) [Pc = unsubstituted phthalocyaninate; Pc(15C5) = 2,3-(15-crown-5)phthalocyaninate; Pc(opp-15C5)2 = 2,3,16,17-bis(15-crown-5)phthalocyaninate; Pc(adj-15C5)2 = 2,3,9,10-bis(15-crown-5)phthalocyaninate; Pc(15C5)3 = 2,3,9,10,16,17-tris(15-crown-5)phthalocyaninate, Pc(15C5)4 = 2,3,9,10,16,17,24,25-tetrakis(15-crown-5)phthalocyaninate], with one, two, three, and four 15-crown-5 voids attached at different positions of one of the two phthalocyaninato ligands in the double-decker molecules, have been devised and prepared by Eu(Pc)(acac)-induced (Hacac = acetylacetone) mixed cyclization of the two corresponding phthalonitriles in the presence of organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in n-pentanol. For the purpose of comparative studies, homoleptic counterparts Eu(Pc)2 (1) and Eu[Pc(15C5)4]2 (7) have also been prepared. These sandwich double-decker complexes have been characterized by a wide range of spectroscopic methods in addition to elemental analysis. Their electrochemistry has also been studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The molecular structure of Eu(Pc)[Pc(15C5)4] (6) has been determined by X-ray diffraction analysis. Their supramolecular structure-formation properties, in particular for compounds 5 and 6 in the presence of potassium ions, have also been comparatively studied for the purpose of future functional investigation.     

Simultaneous separation of common mono- and divalent cations on a calcinated silica gel column by ion chromatography with indirect photometric detection and aromatic monoamines-oxalic acid,containing crown ethers,used as eluent

The application of unmodified silica gel (Super Micro Bead Silica Gel B-5, SMBSG B-5) as a cation-exchange stationary phase in ion chromatography with indirect photometric detection (IC-IPD) for the separation of common mono- and divalent cations (Li+, Na+, NH4+, K+, Mg2+ and Ca2+) was carried out using various aromatic monoamines [tyramine [4-(2-aminoethyl)phenol], benzylamine, phenylethylamine, 2-methylpyridine and 2,6-dimethylpyridine] as eluents. When using these amines as eluents, the peak resolution between these mono- and divalent cations was not quite satisfactory and the peak shapes of NH4+ and K+ were largely destroyed on the SMBSG B-5 silica gel column. Hence, the application of SMBSG B-5 silica gel calcinated at 200, 400, 600, 800 and 1000 degrees C for 5 h in the IC-IPD was carried out. The peak shapes of the monovalent cations were greatly improved with increasing calcination temperature and, as a result, symmetrical peaks of these mono- and divalent cations were obtained on the SMBSG B-5 silica gel calcinated at 1000 degrees C as the stationary phase. In contrast, the peak resolution between these mono- and divalent cations was not improved. Therefore, crown ethers [18-crown-6 (1,4,7,10,13,15-hexaoxacyclooctadecane), 15-crown-5 (1,4,7,10,13-pentaoxacyclopentadecane)] were added to the eluent for the complete separation of these mono- and divalent cations. Excellent simultaneous separation and highly sensitive detection at 275 nm were achieved in 25 min on a column (150x4.6 mm I.D.) packed with SMBSG B-5 silica gel calcinated at 1000 degrees C by elution with 0.75 mM tyramine-0.25 mM oxalic acid at pH 5.0 containing either 1.0 mM 18-crown-6 or 10 mM 15-crown-5.     

Reactivity of a heterocyclic As-Se compound with metal salts: syntheses and structures of the first copper complexes and of new alkali metal salts containing As-Se anions

The structures of the new compounds [Cu8(Ph2As2Se2)2(PhAsSe2)2(dppm)4] (1) (dppm = bis-diphenylphosphinomethane), [Cu4(Ph2As2Se2)2(PPh3)4] (2), [{K(18-crown-6)}2(PhAsSe3)] (3), [Na12(PhAsSe3)6(15-crown-5)6] (4) and 1/x[Na2(PhAsSe3)(thf)(H2O)3]x (5) are reported. 2-5 were prepared by reactions of metal thiolates with [(PhAs)2(mu-Se)(mu-Se2)].     

Syntheses; 77Se, 203Tl, and 205Tl NMR; and theoretical studies of the Tl2Se6(6-), Tl3Se6(5-), and Tl3Se7(5-) anions and the X-ray crystal structures of [2,2,2-crypt-Na]4[Tl4Se8].en and [2,2,2-crypt-Na]2[Tl2Se4](infinity)1.en

The 2,2,2-crypt salts of the Tl4Se8(4-) and [Tl2Se4(2-)]infinity1 anions have been obtained by extraction of the ternary alloy NaTl0.5Se in ethylenediamine (en) in the presence of 2,2,2-crypt and 18-crown-6 followed by vapor-phase diffusion of THF into the en extract. The [2,2,2-crypt-Na]4[Tl4Se8].en crystallizes in the monoclinic space group P2(1)/n, with Z = 2 and a = 14.768(3) angstroms, b = 16.635(3) angstroms, c = 21.254(4) angstroms, beta = 94.17(3) degrees at -123 degrees C, and the [2,2,2-crypt-Na]2[Tl2Se4]infinity1.en crystallizes in the monoclinic space group P2(1)/c, with Z = 4 and a = 14.246(2) angstroms, b = 14.360(3) angstroms, c = 26.673(8) angstroms, beta = 99.87(3) degrees at -123 degrees C. The TlIII anions, Tl2Se6(6-) and Tl3Se7(5-), and the mixed oxidation state TlI/TlIII anion, Tl3Se6(5-), have been obtained by extraction of NaTl0.5Se and NaTlSe in en, in the presence of 2,2,2-crypt and/or in liquid NH3, and have been characterized in solution by low-temperature 77Se, 203Tl, and 205Tl NMR spectroscopy. The 1J(203,205Tl-77Se) and 2J(203,205Tl-203,205Tl) couplings of the three anions have been used to arrive at their solution structures by detailed analyses and simulations of all spin multiplets that comprise the 205,203Tl NMR subspectra arising from natural abundance 205,203Tl and 77Se isotopomer distributions. The structure of Tl2Se6(6-) is based on a Tl2Se2 ring in which each thallium is bonded to two exo-selenium atoms so that these thalliums are four-coordinate and possess a formal oxidation state of +3. The Tl4Se8(4-) anion is formally derived from the Tl2Se6(6-) anion by coordination of each pair of terminal Se atoms to the TlIII atom of a TlSe+ cation. The structure of the [Tl2Se4(2-)]infinity1 anion is comprised of edge-sharing distorted TlSe4 tetrahedra that form infinite, one-dimensional [Tl2Se42-]infinity1 chains. The structures of Tl3Se6(5-) and Tl3Se7(5-) are derived from Tl4Se4-cubes in which one thallium atom has been removed and two and three exo-selenium atoms are bonded to thallium atoms, respectively, so that each is four-coordinate and possesses a formal oxidation state of +3 with the remaining three-coordinate thallium atom in the +1 oxidation state. Quantum mechanical calculations at the MP2 level of theory show that the Tl2Se6(6-), Tl3Se6(5-), Tl3Se7(5-), and Tl4Se8(4-) anions exhibit true minima and display geometries that are in agreement with their experimental structures. Natural bond orbital and electron localization function analyses were utilized in describing the bonding in the present and previously published Tl/Se anions, and showed that the Tl2Se6(6-), Tl3Se6(5-), Tl3Se7(5-), and Tl4Se8(4-) anions are electron-precise rings and cages.     

二维网状冠醚配合物－苯并15－冠－5、二苯并18－冠－6与Na_2[Pt(SCN)_6]配合物的合成与结构

合成了苯并15-冠-5、二苯并18-冠-6与Na_2[Pt(SCN)_6]的配合物：[Na(B15- C-5)]_2[Pt(SCN)_6] (1),[Na(DB18-C-6)]_2[Pt(SCN)_6] (2),并通过元素分析 、红外光谱、单晶X射线衍射进行了表征。1为单斜晶系,空间群P2_1/c,a = 1. 0974(5) nm,b = 1.5187(7) nm,c = 1.3632(6) nm,β = 96.407(7)°,V = 2. 2568(18) nm~3,Z = 2,D_(calcd) = 1.746 g/cm~3,F(000) = 1184,R_1 = 0. 0357,wR_2 = 0.0868。 2为三斜晶系,空间群 P1-bar,a = 1.2500(3) nm,b = 1.2825(3) nm,c = 1.9342(4) nm,α = 106.82(3)°,β = 102.51(3)°,γ = 103.04(3)°,V = 2.7562 nm~3,Z = 2,D_(calcd) = 1.579 g/cm~3,F(000) = 1316,R_1 = 0.0364,wR_2 = 0.0771。配合物分别由两个[Na(B15-C-5)]~+, [Na(DB18-C-6)]~+配阳离子和一个[Pt(SCN)_6]~(2-)配阴离子组成。配阳离子和配 阴离子通过Na-N键形成二维网状结构。     

New 13-vertex metallacarborane sandwich compounds; synthetic and structural studies

Reduction of 1,12-closo-C2B10H12 followed by reaction with the appropriate metal halide and metathesis with either [K(18-crown-6)]Br or [BTMA]Cl ([BTMA] = [C6H5CH2N(CH3)3]+) affords isolable salts of the supraicosahedral metallacarborane sandwich anions [4,4-M-(1,10-closo-C2B10H12)2]n- in moderate to good yield. Compounds prepared are [BTMA][4,4-Co-(1,10-closo-C2B10H12)2] ( 1), [K(18-crown-6)][4,4-Co-(1,10-closo-C2B10H12)2] ( 2), [K(18-crown-6)]2[4,4-Ni-(1,10-closo-C2B10H12)2] ( 3), [K(18-crown-6)]2[4,4-Fe-(1,10-closo-C2B10H12)2] ( 4), [BTMA]2[4,4-Fe-(1,10-closo-C2B10H12)2] ( 5) and [K(18-crown-6)]2[4,4-Ti-(1,10-closo-C2B10H12)2] ( 6). Oxidation of the iron(II) species 4 and 5 with FeCl3 in THF generates the iron(III) analogues [K(18-crown-6)][4,4-Fe-(1,10-closo-C2B10H12)2] ( 7) and [BTMA][4,4-Fe-(1,10-closo-C2B10H12)2] ( 8), respectively. All diamagnetic compounds were characterised spectroscopically and the structures of 1, 3, 4, 6, 7 and 8 were established by single crystal X-ray diffraction. All anions have the anticipated cluster structures with two docosahedral 13-vertex cages joined at the central metal atom (the common degree-six vertex 4). Carbon atoms occupy the degree-four vertex 1 and the degree-five vertex 10. 11B NMR spectroscopy suggests the anions have, on the NMR timescale, C2h symmetry in solution at room temperature, consistent with free rotation, or at least substantial libration, of cage units about the long molecular axis. In the solid state the relative conformations of the two cages may be rationalised by simple bonding arguments, the single exception being the conformation of 4, in which both cages are subject to directional B-H...K+ interactions to the [K(18-crown-6)]+ counterion. The salts 3, 6 and 7 also show B-H...K+ interactions but involving one cage only.     

The coordination chemistry of the hydrotris(3-diphenylmethylpyrazol-1-yl)borate (Tp(CHPh2)) ligand

The new ligand, hydrotris[3-(diphenylmethyl)pyrazol-1-yl]borate, Tp(CHPh2), has been synthesized and its coordination chemistry was compared with that of the analogous Tp(iPr). The new ligand was converted to a variety of complexes, such as M[Tp(CHPh2)]X (M = Co, Ni, Zn; X = Cl, NCO, NCS), Pd[Tp(CHPh2)][eta3-methallyl], Co[Tp(CHPh2)](acac), and Co[Tp(CHPh2)](scorpionate ligand). Compounds Tl[Tp(CHPh2)], 1, Co[Tp(CHPh2)]Cl, 2, Co[Tp(CHPh2)](NCS)(DMF), 3, Ni[Tp(CHPh2)](NCS)(DMF)2, 4, Co[Tp(CHPh2)](acac), 5, Co[Tp(CHPh2)][Ph2Bp], 6, Co[Tp(CHPh2)][Bp(Ph)], 7, Co[Tp(CHPh2)][Tp], 8, and (Ni[Tp(CHPh2)])2[C2O4](H2O)2, 9, were structurally characterized.     

Salts of the cobalt(I) complexes [Co(CO)5]+ and [Co(CO)2(NO)(2)]+ and the Lewis acid-base adduct [Co2(CO)7CO--B(CF3)3

The reaction of [Co(2)(CO)(8)] with (CF(3))(3)BCO in hexane leads to the Lewis acid-base adduct [Co(2)(CO)(7)CO--B(CF(3))(3)] in high yield. When the reaction is performed in anhydrous HF solution [Co(CO)(5)][(CF(3))(3)BF] is isolated. The product contains the first example of a homoleptic metal pentacarbonyl cation with 18 valence electrons and a trigonal-bipyramidal structure. Treatment of [Co(2)(CO)(8)] or [Co(CO)(3)NO] with NO(+) salts of weakly coordinating anions results in mixed crystals containing the [Co(CO)(5)](+)/[Co(CO)(2)(NO)(2)](+) ions or pure novel [Co(CO)(2)(NO)(2)](+) salts, respectively. This is a promising route to other new metal carbonyl nitrosyl cations or even homoleptic metal nitrosyl cations. All compounds were characterized by vibrational spectroscopy and by single-crystal X-ray diffraction.     

Weak carbon-hydrogen-nitrogen interactions affect the heterocyclic ligand bonding modes in barium complexes containing eta2-tetrazolato and eta2-pentazolato ligands

Treatment of Ba[N(SiMe3)2]2(THF)2 with 2 equiv of dimethylaminotetrazole or diisopropylaminotetrazole and 1 equiv of 18-crown-6 afforded Ba[CN4(NMe2)]2(18-crown-6) (87%) and Ba[CN4(NiPr2)]2(18-crown-6) (79%) as colorless crystalline solids. Ba[CN4(NMe2)]2(18-crown-6) contains two 1,2-eta2-tetrazolato ligands and one eta6-18-crown-6 ligand. The molecular structure of Ba[CN4(NiPr2)]2(18-crown-6) is similar to that of Ba[CN4(NMe2)]2(18-crown-6), except that the tetrazolato ligands exhibit the isomeric 2,3-eta2-coordination mode and the tetrazolato ligand CN4 cores are bent significantly toward the 18-crown-6 ligands. Molecular orbital calculations were carried out on the model complexes Ba(azolate)2(18-crown-6) (azolate = 1,2-eta2-CHN4, 2,3-eta2-CHN4, and eta2-N5) and demonstrate that the ligand coordination modes are influenced by intramolecular interactions between filled nitrogen orbitals on the azolato ligands and empty C-H sigma* orbitals on the 18-crown-6 ligands.     

Synthesis, Properties, and Crystal Structures of Benzene-1,2-dithiolato Complexes of Thallium(I) and -(III)

The syntheses, molecular structures and properties of homoleptic 1,2-S(2)C(6)H(4) complexes of thallium(I) and thallium(III) with four-coordinated metal centers are described. Anaerobic treatment of TlCl, TlNO(3), or Tl(2)CO(3) with solutions of sodium methanolate and 1,2-(HS)(2)C(6)H(4) in methanol gave after metathesis with [NEt(4)]Br yellow solutions of [NEt(4)](2)[{Tl(1,2-(&mgr;-S)(2)C(6)H(4))}(2)] ([NEt(4)](2)1). Yellow single crystals were obtained from saturated acetone solutions at -10 degrees C and the crystal data for [NEt(4)](2)1 are monoclinic, P2(1)/c, with Z = 2, a = 7.440(1) ?, b = 16.373(3) ?, c = 13.201(2) ?, and beta = 97.08(1) degrees. Complex 1(2)(-)(), the first structurally characterized homoleptic ionic thiolate complex of thallium(I), contains rectangular bipyramidal [TlS(4)Tl] cages with the four sulfur atoms defining the equatorial plane and the two thallium atoms in axial positions. The S(2)C(6)H(4) fragments are almost coplanar with the S(4) plane. In the crystal lattice, nearly linear Tl.Tl chains align along the a-axis (offset ca. 3.0 degrees ) with the ligand planes parallel to the bc-plane. Within and between dimers short Tl.Tl distances are observed (Tl.Tl' within a dimeric unit, 3.5116(4) ?; Tl.Tl between dimeric units, 3.9371(3) ?) with the distance between dimeric units being the shortest contact between anions-Tl.S distances between dimeric units are longer than 5.8 ?. Aerobic treatment of TlCl, TlNO(3), or Tl(2)CO(3) with solutions of sodium methanolate and 1,2-(HS)(2)C(6)H(4) in methanol and metathesis with [NEt(4)]Br led to [NEt(4)][Tl(1,2-S(2)C(6)H(4))(2)] ([NEt(4)]2). Yellow single crystals were obtained from saturated acetone solutions at 0 degrees C and the crystal data for [NEt(4)]2 are orthorhombic, Pnn2, with Z = 2, a = 11.449(2) ?, b = 10.060(2) ?, c = 9.950(2) ?. Complex 2(-) is the first homoleptic four-coordinate thiolate of thallium(III) and contains the unusually short Tl-S distance of 2.469(4) ?. In solution, ion pairing results in chemical and magnetic inequivalence of the S(2)C(6)H(4) ligands. Although both preparations employ the reaction of thallium(I) salts with 1,2-(NaS)(2)C(6)H(4) in a 1:2 stoichiometry, complex 1(2)(-) is probably not an intermediate to the formation of 2(-). Exposing anaerobically prepared solutions of 1(2)(-) to air results in a series of color changes in the solution over a 20 min period; however, 2(-) could not be observed by NMR spectroscopy.     

Homoleptic diphosphacyclobutadiene complexes [M(η(4)-P2C2R2)2]x- (M = Fe, Co; x = 0, 1)

The preparation and comprehensive characterization of a series of homoleptic sandwich complexes containing diphosphacyclobutadiene ligands are reported. Compounds [K([18]crown-6)(thf)(2)][Fe(η(4)-P(2)C(2)tBu(2))(2)] (K1), [K([18]crown-6)(thf)(2)][Co(η(4)-P(2)C(2)tBu(2))(2)] (K2), and [K([18]crown-6)(thf)(2)][Co(η(4)-P(2)C(2)Ad(2))(2)] (K3, Ad = adamantyl) were obtained from reactions of [K([18]crown-6)(thf)(2)][M(η(4)-C(14)H(10))(2)] (M = Fe, Co) with tBuC[triple bond]P (1, 2), or with AdC[triple bond]P (3). Neutral sandwiches [M(η(4)-P(2)C(2)tBu(2))(2)] (4: M = Fe 5: M = Co) were obtained by oxidizing 1 and 2 with [Cp(2)Fe]PF(6). Cyclic voltammetry and spectro-electrochemistry indicate that the two [M(η(4)-P(2)C(2)tBu(2))(2)](-)/[M(η(4)-P(2)C(2)tBu(2))(2)] moieties can be reversibly interconverted by one electron oxidation and reduction, respectively. Complexes 1-5 were characterized by multinuclear NMR, EPR (1 and 5), UV/Vis, and M?ssbauer spectroscopies (1 and 4), mass spectrometry (4 and 5), and microanalysis (1-3). The molecular structures of 1-5 were determined by using X-ray crystallography. Essentially D(2d)-symmetric structures were found for all five complexes, which show the two 1,3-diphosphacyclobutadiene rings in a staggered orientation. Density functional theory calculations revealed the importance of covalent metal-ligand π bonding in 1-5. Possible oxidation state assignments for the metal ions are discussed.     

Properties of the polyhydride anions [WH5(PMe2Ph)3]- and [ReH4(PMePh2)3]- and periodic trends in the acidity of polyhydride complexes

The new anionic complexes [K(18-crown-6)][WH5(PMe2Ph)3], [K(1,10-diaza-18-crown-6)][WH5(PMe2Ph)3], [K(2,2,2-crypt)][ReH4(PMePh2)3], and [K(1,10-diaza-18-crown-6)][ReH4(PMePh2)3] were prepared by reaction of KH/crown or KH/crypt with the appropriate neutral polyhydride WH6(PMe2Ph)3 or ReH5(PMePh2)3. The rate of deprotonation of the rhenium hydride in THF is much greater for the reaction involving crypt compared with that of crown. The structure of [ReH4(PMePh2)3]- is distorted pentagonal bipyramidal as determined by an X-ray diffraction study of the crypt salt. No hydridic-protonic M-H...HN bonding is detected between the hydrides of the anionic hydrides and the amino hydrogens of the cations [K(1,10-diaza-18-crown-6)]+ suggesting that stronger M-H...K interactions are present. Acid dissociation constants Ka of polyhydride complexes in THF, approximately corrected for ion pairing, are determined by NMR in order to better understand the periodic trends of metal hydrides. The pKalphaTHF of (WH6(PMe2Ph)3/[WH5(PMe2Ph)3]-) is 42+/-4 according to the equilibrium set up by reacting WH6(PMe2Ph)3 with [K(2,2,2-crypt)][ReH6(PCy3)2]. The pKalphaTHF for ReH5(PMePh2)3 can be estimated as greater than the pKalphaTHF of 38 for HNPh2 and less than the pKalphaTHF of 41 for ReH7(PCy3)2. Reaction of the phosphazene base P4-tBu with ReH7(PCy3)2 gave an equilibrium with [HP4-tBu]+[ReH6(PCy3)2]- whereas reaction with WH6(PMe2Ph)3 gave an equilibrium with [HP4-tBu]+[WH5(PMe2Ph)3]-. From these and a related equilibrium, the pKalphaTHF of [HP4-tBu]+ is found to be 40+/-4. In general, neutral complexes MHx(PR3)n (M=W, Re, Ru, Os, Ir; n=3, 2) studied to date have pKalphaTHF values from 30 to 44 on going from phenyl-substituted to alkyl-substituted phosphine ligands whereas MHx(PR3)n+ (M=Re, Fe, Ru, Os, Co, Rh, Ni, Pd, Pt; n=4, 3), including diphosphine ligands ((PR3)2=PR2-PR2), have values from 12 to 23. From the equilibrium established from the reaction of [HP2-tBu][BPh4] and [K(2,2,2-crypt)][OP(OEt)2NPh], [HP2-tBu]+ was calculated to have a pKalphaTHF of 30+/-4. The equilibrium constant for the similar deprotonation reaction with [K(18-crown-6)][{ReH2(PMePh2)2}2(mu-H)3] confirmed this value.