Anion recognition of chloride and bromide by a rigid dicobalt(II) cryptate

The crystal structures of [Co 2L(Cl)](ClO 4) 3 ( 1), [Co 2L(Br)](ClO 4) 3 ( 2), [Co 2L(OH)(OH 2)]I 3 ( 3), and [Co 2L (1)(Cl)](ClO 4) 3 ( 4), the density functional theory calculations, as well as the binding constants of [Co 2L] (4+) toward Cl (-) and Br (-) and of [Co 2L (1)] (4+) toward Cl (-), are reported in this paper (L = N[(CH 2) 2NHCH 2(C 6H 4- p)CH 2NH(CH 2) 2] 3N, L (1) = N[(CH 2) 2NHCH 2(C 6H 4- m)CH 2NH(CH 2) 2] 3N). The rigid dicobalt(II) cryptate [Co 2L] (4+) shows the recognition of Cl (-) and Br (-) but not of F (-) and I (-), because of the size matching to its rigid cavity. We also found that the relative rigid tripodal skeleton of L than that of L (1) results in the higher affinity of [Co 2L] (4+) toward Cl (-). Magnetic susceptibility measurements of 1 and 2 indicate that the two Co(II) atoms in the cryptates are antiferromagnetically coupled through the Cl (-)/Br (-) bridge, with g = 2.19, J = -13.7 cm (-1) for 1, and g = 2.22, J = -17.1 cm (-1) for 2.     

Substituted N-picolylethylenediamines of the type (ArNHCH2CH2){(2-C5H4N)CH2}NR [R = Me, 4-CH2=CH(C6H4)CH2, (2-C5H4N)CH2] and their transition metal(II) halide complexes

Alkylation of (ArNHCH2CH2){(2-C5H4N)CH2}NH with RX [RX = MeI, 4-CH2=CH(C6H4)CH2Cl) and (2-C5H5N)CH2Cl] in the presence of base has allowed access to the sterically demanding multidentate nitrogen donor ligands, {(2,4,6-Me3C6H2)NHCH2CH2}{(2-C5H4N)CH2}NMe (L1), {(2,6-Me3C6H3)NHCH2CH2}{(2-C5H4N)CH2}NCH2(C6H4)-4-CH=CH2 (L2) and (ArNHCH2CH2){(2-C5H4N)CH2}2N (Ar = 2,4-Me2C6H3 L3a, 2,6-Me2C6H3 L3b) in moderate yield. L3 can also be prepared in higher yield by the reaction of (NH2CH2CH2){(2-C5H4N)CH2}2N with the corresponding aryl bromide in the presence of base and a palladium(0) catalyst. Treatment of L1 or L2 with MCl2 [MCl2 = CoCl2.6H2O or FeCl2(THF)1.5] in THF affords the high spin complexes [(L1)MCl2](M = Co 1a, Fe 1b) and [(L2)MCl2](M = Co 2a, Fe 2b) in good yield, respectively; the molecular structure of reveals a five-coordinate metal centre with bound in a facial fashion. The six-coordinate complexes, [(L3a)MCl2](M = Co 3a, Fe 3b, Mn 3c) are accessible on treatment of tripodal L3a with MCl2. In contrast, the reaction with the more sterically encumbered leads to the pseudo-five-coordinate species [(L3b)MCl2](M = Co 4a, Fe 4b) and, in the case of manganese, dimeric [(L3b)MnCl(mu-Cl)]2 (4c); in 4a and 4b the aryl-substituted amine arm forms a partial interaction with the metal centre while in 4c the arm is pendant. The single crystal X-ray structures of , 1a, 3b.MeCN, 3c.MeCN, 4b.MeCN and 4c are described as are the solution state properties of 3b and 4b.     

Syntheses and reactions of hexavalent organotellurium compounds bearing five or six tellurium-carbon bonds

A variety of hexaorganotellurium compounds, Ar(6-n)(CH3)nTe [Ar=4-CF3C6H4, n=0 (1a), n=1 (3a), n=2 (trans-4a and cis-4a), n=3 (mer-5a), n=4 (trans-6a); Ph, n=0 (1b), n=1 (3b), n=2 (trans-4b); 4-CH3C6H4, n=0 (1c), n=1 (3c), n=2 (trans-4c), n=4 (trans-6c); 4-BrC6H4, n=0 (1d)] and Ar5(R)Te [Ar=4-CF3C6H4, R=4-CH3OC6H4 (8); Ar=4-CF3C6H4, R=vinyl (9), Ar=Ph, R=vinyl (10), Ar=4-CF3C6H4, R=PhSCH2 (11), Ar=Ph, R=PhSCH2 (12), Ar=4-CF3C6H4, R=nBu (13)] and pentaorganotellurium halides, Ar5TeX [Ar=4-CF3C6H4, X=Cl (2a-Cl), X=Br (2a-Br); Ar=Ph, X=Cl (2b-Cl), X=Br (2b-Br); Ar=4-CH3C6H4, X=Cl (2c-Cl), X=Br (2c-Br); Ar=4-BrC6H4, X=Br (2d-Br)] and (4-CF3C6H4)4(CH3)TeX [X=Cl (trans-7a-Cl) and X=Br (trans-7a-Br)] were synthesized by the following methods: 1) one-pot synthesis of 1 a, 2) the reaction of SO2Cl2 or Br2 with Ar5Te(-)Li+ generated from TeCl4 or TeBr4 with five equivalents of ArLi, 3) reductive cleavage of Ar(6-m)(CH3)(m)Te (m=0 or 2) with KC8 followed by treatment with CH3I, 4) valence expansion reaction from low-valent tellurium compounds by treatment with KC8 followed by reaction with CH3I, 5) nucleophilic substitution of Ar(6-y-z)(CH3)zTeX(y-z) (X=Cl, Br, OTf; z=0, 1; y=1, 2) with organolithium reagents. The scope and limitations and some details for each method are discussed and electrophilic halogenation of the hexaorganotellurium compounds is also described.     

Ionic iron(iii) complexes of bis(phenol)-functionalized imidazolium cations: synthesis, structures and catalysis for aryl Grignard cross-coupling of alkyl halides

A series of bis(phenol)-functionalized imidazolium salts, 1,3-bis(4,6-di-R(1)-2-hydroxybenzyl)-2-R(2)-4,5-di-R(3)-imidazolium chlorides H(3)L(n)Cl (R(1) = (t)Bu, R(2) = R(3) = H, H(3)L(1)Cl, 1; R(1) = CH(3), R(2) = R(3) = H, H(3)L(2)Cl, 2; R(1) = (t)Bu, R(2) = H, R(3) = Cl, H(3)L(3)Cl, 3; R(1) = (t)Bu, R(2) = CH(3), R(3) = H, H(3)L(4)Cl, 4), were used to produce a novel series of ionic iron(iii) complexes [H(3)L(n)][FeX(4)] (n = 1, X = Cl, 5; n = 2, X = Cl, 6; n = 3, X = Cl, 7; n = 4, X = Cl, 8; n = 1, X = Br, 9; n = 3, X = Br, 10). All of the complexes were characterized by Raman spectroscopy and electrospray ionization mass spectrometry. Elemental analysis and X-ray crystallography were also used. All of the complexes were non-hygroscopic and air-stable, with five of them existing as solids (5, 7-10) and one as an oil (6) at room temperature. A preliminary catalytic study on the cross-coupling reactions of aryl Grignard reagents with primary and secondary alkyl halides bearing β-hydrogens, revealed that all of the ionic iron(iii) complexes exhibited good to excellent catalytic activity. Complexes 5, 6 and 8 exhibited optimal activity, whereas 7, 9 and 10 showed only moderate activity. Furthermore, by simply decanting the cross-coupling product in the ether layer, complexes 5 and 6 could be reused in at least seven successive runs without significant loss in catalytic activity.     

Vanadium complexes of the N(CH2CH2S)3(3-) and O(CH2CH2S)2(2-) ligands with coligands relevant to nitrogen fixation processes

Vanadium(III) and vanadium(V) complexes derived from the tris(2-thiolatoethyl)amine ligand [(NS3)3-] and the bis(2-thiolatoethyl)ether ligand [(OS2)2-] have been synthesized with the aim of investigating the potential of these vanadium sites to bind dinitrogen and activate its reduction. Evidence is presented for the transient existence of (V(NS3)(N2)V(NS3), and a series of mononuclear complexes containing hydrazine, hydrazide, imide, ammine, organic cyanide, and isocyanide ligands has been prepared and the chemistry of these complexes investigated. [V(NS3)O] (1) reacts with an excess of N2H4 to give, probably via the intermediates (V(NS3)(NNH2) (2a) and (V(NS3)(N2)V(NS3) (3), the V(III) adduct [V(NS3)(N2H4)] (4). If 1 is treated with 0.5 mol of N2H4, 0.5 mol of N2 is evolved and green, insoluble [(V(NS3))n] (5) results. Compound 4 is converted by disproportionation to [V(NS3)(NH3)] (6), but 4 does not act as a catalyst for disproportionation of N2H4 nor does it act as a catalyst for its reduction by Zn/HOC6H3Pri2-2,6. Compound 1 reacts with NR1(2)NR2(2) (R1 = H or SiMe3; R2(2) = Me2, MePh, or HPh) to give the hydrazide complexes [V(NS3)(NNR2(2)] (R2(2) = Me2, 2b; R2(2) = MePh, 2c; R2(2) = HPh, 2d), which are not protonated by anhydrous HBr nor are they reduced by Zn/HOC6H3Pri2-2,6. Compound 2b can also be prepared by reaction of [V(NNMe2)(dipp)3] (dipp = OC6H3Pri2-2,6) with NS3H3. N2H4 is displaced quantitatively from 4 by anions to give the salts [NR3(4)][V(NS3)X] (X = Cl, R3 = Et, 7a; X = Cl, R3 = Ph, 7b; X = Br, R3 = Et, 7c; X = N3, R3 = Bu(n), 7d; X = N3, R3 = Et, 7e; X = CN, R3 = Et, 7f). Compound 6 loses NH3 thermally to give 5, which can also be prepared from [VCl3(THF)3] and NS3H3/LiBun. Displacement of NH3 from 6 by ligands L gives the adducts [V(NS3)(L)] (L = MeCN, nu CN 2264 cm-1, 8a; L = ButNC, nu NC 2173 cm-1, 8b; L = C6H11NC, nu NC 2173 cm-1, 8c). Reaction of 4 with N3SiMe3 gives [V(NS3)(NSiMe3)] (9), which is converted to [V(NS3)(NH)] (10) by hydrolysis and to [V(NS3)(NCPh3)] (11) by reaction with ClCPh3. Compound 10 is converted into 1 by [NMe4]OH and to [V(NS3)NLi(THF)2] (12) by LiNPri in THF. A further range of imido complexes [V(NS3)(NR4)] (R4 = C6H4Y-4 where Y = H (13a), OMe (13b), Me (13c), Cl (13d), Br (13e), NO2 (13f); R4 = C6H4Y-3, where Y = OMe (13g); Cl (13h); R4 = C6H3Y2-3,4, where Y = Me (13i); Cl (13j); R4 = C6H11 (13k)) has been prepared by reaction of 1 with R4NCO. The precursor complex [V(OS2)O(dipp)] (14) [OS2(2-) = O(CH2CH2S)2(2-)] has been prepared from [VO(OPri)3], Hdipp, and OS2H2. It reacts with NH2NMe2 to give [V(OS2)(NNMe2)(dipp)] (15) and with N3SiMe3 to give [V(OS2)(NSiMe3)(dipp)] (16). A second oxide precursor, formulated as [V(OS2)1.5O] (17), has also been obtained, and it reacts with SiMe3NHNMe2 to give [V(OS2)(NNMe2)(OSiMe3)] (18). The X-ray crystal structures of the complexes 2b, 2c, 4, 6, 7a, 8a, 9, 10, 13d, 14, 15, 16, and 18 have been determined, and the 51V NMR and other spectroscopic parameters of the complexes are discussed in terms of electronic effects.     

Influence of ligand polarizability on the reversible binding of O2 by trans-[Rh(X)(XNC)(PPh3)2] (X = Cl, Br, SC6F5, C2Ph; XNC = xylyl isocyanide). Structures and a kinetic study

The complexes trans-[Rh(X)(XNC)(PPh 3) 2] (X = Cl, 1; Br, 2; SC 6F 5, 3; C 2Ph, 4; XNC = xylyl isocyanide) combine reversibly with molecular oxygen to give [Rh(X)(O 2)(XNC)(PPh 3) 2] of which [Rh(SC 6F 5)(O 2)(XNC)(PPh 3) 2] ( 7) and [Rh(C 2Ph)(O 2)(XNC)(PPh 3) 2] ( 8) are sufficiently stable to be isolated in crystalline form. Complexes 2, 3, 4, and 7 have been structurally characterized. Kinetic data for the dissociation of O 2 from the dioxygen adducts of 1- 4 were obtained using (31)P NMR to monitor changes in the concentration of [Rh(X)(O 2)(XNC)(PPh 3) 2] (X = Cl, Br, SC 6F 5, C 2Ph) resulting from the bubbling of argon through the respective warmed solutions (solvent chlorobenzene). From data recorded at temperatures in the range 30-70 degrees C, activation parameters were obtained as follows: Delta H (++) (kJ mol (-1)): 31.7 +/- 1.6 (X = Cl), 52.1 +/- 4.3 (X = Br), 66.0 +/- 5.8 (X = SC 6F 5), 101.3 +/- 1.8 (X = C 2Ph); Delta S (++) (J K (-1) mol (-1)): -170.3 +/- 5.0 (X = Cl), -120 +/- 13.6 (X = Br), -89 +/- 18.2 (X = SC 6F 5), -6.4 +/- 5.4 (X = C 2Ph). The values of Delta H (++) and Delta S (++) are closely correlated (R (2) = 0.9997), consistent with a common dissociation pathway along which the rate-determining step occurs at a different position for each X. Relative magnitudes of Delta H (++) are interpreted in terms of differing polarizabilities of ligands X.     

Novel stannatranes of the type N(CH2CMe2O)3SnX (X = OR, SR, OC(O)R, SP(S)Ph2, halogen). Synthesis, molecular structures, and electrochemical properties

The syntheses of the stannatrane derivatives of the type N(CH(2)CMe(2)O)(3)SnX (1, X = Ot-Bu; 2, X = Oi-Pr; 3, X = 2,6-Me(2)C(6)H(3)O; 4, X = p-t-BuC(6)H(4)O; 5, X = p-NO(2)C(6)H(4)O; 6, X = p-FC(6)H(4)O; 7, X = p-PPh(2)C(6)H(4)O; 8, X = p-MeC(6)H(4)S; 9, X = o-NH(2)C(6)H(4)O; 10, X = OCPh(2)CH(2)NMe(2); 11, X = Ph(2)P(S)S; 12, X = p-t-BuC(6)H(4)C(O)O; 13, X = Cl; 14, X = Br; 15, X = I; 16, X = p-N(CH(2)CMe(2)O)(3)SnOSiMe(2)C(6)H(4)SiMe(2)O) are reported. The compounds are characterized by X-ray diffraction analyses (3-8, 11-16), multinuclear NMR spectroscopy, (13)C CP MAS (14) and (119)Sn CP MAS NMR (13, 14) spectroscopy, mass spectrometry and osmometric molecular weight determination (13). Electrochemical measurements show that anodic oxidation of the stannatranes 4 and 8 occurs via electrochemically reversible electron transfer resulting in the corresponding cation radicals. The latter were detected by cyclic voltammetry (CV) and real-time electron paramagnetic resonance spectroscopy (EPR). DFT calculations were performed to compare the stannatranes 4, 8, and 13 with the corresponding cation radicals 4(+?), 8(+?), and 13(+?), respectively.     

Ligand effects in the syntheses and structures of novel heteroleptic and homoleptic bismuth(III) formamidinate complexes

Metathesis reactions of the alkali metal formamidinates M(RNC(H)NR), M = Li or K; R = C(6)H(3)-2,6-Pr(i)(2) (L(1)), C(6)H(3)-2,6-Et(2) (L(2)); C(6)H(2)-2,4,6-Me(3) (L(3)), C(6)H(3)-2,6-Me(2) (L(4)) or C(6)H(4)-2-Ph (L(5)), with BiX(3) (X = Cl or Br) gave a range of bismuth(iii) formamidinate complexes [Bi(L)Br(micro-Br)(thf)](2) (L = L(1), L(4)), [{Bi(L(1))Cl(2)(thf)}(2)Bi(L(1))Cl(2)], [Bi(L)(2)X] (L = L(2), L(5), X = Br; L = L(1), X = Cl), and [Bi(L)(3)] (L = L(2), L(3)). An analogous organometallic complex Bi(L(1))(2)Bu(n) was also isolated as a side product in one instance. Structural characterisation of the di-halide complexes show symmetrical dimers for X = Br, with two bromide bridges, and a coordinated thf molecule on each Bi atom, whereas for X = Cl a thf deficient species was crystallised, and has a weakly associated trinuclear array with two coordinated thf molecules per three Bi atoms. Complexes of the form Bi(L)(2)X (X = Br, Cl, Bu(n)) and Bi(L)(3) all have monomeric structures but the Bi(L)(3) species show marked asymmetry of the formamidinate binding, suggesting that they have reached coordination saturation.     

Synthesis of the pivalamidate-bridged pentanuclear platinum(II,III) linear complexes with Pt...Pt interactions

Pentanuclear linear chain Pt(II,III) complexes [[Pt2(NH3)2X2((CH3)3CCONH)2(CH2COCH3)]2[PtX'4]].nCH3COCH3 (X = X' = Cl, n = 2 (1a), X = Cl, X' = Br, n = 1 (1b), X = Br, X' = Cl, n = 2 (1c), X = X' = Br, n = 1 (1d)) composed of a monomeric Pt(II) complex sandwiched by two amidate-bridged Pt dimers were synthesized from the reaction of the acetonyl dinuclear Pt(III) complexes having equatorial halide ligands [Pt2(NH3)2X2((CH3)3CCONH)2(CH2COCH3)]X' ' (X = Cl (2a), Br (2b), X' ' = NO3-, CH3C6H4SO3-, BF4-, PF6-, ClO4-), with K2[PtX'4] (X' = Cl, Br). The X-ray structures of 1a-1d show that the complexes have metal-metal bonded linear Pt5 structures, and the oxidation state of the metals is approximately Pt(III)-Pt(III)...Pt(II)...Pt(III)-Pt(III). The Pt...Pt interactions between the dimer units and the monomer are due to the induced Pt(II)-Pt(IV) polarization of the Pt(III) dimeric unit caused by the electron withdrawal of the equatorial halide ligands. The density functional theory calculation clearly shows that the Pt...Pt interactions between the dimers and the monomer are made by the electron transfer from the monomer to the dimers. The pentanuclear complexes have flexible Pt backbones with the Pt chain adopting either arch or sigmoid structures depending on the crystal packing.     

Solid state structure and solution behaviour of organoselenium(II) compounds containing 2-{E(CH2CH2)2NCH2}C6H4 groups (E = O, NMe)

Cleavage of the Se-Se bond in [2-{O(CH(2)CH(2))(2)NCH(2)}C(6)H(4)](2)Se(2) (1) and [2-{MeN(CH(2)CH(2))(2)NCH(2)}C(6)H(4)](2)Se(2) (2) by treatment with SO(2)Cl(2), bromine or iodine (1 : 1 molar ratio) yielded [2-{O(CH(2)CH(2))(2)NCH(2)}C(6)H(4)]SeX [X = Cl (3), Br (4), I (5)] and [2-{MeN(CH(2)CH(2))(2)NCH(2)}C(6)H(4)]SeI (6). The compounds were characterized in solution by NMR spectroscopy (1H, 13C, 15N, 77Se, 2D experiments). The solid-state molecular structures of 1-3, 4.HBr, 5 and 6 were established by single crystal X-ray diffraction. In all cases T-shaped coordination geometries, i.e. (C,N)SeSe (1, 2), (C,N)SeX (3, 5, 6; X = halogen) or CSeBr(2) (4.HBr), were found. Supramolecular associations in crystals based on hydrogen contacts are discussed.     

Assembly of Carbohydrates on a Nickel(II) Center by Utilizing N-Glycosidic Bond Formation with Tris(2-aminoethyl)amine (tren). Syntheses and Characterization of [Ni{N-(aldosyl)-tren}(H(2)O)](2+), [Ni{N,N'-bis(aldosyl)-tren}](2+) and [Ni{N,N',N"-tris(aldosyl)-tren}](2+)

Reactions of [Ni(tren)(H(2)O)(2)]X(2) (tren = tris(2-aminoethyl)amine; X = Cl (1a), Br (1b); X(2) = SO(4) (1c)) with mannose-type aldoses, having a 2,3-cis configuration (D-mannose and L-rhamnose), afforded {bis(N-aldosyl-2-aminoethyl)(2-aminoethyl)amine}nickel(II) complexes, [Ni(N,N'-(aldosyl)(2)-tren)]X(2) (aldosyl = D-mannosyl, X = Cl (2a), Br (2b), X(2) = SO(4) (2c); aldosyl = L-rhamnosyl, X(2) = SO(4) (3c)). The structure of 1c was confirmed by X-ray crystallography to be a mononuclear [Ni(II)N(4)O(2)] complex with the tren acting as a tetradentate ligand (1c.2H(2)O: orthorhombic, Pbca, a = 15.988(2) ?, b = 18.826(4) ?, c = 10.359(4) ?, V = 3118 ?(3), Z = 8, R = 0.047, and R(w) = 0.042). Complexes 2a,c and 3c were characterized by X-ray analyses to have a mononuclear octahedral Ni(II) structure ligated by a hexadentate N-glycoside ligand, bis(N-aldosyl-2-aminoethyl)(2-aminoethyl)amine (2a.CH(3)OH: orthorhombic, P2(1)2(1)2(1), a = 16.005(3) ?, b = 20.095(4) ?, c = 8.361(1) ?, V = 2689 ?(3), Z = 4, R = 0.040, and R(w) = 0.027. 2c.3CH(3)OH: orthorhombic, P2(1)2(1)2(1), a = 14.93(2) ?, b = 21.823(8) ?, c = 9.746(2) ?, V = 3176 ?(3), Z = 4, R = 0.075, and R(w) = 0.080. 3c.3CH(3)OH: orthorhombic, P2(1)2(1)2(1), a = 14.560(4) ?, b = 21.694(5) ?, c = 9.786(2) ?, V = 3091 ?(3), Z = 4, R = 0.072, and R(w) = 0.079). The sugar part of the complex involves novel intramolecular sugar-sugar hydrogen bondings around the metal center. The similar reaction with D-glucose, D-glucosamine, and D-galactosamine, having a 2,3-trans configuration, resulted in the formation of a mono(sugar) complex, [Ni(N-(aldosyl)-tren)(H(2)O)(2)]Cl(2) (aldosyl = D-glucosyl (4b), 2-amino-2-deoxy-D-glucosyl (5a), and 2-amino-2-deoxy-D-galactosyl (5b)), instead of a bis(sugar) complex. The hydrogen bondings between the sugar moieties as observed in 2 and 3 should be responsible for the assembly of two sugar molecules on the metal center. Reactions of tris(N-aldosyl-2-aminoethyl)amine with nickel(II) salts gave the tris(sugar) complexes, [Ni(N,N',N"-(aldosyl)(3)-tren)]X(2) (aldosyl = D-mannosyl, X = Cl (6a), Br (6b); L-rhamnosyl, X = Cl (7a), Br (7b); D-glucosyl, X = Cl (9); maltosyl, X = Br (10); and melibiosyl, X = Br (11)), which were assumed to have a shuttle-type C(3) symmetrical structure with Delta helical configuration for D-type aldoses on the basis of circular dichroism and (13)C NMR spectra. When tris(N-rhamnosyl)-tren was reacted with NiSO(4).6H(2)O at low temperature, a labile neutral complex, [Ni(N,N',N"-(L-rhamnosyl)(3)-tren)(SO(4))] (8), was successfully isolated and characterized by X-ray crystallography, in which three sugar moieties are anchored only at the N atom of the C-1 position (8.3CH(3)OH.H(2)O: orthorhombic, P2(1)2(1)2(1), a = 16.035(4) ?, b = 16.670(7) ?, c = 15.38(1) ?, V = 4111 ?(3), Z = 4, R = 0.084, and R(w) = 0.068). Complex 8 could be regarded as an intermediate species toward the C(3) symmetrical tris(sugar) complexes 7, and in fact, it was readily transformed to 7b by an action of BaBr(2).     

Preparation and characterization of diarylphosphazene and diarylphosphinohydrazide complexes of titanium, tungsten and ruthenium and phosphorylketimido complexes of rhenium

Reaction of the proligand Ph2PN(SiMe3)2 (L1) with WCl6 gives the oligomeric phosphazene complex [WCl4(NPPh2)]n, 1 and subsequent reaction with PMe2Ph or NBu4Cl gives [WCl4(NPPh2)(PMe2Ph)] (2) or [WCl5(NPPh2)][NBu4] (3), respectively. DF calculations on [WCl5(NPPh2)][NBu4] show a W=N double bond (1.756 A) and a P-N bond distance of 1.701 A, which combined with the geometry about the P atom suggests, there is no P-N multiple bonding. Reaction of L1 with [ReOX3(PPh3)2] in MeCN (X = Cl or Br) gives [ReX2(NC(CH3)P(O)Ph2)(MeCN)(PPh3)](X = Cl, 4, X = Br, 5) which contains the new phosphorylketimido ligand. It is bound to the rhenium centre with a virtually linear Re-N-C arrangement (Re-N-C angle = 176.6 degrees, when X = Cl) and there is multiple bonding between Re and N (Re-N = 1.809(7) A when X = Cl). The proligand Ph2PNHNMe2(L2H) reacts with [(C5H5)TiCl3] to give [(C5H5)TiCl2(Me2NNPPh2)] (6). An X-ray crystal structure of the complex shows the ligand (L2) is bound by both nitrogen atoms. Reaction of the proligands Ph2PNHNR2[R2 = Me2 (L2H), -(CH2CH2)2NCH3 (L3H), (CH2CH2)2CH2 (L4H)] with [{RuCl(mu-Cl)(eta6-p-MeC6H4iPr)}2] gave [RuCl2(eta6-p-MeC6H4iPr)L] {L = L2H (7), L3H (8), L4H (9)}. The X-ray crystal structures of 7-9 confirmed that the phosphinohydrazine ligand is neutral and bound via the phosphorus only. Reaction of complexes 7-9 with AgBF4 resulted in chloride ion abstraction and the formation of the cationic species [RuCl(6-p-MeC6H4iPr)(L)]+ BF4- {(L = L2H (10), L3H (11), L4H (12)}. Finally, reaction of complex 6 with [{RuCl(mu-Cl)(eta6-p-MeC6H4iPr)}2] gave the binuclear species [(eta6-p-MeC6H4iPr)Cl2Ru(mu2,eta3-Ph2PNNMe2)TiCl2(C5H5)], 13.     

Synthesis and structures of beta-diketiminatotin(II) halides, an amide and of Sn(=E)[{N(R)C(Ph)}2CH](NR2) (E = S or Se, R = SiMe3)

Treatment of [Li(L1)]2 (1) or K(L2) (2) with SnX2 in Et2O yielded the heteroleptic beta-diketiminatotin(II) halides Sn(L1)Cl (3a), Sn(L1)Br (3b) or Sn(L2)Cl (4), even when an excess of the alkali metal beta-diketiminate was used [L1={N(R)C(Ph)}2CH, L2={N(R)C(Ph)CHC(But)N(R)}, R = SiMe3]. From and half an equivalent each of SnCl2.2H2O and SnCl2, or one equivalent of SnCl2.2H2O, the product was Sn(L3)Cl (5) or Sn(L4)Cl (6), in which one or both of the N-R bonds of L1 had been hydrolytically cleaved; the compound Sn(L5)Cl (7) was similarly obtained from and an equivalent portion of SnCl2.2H2O [L3={N(R)C(Ph)CHC(But)N(H)}, L4={N(H)C(Ph)CHC(But)N(H)} and L5={N(H)C(Ph)}2CH]. The halide exchange between 3a and 3b, studied by two-dimensional (119)Sn{1H}-NMR spectroscopy, is attributed to implicate a (mu-Cl)(mu-Br)-dimeric intermediate or transition state. The 13C{1H}-NMR spectra of or showed two distinct resonances for each group, which coalesced on heating, corresponding to DeltaG(338 K)= 69.4 (3a) or 72.8 (3b) kJ mol(-1). The chloride ligand of was readily displaced by treatment with NaNR2, CF3SO3H or CH2(COPh)2, yielding Sn(L1)X [X = NR2 (8), O3SCF3 (9) or {OC(Ph)}2CH (10)]. Oxidative addition of sulfur or selenium to gave the tin(IV) terminal chalcogenides Sn(E)(L1)(NR2)[E = S (11) or Se (12)]. The X-ray structures of the cocrystal of 3a/3b and of the crystalline compounds 5, 6, 8, 11 and are presented, as well as multinuclear NMR spectra of each of the new compounds.     

Spacially confined M2 centers (M = Fe, Co, Ni, Zn) on a sterically bulky binucleating support: synthesis, structures and ethylene oligomerization studies

Two new bulky aryl-bridged pyridyl-imine compartmental (pro)ligands, 2,6-{(2,6-i-Pr(2)C6H3)N=C(Me)C5H3N}2C6H3Y (Y = H L1, OH L2-H), have been prepared in moderate to good overall yields via a Stille-type cross-coupling approach. The molecular structure of L2-H reveals a transoid configuration within the pyridyl-imine units with a hydrogen-bonding interaction maintaining the phenol coplanar with one of the adjacent pyridine rings. The interaction of 2 equiv of MX2 with L1 in n-BuOH at 110 degrees C gives the binuclear complexes, [(L1)M2X4] (M = Fe, X = Cl (1a); M = Co, X = Cl (1b); M = Ni, X = Br (1c); M = Zn, X = Cl (1d)), in which the metal centers adopt distorted tetrahedral geometries and occupy the two pyridyl-imine cavities in L1. In contrast, deprotonation of L2-H occurs upon reaction with 2 equiv of MX2 to afford the phenolate-bridged species [(L2)M2(mu-X)X2] (M = Fe, X = Cl (2a); M = Co, X = Cl (2b); M = Ni, X = Br (2c); M = Zn, X = Cl (2d)). 1H NMR studies of diamagnetic 1d and 2d reveal that the limited rotation of the N-aryl groups in 1d is further impeded in 2d by steric interactions imparted by the two closely located N-aryl groups. Partial displacement of the bridging bromide in 2c results upon its treatment with acetonitrile to afford [(L2)Ni2Br3(NCMe)] [2c(MeCN)]; no such reaction occurs for 2a, 2b, or 2d. Upon activation with excess methylalumoxane (MAO), 1b, 1c, 2b, and 2c show some activity for alkene oligomerization forming low molecular-weight materials with methyl-branched products predominating for the nickel systems. Single-crystal X-ray diffraction studies have been performed on L2-H, 1c, 2b, 2c, 2c(NCMe), and 2d.     

CRYSTAL STRUCTURES OF COPPER (Ⅱ) AND COBALT (Ⅲ) COM- PLEXES OF o-HYDROXYBENZYLGLYCINATE (HBG)

<正> The structures of two complexes C(CuOC6H4CH2NHCH2COO)2 (H2 O)]·H2P(1) and [Co(NH3)6[Co(OC6H4CH2NHCH2COO)2]2[C1]·10H2O (2) were determined by X-ray analyses. Compound (1) crystallizes in the orthorhombic space group P212121 with a=11. 357(1),b= 24. 304(2),c=7.317(4) A,Z= 4;While compound (2) in the monoclinic space group A2/a(C2/c) with a=23. 486(9) ,b=26. 605(6) ,c= 10. 542(1) A,γ= 128. 42(4)°,Z= 4. In compound (1),two Cu(Ⅱ) ions are bonded together by the phenolic oxygen atoms of two tridentate chelating ligands and each of them is separately coordinated by the carboxyl oxygen,amino nitrogen of each chelate ligand and by the fifth oxygen atom as well (from aqua or the carbonyl group in adjacent molecule). Thus the coordination of each Cu(Ⅱ) is a square pyramid with distances of 1. 93- 1. 97A to the four corner atoms and 2. 30 and 2. 32 A to the apex atoms. The whole molecule has an approximately planar configuratioir with the two pyramid apexes pointing towards one side. Compound (2) consists of     

Ni(II), Pd(II), Pt(II)环戊基(苯基)和膦配合物的低频振动光谱及构型

本工作合成了下述金属配合物: MCl2L2(M=Pd, Pt), NiX2L2(X=Cl, Br, I),L=PPh3-x(C5H9)x(x=0-3), 并研究了它们的远红外光谱和某些低频Raman光谱, 对某些M-P, M-X振动谱带做出了归属, 并提供结构信息。     

TeX(4) (X = F, Cl, Br) as Lewis acids - complexes with soft thio- and seleno-ether ligands

TeF(4) reacts with OPR(3) (R = Me or Ph) in anhydrous CH(2)Cl(2) to give the colourless, square based pyramidal 1?:?1 complexes [TeF(4)(OPR(3))] only, in which the OPR(3) is coordinated basally in the solid state, (R = Me: d(Te-O) = 2.122(2) ?; R = Ph: d(Te-O) = 2.1849(14) ?). Variable temperature (19)F{(1)H}, (31)P{(1)H} and (125)Te{(1)H} NMR spectroscopic studies strongly suggest this is the low temperature structure in solution, although the systems are dynamic. The much softer donor ligands SMe(2) and SeMe(2) show a lower affinity for TeF(4), although unstable, yellow products with spectroscopic features consistent with [TeF(4)(EMe(2))] are obtained by the reaction of TeF(4) in neat SMe(2) or via reaction in CH(2)Cl(2) with SeMe(2). TeX(4) (X = F, Cl or Br) causes oxidation and halogenation of TeMe(2) to form X(2)TeMe(2). The Br(2)TeMe(2) hydrolyses in trace moisture to form [BrMe(2)Te-O-TeMe(2)Br], the crystal structure of which has been determined. TeX(4) (X = Cl or Br) react with the selenoethers SeMe(2), MeSe(CH(2))(3)SeMe or o-C(6)H(4)(SeMe)(2) (X = Cl) in anhydrous CH(2)Cl(2) to give the distorted octahedral monomers trans-[TeX(4)(SeMe(2))(2)], cis-[TeX(4){MeSe(CH(2))(3)SeMe}] and cis-[TeCl(4){o-C(6)H(4)(SeMe)(2)}], which have been characterised by IR, Raman and multinuclear NMR ((1)H, (77)Se{(1)H} and (125)Te{(1)H}) spectroscopy, and via X-ray structure determinations of representative examples. Tetrahydrothiophene (tht) can form both 1?:?1 and 1?:?2 Te?:?L complexes. For X = Br, the former has been shown to be a Br-bridged dimer, [Br(3)(tht)Te(μ-Br)(2)TeBr(3)(tht)], by crystallography with the tht ligands anti, whereas the latter are trans-octahedral monomers. Like its selenoether analogue, MeS(CH(2))(3)SMe forms distorted octahedral cis-chelates, [TeX(4){MeS(CH(2))(3)SMe}], whereas the more rigid o-C(6)H(4)(SMe)(2) unexpectedly forms a zig-zag chain polymer in the solid state, [TeCl(4){o-C(6)H(4)(SMe)(2)}](n), in which the dithioether adopts an extremely unusual bridging mode. This is in contrast to the chelating monomer, cis-[TeCl(4){o-C(6)H(4)(SeMe)(2)}], formed with the analogous selenoether and may be attributed to small differences in the ligand chelate bite angles. The wider bite angle xylyl-linked bidentates, o-C(6)H(4)(CH(2)EMe(2))(2) behave differently; the thioether forms cis-chelated [TeX(4){o-C(6)H(4)(CH(2)SMe)(2)}] confirmed crystallographically, whereas the selenoether undergoes C-Se cleavage and rearrangement on treatment with TeX(4), forming the cyclic selenonium salts, [C(9)H(11)Se](2)[TeX(6)]. The tetrathiamacrocycle, [14]aneS(4) (1,4,8,11-tetrathiacyclotetradecane), does not react cleanly with TeCl(4), but forms the very poorly soluble [TeCl(4)([14]aneS(4))](n), shown by crystallography to be a zig-zag polymer with exo-coordinated [14]aneS(4) units linked via alternate S atoms to a cis-TeCl(4) unit. Trends in the (125)Te{(1)H} NMR shifts for this series of Te(iv) halides chalcogenoether complexes are discussed.     

Biaryl formation in the synthesis of endo and exo-platinacycles

The reactions of cis-[Pt(2)(4-MeC(6)H(4))(4)(μ-SEt(2))(2)] with bifunctional ligands ArCH=NCH(2)(2-XC(6)H(4)) containing a C-X bond at the ortho positions of the benzyl ring (Ar = 4-ClC(6)H(4), X = Br (1d); Ar = 2,4,6-(CH(3))(3)C(6)H(2), X = Br (1e); Ar = 2,4,6-(CH(3))(3)C(6)H(2), X = Cl (1f); Ar = 2-CH(3)C(6)H(4), X = Br (1h); Ar = 2,6-F(2)C(6)H(3), X = Br (1i)) in refluxing toluene were studied. Several types of platinum(II) cyclometallated compounds containing a biaryl linkage were obtained: i) endo-five-membered with a Pt-C(sp(2)) bond (2d, 2h), ii) endo-six-membered with a Pt-C(sp(3)) bond (2e, 2f), and iii) exo-five membered with a Pt-C(sp(2)) bond (2i). The formed biaryl linkage involves the metallated ring for 2i and the non-metallated ring for the endo-metallacycles. The reaction of compounds 2 with PPh(3) produced the corresponding phosphine derivatives, some of which (3d, 3e, 3h and 3i) were characterised crystallographically. In addition, compound [PtBr{2-CH(3)C(6)H(3)C(6)H(4)CH=NCH(2)(2-C(6)H(4)Br)}SEt(2)] (2c) containing a seven-membered endo-metallacycle was also obtained and characterised crystallographically.     

Reactivity of an anionic Pd(II) metallacycle with CH2X2 (X=Cl, Br, I): formal insertion of methylene into a Pd-C(aryl) bond

Whereas the reaction of the anionic palladium metallacycle [K[Pd(CH2CMe2-o-C6H4)(kappa2-Tp)]] with CH2Cl2 leads to the isolation of the stable Pd(IV) chloromethyl complex [Pd(CH2CMe2-o-C6H4)(kappa3-Tp)(CH2Cl)], the analogous reactions with CH2Br2 and CH2I2 give rise to the six membered metallacycles [Pd(CH2CMe2-o-C6H4(CH2))(kappa3-Tp)X](X = Br or I), as a result of the formal insertion of CH2 into the Pd-C(aryl) bond.     

Mono- vs. bi-metallic assembly on a bulky bis(imino)terpyridine framework: a combined experimental and theoretical study

The bis(imino)terpyridine ligands, 6,6'-{(2,6-i-Pr2C6H3)N=CR}2-2,2':6',2'-C15H9N3 (R = H L1, Me L2), have been prepared in high yield from the condensation reaction of the corresponding carbonyl compound with two equivalents of 2,6-diisopropylaniline. The molecular structure of L2 reveals a transoid relationship between the imino and pyridyl nitrogen groups throughout the ligand framework. Treatment of aldimine-containing L1 with one equivalent or an excess of MX2 in n-BuOH at 110 degrees C gives the mononuclear five-coordinate complexes, [(L1)MX2] (M = Fe, X = Cl 1a; M = Ni, X = Br 1b; M = Zn, X = Cl 1c), in which the metal centre occupies the terpyridine cavity and the imino groups pendant. Conversely, reaction of ketimine-containing L2 with excess MX2 in n-BuOH at 110 degrees C affords the binuclear complexes, [(L2)M2X4] (M = Fe, X = Cl 3a; M = Ni, X = Br 3b; M = Zn, X = Cl 3c), in which one metal centre occupies a bidentate pyridylimine cavity while the other a tridentate bipyridylimine cavity. 1H NMR studies on diamagnetic 3c suggests a fluxional process is operational at ambient temperature in which the central pyridine ring undergoes an exchange between metal coordination. Under less forcing conditions (room temperature in dichloromethane), the monometallic counterpart of 1b [(L2)NiBr2] (2b) has been isolated which can be converted to 3b by addition of one equivalent of (DME)NiBr2 (DME = 1,2-dimethoxyethane) in n-BuOH at 110 degrees C. Quantum mechanical calculations (DFT) have been performed on [(L1)ZnCl2] and [(L2)ZnCl2] for different monometallic conformations and show that 1a is the energetically preferred structure for L1 while there is evidence for dynamic behaviour in L2-containing species leading to bimetallic formation. Single-crystal X-ray diffraction studies have been performed on 1a, 1b, 1c, 2b, 3a, 3b(H2O) and 3c.