Silver(I) complexes of a sterically demanding fluorinated triazapentadienyl ligand [N((C3F7)C(Dipp)N)2]- (Dipp = 2,6-diisopropylphenyl)

Sterically demanding triazapentadiene [N((C3F7)C(Dipp)N)2]H affords the isolation of thermally stable, two- and three-coordinate silver complexes. The free ligand [N((C3F7)C(Dipp)N)2]H has a W-shaped ligand backbone in the solid state.[N((C3F7)C(Dipp)N)2]H reacts with silver(I) oxide in acetonitrile leading to CH(3)CNAg [N((C3F7)C(Dipp)N)2]HIt features a two-coordinate silver center and a kappa(1)-coordinated triazapentadienyl ligand. This silver acetonitrile complex serves as an excellent precursor to obtain thermally stable, silver isocyanide t-BuNCAg [N((C3F7)C(Dipp)N)2]Hand silver phosphine [[N((C3F7)C(Dipp)N)2]HAgPPh(3) adducts. IR spectroscopic data for the silver(I) isocyanide t-BuNCAg [N((C3F7)C(Dipp)N)2]Hshows nu(CN) at 2219 cm(-)(1). The silver ion coordinates to the triazapentadienyl ligand via the central nitrogen atom. The silver PPh(3) adduct,[N((C3F7)C(Dipp)N)2]HAgPPh(3), was synthesized by treating CH3CNAg [N((C3F7)C(Dipp)N)2]Hwith PPh(3). It displays relatively large Ag-P coupling in the (31)P NMR spectrum. The triazapentadienyl ligand in[N((C3F7)C(Dipp)N)2]HAgPPh(3) acts as a chelating kappa(2)-donor. The Ag-P bond is relatively short (2.3487(10) A).     

Oxidative addition reactions of alkyl halides with the group 13 carbene analogue [In{N(Dipp)C(Me)}2CH] (Dipp=2,6-iPr2C6H3)

Reactions of the well-defined two-coordinate indium "carbene analogue" [In{N(Dipp)-C(Me)}2CH] (Dipp=2,6-iPr2C6H3) have been studied. Reactions of MeI, iPrI, and tBuI with [In{N(Dipp)C(Me)}2CH] formed by the in situ reaction of InI, [K{N(SiMe3)2}], and the iminoenamine ligand precursor successfully yielded the oxidative addition products [InRI{N(Dipp)C(Me)}2CH] (R=Me, iPr, tBu). The results of NMR investigations, which indicated the formation of a series of four-coordinate indium(III) complexes in C6D6 solution, were confirmed in the solid-state by single-crystal X-ray diffraction. Similar reactions employing alkyl bromides were unsuccessful and resulted in the isolation of the corresponding iodides, apparently by metathesis of the bromide oxidative addition product with KI formed during the initial InI metathesis. Reactions of isolated samples of [In{N(Dipp)C(Me)}2CH] with iPrBr and tBuBr, however, were straightforward and resulted in the successful isolation of the analogous iso-propyl and tert-butyl indium(III) bromide complexes. These were also fully characterized by 1H and 13C NMR and single-crystal X-ray diffraction experiments. In contrast, no reaction was observed between [In{N(Dipp)-C(Me)}2CH] and aryl halides or alkyl chlorides.     

Synthesis and characterization of HC[C(Me)N(C(6)H(3)-2,6-i-Pr(2))](2)MX(2) (M = Al, X = Cl, I; M = Ga, In, X = Me, Cl, I): sterically encumbered beta-diketiminate group 13 metal derivatives

A series of group 13 metal complexes featuring the beta-diketiminate ligand [[(C(6)H(3)-2,6-i-Pr(2))NC(Me)](2)CH](-) (i.e., [Dipp(2)nacnac](-), Dipp = C(6)H(3)-2,6-i-Pr(2)) have been prepared and spectroscopically and structurally characterized. The chloride derivatives Dipp(2)nacnacMCl(2) (M = Al (3), Ga (5), In (8)) were isolated in good yield by the reaction of 1 equiv of Dipp(2)nacnacLi.Et(2)O (2) and the respective metal halides. The iodide derivatives Dipp(2)nacnacMI(2) (M = Al (4), Ga (6), In (9)), which are useful for reduction to afford M(I) species, were made by a variety of routes. Thus, 4 was obtained by treatment of the previously reported Dipp(2)nacnacAlMe(2) with I(2), whereas the gallium analogue 6 was obtained as a product of the reaction of "GaI" with Dipp(2)nacnacLi.Et(2)O, and 9 was obtained by direct reaction of InI(3) and the lithium salt. The methyl derivatives Dipp(2)nacnacMMe(2) (M = Ga (7), In (10)), which are analogous to the previously reported Dipp(2)nacnacAlMe(2), were synthesized by the reaction of GaMe(3) with Dipp(2)nacnacH (1) or by reaction of the indium chloride derivative 8 with 2 equiv of MeMgBr in diethyl ether. The compounds 3-10 exist as colorless, air- and moisture-sensitive crystalline solids. Their X-ray crystal structures feature nearly planar C(3)N(2) arrays in the Dipp(2)nacnac ligand backbone with short C-C and C-N distances that are consistent with a delocalized structure. However, there are large dihedral angles between the C(3)N(2) plane and the N(2)M metal coordination plane which have been attributed mainly to steric effects. The relatively short M-N distances are consistent with the coordination numbers of the metals and the normal/dative character of the nitrogen ligands. The compounds were also characterized by (1)H and (13)C NMR spectroscopy. (1)H NMR data for 7 revealed equivalent methyl groups whereas the spectrum of 10 displayed two In-Me signals which indicated that ring wagging was slow on the (1)H NMR time scale.     

Organoiron compounds derived from the indium 'carbene analogues', [In(N(Ar)C(Me))2CH] (Ar = dipp = 2,6-iPr2C6H3; = Mes = 2,4,6-Me3C6H2)

Oxidative insertion of the In(I) 'carbene analogues', [In{N(Dipp)C(Me))2CH] (Ar = Dipp = 2,6-iPr2C6H3; Ar = Mes = 2,4,6-Me3C6H2) into the Fe-I bond of [CpFe(CO)2I] occurred cleanly and under mild conditions to yield the In(III) compounds [CH((CH3)2CN-2,6-iPr2C6H3)2In(I)FeCp(CO)2] and [CH( (CH3)2CN-2,4,6-Me3C6H3)2In(I)FeCp(CO)2], which have been fully characterised in solution and the solid state. Attempts to abstract the iodide anion from [CH( (CH3)2CN-2,6-iPr2C6H3)2In(I)FeCp(CO)2] to form cationic species containing a coordinated indium diyl were unsuccessful and resulted in a complex mixture of products from which two ionic species were isolated. Neither cation was found to contain indium by X-ray crystallographic analysis. These observations were indicative of ill-defined decomposition pathways as have been noted by previous workers. A further attempt to form a cationic iron species containing a coordinated [In(N(Dipp)C(Me) )2CH] fragment resulted in oxidation of the iron centre from Fe(II) to Fe(III), with deposition of indium metal, and the isolation of a cationic Fe(III) beta-diketiminate complex.     

Magnesium(II) complexes of 2,4-N,N'-disubstituted 1,3,5-triazapentadienyl ligands: synthesis and characterization of [N(Dipp)C(NMe2)NC(NMe(2))N(SiMe3)MgBr]2 and [N(R)C(R')NC(R')N(SiMe3)]2Mg (Dipp = 2,6-iPr2-C6H3, R = Ph, SiMe(3); R' = NMe2, 1-piperidino)

Treatment of the appropriate lithium or sodium 2,4-N,N'-disubstituted 1,3,5-triazapentadienate [RNC(R')NC(R')N(SiMe(3))M](2) (R = Ph, 2,6-(i)Pr(2)-C(6)H(3)(Dipp) or SiMe(3); R' = NMe(2) or 1-piperidino; M = Li or Na) with one or half equivalent portion of MgBr(2)(THF)(2) in Et(2)O under mild conditions furnishes in good yield the first structurally characterized molecular magnesium 2,4-N,N'-disubstituted 1,3,5-triazapentadienates [DippNC(NMe(2))NC(NMe(2))N(SiMe(3))MgBr](2) (1), [{RNC(R')NC(R')N(SiMe(3))}(2)Mg] (R = Ph, R' = NMe(2) 2; R = Ph, R' = 1-piperidino 3; R = SiMe(3), R' = 1-piperidino 4). The solid-state structure of 1 is dimeric and those of 2, 3, and 4 are monomeric. The ligand backbone NCNCN in 1 adopts a W-shaped configuration, while in 2, 3 and 4 adopts a U-shaped configuration.     

Synthesis and structures of selected triazapentadienate of Li, Mn, Fe, Co, Ni, Cu(I), and Cu(II) using 2,4-N,N'-disubstituted 1,3,5-triazapentadienate anions as ancillary ligands: [N(Ar)C(NMe2)NC(NMe2)N(R)](-) (Ar = Ph, 2,6-(i)Pr2-C6H3; R = H, SiMe3)

Addition reaction of ArN(SiMe 3)M (Ar = Ph or 2,6 - (i) Pr 2-C 6H 3 (Dipp); M = Li or Na) to 2 equivalents of alpha-hydrogen-free nitrile RCN (R = dimethylamido) gave the dimeric [M{N(Ar)C(NMe 2)NC(NMe 2)N(SiMe 3)}] 2 ( 1a, Ar = Ph, M = Li; 1b, Ar = Ph, M = Na; 1c, Ar = Dipp, M = Li). 1d was obtained by hydrolysis of 1c at ambient temperature. Treatment of a double ratio of 1a or 1b with anhydrous MCl 2 (M = Mn, Fe, Co) yielded the 1,3,5-triazapentadienato complexes [M{N(Ph)C(NMe 2)NC(NMe 2)N(SiMe 3)} 2] (M = Mn, 2; Fe, 3; Co, 4) and with NiCl 2.6H 2O gave [M{N(Ph)C(NMe 2)NC(NMe 2)N(H)} 2] (M = Ni, 5). Treatment of an equiv of 1c with anhydrous CuCl in situ and in air led to complexes [{N(Dipp)C(NMe 2)NC(NMe 2)N(SiMe 3)}CuPPh 3] 6 and [Cu{N(Dipp)C(NMe 2)NC(NMe 2)N(H)} 2] 7, respectively. 1c, 1d, and 2- 7 were characterized by X-ray crystallography and microanalysis. 1c, 1d, 5, and 6 were well characterized by (1)H, (13)C NMR, 1c by (7)Li, and 6 by (31)P NMR as well. The structural features of these complexes were described in detail.     

A new zinc-zinc-bonded compound with a dianionic alpha-diimine ligand: synthesis and structure of [Na(THF)2]2 x [LZn-ZnL] (L = [(2,6-(i)Pr2C6H3)N(Me)C]2(2-))

The synthesis and structure of a Zn-Zn-bonded compound supported by a doubly reduced alpha-diimine ligand, [Na(THF)2]2 x [LZn-ZnL] (L = [(2,6-(i)Pr2C6H3)N(Me)C]2(2-)) are reported, with a Zn-Zn bond length of 2.399(1) angstroms.     

Syntheses of highly fluorinated 1,3,5-triazapentadienyl ligands and their use in the isolation of copper(I)-carbonyl and copper(I)-ethylene complexes

Fully fluorinated triazapentadienyl ligand [N{(C3F7)C(C6F5)N}2]- and the related [N{(C3F7)C(2-F,6-(CF3)C6H3)N}2]- have been synthesized in good yield via a convenient route and used in the isolation of three- and four-coordinate copper(I)-carbon monoxide complexes. They show fairly high nu(CO) values (>2100 cm(-1)), indicating the presence of electron-poor Cu sites. The copper(I)-ethylene adduct [N{(C3F7)C(C6F5)N}2]Cu(C2H4), featuring a three-coordinate Cu site, has also been synthesized using [N{(C3F7)C(C6F5)N}2]CuNCCH3 and C2H4.     

CRYSTAL AND MOLECULAR STRUCTURE OF THE HEXANUCLE-AR DIAZENIDO-OXOMOLYBDATE [(n-C_4H_9)_4N]_3[Mo_6O_(18)-(N_2C_6H_3-2,4-(NO_2)_2]

<正> Crystal of the title complex [(n-C4H9)4N]3[Mo6O18(N2C6H3-2,4-(NO2)2](Mr= 1710. 5) is orthorhombic with space group P21cn (Pna21), a = 17. 304(3), b = 17.580(2), c=24. 355(4) (?), V = 7409(2)(?)3, Z = 4, Dc=1. 60g/ cm3, μ=10. 29cm-1, F (000) = 3647. The structural solutions and refinements based on 3900 reflections (I≥3σ(I)) converged at R = 0. 0575, Rw =0. 0498. The atoms of Mo(3), Mo(4), O(1), O(5), O(9), O(11) and the [N2C6H3-2,4-(NO2)2] unit in the complex anion locate approximately in a plane about which the complex anion is nearly symmetrical.     

Gold(I) ethylene and copper(I) ethylene complexes supported by a polyhalogenated triazapentadienyl ligand

A rare gold(I) ethylene complex and the closely related copper(I) ethylene adduct have been isolated using [N{(C3F7)C(2,6-Cl2C6H3)N}2]- as the supporting ligand. [N{(C3F7)C(2,6-Cl2C6H3)N}2]Au(C2H4) (1) is an air-stable solid. It features a U-shaped triazapentadienyl ligand backbone and a three-coordinate, trigonal-planar gold center. The copper(I) adduct [N{(C3F7)C(2,6-Cl2C6H3)N}2]Cu(C2H4) (2) also has a similar structure. The 13C NMR signal corresponding to the ethylene carbons of 1 appears at about 64 ppm upfield from the free ethylene, while the ethylene carbons of 2 show a relatively smaller (39 ppm) upfield shift. [N{(C3F7)C(2,6-Cl2C6H3)N}2]M(C2H4) (M=Cu, Au) mediate carbene-transfer reactions from ethyl diazoacetate to saturated and unsaturated hydrocarbons.     

Monomeric lithium triazapentadienyl complexes

Treatment of 1,3,5-triazapentadienes [N{(C3F7)C(Mes)N}2]H and [N{(C3F7)C(Dipp)N}2]H (where Mes = 2,4,6-Me3C6H2; Dipp = 2,6-Pr(i)2C6H3) with n-BuLi in hexane, followed by the crystallization from hexane-THF mixture afforded the corresponding lithium 1,3,5-triazapentadienyl complexes as their THF solvates. X-Ray crystallographic analyses revealed that [N{(C3F7)C(Mes)N}2]Li(THF)2 and [N{(C3F7)C(Dipp)N}2]Li(THF) are monomeric in the solid state. [N{(C3F7)C(Mes)N}2]Li(THF)2 has a four-coordinate lithium center with a distorted tetrahedral geometry, and features a boat-shaped C2N3Li metallacycle. [N{(C3F7)C(Dipp)N}2]Li(THF) has a three-coordinate lithium atom and a planar, U-shaped C2N3 ligand backbone. The synthesis, solid-state structure, and 1H and 19F NMR spectroscopic details of [N{(C3F7)C(Mes)N}2]H are also reported.     

Synthesis and reactivity of copper(I) complexes containing a bis(imidazolin-2-imine) pincer ligand

The new pincer ligand 2,6-bis[(1,3-di-tert-butylimidazolin-2-imino)methyl]pyridine (TL(tBu)) has been prepared in high yield from 2,6-bis(hydroxymethyl)pyridine (1) and 1,3-di-tert-butylimidazolin-2-imine (3). Reaction of TL(tBu) with [Cu(MeCN)4]PF6 affords the highly reactive copper(I) complex [(TL(tBu))Cu]PF6, [5]PF6, which forms the stable copper(I) isocyanide complexes [6a]PF6 (nu(CN) = 2179 cm(-1)) and [6b]PF6 (nu(CN) = 2140 cm(-1)) upon addition of tert-butyl or 2,6-dimethylphenyl isocyanide, respectively. For the cations 6a and 6b, DFT calculations reveal ground-state electronic structures of the type [(TL(tBu)-kappaN(1):kappaN(2))Cu(CNR)] with tricoordinate geometries around the copper atoms. Exposure of [5]PF6 to the air readily leads to trapping of atmospheric CO2 to form the square-planar complex [(TL(tBu))Cu(HCO3-kappaO)]PF6, [7]PF6, with the bicarbonate ligand adopting a rarely observed monodentate coordination mode. In chlorinated solvents such as dichloromethane or chloroform, [5]PF(6) rapidly abstracts chloride by reductive dechlorination of the solvent to yield [(TL(tBu))CuCl]PF6, [8]PF6 quantitatively. Reaction of TL(tBu) with copper(I) bromide or chloride affords complexes 9a and 9b, respectively, for which X-ray diffraction analysis, low-temperature NMR experiments and DFT calculations reveal the presence of a kappa(2)-coordinated ligand of the type [(TL(tBu)-kappaN(1):kappaN(2))CuX]. In solution, complex 9b undergoes slow disproportionation forming the mixed-valence copper(II)/copper(I) system [(TL(tBu))CuCl][CuCl2], [8]CuCl2 with a linear dichlorocuprate(I) counterion.     

Two new groups of homoleptic rare earth pyridylbenzimidazolates: (NC12H8(NH)2)[Ln(N3C12H8)4] with Ln = Y,Tb, Yb,and [Ln(N3C12H8)2(N3C12H9)2][Ln(N3C12H8)4](N3C12H9)2 with Ln = La,Sm, Eu

The compounds (NC(12)H(8)(NH)(2))[Ln(N(3)C(12)H(8))(4)], Ln = Y, Tb, Yb, and [Ln(N(3)C(12)H(8))(2)(N(3)C(12)H(9))(2)][Ln(N(3)C(12)H(8))(4)](N(3)C(12)H(9))(2), with Ln = La, Sm, Eu, were obtained by reactions of the group 3 metals yttrium and lanthanum as well as the lanthanides europium, samarium, terbium, and ytterbium with 2-(2-pyridyl)-benzimidazole. The reactions were carried out in melts of the amine without any solvent and led to two new groups of homoleptic rare earth pyridylbenzimidazolates. The trivalent rare earth atoms have an eightfold nitrogen coordination of four chelating pyridylbenzimidazolates giving an ionic structure with either pyridylbenzimidazolium or [Ln(N(3)C(12)H(8))(2)(N(3)C(12)H(9))(2)](+) counterions. With Y, Eu, Sm, and Yb, single crystals were obtained whereas the La- and Tb-containing compounds were identified by powder methods. The products were investigated by X-ray single crystal or powder diffraction and MIR and far-IR spectroscopy, and with DTA/TG regarding their thermal behavior. They are another good proof of the value of solid-state reaction methods for the formation of homoleptic pnicogenides of the lanthanides. Despite their difference in the chemical formula, both types (NC(12)H(8)(NH)(2))[Ln(N(3)C(12)H(8))(4)], Ln = Y (1), Tb (2), Yb (3), and [Ln(N(3)C(12)H(8))(2)(N(3)C(12)H(9))(2)][Ln(N(3)C(12)H(8))(4)](N(3)C(12)H(9))(2), Ln = La (4), Sm (5), Eu (6), crystallize isotypic in the tetragonal space group I4(1). Crystal data for (1): T = 170(2) K, a = 1684.9(1) pm, c = 3735.0(3) pm, V = 10603.5(14) x 10(6) pm(3), R1 for F(o) > 4sigma(F(o)) = 0.053, wR2 = 0.113. Crystal data for (3): T = 170(2) K, a = 1683.03(7) pm, c = 3724.3(2) pm, V = 10549.4(14) x 10(6) pm(3), R1 for F(o) > 4sigma(F(o)) = 0.047, wR2 = 0.129. Crystal data for (5): T = 103(2) K, a = 1690.1(2) pm, c = 3759.5(4) pm, V = 10739(2) x 10(6) pm(3), R1 for F(o) > 4sigma(F(o)) = 0.050, wR2 = 0.117. Crystal data for (6): T = 170(2) K, a = 1685.89(9) pm, c = 3760.0(3) pm, V = 10686.9(11) x 10(6) pm(3), R1 for F(o) > 4sigma(F(o)) = 0.060, wR2 = 0.144.     

Reactivity at the beta-diketiminate ligand Nacnac- on titanium(IV) (Nacnac- = [Ar]NC(CH3)CHC(CH3)N[Ar], Ar = 2,6-[CH(CH3)2]2C6H3). Diimine-alkoxo and bis-anilido ligands stemming from the Nacnac- skeleton

The reaction of ketene OCCPh(2) with the four-coordinate titanium(IV) imide (L(1))Ti[double bond]NAr(OTf) (L(1)(-) = [Ar]NC(CH(3))CHC(CH(3))N[Ar], Ar = 2,6-[CH(CH(3))(2)](2)C(6)H(3)) affords the tripodal dimine-alkoxo complex (L(2))Ti[double bond]NAr(OTf) (L(2)(-) = [Ar]NC(CH(3))CHC(O)[double bond]CPh(2)C(CH(3))N[Ar]). Complex (L(2))Ti[double bond]NAr(OTf) forms from electrophilic attack of the beta-carbon of the ketene on the gamma-carbon of the Nacnac(-) NCC(gamma)CN ring. On the contrary, nucleophiles such as LiR (R(-) = Me, CH(2)(t)Bu, and CH(2)SiMe(3)) deprotonate cleanly in OEt(2) the methyl group of the beta-carbon on the former Nacnac(-) backbone to yield the etherate complex (L(3))Ti[double bond]NAr(OEt(2)), a complex that is now supported by a chelate bis-anilido ligand (L(3)(2)(-) = [Ar]NC(CH(3))CHC(CH(2))N[Ar]). In the absence of electrophiles or nucleophiles, the robust (L(1))Ti[double bond]NAr(OTf) template was found to form simple adducts with Lewis bases such as CN(t)Bu or NCCH(2)(2,4,6-Me(3)C(6)H(2)). Complexes (L(2))Ti[double bond]NAr(OTf), (L(3))Ti[double bond]NAr(OEt(2)), and the adducts (L(1))Ti[double bond]NAr(OTf)(XY) [XY = CN(t)Bu and NCCH(2)(2,4,6-Me(3)C(6)H(2))] were structurally characterized by single-crystal X-ray diffraction studies.     

Reactions of the perfluoroalkyltriazapentadiene Ph2N3C2(C3F7)2H with acids,bases, and water

Treatment of the bis(perfluoroalkyl)triazapentadiene PhN=C(C(3)F(7))-N=C(C(3)F(7))-NHPh, 2, with bases affords salts of the conjugate base. Alkylation of the Na(+) salt with CH(3)I yields PhN=C(C(3)F(7))-N=C(C(3)F(7))-NMePh. The crystal structure of [Bu(4)N][Ph(2)N(3)C(2)(C(3)F(7))(2)] demonstrates a twisted, zigzag geometry for the anion in the solid state, but in solution, it is conformationally unstable. Both compounds are stable in aqueous methanol, but hydrolysis occurs under acidic conditions. Protonation with CF(3)SO(3)H acid occurs at the sp(2) nitrogen to give [PhN-(H) HC(C(3)F(7))-C(C(3)F(7))-NHPh][CF(3)SO(3)]. Heating 2 in CF(3)SO(3)H produces 2,4-bis(heptafluoropropyl)-1,3-quinazoline.     

Copper(I) complex O(2)-reactivity with a N(3)S thioether ligand: a copper-dioxygen adduct including sulfur ligation, ligand oxygenation, and comparisons with all nitrogen ligand analogues

In order to contribute to an understanding of the effects of thioether sulfur ligation in copper-O(2) reactivity, the tetradentate ligands L(N3S) (2-ethylthio-N,N-bis(pyridin-2-yl)methylethanamine) and L(N3S')(2-ethylthio-N,N-bis(pyridin-2-yl)ethylethanamine) have been synthesized. Corresponding copper(I) complexes, [CuI(L(N3S))]ClO(4) (1-ClO(4)), [CuI(L(N3S))]B(C(6)F(5))(4) (1-B(C(6)F(5))(4)), and [CuI(L(N3S'))]ClO(4) (2), were generated, and their redox properties, CO binding, and O(2)-reactivity were compared to the situation with analogous compounds having all nitrogen donor ligands, [CuI(TMPA)(MeCN)](+) and [Cu(I)(PMAP)](+) (TMPA = tris(2-pyridylmethyl)amine; PMAP = bis[2-(2-pyridyl)ethyl]-(2-pyridyl)methylamine). X-ray structures of 1-B(C(6)F(5))(4), a dimer, and copper(II) complex [Cu(II)(L(N3S))(MeOH)](ClO(4))(2) (3) were obtained; the latter possesses axial thioether coordination. At low temperature in CH(2)Cl(2), acetone, or 2-methyltetrahydrofuran (MeTHF), 1 reacts with O(2) and generates an adduct formulated as an end-on peroxodicopper(II) complex [{Cu(II)(L(N3S))}(2)(mu-1,2-O(2)(2-))](2+) (4)){lambda(max) = 530 (epsilon approximately 9200 M(-1) cm(-1)) and 605 nm (epsilon approximately 11,800 M(-1) cm(-1))}; the number and relative intensity of LMCT UV-vis bands vary from those for [{Cu(II)(TMPA)}(2)(O(2)(2-))](2+) {lambda(max) = 524 nm (epsilon = 11,300 M(-1) cm(-1)) and 615 nm (epsilon = 5800 M(-1) cm(-1))} and are ascribed to electronic structure variation due to coordination geometry changes with the L(N3S) ligand. Resonance Raman spectroscopy confirms the end-on peroxo-formulation {nu(O-O) = 817 cm(-1) (16-18O(2) Delta = 46 cm(-1)) and nu(Cu-O) = 545 cm(-1) (16-18O(2) Delta = 26 cm(-1)); these values are lower in energy than those for [{Cu(II)(TMPA)}(2)(O(2)(2-))](2+) {nu(Cu-O) = 561 cm(-1) and nu(O-O) = 827 cm(-1)} and can be attributed to less electron density donation from the peroxide pi* orbitals to the Cu(II) ion. Complex 4 is the first copper-dioxygen adduct with thioether ligation; direct evidence comes from EXAFS spectroscopy {Cu K-edge; Cu-S = 2.4 Angstrom}. Following a [Cu(I)(L(N3S))](+)/O(2) reaction and warming, the L(N3S) thioether ligand is oxidized to the sulfoxide in a reaction modeling copper monooxygenase activity. By contrast, 2 is unreactive toward dioxygen probably due to its significantly increased Cu(II)/Cu(I) redox potential, an effect of ligand chelate ring size (in comparison to 1). Discussion of the relevance of the chemistry to copper enzyme O(2)-activation, and situations of biological stress involving methionine oxidation, is provided.     

Synthesis and Crystal Structure of catena-Poly[[[2,4-dibromo-6-[(3-dimethylaminopropylimino)-methyl]phenolato]copper(Ⅱ)]-μ-azido]

A novel end-to-end azido-bridged polynuclear Schiff-base copper(H) complex,[Cu(C12H15Br2N2O)(N3)]n, was prepared and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction.The crystal belongs to the orthorhombic system, space group Pbcn with a = 24.588(5), b = 10.377(2), c = 13.022(3)(A),V= 3322.6(12)(A)3, Z = 8, Dc = 1.874 g/cm3, Mr= 468.65, λ(MoKα) = 0.71073 (A),μ= 6.130 mm-1, F(000) = 1832, R = 0.0637 and wR = 0.1176.The Cu atom in the complex is five-coordinated in a square pyramidal geometry by three donoratoms of the Schiff-base ligand, and two N atoms from two bridging azide ligands.The [2,4-dibromo-6-[(3-dimethylaminopropylimino)methyl]phenolato]copper(Ⅱ) units are linked by the bridging azide ligands, giving zigzag polymeric chains with backbones of the [-Cu-N-N-N-Cu]n type running along the b axis.     

Synthesis and Crystal Structure of a One-dimensional Ladder-like Complex [Cu2(L)(dca)2]n (dca = [N(CN)2]-,L = 1,4-Bis(3-furanyl)-2,3-diaza-1,3-butadiene)

A new Cu(I)-dicyanamide with formula [Cu2(L)(dca)2]n (dca = dicyanamide anion, L = 1,4-bis(3-furanyl)-2,3-diaza-1,3-butadiene) has been synthesized and structurally characterized.The complex crystallizes in the monoclinic system, space group P21/n with a = 9.271(2), b = 7.7355(16), c = 11.967(3) -, β = 102.693(3)°, V = 837.3(3) -3, Z = 4, Mr = 223.68, Dc = 1.775 g/cm3, μ(MoKα) = 2.567 mm-1, F(000) = 444, R = 0.0782 and wR = 0.2582 for 951 observed reflections (I > 2σ(I)).Single-crystal X-ray analysis reveals that the copper atom is three-coordinated by two nitrogen atoms from two dicyanamide anions and another one from the ligand, and each copper atom is connected by two [N(CN)2]- anions to form an infinite double-stranded bridge fashion leading to 1D ladder-like motifs.     

Synthesis of triamidoamine ligands of the type (ArylNHCH(2)CH(2))(3)N and molybdenum and tungsten complexes that contain an [ArylNCH(2)CH(2))(3)N]3- ligand

Aryl bromides react with (H(2)NCH(2)CH(2))(3)N in a reaction catalyzed by Pd(2)(dba)(3) in the presence of BINAP and NaO-t-Bu to give the arylated derivatives (ArylNHCH(2)CH(2))(3)N [Aryl = C(6)H(5) (1a), 4-FC(6)H(4) (1b), 4-t-BuC(6)H(4) (1c), 3,5-Me(2)C(6)H(3) (1d), 3,5-Ph(2)C(6)H(3) (1e), 3,5-(4-t-BuC(6)H(4))(2)C(6)H(3) (1f), 2-MeC(6)H(4) (1g), 2,4,6-Me(3)C(6)H(2) (1h)]. Reactions between (ArNHCH(2)CH(2))(3)N (Ar = C(6)H(5), 4-FC(6)H(4), 3,5-Me(2)C(6)H(3), and 3,5-Ph(2)C(6)H(3)) and Mo(NMe(2))(4) in toluene at 70 degrees C lead to [(ArNHCH(2)CH(2))(3)N]Mo(NMe(2)) complexes in yields ranging from 64 to 96%. Dimethylamido species (Ar = 4-FC(6)H(4), 3,5-Me(2)C(6)H(3)) could be converted into paramagnetic [(ArNHCH(2)CH(2))(3)N]MoCl species by treating them with 2,6-lutidinium chloride in tetrahydrofuran (THF). The "direct reaction" between 1a-f and MoCl(4)(THF)(2) in THF followed by 3 equiv of MeMgCl yielded [(ArNHCH(2)CH(2))(3)N]MoCl species (3a-f) in high yield. If 4 equiv of LiMe instead of MeMgCl are employed in the direct reaction, then [(ArNHCH(2)CH(2))(3)N]MoMe species are formed. Tungsten species, [(ArNHCH(2)CH(2))(3)N]WCl, could be prepared by analogous "direct" methods. Cyclic voltammetric studies reveal that MoCl complexes become more difficult to reduce as the electron donating ability of the [ArylNCH(2)CH(2))(3)N]3- ligand increases, and the reductions become less reversible, consistent with ready loss of chloride from ([(ArNHCH(2)CH(2))(3)N]MoCl)(-). Tungsten complexes are more difficult to reduce, and reductions are irreversible on the CV time scale.     

From a cycloheptatrienylzirconium allyl complex to a cycloheptatrienylzirconium imidazolin-2-iminato "pogo stick" complex with imido-type reactivity

The reaction of the cycloheptatrienylzirconium half-sandwich complex [(η(7)-C(7)H(7))ZrCl(tmeda)] (1) (tmeda = N,N,N',N'-tetramethylethylenediamine) with Li(Im(Dipp)N), generated from bis(2,6-diisopropylphenyl)imidazolin-2-imine (Im(Dipp)NH) with methyllithium, yields the imidazolin-2-iminato complex [(η(7)-C(7)H(7))Zr(Im(Dipp)N)(tmeda)] (2). The corresponding tmeda-free complex [(η(7)-C(7)H(7))Zr(Im(Dipp)N)] (5) can be synthesized via the 1,3-bis(trimethylsilyl)allyl complex [(η(7)-C(7)H(7))Zr{η(3)-C(3)H(3)(TMS)(2)}(THF)] (3; TMS = SiMe(3)), which undergoes an acid-base reaction with Im(Dipp)NH to form 5 and 1,3-bis(trimethylsilyl)propene. 5 exhibits an unusual one-legged piano stool ("pogo stick") geometry with a particularly short Zr-N bond of 1.997(2) ?. Addition of 2,6-dimethylphenyl or tert-butyl isocyanide affords the complexes [(η(7)-C(7)H(7))Zr(Im(Dipp)N)(CNR)] (R = o-Xy, 6; R = t-Bu, 7), while the reaction with 2,6-dimethylphenyl isocyanate results in a [2 + 2] cycloaddition to form the ureato(1-) complex [(η(7)-C(7)H(7))Zr{Im(Dipp)N(C═O)N-o-Xy}] (8). 5 can also act as an initiator for the ring-opening polymerization of ε-caprolactone. These reactivity patterns together with density functional theory calculations reveal a marked similarity of the bonding in imidazolin-2-iminato and conventional imido transition-metal complexes.