Synthesis and structure of diamido ether uranium(IV) and thorium(IV) halide "ate" complexes and their conversion to salt-free bis(alkyl) complexes

The high-yield synthesis, spectroscopic and structural determination of three new uranium(IV) and thorium(IV)ate complexes supported by three different diamido ether ligands are reported. The reaction of Li2[2,6-iPr2PhN(CH2CH2)]2O (Li2[DIPPNCOCN]) with 1 equiv. of UCl4 in THF generates [DIPPNCOCN]UCl3Li(THF)2(1), while reaction in toluene/ether gives salt-free [DIPPNCOCN]UCl2.1/2C7H8(2), which was identified by paramagnetically shifted 1H NMR. Reaction of 0.5 equiv. of {[tBuNON]UCl2}2([tBuNON]=[(CH3)3CN(Si(CH3)2)]2O2-) with 3.5 equiv. LiI in toluene and a minimal amount of THF results in [tBuNON]UI3Li(THF)2(3) and is very similar in structure to 1. {[MesNON]ThCl3Li(THF)}2(4), a dimeric complex with a Th2Li2Cl6 core, is prepared by reaction of Li2[2,4,6-Me3PhN(Si(CH3)2)]2O (Li2[MesNON]) with ThCl4 in THF. The analogous reaction in toluene did not yield the salt-free complex but rather a sterically crowded diligated compound, [MesNON]2Th (5), which was also structurally characterized. Complex 5 was prepared rationally by reacting 2 equiv. Li2[MesNON] with ThCl4 in toluene. The reaction of 1 and 3 with 2 equiv. of LiCH2Si(CH3)3 generates the stable, salt-free organoactinides [DIPPNCOCN]U(CH2Si(CH3)3)2(6) and [tBuNON]U(CH2Si(CH3)3)2(7). Complex 6 was structurally characterized. These reactions illustrate the viability of ate complexes as useful synthetic precursors.     

Probing the 5f orbital contribution to the bonding in a U(V) ketimide complex

Reaction of UCl(4) with 5 equiv of Li(N═C(t)BuPh) generates the homoleptic U(IV) ketimide complex [Li(THF)(2)][U(N═C(t)BuPh)(5)] (1) in 71% yield. Similarly, reaction of UCl(4) with 5 equiv of Li(N═C(t)Bu(2)) affords [Li(THF)][U(N═C(t)Bu(2))(5)] (2) in 67% yield. Oxidation of 2 with 0.5 equiv of I(2) results in the formation of the neutral U(V) complex U(N═C(t)Bu(2))(5) (3). In contrast, oxidation of 1 with 0.5 equiv of I(2), followed by addition of 1 equiv of Li(N═C(t)BuPh), generates the octahedral U(V) ketimide complex [Li][U(N═C(t)BuPh)(6)] (4) in 68% yield. Complex 4 can be further oxidized to the U(VI) ketimide complex U(N═C(t)BuPh)(6) (5). Complexes 1-5 were characterized by X-ray crystallography, while SQUID magnetometry, EPR spectroscopy, and UV-vis-NIR spectroscopy measurements were also preformed on complex 4. Using this data, the crystal field splitting parameters of the f orbitals were determined, allowing us to estimate the amount of f orbital participation in the bonding of 4.     

Synthesis, crystal structure and reactivity of uranium(IV) complexes with p-tert-butylcalix[4]arene ligands

Reactions of UCl4 with 25,27-dimethoxy-5,11,17,23-tetra-tert-butylcalix[4]arene (H2Me2calix) in THF or pyridine at 80 degrees C gave [UCl2(Me2calix)L2] [L = THF (1) or pyridine (2)]. Similar treatment of U(acac)(4) (acac = MeCOCHCOMe) with H2Me2calix in THF or pyridine afforded [U(acac)2(Me2calix)] (3). The bis-calixarene compound [U(Me2calix)(H2calix)] (4) was obtained by reaction of U(OTf)4 or U(OTf)3 with H2Me2calix in pyridine at 110 degrees C. Treatment of UCl4 with H2Me2calix in pyridine at 110 degrees C gave [Mepy][UCl2(Hcalix)(py)2] (5) resulting from demethylation and acid cleavage of the methoxy groups of the calixarene ligand of 2. Adventitious traces of air were responsible for the formation of [Hpy][Mepy]4[{UCl(calix)}3(mu3-O)][UCl6] (6) during the reaction of UCl4 and H2Me2calix, and of [{U(Me2calix)(mu3-O)LiCl(THF)}2] (7) during the reaction of 2 with tBuLi. The X-ray crystal structures of 1.2THF, 2.2py, 3.0.25L (L = THF and py), 4.2py, 5, 6.3py and 7.THF have been determined.     

Polylithiated tetraaminosilanes: synthesis and characterization of (Et2O.Li)4[Si(Nnaph)4] and X-ray structure of (THF.Li3[Si(NiPr)3(NHiPr)])2

The treatment of SiCl4 with 4 equiv of Li2(Nnaph) (naph = 1-naphthyl) in diethyl ether gives (Et2O.Li)4[Si(Nnaph)4] (4), which, upon reaction with excess tBuNH3Cl or MeO3SCF3, generates Si[N(H)naph]4 (5) or Si[N(Me)naph]4 (6), respectively. The centrosymmetric dimer (THF.Li3[Si(NiPr)3(NHiPr)])2 (7), formed via trilithiation of Si[N(H)iPr]4 with n-butyllithium, consists of a bis-THF-solvated Li6(NiPr)6 cyclic ladder bicapped by two SiN(H)iPr units. Crystal data for 7: C32H74Li6N8O2Si2, monoclinic, P2(1)/n, a = 10.661(7) A, b = 16.964(5) A, c = 12.405(4) A, beta = 93.22(4) degrees, V = 2239.9(15) A3, and Z = 2.     

High-valent uranium alkyls: evidence for the formation of U(VI)(CH2SiMe3)6

Oxidation of [Li(DME)(3)][U(CH(2)SiMe(3))(5)] with 0.5 equiv of I(2), followed by immediate addition of LiCH(2)SiMe(3), affords the high-valent homoleptic U(V) alkyl complex [Li(THF)(4)][U(CH(2)SiMe(3))(6)] (1) in 82% yield. In the solid-state, 1 adopts an octahedral geometry as shown by X-ray crystallographic analysis. Addition of 2 equiv of tert-butanol to [Li(DME)(3)][U(CH(2)SiMe(3))(5)] generates the heteroleptic U(IV) complex [Li(DME)(3)][U(O(t)Bu)(2)(CH(2)SiMe(3))(3)] (2) in high yield. Treatment of 2 with AgOTf fails to produce a U(V) derivative, but instead affords the U(IV) complex (Me(3)SiCH(2))Ag(μ-CH(2)SiMe(3))U(CH(2)SiMe(3))(O(t)Bu)(2)(DME) (3) in 64% yield. Complex 3 has been characterized by X-ray crystallography and is marked by a uranium-silver bond. In contrast, oxidation of 2 can be achieved via reaction with 0.5 equiv of Me(3)NO, producing the heteroleptic U(V) complex [Li(DME)(3)][U(O(t)Bu)(2)(CH(2)SiMe(3))(4)] (4) in moderate yield. We have also attempted the one-electron oxidation of complex 1. Thus, oxidation of 1 with U(O(t)Bu)(6) results in formation of a rare U(VI) alkyl complex, U(CH(2)SiMe(3))(6) (6), which is only stable below -25 °C. Additionally, the electronic properties of 1-4 have been assessed by SQUID magnetometry, while a DFT analysis of complexes 1 and 6 is also provided.     

Uranium(IV) complexes of calix[n]arenes (n = 4, 6 and 8)

Reaction of UCl4 with calix[n]arenes (n = 4, 6 and 8) in THF or pyridine gave the mononuclear [UCl2(calix[4]arene--2H)(THF)2], bis-binuclear [U2Cl2(calix[6]arene--6H)(THF)3]2 and trinuclear [Hpy]6[U3Cl11(calix[8]arene--7H)] complexes, respectively, which are the first U(IV) complexes of O-unsubstituted calixarenes.     

Synthesis and crystal structure of uranium(IV) complexes with calix[n]arenes (n = 4, 6 and 8): mononuclear, polynuclear and 1D polymeric species

Reactions of UCl4 with calix[n]arenes (n = 4, 6) in THF gave the mononuclear [UCl2(calix[4]arene - 2H)(THF)2].2THF (.2THF) and the bis-dinuclear [U2Cl2(calix[6]arene - 6H)(THF)3]2.6THF (.6THF) complexes, respectively, while the mono-, di- and trinuclear compounds [Hpy]2[UCl3(calix[4]arene - 3H)].py (.py), [Hpy](4)[U2Cl6(calix[6]arene - 6H)].3py (.3py), [Hpy]3[U2Cl5(calix[6]arene - 6H)(py)].py (.py) and [Hpy]6[U3Cl11(calix[8]arene - 7H)].3py (.3py) were obtained by treatment of UCl4 with calix[n]arenes (n = 4, 6, 8) in pyridine. The sodium salt of calix[8]arene reacted with UCl4 to give the pentanuclear complex [U{U2Cl3(calix[8]arene - 7H)(py)5}2].8py (.8py). Reaction of U(acac)4 (acac = MeCOCHCOMe) with calix[4]arene in pyridine afforded the mononuclear complex [U(acac)2(calix[4]arene - 2H)].4py (.4py) and its treatment with the sodium salt of calix[8]arene led to the formation of the 1D polymer [U2(acac)6(calix[8]arene - 6H)(py)4Na4]n. The sandwich complex [Hpy]2[U(calix[4]arene - 3H)2][OTf].4py (.4py) was obtained by treatment of U(OTf)4 (OTf = OSO2CF3) with calix[4]arene in pyridine. All the complexes have been characterized by X-ray diffraction analysis.     

Synthesis and single-crystal x-ray diffraction examination of a structurally homologous series of tetracoordinate heteroleptic anionic lanthanide complexes: Ln[N[Si(CH3)2CH2CH2Si(CH3)2]]3(mu-Cl)Li(L)3 (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb; (L)3 =(THF)3, (Et2O)3, (THF)2(Et2O)

Anhydrous lanthanide(III) chlorides (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb) react with 3 equiv of lithium 2,2,5,5-tetramethyl-2,5-disila-1-azacyclopentanide, Li[N[Si(CH3)2CH2Ch2Si(CH3)2]], in THF or Et(2)O to afford the monomeric four-coordinate heteroleptic ate complexes Ln[N[Si(CH3)2CH2CH2Si(CH3)2]]3(mu-Cl)Li(THF/Et2O)3 (Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7), Tm (8), Yb (9)), whose solid-state structures were determined by the single-crystal X-ray diffraction technique. All complexes additionally were characterized by melting point determination, elemental analyses, and mass spectrometry.     

New efficient synthesis of [Ul4(meCN)4]. X-ray crystal structures of [Ul2(MeCN)7][Ul6], [Ul4(py)3], and [U(dmf)9]l4

Reaction of UCl4 and excess Me3Sil in acetonitrile provides a convenient route to [Ul4(MeCN)4] (1), which was isolated in excellent yield and crystallized in acetonitrile as the ion pair complex [Ul2(MeCN)7][Ul6] (2). Compound 1 was transformed in pyridine (py) and dimethylformamide (dmf) into the Lewis base adducts [Ul4(py)3] (3) and [Ul4(dmf)6] (4). Crystals of 3 and [U(dmf)9]l4 (5) were obtained by slow diffusion of diethyl ether into pyridine or dmf solutions of 1; compound 5 is the first tetracationic {U4+} entity to have been crystallographically characterized.     

Homoleptic tris(dithiolene) and tetrakis(dithiolene) complexes of uranium(IV)

Reaction of UCl4 with 3 or 4 mol equiv of Na2dddt (dddt = 5,6-dihydro-1,4-dithiine-2,3-dithiolate) in THF afforded the first example of a tetrakis(dithiolene) metal compound, [Na4(THF)8U(dddt)4](infinity) (1). The red crystals of 1 are composed of infinite zigzag chains in which Na2(micro-THF)3 fragments ensure the linking of Na2(THF)5U(dddt)4 moieties; the uranium atom is in a dodecahedral environment of eight sulfur atoms. Treatment of UCl4 with 3 mol equiv of Na2dddt in pyridine gave a mixture of tris- and tetrakis(dithiolene) compounds. After addition of 18c6 (18-crown-6), only the tris(dithiolene) complex was obtained and crystallized as orange crystals of [Na(18c6)(py)2]2[U(dddt)3].2py (2.2py) in which the isolated [U(dddt)3]2- anion adopts a slightly distorted trigonal prismatic configuration. A few red crystals of the unsolvated complex 2 and the trinuclear anionic compound [Na(18c6)(py)2]3[Na{U(dddt)3}2] (3) were also obtained along with orange crystals of 2.2py. All the tris(dithiolene) compounds exhibit large folding of the dddt ligand and significant interaction between the C=C double bond and the metal center.     

Poly(pyrazolyl)aluminate complexes containing aluminum-hydrogen bonds

The treatment of LiAlH(4) with 2, 3, or 4 equiv of the 3,5-disubstituted pyrazoles Ph(2)pzH or iPr(2)pzH afforded [Li(THF)(2)][AlH(2)(Ph(2)pz)(2)] (97%), [Li(THF)][AlH(Ph(2)pz)(3)] (96%), [Li(THF)(4)][Al(Ph(2)pz)(4)] (95%), and [Li(THF)][AlH(iPr(2)pz)(3)] (89%). The treatment of ZnCl(2) with [Li(THF)][AlH(Ph(2)pz)(3)] afforded Zn(AlH(Ph(2)Pz)(3))H (70%). X-ray crystal structures of these complexes demonstrated κ(2) or κ(3) coordination of the aluminum-based ligands to the Li or Zn ions. The treatment of [Li(THF)][AlH(Ph(2)pz)(3)] with MgBr(2) or CoCl(2) in THF/Et(2)O solutions, by contrast, afforded the pyrazolate transfer products Mg(2)Br(2)(Ph(2)pz)(2)(THF)(3)·2THF (25%) and Co(2)Cl(2)(Ph(2)pz)(2)(THF)(3)·THF (23%) as colorless and blue crystalline solids, respectively. An analogous treatment of [Li(THF)][AlH(Ph(2)pz)(3)] with MCl(2) (M = Mn, Fe, Ni, Cu) afforded metal powders and H(2), illustrating hydride transfer from Al to M as a competing reaction path.     

Analogy of the coordination chemistry of alkaline earth metal and lanthanide Ln(2+) ions: the isostructural zoo of mixed metal cages [IM(OtBu)4{Li(thf)}4(OH)] (M=Ca, Sr, Ba, Eu), [MM'6(OPh)8(thf)6] (M=Ca, Sr, Ba, Sm, Eu, M'=Li, Na), and their derivatives with 1,2-dimethoxyethane

As previously shown, alkali and alkaline earth metal iodides in nonaqueous, aprotic solvents behave like transition metal halides, forming cis- and trans-dihalides with various neutral O-donor ligands. These compounds can be used as precursors for the synthesis of new mixed alkali/alkaline earth metal aggregates. We show here that Ln2+ ions form isostructural cluster compounds. Thus, with LiOtBu, 50% of the initial iodide can be replaced in MI2, M=Ca, Sr, Ba, Eu, to generate the mixed-metal alkoxide aggregates [IM(OtBu)4{Li(thf)}4(OH)], for which the M--OH contacts were investigated by theoretical methods. With M'OPh (M'=Li, Na), a new mixed-metal aryloxide cluster type [MM'6(OPh)8(thf)6] is obtained for M=Ca, Sr, Ba, Sm, Eu. Their stability versus DME (DME=1,2-dimethoxyethane) as bidentate ligand is studied.     

Oxo- and imidovanadium complexes incorporating methylene- and dimethyleneoxa-bridged calix[3]- and -[4]arenes: synthesis, structures and ethylene polymerisation catalysis

Reaction of [V(X)(OR)3] (X=O, Np-tolyl; R=Et, nPr or tBu) with p-tert-butylhexahomotrioxacalix[3]areneH3, LH3, affords the air-stable complexes [{V(X)L}n] (X=O, n=1 (1); X=Np-tolyl, n=2 (2)). Alternatively, 1 is readily available either from interaction of [V(mes)3THF] with LH3, and subsequent oxidation with O2 or upon reaction of LLi3 with [VOCl3]. Reaction of [V(Np-tolyl)(OtBu)3] with 1,3-dimethylether-p-tert-butylcalix[4]areneH2, Cax(OMe)2(OH)2, afforded [{VO(OtBu)}2(mu-O)Cax(OMe)2(O)2].2 MeCN (42 MeCN), in which two vanadium atoms are bound to just one calix[4]arene ligand; the n-propoxide analogue of 4, namely [{VO(OnPr)}2(mu-O)Cax(OMe)2(O)2].1.5 MeCN (51.5 MeCN), has also been isolated from a similar reaction using [V(O)(OnPr)3]. Reaction of [VOCl3], LiOtBu, (Me3Si)2O and Cax(OMe)2(OH)2 gave [{VO(OtBu)Cax(OMe)2(O)2}2Li4O2].8 MeCN (68 MeCN), in which an Li4O4 cube (two of the oxygen atoms are derived from the calixarene ligands) is sandwiched between two Cax(OMe)2(O)2. The reaction between [V(Np-tolyl)(OtBu)3] and Cax(OMe)2(OH)2, afforded [V(Np-tolyl)(OtBu)2Cax(OMe)2(O)(OH)]5 MeCN (75 MeCN), in which two tert-butoxide groups remain bound to the tetrahedral vanadium atom, which itself is bound to the calix[4]arene through only one phenolic oxygen atom. Reaction of p-tert-butylcalix[4]areneH4, Cax(OH)4 and [V(Np-tolyl)(OnPr)3] led to loss of the imido group and formation of the dimeric complex [{VCax(O)4(NCMe)}2].6 MeCN (86 MeCN). Monomeric vanadyl oxo- and imidocalix[4]arene complexes [V(X)Cax(O)3(OMe)(NCMe)] (X=O (11), Np-tolyl (12)) were obtained by the reaction of the methylether-p-tert-butylcalix[4]areneH3, Cax(OMe)(OH)3, and [V(X)(OR)3] (R=Et or nPr). Vanadyl calix[4]arene fragments can be linked by the reaction of 2,6-bis(bromomethyl)pyridine with Cax(OH)4 and subsequent treatment with [VOCl3] to afford the complex [{VOCax(O)4}2(mu-2,6-(CH2)2C5H3N)].4 MeCN (134 MeCN). The compounds 1-13 have been structurally characterised by single-crystal X-ray diffraction. Upon activation with methylaluminoxane, these complexes displayed poor activities, however, the use of dimethylaluminium chloride and the reactivator ethyltrichloroacetate generates highly active, thermally stable catalysts for the conversion of ethylene to, at 25 degrees C, ultra-high-molecular-weight (>5, 500,000), linear polyethylene, whilst at higher temperature (80 degrees C), the molecular weight of the polyethylene drops to about 450,000. Using 1 and 2 at 25 degrees C for ethylene/propylene co-polymerisation (50:50 feed) leads to ultra-high-molecular-weight (>2,900,000) polymer with about 14.5 mol% propylene incorporation. The catalytic systems employing the methyleneoxa-bridged complexes 1 and 2 are an order of magnitude more active than the bimetallic complexes 5 and 13, which, in turn, are an order of magnitude more active than pro-catalysts 8, 11 and 12. These differences in activity are discussed in terms of the structures of each class of complex.     

First complexes of scandium and yttrium with NNO and NNS heteroscorpionate ligands

The reaction of ScCl(3)(THF)(3) or YCl(3) in a 1:1 molar ratio under reflux for 8 h with [{Li(bdmpza)(H(2)O)}(4)] [bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetate], [{Li(bdmpzdta)(H(2)O)}(4)] [bdmpzdta = bis(3,5-dimethylpyrazol-1-yl)dithioacetate], and (Hbdmpze) [bdmpze = 2,2-bis(3,5-dimethylpyrazol-1-yl)ethoxide] affords the corresponding complexes [MCl(2)(kappa(3)-bdmpzx)(THF)] (x = a, M = Sc (1), Y (2); x = dta, M = Sc (3), Y (4); x = e, M = Sc (5), Y (6)). However, when the reaction was carried out for 1 h under reflux between ScCl(3)(THF)(3) and [{Li(bdmpzdta)(H(2)O)}(4)], a new anionic complex [Li(THF)(4)][ScCl(3)(kappa(3)-bdmpzdta)] (7) was obtained. Reaction of [{Li(bdmpza)(H(2)O)}(4)] with YCl(3) in a 2:1 molar ratio under reflux for 8 h gave the complex [YCl(kappa(3)-bdmpza)(2)] (8). The same reaction, but with the lithium compound [{Li(bdmpzdta)(H(2)O)}(4)], led to the formation of an anionic complex [Li(THF)(4)][YCl(3)(kappa(3)-bdmpzdta)] (9). The X-ray crystal structures of 7 and 9 were established. Finally, the addition of 1 equiv of [{Li(bdmpza)(H(2)O)}(4)] or [{Li(bdmpzdta)(H(2)O)}(4)] to a solution of YCl(3) in THF under reflux, followed by the addition of 1 equiv of 1,10-phenanthroline, resulted in the formation of the corresponding complexes [YCl(2)(kappa(3)-bdmpzx)(phen)] (x = a (10), x = dta (11)). These complexes are the first examples of group 3 metals stabilized by heteroscorpionate ligands. In addition, we have explored the reactivity of some of these complexes with alcohols and amides. For example, the direct reaction of [YCl(2)(kappa(3)-bdmpza)(THF)] (2) with several alcohols gave the alkoxide complexes [YCl(kappa(3)-bdmpza)(OR)] (R = Et (12), iPr (13)). Finally, the reaction between [ScCl(2)(kappa(3)-bdmpzdta)(THF)] (3) or [Li(THF)(4)][ScCl(3)(kappa(3)-bdmpzdta)] (7) and LiN(SiMe(3))(2).Et(2)O in 1:1 and 1:2 molar ratios gave rise to the complexes [ScCl(kappa(3)-bdmpzdta){N(SiMe(3))(2)}] (14) and [Sc(kappa(3)-bdmpzdta){N(SiMe(3))(2)}(2)] (15), respectively.     

Synthesis and characterization of [(diene)Rh[mu-OSi(OtBu)3]]2, a precursor to silica-bound rhodium

Reaction of [(diene)RhCl]2 with 2 equiv of KOSi(OtBu)3 afforded [(diene)Rh[mu-OSi(OtBu)3]]2, where diene=cod (1) and nbd (2). Multinuclear NMR studies reveal that 1 and 2 have a dimeric structure with bridging tris(tert-butoxy)siloxy ligands. These dimers are folded along the O...O axis. Complexes and reacted with PR3(R=Me, Ph) to give monomeric products, the formulae of which depend on the amount of PR3 added ((diene)Rh[OSi(OtBu)3](PR3) and Rh[OSi(OtBu)3](PMe3)3). The behavior of 1 towards water and methanol is discussed. Thermogravimetric analyses (TGAs) of 1 and 2 reveal rather sharp conversions to rhodium-containing materials. Thermolysis of 1 in toluene at 180 degrees C resulted in formation of a black precipitate, which contained rhodium nanoparticles with an average diameter of 22 nm, as determined by powder X-ray diffraction (PXRD), after calcination at 300 degrees C for 1 h.     

Construction of new heteroselenometallic clusters: formation of crownlike [Et4N]4[(mu5-WSe4)(CuI)5(mu-I)2] and octahedral polymeric [(mu6-WSe4)Cu6I4(py)4]n from planar [Et4N]4[(mu4-WSe4)Cu4I6] with additional faces

The coplanar cluster compound [Et4N]4[(mu4-WSe4)Cu4I6] (1) was prepared from reaction of [Et4N]2[WSe4] with 4 equiv of CuI in N,N-dimethylformamide (DMF) solution in the presence of [Et(4)N]I. Treatment of 1 with pyridine (py) in dry MeCN gave the neutral cluster [(mu4-WSe4)Cu4(py)6I2] (2) in good yield. Recrystallization of 1 from py/i-PrOH resulted in the reorganization of the coplanar WSe4Cu4 core and the formation of a neutral polymeric cluster [(mu3-WOSe3)Cu3(py)3(mu-I)]n (3) containing a nest-shaped OWSe3Cu3 core and a terminal W=O bond. The interaction of cluster 1 with excess PPh3 in CH3Cl3 gave [(mu3-WSe4)Cu3(PPh3)3(mu3-I)] (4) which has a cubanelike SeWSe3Cu3I core. Treatment of 1 with 1 equiv of CuI in dimethyl sulfoxide (DMSO) yielded [Et4N]4[(mu5-WSe4)(CuI)5(mu-I)2] (5) which has a crown-like core structure. Treatment of 1 in DMF with 2 equiv of CuI in the presence of py resulted in the formation of a two-dimensional polymeric cluster, [(mu6-WSe4)Cu6I4(py)4]n (6), consisting of an octahedral WSe4Cu6 repeating unit. The solid-state structures of clusters 3, 5, and 6 have been further established by X-ray crystallography. The nonlinear optical properties of 6 have been also investigated. Cluster 6 was found to exhibit good photostability and a large optical limiting effect with the limiting threshold being ca. 0.3 J cm(-2).     

Vapochromic behavior of {Ag2(Et2O)2[Au(C6F5)2]2}n with volatile organic compounds

The vapochromic behaviors of {Ag2L2[Au(C6F5)2]2}n (L = Et2O (1), Me2CO (2), THF (3), CH3CN (4)) were studied. {Ag2L2[Au(C6F5)2]2}n (L = Et2O (1)) was synthesized by the reaction of [Bu4N][Au(C6F5)2] with AgOClO3 in 1:1 molar ratio in CH2Cl2/Et2O (1:2). 1 was used as starting material with THF to form {Ag2L2[Au(C6F5)2]2}n (L = THF (3)). 3 crystallizes in the monoclinic space group C2/c and consists of tetranuclear units linked together via aurophilic contacts resulting in the formation of a 1D polymer that runs parallel to the crystallographic z axis. The gold(I) atoms are linearly coordinated to two pentafluorophenyl groups and display additional Au...Ag close contacts within the tetranuclear units with distances of 2.7582(3) and 2.7709(3) A. Each silver(I) center is bonded to the two oxygen atoms of the THF molecules with a Ag-O bond distance of 2.307(3) A. TGA analysis showed that 1 loses two molecules of the coordinated solvent per molecular unit (1st one: 75-100 degrees, second one: 150-175 degrees C), whereas 2, 3, and 4 lose both volatile organic compounds (VOCs) and fluorinated ligands in a less well defined manner. Each complex loses both the fluorinated ligands and the VOCs by a temperature of about 325 degrees C to give a 1:1 gold/silver product. X-ray powder diffraction studies confirm that the reaction of vapors of VOCs with 1 in the solid state produce complete substitution of the ether molecules by the new VOC. The VOCs are replaced in the order CH3CN > Me2CO > THF > Et2O, with the ether being the easiest to replace. {Ag2(Et2O)2[Au(C6F5)2]2}n and {Ag2(THF)2[Au(C6F5)2]2} n both luminesce at room temperature and at 77 K in the solid state. Emission maxima are independent of the excitation wavelength used below about 500 nm. Emission maxima are obtained at 585 nm (ether) and 544 nm (THF) at room temperature and at 605 nm (ether) and 567 nm (THF) at 77 K.     

Tetraaza analogues of lithium and sodium alums: synthesis and X-ray structures of the single strand polymer [Li(THF)2(Al[SO2(NtBu)2]2)] infinity and the contact ion pairs [Na(15-crown-5)][Al(SO2(NtBu)2)2] and ([Na(15-crown-5)][O2S(mu-NBn)2Al(mu-NBnSO2NBn)])2

The reaction of an alkali metal aluminohydride MAlH4 (M = Li, Na) with N,N'-bis-(tert-butyl)sulfamide or N,N'-bis-(benzyl)sulfamide in THF produces the complex ions (Al[SO2(NR)2]2)- (R = tBu, Bn). The X-ray structures of [Li(THF)2(Al[SO2(NtBu)2]2)] infinity (1), [Na(15-crown-5)][Al(SO2(NtBu)2)2], (2) and ([Na(15-crown-5)][O2S(mu-NBn)2Al(mu-NBnSO2NBn)])2 (3.3THF) are reported. The two diazasulfate ligands [SO2(NtBu)2]2- are N,N' chelated to Al3+ in both 1 and 2. In the lithium derivative 1 the spirocyclic (Al[SO2(NtBu)2]2)- anions are bridged by the bis-solvated cations Li(THF)2+ to give a polymeric strand. In the sodium salt 2 the complex anion is O,O' chelated to Na+, which is further encapsulated by a 15-crown-5 ligand to give a monomeric ion-pair complex. By contrast, the benzyl derivative 3 forms a dimer in which the terminal [SO2(NBn)2]2- ligands are (N,N'),(O,O') bis-chelated to Al3+ and Na+, respectively, and the bridging ligands adopt a novel N,O-chelate, N'-monodentate bonding mode. The central core of 3 consists of two four-membered AlOSN rings bridged by two NtBu groups. Crystal data: 1, orthorhombic, Pna2(1), a = 20.159(5) degrees, b = 10.354(3) degrees, c = 15.833(4) degrees, alpha = beta = gamma = 90 degrees, V = 3304.7(15) A3, Z = 4; 2, monoclinic, P2(1)/n, a = 16.031(2) A, b = 9.907(2) A, c = 23.963(4) A, beta = 103.326(2) degrees, Z = 4; 3, triclinic, P1, a = 12.7237(11) A, b = 14.0108(13) A, c = 16.2050(14) A, alpha = 110.351(2) degrees, beta = 111.538(2) degrees, gamma = 97.350(2) degrees, Z = 1.     

Synthesis and structural analysis of the polymetallated alkali calixarenes [M4(p-tert-butylcalix[4]arene-4H)(thf)x]2.n THF (M=Li,K; n=6 or 1; x=4 or 5) and [Li2(p-tert-butylcalix[4]arene-2H)(H2O)(mu-H2O)(thf)].3 THF

To study the structures and reactivities of alkali metallated intermediates of calix[4]arenes, three compounds were isolated: [Li(4)(p-tert-butylcalix[4]arene-4H)(thf)(4)](2).6 THF (1), [Li(2)(p-tert-butylcalix[4]arene-2H)(H(2)O)(mu-H(2)O)(thf)].3 THF (2), and [K(4)(p-tert-butylcalix[4]arene-4H)(thf)(5)](2).THF (3). The structure of 1 is shown to be dependent on the coordinating solvent. Partial hydrolysis of 1 leads to the formation of 2. The potassium compound 3 features a different structure to that of 1, due to a higher coordination number as well as stronger cation-pi-bonding interactions.     

Structural diversity in solvated lithium aryloxides. Syntheses, characterization, and structures of [Li(OAr)(THF)x]n and [Li(OAr)(py)x]2 complexes where OAr = OC6H5, OC6H4(2-Me), OC6H3(2,6-(Me))2, OC6H4(2-Pr(i)), OC6H3(2,6-Pr(i)))2, OC6h4(2-Bu(t)), OC6H3(2,6-Bu(t)))2

A series of sterically varied aryl alcohols H-OAr [OAr = OC6H5 (OPh), OC6H4(2-Me) (oMP), OC6H3(2,6-(Me))2 (DMP), OC6H4(2-Pr(i)) (oPP), OC6H3(2,6-(Pr(i)))2 (DIP), OC6H4(2-Bu(t)) (oBP), OC6H3(2,6-(Bu(t)))2 (DBP); Me = CH3, Pr(i) = CHMe2, and Bu(t) = CMe3] were reacted with LiN(SiMe3)2 in a Lewis basic solvent [tetrahydrofuran (THF) or pyridine (py)] to generate the appropriate "Li(OAr)(solv)x". In the presence of THF, the OPh derivative was previously identified as the hexagonal prismatic complex [Li(OPh)(THF)]6; however, the structure isolated from the above route proved to be the tetranuclear species [Li(OPh)(THF)]4 (1). The other "Li(OAr)(THF)x" products isolated were characterized by single-crystal X-ray diffraction as [Li(OAr)(THF)]4 [OAr = oMP (2), DMP (3), oPP (4)], [Li(DIP)(THF)]3 (5), [Li(oBP)(THF)2]2, (6), and [Li(DBP)(THF)]2, (7). The tetranuclear species (1-4) consist of symmetric cubes of alternating tetrahedral Li and pyramidal O atoms, with terminal THF solvent molecules bound to each metal center. The trinuclear species 5 consists of a six-membered ring of alternating trigonal planar Li and bridging O atoms, with one THF solvent molecule bound to each metal center. Compound 6 possesses two Li atoms that adopt tetrahedral geometries involving two bridging oBP and two terminal THF ligands. The structure of 7 was identical to the previously reported [Li(DBP)(THF)]2 species, but different unit cell parameters were observed. Compound 7 varies from 6 in that only one solvent molecule is bound to each Li metal center of 7 because of the steric bulk of the DBP ligand. In contrast to the structurally diverse THF adducts, when py was used as the solvent, the appropriate "Li(OAr)(py)x" complexes were isolated as [Li(OAr)(py)2]2 (OAr = OPh (8), oMP (9), DMP (10), oPP (11), DIP (12), oBP (13)) and [Li(DBP)(py)]2 (14). Compounds 8-13 adopt a dinuclear, edge-shared tetrahedral complex. For 14, because of the steric crowding of the DBP ligand, only one py is coordinated, yielding a dinuclear fused trigonal planar arrangement. Two additional structure types were also characterized for the DIP ligand: [Li(DIP)(H-DIP)(py)]2 (12b) and [Li2(DIP)2(py)3] (12c). Multinuclear (6,7Li and 13C) solid-state MAS NMR spectroscopic studies indicate that the bulk powder possesses several Li environments for "transitional ligands" of the THF complexes; however, the py adducts possess only one Li environment, which is consistent with the solid-state structures. Solution NMR studies indicate that "transitional" compounds of the THF precursors display multiple species in solution whereas the py adducts display only one lithium environment.