Novel Pb(II), Zn(II), and Cd(II) coordination polymers constructed from ferrocenyl-substituted carboxylate and bipyridine-based ligands

Treatment of two kinds of ferrocenyl-substituted carboxylate ligands (3-ferrocenyl-2-crotonic acid, HOOC-CH=(CH(3))CFc (Fc=(eta(5)-C(5)H(5))Fe(eta(5)-C(5)H(4))) or O-ferrocecarbonyl benzoic acid, o-HOOCC(6)H(4)COFc with Pb(OAc)(2).3H(2)O, Zn(OAc)(2).2H(2)O, or Cd(OAc)(2).2H(2)O) resulted in four novel ferrocene-containing coordination polymers [[Pb(mu(2)-eta(2)-OOCCH=(CH(3))CFc)(2)].MeOH](n) (1), [[Zn(o-OOCC(6)H(4)COFc)(2)(4,4'-bipy)(H(2)O)(2)].2MeOH.2H(2)O](n) (4,4'-bipy = 4,4'-bipyridine) (2), [[Cd(o-OOCC(6)H(4)COFc)(2)(bpe)(MeOH)(2)].2H(2)O](n) (bpe = 1,2-bis(4-pyridyl)ethene) (3), and [Pb(o-OOCC(6)H(4)COFc)(eta(2)-o-OOCC(6)H(4)COFc)(bpe)](n)() (4). Their crystal structures have been characterized by single X-ray determinations. In polymer 1, Pb(II) ions are bridged by tridentate FcC(CH(3))=CHCOO(-) anions, forming an infinite chain [Pb(mu(2)-eta(2)-OOC=CH(CH(3))CFc)(2)](n). In polymers 2-4, there are three kinds of components, metal ions, o-FcCOC(6)H(4)COO(-) units, and organic bridging ligands. The bipyridine-based ligands connect metal ions leading to a one-dimensional chain with o-FcCOC(6)H(4)COO(-) units acting as monodentate or chelate ligands in the side chain. Such coordination polymers containing ferrocenyl-substituted carboxylate and bipyridine-based ligands are very rare. The solution-state differential pulse voltammetries of polymers 1-4 were determined. The results indicate that the half-wave potential of the ferrocenyl moieties is influenced by the Pb(II) ions in polymer 1 and strongly influenced by Zn(II), Cd(II), or Pb(II) ions in polymers 2-4. The thermal properties of the four polymers were also investigated.     

Synthesis, structure, and reactivity of 13-vertex carboranes and 14-vertex metallacarboranes

Syntheses, properties, and synthetic applications of 13-vertex closo- and nido-carboranes are reported. Reactions of the nido-carborane salt [(CH2)3C2B10H10]Na2 with dihaloborane reagents afforded 13-vertex closo-carboranes 1,2-(CH2)3-3-R-1,2-C2B11H10 (R = H (2), Ph (3), Z-EtCH=C(Et) (4), E-(t)BuCH=CH (5)). Treatment of the arachno-carborane salt [(CH2)3C2B10H10]Li4 with HBBr2.SMe2 gave both the 13-vertex carborane 2 and a 14-vertex closo-carborane (CH2)3C2B12H12 (8). On the other hand, the reaction of [C6H4(CH2)2C2B10H10]Li4 with HBBr2.SMe2 generated only a 13-vertex closo-carborane 1,2-C6H4(CH2)2-1,2-C2B11H11 (9). Electrophilic substitution reactions of 2 with excess MeI, Br2, or I2 in the presence of a catalytic amount of AlCl3 produced the hexa-substituted 13-vertex carboranes 8,9,10,11,12,13-X6-1,2-(CH2)3-1,2-C2B11H5 (X = Me (10), Br (11), I (12)). The halogenated products 11 and 12 displayed unexpected instability toward moisture. The 13-vertex closo-carboranes were readily reduced by groups 1 and 2 metals. Accordingly, several 13-vertex nido-carborane dianionic salts [nido-1,2-(CH2)3-1,2-C2B11H11][Li2(DME)2(THF)2] (13), [[nido-1,2-(CH2)3-1,2-C2B11H11][Na2(THF)4]]n (13a), [[nido-1,2-(CH2)3-3-Ph-1,2-C2B11H10][Na2(THF)4]]n (14), [[nido-1,2-C6H4(CH2)2-1,2-C2B11H11][Na2(THF)4]]n (15), and [nido-1,2-(CH2)3-1,2-C2B11H11][M(THF)5] (M = Mg (16), Ca (17)) were prepared in good yields. These carbon-atom-adjacent nido-carboranes were not further reduced to the corresponding arachno species by lithium metal. On the other hand, like other nido-carborane dianions, they were useful synthons for the production of super-carboranes and supra-icosahedral metallacarboranes. Interactions of 13a with HBBr2.SMe2, (dppe)NiCl2, and (dppen)NiCl2 gave the 14-vertex carborane 8 and nickelacarboranes [eta5-(CH2)3C2B11H11]Ni(dppe) (18) and [eta5-(CH2)3C2B11H11]Ni(dppen) (19), respectively. All complexes were fully characterized by various spectroscopic techniques and elemental analyses. Some were further confirmed by single-crystal X-ray diffraction studies.     

Alkyl carbon-nitrogen reductive elimination from platinum(IV)-sulfonamide complexes

Platinum(IV) complexes containing monodentate sulfonamide ligands, fac-(dppbz)PtMe(3)(NHSO(2)R) (dppbz = o-bis(diphenylphosphino)benzene; R = p-C(6)H(4)(CH2)(3)CH(3) (1a), p-C(6)H(4)CH(3) (1b), CH(3) (1c)), have been synthesized and characterized, and their thermal reactivity has been explored. Compounds 1a-c undergo competitive C-N and C-C reductive elimination upon thermolysis to form N-methylsulfonamides and ethane, respectively. Selectivity for either C-N or C-C bond formation can be achieved by altering the reaction conditions. Good yields of the C-N-coupled products were observed when the thermolyses of 1a-c were conducted in benzene-d(6). In contrast, exclusive C-C reductive elimination occurred upon themolysis of 1a,b in nitrobenzene-d(5). When the thermolyses of 1a were performed in the presence of sulfonamide anion NHSO2R- in benzene-d(6), ethane elimination was completely inhibited and C-N reductive elimination products were formed in high yield. Mechanistic studies support a two-step reaction pathway involving initial dissociation of NHSO(2)R(-) from the platinum center, followed by nucleophilic attack of this anion on a methyl group of the resulting five-coordinate platinum(IV) cation to form MeNHSO(2)R and (dppbz)PtMe(2). C-C reductive elimination to form ethane occurs directly from the five-coordinate Pt(IV) cation.     

Ionic-liquid-promoted decaborane dehydrogenative alkyne-insertion reactions: a new route to o-carboranes

Unlike in conventional organic solvents, where Lewis base catalysts are required, decaborane dehydrogenative alkyne-insertion reactions proceed rapidly in biphasic ionic-liquid/toluene mixtures with a wide variety of terminal and internal alkynes, thus providing efficient, one-step routes to functional o-carborane 1-R-1,2-C2B10H11 and 1-R-2-R'-1,2-C2B10H10 derivatives, including R = C6H5- (1), C6H13- (2), HC[triple bond]C-(CH2)5- (3), (1-C2B10H11)-(CH2)5- (4), CH3CH2C(O)OCH2- (5), (C2H5)2NCH2- (6), NC-(CH2)3- (7), 3-HC[triple bond]C-C6H4- (8), (1-C2B10H11)-1,3-C6H4- (9), HC[triple bond]C-CH2-O-CH2- (10); R,R' = C2H5- (11); R = HOCH2-, R' = CH3- (12); R = BrCH2-; R' = CH3- (13); R = H2C=C(CH3)-, R' = C2H5- (14). The best results were obtained from reactions with only catalytic amounts of bmimCl (1-butyl-3-methylimidazolium chloride), where in many cases reaction times of less than 20 min were required. The experimental data for these reactions, the results observed for the reactions of B10H13(-) salts with alkynes, and the computational studies reported in the third paper in this series all support a reaction sequence involving (1) the initial ionic liquid promoted formation of the B10H13(-) anion, (2) addition of B10H13(-) to the alkyne to form an arachno-R,R'-C2B10H13(-) anion, and (3) protonation of arachno-R,R'-C2B10H13(-) to form the final neutral 1-R-2-R'-1,2-C2B10H10 product with loss of hydrogen.     

Synthesis, structure, and reactivity of Group 4 metallacycles incorporating a Me2C-linked cyclopentadienyl-carboranyl ligand

Group 4 metallacycles [eta5:sigma-Me2C(C5H4)(C2B10H10)]Ti[eta2-N(Me)CH2CH2N(Me)] (1a), [eta5:sigma-Me2C(C5H4)(C2B10H10)]Zr[eta2-N(Me)CH2CH2N(Me)](HNMe2) (1b) and [eta5:sigma-Me2C(C5H4)(C2B10H10)]M[eta2-N(Me)CH2CH2CH2N(Me)] (M = Ti (2a), Zr (2b), Hf (2c)) were synthesized by reaction of [eta5:sigma-Me2C(C5H4)(C2B10H10)]M(NMe2)(2) (M = Ti, Zr, Hf) with MeNH(CH2)(n)NHMe (n = 2, 3). These metal complexes reacted with unsaturated molecules such as 2,6-Me2C6H3NC, PhNCO and PhCN to give exclusively M-N bond insertion products. The M-C(cage) bond remained intact. Such a preference of M-N over M-C(cage) insertion is suggested to most likely be governed by steric factors, and the mobility of the migratory groups plays no obvious role in the reactions. This work also shows that the insertion of unsaturated molecules into the metallacycles is a useful and effective method for the construction of very large ring systems.     

A comparative ab initio study of the primary hydration and proton dissociation of various imide and sulfonic acid ionomers

We compare the role of neighboring group substitutions on proton dissociation of hydrated acidic moieties suitable for proton exchange membranes through electronic structure calculations. Three pairs of ionomers containing similar electron withdrawing groups within the pair were chosen for the study: two fully fluorinated sulfonyl imides (CF(3)SO(2)NHSO(2)CF(3) and CF(3)CF(2)SO(2)NHSO(2)CF(3)), two partially fluorinated sulfonyl imides (CH(3)SO(2)NHSO(2)CF(3) and C(6)H(5)SO(2)NHSO(2)CF(2)CF(3)), and two aromatic sulfonic acid based materials (CH(3)C(6)H(4)SO(3)H and CH(3)OC(6)H(3)OCH(3)C(6)H(4)SO(3)H). Fully optimized counterpoise (CP) corrected geometries were obtained for each ionomer fragment with the inclusion of water molecules at the B3LYP/6-311G** level of density functional theory. Spontaneous proton dissociation was observed upon addition of three water molecules in each system, and the transition to a solvent-separated ion pair occurred when four water molecules were introduced. No considerable quantitative or qualitative differences in proton dissociation, hydrogen bond networks formed, or water binding energies were found between systems containing similar electron withdrawing groups. Each of the sulfonyl imide ionomers exhibited qualitatively similar results regarding proton dissociation and separation. The fully fluorinated sulfonyl imides, however, showed a greater propensity to exist in dissociated and ion-pair separated states at low degrees of hydration than the partially fluorinated sulfonyl imides. This effect is due to the additional electron withdrawing groups providing charge stabilization as the dissociated proton migrates away from the imide anion.     

Proton-ionizable acyclic dibenzopolyethers and their polymers for use in selective lead(II) separation

Abstract

2,2′-[1,2-Ethanediylbis(oxy)]bisbenzoic acid (1), 2,2′-[oxybis(1,2-ethanediyloxy)]bisbenzoic acid (2), 1,2-[2′-(acetoxy)phenoxy] ethane (3), and 1,5-[2′-(acetoxy)phenoxy]-3-oxopentane (4) have been prepared for use in selective Pb(II) separation. The extraction of Pb(II) and Cu(II) from buffered aqueous solutions of varying pH into chloroform by 1–4 is examined in relation to their molecular structure. Compound 1 with an ethylene glycol spacer unit exhibits excellent extraction selectivity for Pb(II) over Cu(II). Lengthening the spacer group to a diethylene glycol unit diminishes the extraction efficiency and selectivity. For 3 and 4, extraction was inefficient due to low lipophilicity and solubility of the ligands in chloroform. Condensation polymerization of compounds 3 and 4 with formaldehyde in formic acid provides stable chelating resins 5 and 6 which contain both ion-exchange and polyether binding sites for metal complexation. Resin 5 with an ethylene glycol spacer group is found to be an effective chelating resin for Pb(II) separation. The sorption mechanism and selectivity are studied and compared with the commercially available iminodiacetic acid resin CR-10.     

Cooperative metal-boron interactions in the reaction of nido-1,2-(Cp*RuH)2B3H7, Cp* = eta5-C5Me5, with HC(triple bond)CPh

Products of the reaction of nido-1,2-(CpRuH)(2)B(3)H(7), 1, and phenylacetylene demonstrate the ways in which cluster metal and main group fragments can combine with an alkyne. Observed at 22 degrees C are (a) reduction to mu-alkylidene Ru-B bridges (isomers nido-1,2-(CpRu)(2)(1,5-mu-C{Ph}Me)B(3)H(7), 2, and nido-1,2-(CpRu)(2)(1,5-mu-C{CH(2)Ph}H)B(3)H(7), 3), (b) reduction to exo-cluster alkyl substituents on boron (nido-1,2-(CpRuH)(2)-3-CH(2)CH(2)Ph-B(3)H(6), 4), (c) cluster insertion with extrusion of a BH(2) fragment into an exo-cluster bridge (nido-1,2-(CpRu)(2)(mu-H)(mu-BH(2))-4-or-5-Ph-4,5-C(2)B(2)H(5), 5), (d) combined insertion with BH(2) extrusion and reduction (nido-1,2-(CpRu)(2)(mu-H)(mu-BH(2))-3-CH(2)CH(2)Ph-5-Ph-4,5-C(2)B(2)H(4), 6), (e) insertion and loss of borane with and without reduction (nido-1,2-(CpRu)(2)-5-Ph-4,5-C(2)B(2)H(7), 7, and isomers nido-1,2-(CpRu)(2)-3-CH(2)CH(2)Ph-4-(and-5-)Ph-C(2)B(2)H(6), 8 and 9), and (f) insertion and borane loss plus reduction (nido-1,2-(CpRu)(2)-3-(trans-CH=CHPh)-5-Ph-4,5-C(2)B(2)H(6), 10). Along with 7, 8, and 10, the reaction at 90 degrees C generates products of insertion and nido- to closo-cluster closure (closo-4-Ph-1,2-(CpRuH)(2)-4,6-C(2)B(2)H(3), 11, closo-1,2-(CpRuH)(2)-3-CH(2)CH(2)Ph-5-Ph-7-CH(2)CH(2)Ph-4,5-C(2)B(3)H(2), 12, closo-1,2-(CpRuH)(2)-5-Ph-4,5-C(2)B(3)H(4), 13, and isomers closo-1,2-(CpRuH)(2)-3-and-7-CH(2)CH(2)Ph-5-Ph-4,5-C(2)B(3)H(3), 14 and 15). The clusters with an exo-cluster bridging BH(2) groups are shown to be intermediates by demonstrating that the major products 5 and 6 rearrange to 13 and convert to 14, respectively. 14 then isomerizes to 15, thus connecting low- and high-temperature products. Finally, all available information shows that the high reactivity of 1 with alkynes can be associated with the "extra" two Ru-H hydrides on the framework of 1 which are required to meet the nido-cluster electron count.     

非对称结构的Salen型镍、铜、锰配合物的合成及性质

本文设计合成了两种新型Salen配体H2L1(N-苯基-N-(2-羟基-5-甲基苯基)-N′-(2,5-二羟基苯基)-4,5-二甲氧基邻苯二胺)和H2L2(N-苯基-N-(2-羟基-5-甲基苯基)-N′-(2-羟基-3,5二叔丁基苯基)-4,5-二甲氧基邻苯二胺)及相应的过渡金属配合物MLn(M=Ni、Cu、Mn;n=1、2)。分别采用核磁、质谱、元素分析、红外光谱和紫外-可见光谱对目标化合物进行了表征。研究了两种配体及其金属配合物的荧光性质,探讨了配体结构及中心金属离子对其荧光性质的影响。研究发现,由于氢键的作用使得配体H2L1的荧光强度远低于H2L2;中心金属离子的嵌入对H2L2的荧光强度有明显的猝灭作用。用循环伏安法研究了配体及其金属配合物的电化学氧化还原性质,并测定了配体及其金属配合物溶液的电导率、摩尔电导率。结果表明,镍、铜、锰配合物的氧化还原过程均为准可逆的单电子过程;且在所研究的配体和配合物中,金属锰配合物溶液的导电能力较强。     

Synthesis and structural characterization of mono- and bisfunctional o-carboranes

Functionalized o-carboranes are interesting ligands for transition metals. Reaction of LiC2B10H11 with Me2NCH2CH2Cl in toluene afforded 1-Me2NCH2CH2-1,2-C2B10H11 (1). Treatment of 1 with 1 equiv. of n-BuLi gave [(Me2NCH2CH2)C2B10H10]Li ([1]Li), which was a very useful synthon for the production of bisfunctional o-carboranes. Reaction of [1]Li with RCH2CH2Cl afforded 1-Me2NCH2CH2-2-RCH2CH2-1,2-C2B10H10 (R = Me2N (2), MeO (3)). 1 and 2 were also prepared from the reaction of Li2C2B10H10 with excess Me2NCH2CH2Cl. Treatment of [1]Li with excess MeI or allyl bromide gave the ionic salts, [1-Me3NCH2CH2-2-Me-1,2-C2B10H10][I] (4) and [1-Me2N(CH2=CHCH2)CH2CH2-2-(CH2=CHCH2)-1,2-C2B10H10][Br] (6), respectively. Interaction of [1]Li with 1 equiv. of allyl bromide afforded 1-Me2NCH2CH2-2-(CH2=CHCH2)-1,2-C2B10H10 (5). Treatment of [1]Li with excess dimethylfulvene afforded 1-Me2NCH2CH2-2-C5H5CMe2-1,2-C2B10H10 (7). Interaction of [1]Li with excess ethylene oxide afforded an unexpected product 1-HOCH2CH2-2-(CH2=CH)-1,2-C2B10H10 (8). 1 and 3 were conveniently converted into the corresponding deborated compounds, 7-Me2NHCH2CH2-7,8-C2B9H11 (9) and 7-Me2NHCH2CH2-8-MeOCH2CH2-7,8-C2B9H10 (10), respectively, in MeOH-MeOK solution. All of these compounds were characterized by various spectroscopic techniques and elemental analyses. The solid-state structures of 4 and 6-10 were confirmed by single-crystal X-ray analyses.     

Metal ion-controlled self-assembly using pyrimidine hydrazone molecular strands with terminal hydroxymethyl groups: a comparison of Pb(II) and Zn(II) complexes

Metal complexation studies were performed with the ditopic pyrimidine-hydrazone (pym-hyz) strand 6-hydroxymethylpyridine-2-carboxaldehyde (2-methyl-pyrimidine-4,6-diyl)bis(1-methylhydrazone) (1) and Pb(ClO(4))(2)·3H(2)O, Pb(SO(3)CF(3))(2)·H(2)O, Zn(SO(3)CF(3))(2), and Zn(BF(4))(2) to examine the ability of 1 to form various supramolecular architectures. X-ray crystallographic and NMR studies showed that coordination of the Pb(II) salts with 1 on a 2:1 metal/ligand ratio in CH(3)CN and CH(3)NO(2) resulted in the linear complexes [Pb(2)1(ClO(4))(4)] (2), [Pb(2)1(ClO(4))(3)(H(2)O)]ClO(4) (3), and [Pb(2)1(SO(3)CF(3))(3)(H(2)O)]SO(3)CF(3) (4). Two unusually distorted [2 × 2] grid complexes, [Pb1(ClO(4))](4)(ClO(4))(4) (5) and [Pb1(ClO(4))](4)(ClO(4))(4)·4CH(3)NO(2) (6), were formed by reacting Pb(ClO(4))(2)·6H(2)O and 1 on a 1:1 metal/ligand ratio in CH(3)CN and CH(3)NO(2). These grids formed despite coordination of the hydroxymethyl arms due to the large, flexible coordination sphere of the Pb(II) ions. A [2 × 2] grid complex was formed in solution by reacting Pb(SO(3)CF(3))(2)·H(2)O and 1 on a 1:1 metal/ligand ratio in CH(3)CN as shown by (1)H NMR, microanalysis, and ESMS. Reacting the Zn(II) salts with 1 on a 2:1 metal/ligand ratio gave the linear complexes [Zn(2)1(H(2)O)(4)](SO(3)CF(3))(4)·C(2)H(5)O (7) and [Zn(2)1(BF(4))(H(2)O)(2)(CH(3)CN)](BF(4))(3)·H(2)O (8). (1)H NMR studies showed the Zn(II) and Pb(II) ions in these linear complexes were labile undergoing metal ion exchange. All of the complexes exhibited pym-hyz linkages in their cisoid conformation and binding between the hydroxymethyl arms and the metal ions. No complexes were isolated from reacting either of the Zn(II) salts with 1 on a 1:1 metal/ligand ratio, due to the smaller size of the Zn(II) coordination sphere as compared to the much larger Pb(II) ions.     

Cyclopentadienylrhodium coordination to alkenylarenes

Photochemical reaction of [Rh(eta-C(5)H(5))(C(2)H(4))(2)] (5) with alkenyl benzene derivatives PhC(R(1))=CHR(2) results in the formation of four types of cyclopentadienylrhodium complexes: the mononuclear ethylene eta(2)-alkenylbenzene complexes [Rh(eta-C(5)H(5))(eta-C(2)H(4))(eta(2)-PhC(R(1))=CHR(2))] 9 a (R(1)=H, R(2)=Ph), 9 b (R(1)=Ph, R(2)=H), 9 c (R(1)=CH(3), R(2)=H), the mononuclear eta(4)-alkenylbenzene complex [Rh(eta-C(5)H(5))[beta,alpha,1,2-eta-C(6)H(5)C(Ph)=CH(2)]] (10), the dinuclear mu-eta(4):eta(4)-alkenylbenzene complex [anti-[Rh(eta-C(5)H(5))](2)[mu-beta,alpha,1,2-eta:3,4,5,6-eta-C(6)H(5)C(Ph)C=CH(2)]] (11), and the dinuclear rhodaindenyl complexes [Rh(eta-C(5)H(5))[1-3,8,9-eta-[1-(eta-C(5)H(5))]-3-R(1)-1-rhodaindenyl]] 12 a (R(1)=Ph), 12 b (R(1)=CH(3)). Reaction of 5 with triisopropenylbenzene gives the dinuclear complex [[Rh(eta-C(5)H(5))](2)(mu-beta,alpha,1,2-eta:beta',alpha',4,3-eta-C(6)H(3)[C(CH(3))=CH(2)](3))] (13). In the complexes 9, only the olefinic side chain of the alkenylbenzene binds to the metal. In the complexes 10, 11, 12, and 13, an arene nucleus coordinates to rhodium as a 1,3-diene moiety (or part thereof). The rhodaindenyl complexes 12 result from C-H activation of the alkenylbenzene at the beta and ortho positions. The crystal and molecular structures of 9 a, 9 b, 10, 11, and 12 a, b were determined. The role of 9-11 and 13 as models for intermediates during alkenylbenzene-assisted self-assembly of tricobalt clusters is discussed.     

1,4-dicyanobenzene as a scaffold for the preparation of bimetallic actinide complexes exhibiting metal-metal communication

Reaction of two equivalents of [(C(5)Me(4)Et)(2)U(CH(3))(Cl)] (6) or [(C(5)Me(5))(2)Th(CH(3))(Br)] (7) with 1,4-dicyanobenzene leads to the formation of the novel 1,4-phenylenediketimide-bridged bimetallic organoactinide complexes [{(C(5)Me(4)Et)(2)(Cl)U}(2)(mu-{N==C(CH(3))-C(6)H(4)-(CH(3))C==N})] (8) and [{(C(5)Me(5))(2)(Br)Th}(2)(mu-{N==C(CH(3))-C(6)H(4)- (CH(3))C==N})] (9), respectively. These complexes were structurally characterized by single-crystal X-ray diffraction and NMR spectroscopy. Metal-metal interactions in these isovalent bimetallic systems were assessed by means of cyclic voltammetry, UV-visible/NIR absorption spectroscopy, and variable-temperature magnetic susceptibility. Although evidence for magnetic coupling between metal centers in the bimetallic U(IV)/U(IV) (5f(2)-5f(2)) complex is ambiguous, the complex displays appreciable electronic communication between the metal centers through the pi system of the dianionic diketimide bridging ligand, as judged by voltammetry. The transition intensities of the f-f bands for the bimetallic U(IV)/U(IV) system decrease substantially compared to the related monometallic ketimide chloride complex, [(C(5)Me(5))(2)U(Cl){-N==C(CH(3))-(3,4,5-F(3)-C(6)H(2))}] (11). Also reported herein are new synthetic routes to the actinide starting materials [(C(5)Me(4)Et)(2)U(CH(3))(Cl)] (6) and [(C(5)Me(5))(2)Th(CH(3))(Br)] (7) in addition to the syntheses and structures of the monometallic uranium complexes [(C(5)Me(4)Et)(2)UCl(2)] (3), [(C(5)Me(4)Et)(2)U(CH(3))(2)] (4), [(C(5)Me(4)Et)(2)U{-N==C(CH(3))-C(6)H(4)-C==N}(2)] (10), and 11.     

Mono- and dinuclear five-coordinate cyclometalated palladium(II) compounds

Reaction of cyclometalated halide-bridged Pd(II) complexes 1-4 with the tertiary triphosphine ligand (Ph2PCH2CH2)2PPh (triphos) yielded complexes [((Ph2PCH2CH2)2PPh-P,P,P)Pd(N(Cy)=(H)C)C6H2(C(H)=N(Cy))Pd((Ph2PCH2CH2)2PPh-P,P,P)][ClO4]2 5, [Pd(C6H4-N=NC6H5)((Ph2PCH2CH2)2PPh-P,P,P)][ClO4] 6, and [Pd(R-C6H3C(H)=NCy)((Ph2PCH2CH2)2PPh-P,P,P)][ClO4] (7; R = 4-CHO, 8; 3-CHO). Spectroscopic and analytic data suggest five-coordination on the palladium atom, which, for complexes 5, 6, and 7, was confirmed by X-ray crystallography. The geometry around palladium may be view as a distorted trigonal bipyramid, with the palladium, nitrogen, and terminal phosphorus atoms in the equatorial plane. Compound 5 is the first doubly cyclometalated palladium(II) compound with two pentacoordinated metal centers. The structure of 6 comprises two discrete cations with slightly different geometries, showing the importance of crystal packing forces in order to determine the coordination arrangement.     

Pb(II) coordination and synergistic ion-exchange extraction by combinations of sulfonamide chelates and 2,2'-bipyridine

The disulfonamide ligands 1,2-C(6)H(4)(NH(2)SO(2)C(6)H(5))(2) (1) and 1,2-C(6)H(4)(NH(2)SO(2)C(6)H(4)-p-Bu(t))(2) (2), which are readily available in good yields from o-phenylenediamine and the corresponding sulfonyl chlorides, efficiently extract Pb(II) from water into 1,2-dichloroethane when used in synergistic combinations with 2,2'-bipyridine via an ion-exchange mechanism. The extraction was shown to proceed via the formation of a ternary Pb-sulfamido-2,2'-bipyridine complex. The X-ray crystal structure of the binary Pb-sulfamido complex 3 shows a coordination polymer with a stereochemically active lone pair on Pb formed by S=O-Pb axial coordination.     

Syntheses of 1-alkyl-1,2,4-triazoles and the formation of quaternary 1-alkyl-4-polyfluoroalkyl-1,2,4-triazolium salts leading to ionic liquids

1,2,4-triazole was alkylated (alkyl = methyl, butyl, heptyl, decyl) at N-1 in >90% isolated yields. The resulting 1-alkyl triazoles were quaternized at N-4 in >98% isolated yields using fluorinated alkyl halides with >98% isolated yields, under neat reaction conditions at 100-120 degrees C to form N1-CH(3)-N4-(CH(2))(2)C(m)F(2)(m)(+ 1)-triazolium (Taz) iodide (m = 1, 6), N1-C(4)H(9)-N4-(CH(2))(2)C(m)F(2)(m)(+ 1)-Taz iodide (m = 1, 4, 6), N1-C(7)H(15)-N4-(CH(2))(2)C(m)F(2)(m)(+ 1)-Taz iodide (m = 1, 4, 6), N1-C(10)H(21)-N4-(CH(2))(2)C(m)F(2)(m)(+1)-Taz iodide (m = 1, 4), and N1-C(n)H(2)(n )(+ 1)-N4-(CH(2))(2)F-Taz bromide (n = 4, 7, 10). Single-crystal X-ray analyses confirmed the structure of [1-CH(3)-4-CH(2)CH(2)CF(3)-Taz](+)I(-). It crystallized in the orthorhombic space group Pccn, and the unit cell dimensions were a = 13.8289(9) A, b = 17.3603(11) A, c = 9.0587(6) A (alpha = beta = gamma = 90 degrees ). Metathesis of these polyfluoroalkyl-substituted triazolium halides with other salts led to the formation of quaternary compounds, some of which comprise ionic liquids, namely, [R(R(f))-Taz](+)Y(-) (Y = NTf(2), BF(4), PF(6), and OTf), in good isolated yields without the need for further purification: N1-CH(3)-N4-(CH(2))(2)C(m)F(2)(m)( +) (1)-Taz Y (m = 1, 6; Y = NTf(2)), N1-C(4)H(9)-N4-(CH(2))(2)C(m)F(2)(m)(+ 1)-Taz Y (m = 1, 4, 6; Y = NTf(2)), N1- C(7)H(15)-N4-(CH(2))(2)C(m)F(2)(m)(+ 1)-Taz Y (m = 1, 4, 6; Y = NTf(2)), N1-C(10)H(21)-N4-(CH(2))(2)C(m)F(2)(m)(+1)-Taz Y (n = 1, 4; Y = NTf(2)), N1-C(n)H(2)(n )(+ 1)-N4-(CH(2))(2)F-Taz Y (n = 7, 10; Y = NTf(2)), N1-C(10)H(21)-N4-(CH(2))(2)F-TazY (Y = OTf), N1-C(7)H(15)-N4-(CH(2))(2)F-TazY (Y = BF(4)), N1-C(4)H(9)-N4-(CH(2))(2)C(m)F(2)(m) (+ 1)-Taz Y (m = 4, 6; Y = PF(6)), N1-C(7)H(15)-N4-(CH(2))(2)C(4)F(9)-Taz Y (Y = PF(6)), N1-C(4)H(9)-N4-(CH(2))(2)C(m)F(2)(m)(+ 1)-Taz Y (m = 4, 6; Y = OTf). All new compounds were characterized by (1)H, (19)F, and (13)C NMR and MS spectra and elemental analyses. T(g)s and T(m)s of ionic liquids were determined by DSC.     

The synthesis and characterisation of 4,1,2-MC2B10 metallacarboranes

Reduction of the tethered carborane 1,2-(CH2)3-1,2-closo-C2B10H10 followed by treatment with CoCl2/NaCp, [(p-cymene)RuCl2]2(p-cymene=C6H4MeiPr-1,4), (PMe2Ph)2PtCl2 or (dppe)NiCl2(dppe=Ph2PCH2CH2PPh2) affords reasonable yields of the new 13-vertex metallacarboranes 1,2-(CH2)3-4-Cp-4,1,2-closo-CoC2B10H10 (1), 1,2-(CH2)3-4-(p-cymene)-4,1,2-closo-RuC2B10H10 (2), 1,2-(CH2)3-4,4-(PMe2Ph)2-4,1,2-closo-PtC2B10H10 (3) and 1,2-(CH2)3-4,4-(dppe)-4,1,2-closo-NiC2B10H10 (4), respectively. All compounds were characterised spectroscopically and crystallographically. The cobalt and ruthenium species 1 and 2 have Cs symmetry in both solution and the solid state, having henicosahedral cage structures featuring a trapezoidal C1C2B9B5 face. The platinum and nickel compounds 3 and 4 have asymmetric docosahedral cage structures in the crystal (the more so for 4 than for 3) although both appear, by 11B and 31P NMR spectroscopy, to have Cs symmetry in solution. Low-temperature experiments on the more soluble platinacarborane could not freeze out the diamond-trapezium-diamond fluctional process that we assume is operating in solution, and we therefore conclude that this process has a relatively low activation barrier, probably <35 kJ mol-1.     

Cycloauration of pyridyl sulfonamides

The pyridyl-2-alkylsulfonamides C(5)H(4)N(CH(2))(n)NHSO(2)R (n = 1,2; R = Me, Ph or p-C(6)H(4)Me) and 8-(p-tosylamino)quinoline undergo facile cycloauration reactions with H[AuCl(4)] in water, giving metallacyclic complexes coordinated through the pyridyl (or quinolyl) nitrogen atom and the deprotonated nitrogen of the sulfonamide group. The complexes have been fully characterised by NMR spectroscopy, ESI mass spectrometry and elemental analysis. The X-ray crystal structures of two derivatives reveal the presence of non-planar sulfonamide nitrogen atoms. The complexes show low activity against P388 murine leukaemia cells, possibly as a result of their ease of reduction with mild reducing agents.     

A photometric study of the complexation reaction between Alizarin complexan and zinc(II), nickel(II), lead(II), cobalt(II) and copper(II)

The complexation reaction between Alizarin complexan ([3-N,N-di(carboxymethyl)aminomethyl]-1,2-dihydroxyanthraquinone; H(4)L) and zinc(II), nickel(II), lead(II), cobalt(II) and copper(II) has been studied by a spectrophotometric method. All these metal ions form 1:1 complexes with HL; 2:1 metal:ligand complex were found only for Pb(II) and Cu(II). The stability constants are (ionic strength I = 0.1, 20 degrees C): Zn(2+) + HL(3-) right harpoon over left harpoon ZnHL(-) log K +/- 3sigma(log K) = 12.19 +/- 0.09 (I = 0.5) Ni(2+) + HL(3-) right harpoon over left harpoon NiHL(-) log K +/- 3sigma(log K) = 12.23 +/- 0.21 Pb(2+) + HL(3-) right harpoon over left harpoon PbHL(-) log K +/- 3sigma(log K) = 11.69 +/- 0.06 PbHL(-) + Pb(2+) right harpoon over left harpoon Pb(2)L + H(+) log K approximately -0.8 Co(2+) + HL(3-) right harpoon over left harpoon CoHL(-) log K 3sigma(log K) = 12.25 + 0.13 Cu(2+) + HL(3-) right harpoon over left harpoon CuHL(-) log K 3sigma(log K) = 14.75 +/- 0.07 Cu(2+) + CuHL(-) right harpoon over left harpoon Cu(2)L + H(+) log K approximately 3.5 The solubility and stability of both the reagent and the complexes and the closenes of the values of the stability constants make this reagent suitable for the photometric detection of several metal ions in the eluate from an ion-exchange column.     

Homolysis of the Ln-N (Ln = Yb, Eu) bond. Synthesis, structural characterization and catalytic activity of ytterbium(II) and europium(II) complexes with methoxyethyl functionalized indenyl ligands

The interaction of methoxyethyl functionalized indene compounds (C(9)H(6)-1-R-3-CH(2)CH(2)OMe, R =t-BuNHSiMe(2)(1), Me(3)Si (2), H (3)) with [(Me(3)Si)(2)N](3)Ln(mu-Cl)Li(THF)(3)(Ln=Yb (4), Eu (5)) produced a series of new ytterbium(II) and europium(II) complexes via tandem silylamine elimination/homolysis of the Ln-N (Ln=Yb, Eu) bond. Treatment of the lanthanide(III) amides [(Me(3)Si)(2)N](3)Ln(mu-Cl)Li(THF)(3)(Ln=Yb (4), Eu (5) with 2 equiv. of, 1,2 and 3, respectively, produced, after workup, the ytterbium(II) complexes [eta5:eta1-Me(2)Si(MeOCH(2)CH(2)C(9)H(5))(NHBu-t)](2)Yb(II) (6), (eta5:eta1-MeOCH(2)CH(2)C(9)H(5)SiMe(3))(2)Yb(II) (7), (eta5:eta1-MeOCH(2)CH(2)C(9)H(6))(2)Yb(II)(8) and the corresponding europium(II) complexes [eta5:eta1-Me(2)Si(MeOCH(2)CH(2)C(9)H(5))(NHBu-t)](2)Eu(II)(9), (eta5:eta1-MeOCH(2)CH(2)C(9)H(5)SiMe(3))(2)Eu(II)(10) and (eta5:eta1-MeOCH(2)CH(2)C(9)H(6))(2)Eu(II)(11) in moderate to good yield. In contrast, interaction of the corresponding indene compounds 1, 2 or 3 with the lanthanide amides [(Me(3)Si)(2)N](3)Ln (Ln = Yb, Eu) was not observed, while addition of 0.5 equiv. of anhydrous LiCl to the corresponding reaction mixture produced, after workup, the corresponding ytterbium(II) or europium(II) complexes. All the new compounds were fully characterized by spectroscopic and elemental analyses. The structures of complexes, and were determined by single-crystal X-ray analyses. The catalytic activity of all the ytterbium(II) and europium(II) complexes on MMA polymerization was examined. It was found that all the ytterbium(II) and europium(II) complexes can function as single-component MMA polymerization catalysts. The temperature, solvent and ligand effects on the catalytic activity were studied.