First examples of thallium chalcogenide cages. Syntheses, 77Se, 203Tl, and 205Tl NMR study of the Tl4Se5(4-) and Tl4Se6(4-) anions, the X-ray crystal structure of (2,2,2-crypt-K+)3Tl5Se5(3-), and theoretical studies

The Tl5Se5(3-) anion has been obtained by extracting KTlSe in ethylenediamine in the presence of 2,2,2-crypt. The salt, (2,2,2-crypt-K+)3Tl5Se5(3-), crystallizes in the triclinic system, space group P1, with Z = 2 and a = 11.676(2) A, b = 16.017(3) A, c = 25.421(5) A, alpha = 82.42(3) degrees, beta = 88.47(3) degrees, gamma = 69.03(3) degrees at -123 degrees C. Two other mixed oxidation state TlI/TlIII anions; Tl4Se5(4-) and Tl4Se6(4-), have been obtained by extracting KTlSe into liquid NH3 in the presence of 2,2,2-crypt and have been characterized in solution by low-temperature 77Se, 203Tl, and 205Tl NMR spectroscopy and were shown to exist as a 1:1 equilibrium mixture at -40 degrees C. The couplings, 1J(203,205Tl-77Se) and 2J(203,205Tl-203,205Tl), have been observed for Tl4Se5(4-) and Tl4Se6(4-) and have been used to arrive at the solution structures of both anions. Structural assignments were achieved by detailed analyses and simulations of all spin multiplets that comprise the 205,203Tl NMR spectra and that arise from natural abundance 205,203Tl and 77Se or enriched 77Se isotopomer distributions. The structures of all three anions are based on a Tl4Se4 cube in which Tl and Se atoms occupy alternate corners. There are one and two exo-selenium atoms bonded to thallium in Tl4Se5(4-) and Tl4Se6(4-), respectively, so that these thalliums are four-coordinate and possess a formal oxidation state of +3 and the remaining three-coordinate thallium atoms are in the +1 oxidation state. The structure of Tl5Se5(3-) may be formally regarded as an adduct in which Tl+ is coordinated to the unique exo-selenium and to two seleniums in a cube face containing the TlIII atom. The Tl4Se5(4-), Tl4Se6(4-), and Tl5Se5(3-) anions and the presently unknown, but structurally related, Tl4Se4(4-) anion can be described as electron-precise cages. Ab initio methods at the MP2 level of theory show that Tl4Se5(4-), Tl4Se6(4-), and Tl5Se5(3-) exhibit true minima and display geometrical parameters that are in excellent agreement with their experimental cubanoid structures, and that Tl4Se4(4-) is cube-shaped (Td point symmetry). The gas-phase energetics associated with plausible routes to the formation and interconversions of these anions have been determined by ab initio methods and assessed. It is proposed that all three cubanoid anions are derived from the known Tl2Se2(2-), TlSe3(3-), Se2(2-), and polyselenide anions that have been shown to be present in the solutions they are derived from.     

203,205Tl NMR studies of crystallographically characterized thallium alkoxides. X-ray Structures of [TI(OCH2CMe3)]4 and [TI(OAr)]infinity, where OAr = OC6H3(Me)2-2,6 and OC6H3(CHMe2)2-2,6

[Tl(OCH2Me)]4 (1) was reacted with excess HOR to prepare a series of [Tl(OR)]n, where OR = OCHMe2 (2, n = 4), OCMe3 (3, n = 4), OCH2CMe3 (4, n = 4), OC6H3(Me)2-2,6 (5, n = infinity), and OC6H3(CHMe2)2-2,6 (6, n = infinity). Single-crystal X-ray diffraction experiments revealed that in the solid state the alkoxide-ligated compound 4 adopts a cubane structure, whereas the aryloxide derivatives, 5 and 6, formed polymeric chains. Compounds 1-6 were also characterized by 203,205Tl solution and 205Tl solid-state NMR spectroscopy. In solution it was determined that 1-4 retained the [Tl-O]4 cube structure, whereas the polymeric species 5 and 6 appeared to be fluxional. Variations in the solution and solid-state structures for the [Tl(OR)]4 cubes and polymeric [Tl(OAr)]infinity are influenced by the steric hindrance of the ligand. The acidity of the parent alcohol influences the degree of covalency at the Tl metal center, which is reflected in the 203,205Tl chemical shifts for 1-6.     

Synthesis, Structure, and Reactivities of [eta(2)-P(7)M(CO)(4)](3)(-), [eta(2)-HP(7)M(CO)(4)](2)(-), and [eta(2)-RP(7)M(CO)(4)](2)(-) Zintl Ion Complexes Where M = Mo, W

Ethylenediamine (en) solutions of [eta(4)-P(7)M(CO)(3)](3)(-) ions [M = W (1a), Mo (1b)] react under one atmosphere of CO to form microcrystalline yellow powders of [eta(2)-P(7)M(CO)(4)](3)(-) complexes [M = W (4a), Mo (4b)]. Compounds 4 are unstable, losing CO to re-form 1, but are highly nucleophilic and basic. They are protonated with methanol in en solvent giving [eta(2)-HP(7)M(CO)(4)](2)(-) ions (5) and are alkylated with R(4)N(+) salts in en solutions to give [eta(2)-RP(7)M(CO)(4)](2)(-) complexes (6) in good yields (R = alkyl). Compounds 5 and 6 can also be prepared by carbonylations of the [eta(4)-HP(7)M(CO)(3)](2)(-) (3) and [eta(4)-RP(7)M(CO)(3)](2)(-) (2) precursors, respectively. The carbonylations of 1-3 to form 4-6 require a change from eta(4)- to eta(2)-coordination of the P(7) cages in order to maintain 18-electron configurations at the metal centers. Comparative protonation/deprotonation studies show 4 to be more basic than 1. The compounds were characterized by IR and (1)H, (13)C, and (31)P NMR spectroscopic studies and microanalysis where appropriate. The [K(2,2,2-crypt)](+) salts of 5 were characterized by single crystal X-ray diffraction. For 5, the M-P bonds are very long (2.71(1) ?, average). The P(7)(3)(-) cages of 5 are not displaced by dppe. The P(7) cages in 4-6 have nortricyclane-like structures in contrast to the norbornadiene-type geometries observed for 1-3. (31)P NMR spectroscopic studies for 5-6 show C(1) symmetry in solution (seven inequivalent phosphorus nuclei), consistent with the structural studies for 5, and C(s)() symmetry for 4 (five phosphorus nuclei in a 2:2:1:1:1 ratio). Crystallographic data for [K(2,2,2-crypt)](2)[eta(2)-HP(7)W(CO)(4)].en: monoclinic, space group C2/c, a = 23.067(20) ?, b = 12.6931(13) ?, c = 21.433(2) ?, beta = 90.758(7) degrees, V = 6274.9(10) ?(3), Z = 4, R(F) = 0.0573, R(w)(F(2)) = 0.1409. For [K(2,2,2-crypt)](2)[eta(2)-HP(7)Mo(CO)(4)].en: monoclinic, space group C2/c, a = 22.848(2) ?, b = 12.528(2) ?, c = 21.460(2) ?, beta = 91.412(12) degrees, V = 6140.9(12) ?(3), Z = 4, R(F) = 0.0681, R(w)(F(2)) = 0.1399.     

Mixed-valent selenidoantimonates(III,V) with transition-metal complexes as counterions: solvothermal syntheses and characterization of [M(dien)2]2Sb4Se9 (M = Mn, Fe), [Co(dien)2]2Sb2Se6, and [Ni(dien)2]2Sb2Se5

Novel selenidoantimonate compounds [M(dien)2]2Sb4Se9 [M = Mn (1), Fe (2)], [Co(dien)2]2Sb2Se6 (3), and [Ni(dien)2]2Sb2Se5 (4) (dien = diethylenetriamine) were solvothermally synthesized and characterized. The unique features of compounds 1-3 are the mixed-valent anionic structures constructed by the Sb(III)Se3 trigonal pyramid and Sb(V)Se4 tetrahedron. Three Sb(III)Se3 pyramids share common corners, forming a heterocyclic Sb3Se6 moiety, and the Sb3Se6 moieties are further connected with Sb(V)Se4 tetrahedra to form the novel one-dimensional [Sb4Se9(4-)]n anionic chain in 1 and 2. The discrete [Sb2Se6]4- anion in 3 is formed by an Sb(III)Se3 trigonal pyramid and an Sb(V)Se4 tetrahedron sharing a common corner. The [Sb2Se5]4- anion in 4 is composed of two Sb(III)Se3 trigonal pyramids connected in the same manner as the [Sb2Se6]4- anion. The mixed-valent [Sb4Se9(4-)]n and [Sb2Se6]4- anions were not observed before. The synthesis and solid-state structural studies of the title compounds show that the transition-metal complexes exhibit different structure-directing effects on the formation of selenidoantimonates in dien. Extensive N-H...Se hydrogen bonds are observed between cations and anions in compounds 1-4, resulting in three-dimensional network structures. Optical and thermal properties of the compounds are reported.     

31P solid state NMR studies of metal selenophosphates containing [P2Se6]4-, [P4Se10]4-, [PSe4]3-, [P2Se7]4-, and [P2Se9]4- ligands

31P solid-state nuclear magnetic resonance (NMR) spectra of 12 metal-containing selenophosphates have been examined to distinguish between the [P(2)Se(6)](4-), [PSe(4)](3-), [P(4)Se(10)](4-), [P(2)Se(7)](4-), and [P(2)Se(9)](4-) anions. There is a general correlation between the chemical shifts (CSs) of anions and the presence of a P[bond]P. The [P(2)Se(6)](4-) and [P(4)Se(10)](4-) anions both contain a P[bond]P and resonate between 25 and 95 ppm whereas the [PSe(4)](3-), [P(2)Se(7)](4-), and [P(2)Se(9)](4-) anions do not contain a P[bond]P and resonate between -115 and -30 ppm. The chemical shift anisotropies (CSAs) of compounds containing [PSe(4)](3-) anions are less than 80 ppm, which is significantly smaller than the CSAs of any of the other anions (range: 135-275 ppm). The smaller CSAs of the [PSe(4)](3-) anion are likely due to the unique local tetrahedral symmetry of this anion. Spin-lattice relaxation times (T(1)) have been determined for the solid compounds and vary between 20 and 3000 s. Unlike the CS, T(1) does not appear to correlate with P-P bonding. (31)P NMR is also shown to be a good method for impurity detection and identification in the solid compounds. The results of this study suggest that (31)P NMR will be a useful tool for anion identification and quantitation in high-temperature melts.     

Solubility, complex formation, and redox reactions in the Tl2O3-HCN/CN(-)-H2O system. Crystal structures of the cyano compounds Tl(CN)3.H2O, Na[Tl(CN)4].3H2O, K[Tl(CN)4], and Tl(I)[Tl(III)(CN)4] and of Tl(I)2C2O4

Thallium(III) oxide can be dissolved in water in the presence of strongly complexing cyanide ions. Tl(III) is leached from its oxide both by aqueous solutions of hydrogen cyanide and by alkali-metal cyanides. The dominating cyano complex of thallium(III) obtained by dissolution of Tl2O3 in HCN is [Tl(CN)3(aq)] as shown by 205Tl NMR. The Tl(CN)3 species has been selectively extracted into diethyl ether from aqueous solution with the ratio CN-/Tl(III) = 3. When aqueous solutions of the MCN (M = Na+, K+) salts are used to dissolve thallium(III) oxide, the equilibrium in liquid phase is fully shifted to the [Tl(CN)4]- complex. The Tl(CN)3 and Tl(CN)4- species have for the first time been synthesized in the solid state as Tl(CN)3.H2O (1), M[Tl(CN)4] (M = Tl (2) and K (3)), and Na[Tl(CN)4].3H2O (4) salts, and their structures have been determined by single-crystal X-ray diffraction. In the crystal structure of 1, the thallium(III) ion has a trigonal bipyramidal coordination with three cyanide ions in the equatorial plane, while an oxygen atom of the water molecule and a nitrogen atom from a cyanide ligand, attached to a neighboring thallium complex, form a linear O-Tl-N fragment. In the three compounds of the tetracyano-thallium(III) complex, 2-4, the [Tl(CN)4]- unit has a distorted tetrahedral geometry. Along with the acidic leaching (enhanced by Tl(III)-CN- complex formation), an effective reductive dissolution of the thallium(III) oxide can also take place in the Tl2O3-HCN-H2O system yielding thallium(I), while hydrogen cyanide is oxidized to cyanogen. The latter is hydrolyzed in aqueous solution giving rise to a number of products including (CONH2)2, NCO-, and NH4+ detected by 14N NMR. The crystalline compounds, Tl(I)[Tl(III)(CN)4], Tl(I)2C2O4, and (CONH2)2, have been obtained as products of the redox reactions in the system.     

Na(23)K(9)Tl(15.3): An Unusual Zintl Compound Containing Apparent Tl(5)(7)(-), Tl(4)(8)(-), Tl(3)(7)(-), and Tl(5)(-) Anions

Reaction of the neat elements in tantalum containers at 400 degrees C and then 150 degrees C gives the pure title phase. X-ray crystallography shows that the hexagonal structure (P6(3)/mmc, Z = 2, a = 11.235(1) ?, b = 30.133(5) ?) contains relatively high symmetry clusters Tl(5)(7)(-) (D(3)(h)()), Tl(4)(8)(-) (C(3)(v)(), approximately T(d)), and the new Tl(3)(7)(-) (D(infinity)(h)()) plus Tl(5)(-), the last two disordered over the same elongated site in 1:2 proportions. Cation solvation of these anions is tight and specific, providing good Coulombic trapping of weakly bound electrons on the isolated cluster anions. The observed disorder makes the compound structurally a Zintl phase with a closed shell electron count. EHMO calculations on the novel Tl(3)(7)(-) reveal some bonding similarities with the isoelectronic CO(2), with two good sigma(s,p) bonding and two weakly bonding pi MO's. The Tl-Tl bond lengths therein (3.14 ?) are evidently consistent with multiple bonding. The weak temperature-independent paramagnetism and metallic conductivity (rho(293) approximately 90 &mgr;Omega.cm) of the phase 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.     

Syntheses and characterization of some mixed Te/Se polychalcogenide anions [Te(m)Se(n)]2-

Several mixed Te/Se polychalcogenide anions [Te(m)Se(n)](2-) were synthesized at 293 K by reactions between Te(n)(2-)and Se(n)(2-) anions in N,N-dimethylformamide (DMF) in the presence of different-size ammonium or phosphonium cations, in some cases in the presence of metal species. The structures of these anions were determined by single-crystal X-ray diffraction methods. The crystal structures of [NEt(4)](2)[Te(3)Se(6)] (1) and [NEt(4)](2)[Te(3)Se(7)] (2) consist, respectively, of one-dimensional infinite 1(infinity)[Te(3)Se(6)(2-)] and 1(infinity)[Te(3)Se(7)(2-)] anionic chains separated by NEt(4)(+) cations. In compound 1, each chain comprises Te(3)Se(5) eight-membered rings bridged by Se atoms. The Te(3)Se(5) ring has an "open book" conformation. The NMR spectrum of a DMF solution of [NEt(4)](2)[Te(3)Se(6)] crystals at 223 K shows (77)Se resonances at delta = 290, 349, and 771 ppm and a single (125)Te resonance at delta = 944.7 ppm. In compound 2, each chain comprises Te(3)Se(6) five- and six-membered rings bridged by Se atoms. The Te(3)Se(6) ring can be regarded as an inorganic analogue of bicyclononane. The anion of [PPh(4)](2)[Te(2)Se(2)] (4) contains a Se-Te-Te-Se chain with the terminal Se atoms trans to one another. The new compounds [PPN](2)[TeSe(10)] (3), [NMe(4)](2)[TeSe(3)].DMF (5), and [NEt(4)](2)[TeSe(3)] (6) contain known anions.     

Chloro- und Polyselenoselenate(II) Darstellung,Struktur und Eigenschaften von [Ph3(C2H4OH)P]2[SeCl4] · MeCN, [Ph4P]2[Se2Cl6] und [Ph4P]2[Se(Se5)2]

Chloro- and Polyselenoselenates(II): Synthesis, Structure, and Properties of [Ph₃(C₂H₄OH)P]₂[SeCl₄] · MeCN, [Ph₄P]₂[Se₂Cl₆], and [Ph₄P]₂[Se(Se₅)₂] By symproportionation of elemental selenium and SeCl₄ in polar protic solvents the novel chloroselenates(+II), [SeCl₄]^2? and [Se₂Cl₆]^2?, could be stabilized; they were crystallized with voluminous organic cations. They were characterized from complete X-ray structure analysis. Yellow-orange [Ph₃(C₂H₄OH)P]₂[SeCl₄] · MeCN (space group P1 , a = 10.535(4), b = 12.204(5), c = 16.845(6) Å, α = 77.09(3)°, β = 76.40(3)°, γ = 82.75(3)° at 140 K) contains in its crystal structure monomeric [SeCl₄]^2? anions with square-planar coordination of Se(+II). The mean Se? Cl bond length is 2.441 Å. In yellow [Ph₄P]₂[Se₂Cl₆] (space group P1 , a = 10.269(3), b = 10.836(4), c = 10.872(3) Å, α = 80.26(3)°, β = 79.84(2)°, γ = 72.21(3)° at 140 K) a dinuclear centrosymmetric [Se₂Cl₆]^2? anion, also with square-planar coordinated Se(+II), is observed. The average terminal and bridging Se? Cl bond distances are 2.273 and 2.680 Å, respectively. From redox reactions of elemental Se with boranate/thiolate in ethanol/DMF the bis(pentaselenido)selenate(+II) anion [Se(Se₅)₂]^2? was prepared as a novel type of a mixed-valent chalcogenide. In dark-red-brown [Ph₄P]₂[Se(Se₅)₂] (space group P2₁/n, a = 12.748(4), b = 14.659(5), c = 14.036(5) Å, β = 108.53(3)° at 140 K) centrosymmetric molecular [Se(Se₅)₂]^2? anions with square-planar coordination of the central Se(+II) by two bidentate pentaselenide ligands is observed (mean Se? Se bond lengths: 2.658 Å at Se(+II), 2.322 Å in [Se₅]_2?). The resulting six-membered chelate rings with chair conformation are spirocyclically linked through the central Se(+II). The vibrational spectra of the new anions are reported.     

Heteroatomic deltahedral clusters: synthesis and structures of closo-[Bi3Ni(4)(CO)6]3-, closo-[Bi4Ni4(CO)6]2-, the open cluster [Bi3Ni6(CO)9]3-, and the intermetalloid closo-[Nix@[Bi6Ni6(CO)8)]4-

Reactions of ethylenediamine solutions of K4Bi5 with Ni(PPh3)2(CO)2 yielded four novel hetero-atomic Bi/Ni deltahedral clusters. Three of them, the 7-atom pentagonal bipyramidal [Bi3Ni4(CO)6]3-, the 8-atom dodecahedral [Bi4Ni4(CO)6]2-, and the Ni-centered or empty 12-atom icosahedral [Nix@[Bi6Ni6(CO)8]4-, are closo-species according to both electron count and shape. The centered icosahedral cluster resembles packing in intermetallic compounds and belongs to the emerging class of intermetalloid clusters. The shape of the fourth cluster, [Bi3Ni6(CO)9]3-, can be derived from the icosahedral Ni-centered [Ni@[Bi6Ni6(CO)8]4- by removal of three Bi- and one Ni-atoms of two neighboring triangular faces. The clusters were structurally characterized by single-crystal X-ray diffraction in compounds with potassium cations sequestered by 2,2,2-crypt or 18-crown-6 ether. They were also characterized in solution by electrospray mass spectrometry.     

Syntheses, vibrational spectra, and theoretical studies of the adamantanoid Sn(4)Ch(10)(4-) (Ch = Se, Te) anions: X-ray crystal structures of [18-crown-6-K](4)[Sn4Se10]*5en and [18-crown-6-K](4)[Sn4Te10]*3en*2THF

The salts [18-crown-6-K](4)[Sn(4)Se(10)].5en and [18-crown-6-K](4)[Sn(4)Te(10)].3en.2THF were isolated upon addition of THF to the ethylenediamine (en) extracts of the alloys KSn(0.90)Se(1.93) and K(4)Sn(4)Te(10) that had been extracted in the presence of 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane). The Sn(4)Te(10)(4-) anion has been structurally characterized for the first time by a single-crystal X-ray diffraction study of [18-crown-6-K](4)[Sn(4)Te(10)].3en.2THF: P2(1)/n, a = 22.420(5) A, b = 19.570(4) A, c = 24.680(5) A, beta = 96.90(3)(o), Z = 4, and R(1) = 0.0468 at -183 degrees C. In addition to Si(4)Te(10)(4-) and Ge(4)Te(10)(4-), the Sn(4)Te(10)(4-) anion represents the only other known group 14 adamantanoid telluride. The X-ray crystal structure determination of the related [18-crown-6-K](4)[Sn(4)Se(10)].5en salt has also been determined: P2(1)/n, a = 22.003(2) A, b = 18.966(2) A, c = 24.393(2) A, beta = 97.548(8)(o), Z = 4, and R(1) = 0.0843 at -123 degrees C. The anion geometries are of the adamantanoid type where the Sn(IV) atoms occupy the bridgehead positions and the chalcogen atoms occupy the bridging and terminal sites. The energy minimized geometries of Sn(4)Ch(10)(4-) have also been determined using density functional theory (DFT). Mayer bond order analyses, Mayer valencies, and empirical bond valencies indicate that the terminal Sn-Ch bonds have significant multiple bond character, with the terminal Sn-Se bond having more multiple bond character than the terminal Sn-Te bond. The vibrational frequencies of the Sn(4)Se(10)(4-) and Sn(4)Te(10)(4-) anions have been calculated using DFT methods, allowing the Raman spectrum of Sn(4)Se(10)(4-) to be fully assigned.     

Aqueous solution chemistry of [Mo3CuSe4]n+ (n = 4, 5) and [W3CuQ4]5+ (Q = S, Se) clusters

The triangular cluster [Mo3Se4(H2O)9]4+ reacts with Cu turnings to give a new heterometallic cuboidal cluster [Mo3CuSe4(H2O)10]4+(purple; UV/Vis lambda(epsilon): 352(3907), 509(2613)). The reaction of [Mo3Se4(H2O)9]4+ with CuCl afforded the 5+ cube [Mo3CuSe4(H2O)10]5+(red; UV/Vis lambda(epsilon): 356(5406), 500(3477)). In contrast, [W3Se4(H2O)9]4+ both with Cu and CuCl gives the 5+ cube, [W3CuSe4(H2O)10]5+(yellow-green; UV/Vis lambda(epsilon): 312(5327), 419(3256) and 628(680)). Cyclic voltammetry of [M3CuQ4(H2O)10]5+ in 2 M HCl (M = Mo, W; Q = S, Se) shows a reversible one-electron reduction wave for the Mo clusters, but no reduction occurs for the W clusters prior to H+ reduction. In HCl solutions, Cl is coordinated to the Cu site of the clusters, alongside some less extensive coordination to Mo and W, and for [W3(CuCl)S4(H2O)6Cl3]+, isolated as the supramolecular adduct with cucurbit[6]uril, [W3(CuCl)S4(H2O)6Cl3]2Cl2 x C36H36N24O12 x 12H2O, the crystal structure was determined (Cu-W 2.856(4) angstroms, W-W 2.7432(15) angstroms, Cu-Cl 2.167(13) angstroms).     

The Pb12(2-) and Pb10(2-) zintl ions and the M@Pb12(2-) and M@Pb10(2-) cluster series where M = Ni, Pd, Pt

Ethylenediamine (en) solutions of K4Pb9 react with toluene solutions of ML4 (M = Pt, Pd, L = PPh3; M = Ni, L2= COD) and 2,2,2-crypt to give M@Pb12(2-) cluster anions (M = Pt (1), Pd (2), Ni (3)) as the [K(2,2,2-crypt)]+ salts in low (Ni) to good (Pt) yields. The ions have near perfect Ih point symmetry and have been characterized by X-ray diffraction, 207Pb NMR and LDI-TOF mass spectrometry studies. For M = Ni, the primary product formed is the D4d Ni@Pb10(2-) cluster that has also been structurally characterized. The M@Pb10(2-) clusters (M = Pd, Pt) and the new Zintl ions closo-Pb10(2-) and closo-Pb12(2-) were formed in the gas phase but have not been detected in solution or the solid state. The structural trends of these series of clusters have been investigated through DFT calculations. The Ni@Pb10(2-) cluster is dynamic on the 207Pb NMR time scale at -45 degrees C and 104.7 MHz. The M@Pb12(2-) ions show unusually deshielded 207Pb NMR chemical shifts that presumably arise from sigma-aromatic effects associated with their high symmetries. In the solid state, the salts form superlattices of cations and anions (e.g. the AlB2 lattice of [K(2,2,2-crypt)](2)[Pt@Pb12]) and are prototypes for "assembled cluster materials".     

Alkylation of Deltahedral Zintl clusters: synthesis of [R-Ge9-Ge9-R]4- (R = tBu, sBu, nBu, tAm and structure of [tBu-Ge9-Ge9-tBu]4-

Reactions of nine-atom deltahedral clusters (Zintl ions) of germanium, Ge9n- (n = 2, 3, 4), with alkyl chlorides, RCl (R = tBu, nBu, sBu, tAm), yielded the corresponding dialkylated dimers of Ge9 clusters [R-Ge9-Ge9-R]4-. The tBu derivative with [K(2,2,2-crypt)]+ countercations was characterized in the solid state by single-crystal X-ray diffraction as [K(2,2,2-crypt)]4[tBu-Ge9-Ge9-tBu].7en (monoclinic, C2/c, a = 35.0914(10) A, b = 24.8161(6) A, and c = 16.8782(5) A, beta = 94.0136(17) degrees , V = 14662.0(7) A3, and Z = 4) and in solution by 1H and 13C NMR. All species were also characterized in solution by electrospray mass spectrometry in the negative-ion mode. These are the first main group deltahedral clusters functionalized with purely organic substituents.     

Charged molecular alloys: synthesis and characterization of the binary anions Pd(7)As(16)(4-) and Pd(2)As(14)(4-)

Pd(PCy(3))(2) (Cy = cyclohexyl) reacts with As(7)(3-) in en/tol solvent mixtures to give Pd(2)As(14)(4-) (2) and Pd(7)As(16)(4-) (4) as the [K(2,2,2-crypt)](+) salts. The anions were characterized by EDX, ESI-MS, and single-crystal X-ray diffraction. Anion 2 formally contains two norbornadiene-like As(7)(5-) groups bound to square-planar Pd(III) centers linked by a Pd-Pd bond (d(Pd)(-)(Pd) = 2.7144(6) A). Anion 4 has a highly distorted capped trigonal prismatic Pd(7) core stabilized by 2 As(5)(1-), 2 As(2)(2-), and 2 As(3-) anions. The 6 Pd(I) ions are in distorted 5-coordinate environments whereas the lone Pd(II) ion is square planar. Complexes 2 and 4 are rare examples of organic-free, homoleptic transition metal anions containing group 15 elements, and they represent an emerging class of charged "molecular alloys".     

Heteroatomic molecular clusters derived from Group 15 Zintl ion cages: synthesis and isolation of [M2(HP7)2](2-) (M=Ag, Au), two novel cluster anions exhibiting metallophilic interactions

Ethylenediamine (en) solutions of K(3)P(7) and 2,2,2-crypt (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) were reacted with the homoleptic group 11 complexes [M(nbe)(3)][SbF(6)] (M = Ag, Au; nbe = norbornene) yielding two novel cluster anions, [M(2)(HP(7))(2)](2-), both of which were isolated in low crystalline yields as [K(2,2,2-crypt)](2)[M(2)(HP(7))(2)] (M = Ag (1) and Au (2)). Optimization of the reaction conditions by incorporation of a proton source (ammonium tetraphenylborate) and the replacement of the light-sensitive nbe adducts of silver and gold with the chloride salts MCl (M = Ag, Au) was found to greatly increase the yield and purity in which 1 and 2 were isolated. Compounds 1 and 2 were characterized by single crystal X-ray diffraction, electrospray ionization mass-spectrometry (ESI- MS), elemental analysis, and (1)H and (31)P NMR spectroscopy. Density functional theory (DFT) calculations on the cluster anions were also conducted.     

New Dimeric Selenidoarsenate(Ⅲ): Solvothermal Synthesis and Crystal Structure of [Co(en)3]2As2Se5

A new selenidoarsenate [Co(en)3]2As2Se5 1 (en = ethylenediamine) was synthesized by a reaction of AsCl3, COCl2·6H2O and Se in en under mild solvothermal conditions, and the structure was determined by single-crystal X-ray diffraction. 1 crystallizes in the orthorhombic system, space group Pbca with a = 15.5092(12), b = 11.5756(9), c = 17.8138(14) (A), V= 3198.1(4)(A)3, Mr = 1023.12, Z = 4, Dc = 2.125 g/cm3,μ = 8.807 mm-1, F(000) = 1976, S = 1.171, the final R =0.0591 and wR = 0.1067 for 3170 observed reflections with I ＞ 2σ(Ⅰ). 1 consists of isolated dimeric[As2Se5]4- anion constructed by two comer-sharing AsSe3 trigonal pyramids and transition metal [Co(en)3]2+ cations. The optical absorption property and thermal stability of 1 are reported.     

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.     

Preparation and Structures of the 2.2.2-Cryptand(1+) Salts of the [Sb(2)Se(4)](2)(-), [As(2)S(4)](2)(-), [As(10)S(3)](2)(-), and [As(4)Se(6)](2)(-) Anions

2.2.2-Cryptand(1+) salts of the [Sb(2)Se(4)](2)(-), [As(2)S(4)](2)(-), [As(10)S(3)](2)(-), and [As(4)Se(6)](2)(-) anions have been synthesized from the reduction of binary chalcogenide compounds by K in NH(3)(l) in the presence of the alkali-metal-encapsulating ligand 2.2.2-cryptand (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane), followed by recrystallization from CH(3)CN. The [Sb(2)Se(4)](2)(-) anion, which has crystallographically imposed symmetry 2, consists of two discrete edge-sharing SbSe(3) pyramids with terminal Se atoms cis to each other. The Sb-Se(t) bond distance is 2.443(1) ?, whereas the Sb-Se(b) distance is 2.615(1) ? (t = terminal; b = bridge). The Se(b)-Sb-Se(t) angles range from 104.78(4) to 105.18(5) degrees, whereas the Se(b)-Sb-Se(b) angles are 88.09(4) and 88.99(4) degrees. The (77)Se NMR data for this anion in solution are consistent with its X-ray structure (delta 337 and 124 ppm, 1:1 intensity, -30 degrees C, CH(3)CN/CD(3)CN). Similar to this [Sb(2)Se(4)](2)(-) anion, the [As(2)S(4)](2)(-) anion consists of two discrete edge-sharing AsS(3) pyramidal units. The As-S(t) bond distances are 2.136(7) and 2.120(7) ?, whereas the As-S(b) distances range from 2.306(7) to 2.325(7) ?. The S(b)-As-S(t) angles range from 106.2(3) to 108.2(3) degrees, and the S(b)-As-S(b) angles are 88.3(2) and 88.9(2) degrees. The [As(10)S(3)](2)(-) anion has an 11-atom As(10)S center composed of six five-membered edge-sharing rings. One of the three waist positions is occupied by a S atom, and the other two waist positions feature As atoms with exocyclic S atoms attached, making each As atom in the structure three-coordinate. The As-As bond distances range from 2.388(3) to 2.474(3) ?. The As-S(t) bond distances are 2.181(5) and 2.175(4) ?, and the As-S(b) bond distance is 2.284(6) ?. The [As(4)Se(6)](2)(-) anion features two AsSe(3) units joined by Se-Se bonds with the two exocyclic Se atoms trans to each other. The average As-Se(t) bond distance is 2.273(2) ?, whereas the As-Se(b) bond distances range from 2.357(3) to 2.462(2) ?. The Se(b)-As-Se(t) angles range from 101.52(8) to 105.95(9) degrees, and the Se(b)-As-Se(b) angles range from 91.82(7) to 102.97(9) degrees. The (77)Se NMR data for this anion in solution are consistent with its X-ray structure (delta 564 and 317 ppm, 3:1 intensity, 25 degrees C, DMF/CD(3)CN).