Heteropolynuclear complexes with the ligand Ph2PCH2SPh: theoretical evidence for metallophilic Au-M attractions

Addition of two equivalents of diphenylthiomethylphosphine (PPh2-CH2SPh) to the starting materials [Au(tht)2]A (tht = tetrahydrothiophene), AgCF3SO3, or [Cu(CH3CN)4]CF3SO3 produces the mononuclear derivatives [M(PPh2CH2SPh)2]A (M = Au, A = CF3SO3 (1a); M = Au, A = ClO4 (1b); M = Ag, A = CF3SO3 (4); M = Cu, A = CF3SO3 (5)) which are able to form the heterodinuclear complexes [AuM'(PPh2CH2SPh)2](CF3SO3)2 (M' = Ag (2), Cu (3)) with a P-Au-P environment. If the starting gold complex is [Au(C6F5)(tht)], reaction with the phosphine produces [Au(C6F5)-(PPh2CH2SPh)] (6) from which, by reaction with AgCF3SO3 or [Cu(CH3CN)4]CF3SO3, the "snake"-type linear complexes [Au2M(C6F5)2-(PPh2CH2SPh)2]CF3SO3 (M = Ag (7), Cu (8)) are obtained. If the silver starting complex is AgCF3CO2, reaction in a 1:1 ratio gives the tetranuclear complex [Au2Ag2(C6F5)2(PPh2CH2SPh)2-(CF3CO2)2] (9). When the molar ratio is 1:2 the trinuclear complex [AuAg2(C6F5) (CF3CO2)2(PPh2CH2SPh)] (10) is obtained. According to ab initio calculations, the presence of only one gold atom is enough to induce metallophilic attractions in the group congeners, and this effect can be modulated depending on the gold ligand.     

Synthesis and Structure of μ2-Oxobis(carboxylatotriarylantimony)

Russian Journal of General Chemistry - Binuclear antimony compounds with a bridging oxygen atom [Ph3SbOC(O)R]2O (R = CF2CF3, CF2CF2CF3), [(4-МеC6H4)3SbOC(O)CF2CF3]2O,...     

pH-selective synthesis and structures of alkynyl, acyl, and ketonyl intermediates in anti-Markovnikov and Markovnikov hydrations of a terminal alkyne with a water-soluble iridium aqua complex in water

Chemoselective synthesis and isolation of alkynyl [Cp*Ir(III)(bpy)CCPh]+ (2, Cp* = eta5-C5Me5, bpy = 2,2'-bipyridine), acyl [Cp*Ir(III)(bpy)C(O)CH2Ph]+ (3), and ketonyl [Cp*Ir(III)(bpy)CH2C(O)Ph]+ (4) intermediates in anti-Markovnikov and Markovnikov hydration of phenylacetylene in water have been achieved by changing the pH of the solution of a water-soluble aqua complex [Cp*Ir(III)(bpy)(H2O)]2+ (1) used as the same starting complex. The alkynyl complex [2]2.SO4 was synthesized at pH 8 in the reaction of 1.SO4 with H2O at 25 degrees C, and was isolated as a yellow powder of 2.X (X = CF3SO3 or PF6) by exchanging the counteranion at pH 8. The acyl complex [3]2.SO4 was synthesized by changing the pH of the aqueous solution of [2]2.SO4 from 8 to 1 at 25 degrees C, and was isolated as a red powder of 3.PF6 by exchanging the counteranion at pH 1. The hydration of phenylacetylene with 1.SO4 at pH 4 at 25 degrees C gave a mixture of [2]2.SO4 and [4]2.SO4. After the counteranion was exchanged from SO4(2-) to CF3SO3-, the ketonyl complex 4.CF3SO3 was separated from the mixture of 2.CF3SO3 and 4.CF3SO3 because of the difference in solubility at pH 4 in water. The structures of 2-4 were established by IR with 13C-labeled phenylacetylene (Ph12C13CH), electrospray ionization mass spectrometry (ESI-MS), and NMR studies including 1H, 13C, distortionless enhancement by polarization transfer (DEPT), and correlation spectroscopy (COSY) experiments. The structures of 2.PF6 and 3.PF6 were unequivocally determined by X-ray analysis. Protonation of 3 and 4 gave an aldehyde (phenylacetaldehyde) and a ketone (acetophenone), respectively. Mechanism of the pH-selective anti-Markovnikov vs Markovnikov hydration has been discussed based on the effect of pH on the formation of 2-4. The origins of the alkynyl, acyl, and ketonyl ligands of 2-4 were determined by isotopic labeling experiments with D2O and H2(18)O.     

Crown ethers as ancillary ligands in the assembly of silver(i) aggregates containing embedded acetylenediide

Five silver(I) double salts containing embedded acetylenediide, [Ag([12]crown-4)(2)][Ag(10)(C(2))(CF(3)CO(2))(9)([12]crown-4)(2)(H(2)O)(3)] x H(2)O (2), [Ag(2)C(2) x 5 AgCF(3)CO(2) x (benzo[15]crown-5) x 2 H(2)O] x 0.5 H(2)O (3), [Ag(4)([18]crown-6)(4)(H(2)O)(3)][Ag(18)(C(2))(3)(CF(3)CO(2))(16)(H(2)O)(2.5)] x 2.5 H(2)O (4), [Ag(2)C(2) x 6 AgC(2)F(5)CO(2) x 2([15]crown-5)](2) (5), and [(Ag(2)C(2))(2) x (AgC(2)F(5)CO(2))(9) x ([18]crown-6)(2) x (H(2)O)(3.5)] x H(2)O (6), have been isolated by varying the types of crown ethers and anions employed. Single-crystal X-ray analysis has shown that complex 2 is composed of winding anionic chains with sandwiched [Ag([12]crown-4)(2)](+) ions accommodated in the concave cavities between them. In 3, silver(I) double cages each sandwiched by a couple of benzo[15]crown-5 ligands are linked by [Ag(2)(CF(3)CO(2))(2)] bridges to form a one-dimensional structure. For 4, an anionic silver column is generated through fusion of two kinds of silver polyhedra (triangulated dodecahedron and bicapped trigonal antiprism), and the charge balance is provided by aqua-ligated [Ag([18]crown-6)](+) ions. Complex 5 is a centrosymmetric hexadecanuclear supermolecule composed of two [(eta(5)-[15]crown-5)(2)(C(2)@Ag(7))(mu-C(2)F(5)CO(2))(5)] moieties connected through a [Ag(2)(C(2)F(5)CO(2))(2)] bridge. Compound 6 is a discrete supermolecule containing an asymmetric (C(2))(2)@Ag(13) cluster core capped by two [18]crown-6 ligands in mu(3)-eta(5) and mu(4)-eta(6) ligation modes.     

Synthesis and characterization of novel titanium complexes bearing [ONX]-type β-enaminoketonato ligands and their application to ethylene (co)polymerization

A series of novel titanium complexes bearing tridentate β-enaminoketonato chelating ligands of type, [R(2)NC(CF(3))C(H)CR(1)O]TiCl(3) (2a: R(1) = Ph, R(2) = -C(6)H(4)OMe(o); 2b: R(1) = Ph, R(2) = -C(9)H(6)N; 2c: R(1) = Ph, R(2) = -C(6)H(4)SMe(o); 2d: R(1) = Ph, R(2) = -C(6)H(4)SPh(o); 2e: R(1) = (t)Bu, R(2) = -C(6)H(4)SPh(o)) and [R(2)NC(R(1))C(H)C(CF(3))O]TiCl(3) (2f: R(1) = Ph, R(2) = -C(6)H(4)PPh(2)(o)) were prepared from TiCl(4) by treating with one equiv of deprotonated ligands in toluene. The reaction of 1a with equivalent of TiCl(4) in THF afforded another complex, C(6)H(4)OMeNC(CF(3))C(H)CPhO]TiCl(3)(thf) (3a), in addition to formation of the dichloride complex 4a, [C(6)H(4)(OMe)NC(CF(3))C(H)CPhO](2)TiCl(2). After deprotonation by alkali-metal hydride at -78 °C in diethyl ether, ligand 1a could react with 0.5 equiv of TiCl(4) to form the exclusive and clean dichloride complex 4a in high yield. These complexes were identified by NMR and mass spectra as well as elemental analyses. X-ray diffraction studies on these new trichloride complexes revealed a distorted octahedral coordination of the central metal with three chlorine atoms in a mer disposition. Dichloride complex 4a also adopted a distorted octahedral geometry around the titanium center. Two chlorine atoms are situated in the cis position, as seen in the bond angles for Cl(1)-Ti-Cl(2) (92.64(7)°). The O atom on the heterocyclic group was not coordinated with Ti. When activated by modified methylaluminoxane (MMAO), complexes 2a-e exhibited moderate to high activity towards ethylene (co)polymerization, giving relatively high molecular weight polymers with unimodal molecular weight distribution.     

Novel ruthenium(II)2 carboxylates as catalysts for alkene metathesis

The reactions of [Ru-(=CHR)Cl2(PCy3)2] (1: R = Ph; 1a: R = -CH=CPh2) with silver salts of carboxylic acids afforded new dimeric complexes of the general formula [Ru2(=CHR)2-(R'CO2)2(mu-R'CO2)2(PCy3)2(mu-H2O)] (2: R = Ph, R' = CF3; 3: R = Ph, R' = C2F5; 4: R = -CH=CPh2, R' = CF3; 5: R = Ph, R' = C6F5; 6: R = -CH=CPh2, R' = C6F5; 7: R = -CH=CPh2, R'=CCl3) in good yields. With R' = CF3, C2F5 or CCl3 these complexes are active catalysts for metathesis of acyclic alkenes, including unsaturated fatty acid esters, as well as for ring closing metathesis. The reactivity of these complexes with bases and weak donor solvents has been studied and their half-life times in several media were determined.     

Structure and reactivity studies of the first tungsten cyanoalkylidene complex

Alkylidene complex W(CHCMe2Ph)(NAr)[OCMe(CF3)2]2 (Ar = 2, 6 diisopropylphenyl) (4) reacts with one equivalent of acrylonitrile in methylene chloride to afford the tetrameric, cyanoalkylidene complex [W(CHCN)(NAr)[OCMe(CF3)2]2]4 (5) which reacts with excess acetonitrile to give the tetrameric complex [W(N(H)C(CH3)C(CN)C(CH3)N)(NAr)[OCMe(CF3)2]2]4 (6).     

Ring-opening polymerization of coordination complexes: silver(I) complexes with bis(amidopyridine) ligands derived from thiophene

The thiophene-based bis(N-methylamido-pyridine) ligand SC4H2-2,5-{C(=O)N(Me)-4-C5H4N}2 reacts with silver(I) salts AgX to give 1 : 1 complexes, which are characterized in the solid state as the macrocyclic complexes [Ag(2){SC4H2-2,5-(CONMe-4-C5H4N)2}2][X]2, which have the cis conformation of the C(=O)N(Me) group, when X = CF3CO2, NO3, or CF3SO3 but as the polymeric complex [Ag(n){SC4H2-2,5-(CONMe-4-C5H4N)2}n][X]n, with the unusual trans conformation of the C(=O)N(Me) group, when X = PF6. The bis(amido-pyridine) ligand SC4H2-2,5-{C(=O)NHCH2-3-C5H4N}2 reacts with silver(I) trifluoroacetate to give the polymeric complex [Ag(n){SC4H2-2,5-(CONHCH2-3-C5H4N)2}n][X]n, X = CF3CO2. The macrocyclic complexes contain transannular argentophilic secondary bonds. The polymers self assemble into sheet structures through interchain C=O...Ag and S...Ag bonds in [Ag(n){SC4H2-2,5-(CONMe-4-C5H4N)2}n][PF6]n and through Ag...Ag, C=O...Ag and Ag...O(trifluoroacetate)...HN secondary bonds in [Ag(n){SC4H2-2,5-(CONHCH2-3-C5H4N)2}n][CF3CO2]n.     

Structure and dynamics of tetrakis(thiophosphinato)resorcinarene complexes of silver(I), gold(I), and palladium(II)

The coordination chemistry of the tetrakis(thiophosphinato)resorcinarene sulfur-donor ligands [(C6H2CH{CH2CH2Ph})4{OC(O)R}4{OP(=S)Ph2}4] (L), where R = OCH2Ph, 4-C6H4CH3, C6H11, C4H3S, or OCH2CCH, is reported. Both silver(I) and gold(I) form cationic complexes of the type [LM2]2+, in which the ligand acts as a bis(chelate) in forming complexes with linear S-M-S (M = Ag or Au) stereochemistry. Gold(I) also forms the unusual complex [L(AuCl)2][LAu2]2+, which forms a supramolecular polymer through intermolecular aurophilic attractions. Palladium(II) forms the complex [LPd2Cl2(mu-Cl)2], in which the dipalladium(II) unit extends the natural bowl structure of the resorcinarene. The solid-state and solution conformations of the complexes, as determined by X-ray structure determination and NMR spectroscopy, respectively, are similar, but several complexes were found to exhibit dynamic behavior in solution, involving either conformational mobility of the resorcinarene unit or intermolecular ligand exchange.     

C-Cl bond activation of ortho-chlorinated benzamides by nickel and cobalt compounds supported with phosphine ligands

The C-Cl bonds of ortho-chlorinated benzamides Cl-ortho-C(6)H(4)C(=O)NHR (R = Me (1), nBu (2), Ph (3), (4-Me)Ph (4) and (4-Cl)Ph (5)) were successfully activated by tetrakis(trimethylphosphine)nickel(0) and tetrakis(trimethylphosphine)cobalt(0). The four-coordinate nickel(II) chloride complexes trans-[(C(6)H(4)C([double bond, length as m-dash]O)NHR)Ni(PMe(3))(2)Cl] (R = Me (6), nBu (7), Ph (8) and (4-Me)Ph (9)) as C-Cl bond activation products were obtained without coordination of the amide groups. In the case of 2, the ionic penta-coordinate cobalt(II) chloride [(C(6)H(4)C(=O)NHnBu)Co(PMe(3))(3)]Cl (10) with the [C(phenyl), O(amide)]-chelate coordination as the C-Cl bond activation product was isolated. Under similar reaction conditions, for the benzamides 3-5, hexa-coordinate bis-chelate cobalt(III) complexes (C(6)H(4)C(=O)NHR)Co(Cl-ortho-C(6)H(4)C(=O)NR)(PMe(3))(2) (11-13) were obtained via the reaction with [Co(PMe(3))(4)]. Complexes 11-13 have both a five-membered [C,N]-coordinate chelate ring and a four-membered [N,O]-coordinate chelate ring with two trimethyphosphine ligands in the axial positions. Phosphonium salts [Me(3)P(+)-ortho-C(6)H(4)C(=O)NHR]Cl(-) (R = Ph (14) and (4-Me)Ph (15)) were isolated by reaction of complexes 8 and 9 as a starting material under 1 bar of CO at room temperature. The crystal and molecular structures of complexes 6, 7 and 9-12 were determined by single-crystal X-ray diffraction.     

Mixed-ligand uranyl(V) beta-diketiminate/beta-diketonate complexes: synthesis and characterization

The reaction of [UO 2(Ar 2nacnac)Cl] 2 [Ar 2nacnac = (2,6- (i)Pr 2C 6H 3)NC(Me)CHC(Me)N(2,6- (i)Pr 2C 6H 3)] with Na(RC(O)CHC(O)R) (R = Me, Ph, CF 3) in tetrahydrofuran results in the formation of UO 2(Ar 2nacnac)(RC(O)CHC(O)R) (R = Me, 1; Ph, 2; CF 3, 3), which can be isolated in moderate yields. The structures of 1 and 2 have been confirmed by X-ray crystallography, while the solution redox properties of 1- 3 have been measured by cyclic voltammetry. Complexes 1- 3 exhibit reduction features at -1.82, -1.59, and -1.39 V (vs Fc/Fc (+)), respectively, at a scan rate of 100 mV.s (-1). The decrease in the reduction potential follows the electron-withdrawing ability of each beta-diketonate ligand. Chemical reduction of 1 and 2 with Cp* 2Co in toluene yields [Cp* 2Co][UO 2(Ar 2nacnac)(RC(O)CHC(O)R)] (R = Me, 4; Ph, 5), while reduction of 3 with Cp 2Co provides [Cp 2Co][UO 2(Ar 2nacnac)(CF 3C(O)CHC(O)CF 3)] ( 6). Complexes 4- 6 have been fully characterized, while the solid-state molecular structure of 5 has also been determined. In contrast to the clean reduction that occurs with Cp* 2Co, reduction of 1 with sodium ribbon, followed by cation exchange with [NEt 4]Cl, produces [NEt 4][UO 2(Ar 2nacnac)(H 2CC(O)CH(O)CMe)] ( 7) in modest yield. This product results from the formal loss of H (*) from a methyl group of the acetylacetonate ligand. Alternately, complex 7 can be synthesized by deprotonation of 1 with NaNTMS 2 in good yield.     

Two-, three-, and four-coordination at gold(I) supported by the bidentate selenium ligand [Ph2P(Se)NP(Se)Ph2](-)

Treatment of the gold(I) halide complexes LAuCl (L = PMe3, PPh3, CNC6H3Me2-2,6) with K[Ph2P(Se)NP(Se)Ph2] provides the gold-selenium coordination compounds [(N(Ph2PSe)2-Se,Se')AuL]. However, on standing for a number of days, the complex [(N(Ph2PSe)2-Se,Se')AuPMe3] gains a phosphine to provide the bis(phosphine) species [(N(Ph2PSe)2-Se,Se')Au(PMe3)2]. Treatment of the K[Ph2P(Se)NP(Se)Ph2] ligand with [(Ph3PAu)3O]BF4 allows the isolation of [(N(Ph2PSe)2-Se,Se')(AuPPh3)2]BF4. Reaction of the complex [(dppm)(AuCl)2] with AgSO3CF3 followed by addition of the ligand K[Ph2P(Se)NP(Se)Ph2] results in the formation of [(N(Ph2PSe)2-Se,Se')Au2(dppm)]OSO2CF3 and treatment of [(tht)AuCl] (tht = tetrahydrothiophene) with an equimolar quantity of K[Ph2P(Se)NP(Se)Ph2] affords the complex [(N(Ph2PSe)2-Se,Se')2Au2]. The compounds [(N(Ph2PSe)2-Se,Se')Au2(dppm)]OSO2CF3, [(N(Ph2PSe)2-Se,Se')AuPPh3] and [(N(Ph2PSe)2-Se,Se')Au(PMe3)2] have been investigated crystallographically. The results reveal that the metal centers are two-, three-, and four-coordinate, respectively. The cationic, eight-membered ring complex bearing the dppm ligand displays transannular aurophilic bonding and is further associated into dimers via intermolecular gold-selenium contacts. The six-membered rings in the other two structures have C2-symmetrical twist conformations, however, the Au(I) coordination sphere in [N(PPh2Se)2]AuPPh3 is not fully symmetrical. The Au-Se bond lengths increase dramatically as the coordination number of the metal atom becomes larger.     

Syntheses and structures of thermally stable diketiminato complexes of gold and copper

While most metallic elements across the Periodic Table form stable chelating β-diketiminato complexes, examples of Au(I) are conspicuous by their absence. We report here the reaction of K[HC(F(3)CC=NR)(2)] with AuCl(PPh(3)) which provides a rare example of a thermally stable gold(I) diketiminato complex, (Ph(3)P)Au[RN=C(CF(3))CH(CF(3))C=NR] [R = 3,5-C(6)H(3)(CF(3))(2)]. The complex is highly fluxional in solution but in the solid state adopts a U-conformation. By contrast, the analogous reaction of K[HC(F(3)CC=NR)(2)] with CuBr(PPh(3))(3) gives the rigid 18-electron chelate complex (Ph(3)P)(2)Cu[κ(2)-HC{(CF(3))C=NR}(2)].     

The structural and stereogenic properties of pentaerythritoxy-bridged cyclotriphosphazene derivatives: spiro-spiro, spiro-ansa and ansa-ansa isomers

Reactions of pentaerythritol with hexachlorocyclotriphosphazene, N3P3Cl6, and gem-disubstituted cyclotriphosphazene derivatives, N3P3Cl4R2 [R = Ph, NHBu(t) or (OCH2CF2CF2CH2O)0.5] gave a series of pentaerythritol-bridged derivatives linked spiro-spiro, spiro-ansa and ansa-ansa. The structures and stereogenic properties of the products were characterised by X-ray crystallography and 31P NMR spectroscopy on addition of the chiral solvating agent, (S)-(+)-2,2,2-trifluoro-1-(9-anthryl)ethanol. Molecules with spiro-spiro and spiro-ansa bridged gem-disubstituted cyclophosphazenes [R = Ph, NHBu(t) or (OCH2CF2CF2CH2O)0.5] are found to be chiral and exist as racemates. Molecules with ansa-ansa bridged cyclophosphazenes [R = Cl or (OCH2CF2CF2CH2O)0.5] have been characterised for the first time and are shown to have meso configurations. Analysis of crystal structure data shows that the six-membered chair form of the spiro rings and the eight-membered boat-chair form of the ansa rings in the bridged compounds are similar to analogous spiro and ansa exocyclic ring conformations of 1,3-propanedioxy-derivatives of cyclophosphazenes.     

A new ONO3- trianionic pincer-type ligand for generating highly nucleophilic metal-carbon multiple bonds

Appending an amine to a C═C double bond drastically increases the nucleophilicity of the β-carbon atom of the alkene to form an enamine. In this report, we present the synthesis and characterization of a novel CF(3)-ONO(3-) trianionic pincer-type ligand, rationally designed to mimic enamines within a metal coordination sphere. Presented is a synthetic strategy to create enhanced nucleophilic tungsten-alkylidene and -alkylidyne complexes. Specifically, we present the synthesis and characterization of the new CF(3)-ONO(3-) trianionic pincer tungsten-alkylidene [CF(3)-ONO]W═CH(Et)(O(t)Bu) (2) and -alkylidyne {MePPh(3)}{[CF(3)-ONO]W≡C(Et)(O(t)Bu)} (3) complexes. Characterization involves a combination of multinuclear NMR spectroscopy, combustion analysis, DFT computations, and single crystal X-ray analysis for complexes 2 and 3. Exhibiting unique nucleophilic reactivity, 3 reacts with MeOTf to yield [CF(3)-ONO]W═C(Me)(Et)(O(t)Bu) (4), but the bulkier Me(3)SiOTf silylates the tert-butoxide, which subsequently undergoes isobutylene expulsion to form [CF(3)-ONO]W═CH(Et)(OSiMe(3)) (5). A DFT calculation performed on a model complex of 3, namely, [CF(3)-ONO]W≡C(Et)(O(t)Bu) (3'), reveals the amide participates in an enamine-type bonding combination. For complex 2, the Lewis acids MeOTf, Me(3)SiOTf, and B(C(6)F(5))(3) catalyze isobutylene expulsion to yield the tungsten-oxo complex [CF(3)-ONO]W(O)((n)Pr) (6).     

The reaction of Li[Al(OR)4] R = OC(CF3)2Ph, OC(CF3)3 with NO/NO2 giving NO[Al(OR)4], Li[NO3] and N2O. The synthesis of NO[Al(OR)4] from Li[Al(OR)4] and NO[SbF6] in sulfur dioxide solution

NO[Al(OC(CF(3))(2)Ph)(4)] 1 and NO[Al(OC(CF(3))(3))(4)] 2 were obtained by the metathesis reaction of NO[SbF(6)] and the corresponding Li[Al(OR)(4)] salts in liquid sulfur dioxide solution in ca 40% (1) and 85% (2) isolated yield. 1 and 2, as well as Li[NO(3)] and N(2)O, were also given by the reaction of an excess of mixture of (90 mol%) NO, (10 mol%) NO(2) with Li[Al(OR)(4)] followed by extraction with SO(2). The unfavourable disproportionation reaction of 2NO(2)(g) to [NO](+)(g) and [NO(3)](-)(g)[DeltaH degrees = +616.2 kJ mol(-1)] is more than compensated by the disproportionation energy of 3NO(g) to N(2)O(g) and NO(2)(g)[DeltaH degrees =-155.4 kJ mol(-1)] and the lattice energy of Li[NO(3)](s)[U(POT)= 862 kJ mol(-1)]. Evidence is presented that the reaction proceeds via a complex of [Li](+) with NO, NO(2)(or their dimers) and N(2)O. NO(2) and Li[Al(OC(CF(3))(3))(4)] gave [NO(3)(NO)(3)][Al(OC(CF(3))(3))(4)](2), NO[Al(OC(CF(3))(3))(4)] and (NO(2))[Al(OC(CF(3))(3))(4)] products. The aluminium complex [Li[AlF(OC(CF(3))(2)Ph)(3)]](2) 3 was prepared by the thermal decomposition of Li[Al(OC(CF(3))(2)Ph)(4)]. Compounds 1 and 3 were characterized by single crystal X-ray structural analyses, 1-3 by elemental analyses, NMR, IR, Raman and mass spectra. Solid 1 contains [Al(OC(CF(3))(2)Ph)(4)](-) and [NO](+) weakly linked via donor acceptor interactions, while in the SO(2) solution there is an equilibrium between the associated [NO](+)[Al(OC(CF(3))(2)Ph)(4)](-) and separated solvated ions. Solid 2 contains essentially ionic [NO](+) and [Al(OC(CF(3))(3))(4)](-). Complex 3 consists of two [Li[AlF(OC(CF(3))(2)Ph)(3)]] units linked via fluorine lithium contacts. Compound 1 is unstable in the SO(2) solution and decomposes to yield [AlF(OC(CF(3))(2)Ph)(3)](-), [(PhC(CF(3))(2)O)(3)Al(mu-F)Al(OC(CF(3))(2)Ph)(3)](-) anions as well as (NO)C(6)H(4)C(CF(3))(2)OH, while compound 2 is stable in liquid SO(2). The [small nu](NO(+)) in 1 and [NO](+)(toluene)[SbCl(6)] are similar, implying similar basicities of [Al(OC(CF(3))(2)Ph)(4)](-) and toluene.     

p-tert-Butylcalix[4]arene complexes of molybdenum and tungsten: reactivity of the calixarene methylene C-H bond and the facile migration of the metal around the phenolic rim of the calixarene

p-tert-Butylcalix[4]arene, [CalixBut(OH)4], reacts with Mo(PMe3)6 and W(PMe3)4(eta2-CH2PMe2)H to yield compounds of composition {[CalixBut(OH)2(O)2]M(PMe3)3H2} which exhibit unprecedented use of a C-H bond of a calixarene methylene group as a binding functionality in the form of agostic and alkyl hydride derivatives. Thus, X-ray diffraction studies demonstrate that, in the solid state, the molybdenum complex [CalixBut(OH)2(O)2]Mo(PMe3)3H2 exists as an agostic derivative with a Mo...H-C interaction, whereas the tungsten complex exists as a metallated trihydride [Calix-HBut(OH)2(O)2]W(PMe3)3H3. Solution 1H NMR spectroscopic studies, however, provide evidence that [Calix-HBut(OH)2(O)2]W(PMe3)3H3 is in equilibrium with its agostic isomer [CalixBut(OH)2(O)2]W(PMe3)3H2. Dynamic NMR spectroscopy also indicates that the [M(PMe3)3H2] fragments of both the molybdenum and tungsten complexes [CalixBut(OH)2(O)2]M(PMe3)3H2 migrate rapidly around the phenolic rim of the calixarene on the NMR time scale, an observation that is in accord with incorporation of deuterium into the methylene endo positions upon treatment of the isomeric mixture of [CalixBut(OH)2(O)2]W(PMe3)3H2 and [Calix-HBut(OH)2(O)2]W(PMe3)3H3 with D2. Treatment of {[CalixBut(OH)2(O)2]W(PMe3)3H2} with Ph2C2 gives the alkylidene complex [CalixBut(O)4]W=C(Ph)Ar [Ar = PhCC(Ph)CH2Ph].     

Fluorinated bismuth alkoxides: from monomers to polymers and oxo-clusters

A series of new bismuth fluoroalkoxide compounds have been prepared through the treatment of 1,1,1,3,3,3-hexafluoro-2-propanol with BiAr3 (where Ar=Ph, p-Tol). Reactions were conducted without the use of any additional solvent and the reaction products distilled or extracted with non-polar or polar Lewis base solvents. Structural analyses reveal that under variable reaction conditions the interaction of BiAr3 with (CF3)2CHOH can give a mixture of bismuth complexes with varying degrees of substitution, cluster formation and aggregation. Compounds [Bi(OCH(CF3)2)3(pyr)2] () (pyr=pyridine), [Bi(OCH(CF3)2)3(thf)3] () (thf=tetrahydrofuran), [Bi2(OCH(CF3)2)3(dabco)3] () (dabco=1,4-diazabicyclo[2.2.2]octane), [PhBi(OCH(CF3)2)2]n (), [Bi2O(OCH(CF3)2)4(C7H8)]2 () (C7H8=toluene), [Bi9O7(OCH(CF3)2)13] (), [Bi2O(OCH(CF3)2)4(Et2O)]2 (), [Bi2O(OCH(CF3)2)4(thf)]2 () and [Bi2O(OCH(CF3)2)4(tmeda)2] () (tmeda=N,N,N',N'-tetramethylethylenediamine) have been fully characterised including by single crystal X-ray diffraction.     

Reactions of amides with organoaluminum compounds: factors affecting the coordination mode of aluminum amidates

Factors affecting the coordination mode of an amidato group on aluminum will be presented. The reaction of N-tert-butylalkylacetamide ((t)BuNHCR([double bond]O)) with 1.1 molar equiv of Me(3)Al in refluxing hexane affords a pentacoordinated, dimeric compound [Me(2)Al[eta(2)-(t)BuNC(R)(mu(2)-O)]](2) (3, R = p-(t)Bu-C(6)H(4); 4, R = 2,6-F,F-C(6)H(3); 5, R = Me; 6, R = CF(3); 7, R = p-F(3)C-C(6)H(4)). However, in the presence of 2.2 molar equiv of Me(3)Al, N-tert-butyl-4-tert-butylbenzamide ((t)BuNHC(p-(t)Bu-C(6)H(4))([double bond]O in refluxing hexane gives [Me(2)Al[eta(2)-(t)BuNC(p-(t)Bu-C(6)H(4))(mu(2)-O)]AlMe(3)], 8. In contrast, the reaction of R'NHCR' '([double bond]O) with 1 molar equiv of R(3)Al at room temperature produces tetracoordinated, dimeric, eight-membered ring aluminum compounds [R(2)Al[mu,eta(2)-R'NC(R' ')O]](2) (9, R = Me, R' = 2,6-(i)Pr, (i)()Pr-C(6)H(3), R' ' = Ph; 10, R = Me, R' = (i)Bu, R' ' = Ph; 11, R = Et, R' = Bn, R' ' = Ph; 12, R = Me, R' = Ph, R' ' = CF(3); 13, R = Me, R' = Bn, R' ' = CF(3)). On the other hand, 4'-chlorobenzanilide ((p-Cl-C(6)H(4))NHCPh([double bond]O)) reacts with R(3)Al to produce trimeric, twelve-membered ring aluminum compounds [R(2)Al[mu, eta(2)-(p-Cl-C(6)H(4))NC(Ph)O]](3) (14, R = Me; 15, R = Et). Furthermore, the reaction of 2'-methoxybenzanilide with 1 molar equiv of Me(3)Al in hexane yields a dinuclear aluminum complex [Me(2)Al(o-OMe-Ph)NC(Ph)(O)AlMe(3)], 16.     

Mono- and dinuclear cobalt complexes with chelating or bridging bidentate P,N phosphino- and phosphinito-oxazoline ligands: synthesis, structures and catalytic ethylene oligomerisation

Cobalt(ii) complexes of the type [CoCl(2)(P,N)], where P,N represents a heterobidentate phosphino- or phosphinito-oxazoline-type ligand, have been synthesised and characterised by infrared spectroscopy and elemental analysis. Their molecular structures were established by single-crystal X-ray diffraction in the solid state. Whereas the phosphino-oxazoline complex [CoCl(2){Ph(2)PCH(2)ox(Me2)}] (Ph(2)PCH(2)ox(Me2) = 2-[(diphenylphosphanyl)-methyl]-4,4-dimethyl-4,5-dihydro-oxazole) () and the phosphinito-oxazoline complexes [CoCl(2){Ph(2)POCH(2)ox(Me2)}] (Ph(2)POCH(2)ox(Me2) = 1-[4,4-dimethyl-2{1-oxy(diphenylphosphino)-1-methyl}]-4,5-dihydro-oxazole) () and [CoCl(2){Ph(2)POCMe(2)ox(Me2)}] (Ph(2)POCMe(2)ox(Me2) = 1-[4,4-dimethyl-2- [1-oxy(diphenylphosphino)-1-methylethyl]]-4,5-dihydrooxazole) () are mononuclear, the phosphino-oxazoline complexes [CoCl(2){micro-i-Pr(2)PCH(2)ox}](2) (i-Pr(2)PCH(2)ox = 2-[(diisopropyl-phosphanyl)-methyl]-4,5-dihydro-oxazole) () and [CoCl(2){micro-Ph(2)PCH(2)ox}](2) (Ph(2)PCH(2)ox = 2-[(diphenyl-phosphanyl)-methyl]-4,5-dihydro-oxazole) () are dinuclear compounds and contain two bridging phosphino-oxazoline ligands which form a 10-membered ring. In the course of this work, the zwitterionic complex [CoCl(3){Ph(2)PCH(2)C(O)OCH(2)CMe(2)NH(3)] () was obtained and characterised by X-ray diffraction in which the oxazoline ring has been opened. Air-oxidation of the phosphine function of the mononuclear P,N chelate complex yielded the blue N,O-bridged, centrosymmetric dinuclear complex [[upper bond 1 start]CoCl(2){micro-OPPh(2)CH(2)[lower bond 1 start]C[double bond, length as m-dash]N[upper bond 1 end]CMe(2)CH(2)O[lower bond 1 end]}](2) () which contains a 12-membered ring. All these complexes are paramagnetic and their magnetic moments in solution were measured by the Evans method. Complexes were evaluated in the catalytic oligomerisation of ethylene with AlEtCl(2) or methylaluminoxane (MAO) as cocatalysts and provided moderate activities. In the presence of AlEtCl(2) (6-14 equiv.), the selectivities for ethylene dimers were higher than 92% and complex showed the highest turnover frequency with 14 equiv. of AlEtCl(2). When MAO was used as cocatalyst, the catalytic activities were similar to those with AlEtCl(2) but significant amounts of C(6)-C(12) oligomers were produced.