We report the preparation, structural characterization, and detailed lactide polymerization behavior of a new Zn(II) alkoxide complex, (L1ZnOEt)2 (L1 = 2,4-di-tert-butyl-6-{[(2'-dimethylaminoethyl)methylamino]methyl}phenolate). While an X-ray crystal structure revealed complex to be dimeric in solid state, nuclear magnetic resonance mass spectrometric analyses showed that monomeric form L1ZnOEt predominates solution. The using this proceeded with good molecular weight control gave relatively...

A key step in dioxygen evolution during photosynthesis is the oxidative generation of O-O bond from water by a manganese cluster consisting M 2 (μ-O) units (where manganese). The reverse reaction, reductive cleavage bond, performed at variety dicopper and di-iron active sites enzymes that catalyze important organic oxidations. Both processes can be envisioned to involve interconversion dimetal-dioxygen adducts, (O ), isomers having cores. viability this notion has been demonstrated...

A temperature-dependent, single crystal x-ray diffraction study of the giant magnetocaloric material, Gd5(Si2Ge2), across its Curie temperature (276 K) reveals that simultaneous orthorhombic to monoclinic transition occurs by a shear mechanism in which (Si, Ge)-(Si,Ge) dimers are richer Ge increase their distances 0.859(3) and lead twinning. The structural changes electronic structure, provides an atomic-level model for change magnetic behavior with Gd5(SixGe1-x)(4).

Iron species with terminal oxo ligands are implicated as key intermediates in several synthetic and biochemical catalytic cycles. However, there is a dearth of structural information regarding these types complexes because their instability has precluded isolation under ambient conditions. The characterization an iron(III) complex ligand, derived directly from dioxygen (O 2 ), reported. A stable structure resulted placing the oxoiron unit within cavity lined hydrogen-bonding groups. creates...

The reaction of dihydrogen with a side-on bound dinitrogen complex zirconium was investigated. Instead displacement the moiety, which is common mode reactivity, containing both bridging hydride and hydrazido unit nitrogen-hydrogen bond observed. This extended to primary silanes produce species that contained nitrogen-silicon bond. In addition, an intermediate in addition has been structurally characterized as having unit.

The synthesis and structures of mono- bis(amidinate) aluminum complexes are described. reaction AlMe3 1 equiv carbodiimide, R'NCNR', affords {MeC(NR')2}AlMe2 (1a, R' = iPr; 1b, Cy cyclohexyl). R'NCNR' with MeLi or tBuLi generates Li[RC(NR')2] (2a, R Me, 3a, tBu, 3b, Cy; 3c, SiMe3). 2a, 3b may be isolated reacted in situ, while attempted isolation 3c gave [Li(tBuCN){μ-N(SiMe3)2}]2 (3d). AlCl3 2a 3a−c {RC(NR')2}AlCl2 (4a, Me; 5a−c, tBu), the AlMe2Cl {tBuC(NR')2}AlMe2 (6a−c). Alkylation 5a,b 2...

A description of the structure and bonding novel bis(μ-oxo)dicopper complexes their bis(μ-hydroxo)dicopper decomposition products was derived from combined X-ray crystallographic, spectroscopic, ab initio theoretical studies. The compounds [(LCu)2(μ-O)2]X2 were generated reaction solutions [LCu(CH3CN)]X with O2 at −80 °C (L = 1,4,7-tribenzyl-1,4,7-triazacyclononane, LBn3; 1,4,7-triisopropyl-1,4,7-triazacyclononane, LiPr3; or 1-benzyl-4,7-diisopropyl-1,4,7-triazacyclononane, LiPr2Bn; X...

A new, highly sensitive fluorescent sensor for Zn(II) ion (a tris(2-pyridylmethyl)amine derivative) shows very strong binding and concentration-dependent biexponential time-resolved fluorescence (TRF) decay profiles that can be used ratiometric estimates of concentrations. The ligand−metal complexes were characterized in solution by spectroscopic techniques the solid state X-ray crystallography. TRF studies revealed aggregates absence a ligand manner, complication is discerned but not...

Coordination complexes that pair a zero-valent transition metal (Ni, Co, Fe) and an aluminum(III) center have been prepared. They add to the few examples of structurally characterized alanes are first reported metallalumatranes. To understand M-Al interaction gauge effect varying late metal, were by X-ray crystallography, electrochemistry, UV-Vis-NIR NMR spectroscopies, theoretical calculations. The bond strength decreases with M in order Ni > Co Fe.

To evaluate the fundamental process of O2 activation at a single copper site that occurs in biological and catalytic systems, detailed study binding to Cu(I) complexes β-diketiminate ligands L (L1 = backbone Me; L2 tBu) by X-ray crystallography, absorption spectroscopy (XAS), cryogenic stopped-flow kinetics, theoretical calculations was performed. Using synchrotron radiation, an diffraction data set for L2CuO2 acquired, which led structural parameters close agreement predictions. Significant...

Non-heme iron and manganese species with terminal oxo ligands are proposed to be key intermediates in a variety of biological synthetic systems; however, the stabilization these types complexes has proven difficult because tendency form oxo-bridged complexes. Described herein design, isolation, properties for series mononuclear FeIII MnIII or hydroxo ligands. Isolation was facilitated by tripodal ligand tris[(N'-tert-butylureaylato)-N-ethyl]aminato ([H3 1]3-), which creates protective...

[FeIV(O)(TMG3tren)]2+ (1; TMG3tren = 1,1,1-tris{2-[N2-(1,1,3,3-tetramethylguanidino)]ethyl}amine) is a unique example of an isolable synthetic S 2 oxoiron(IV) complex, which serves as model for the high-valent intermediates observed in nonheme iron enzymes. Congruent with DFT calculations predicting more reactive center, 1 has lifetime significantly shorter than those related complexes. The self-decay exhibits strictly first-order kinetic behavior and unaffected by solvent deuteration,...

With a little help from some friends: the aid of HClO4 as proton and BPh4− electron source, Fe complex pentadentate pyridyl-appended cyclam ligand can activate dioxygen to yield corresponding oxoiron(IV) (see scheme; TMC-py=1-(2′-pyridylmethyl)-4,8,11-trimethyl-1,4,8,11-tetraazacyclotetradecane; C gray, magenta, N blue, O red). This transformation is proposed occur via hydroperoxoiron(III) intermediate. Supporting information for this article available on WWW under...

Correlations among the molecular structure, crystal electronic and charge-carrier transport phenomena have been derived from six congeners (2–7) of rubrene (1). The were synthesized via a three-step route known 6,11-dichloro-5,12-tetracenedione. After crystallization, their packing structures solved using single-crystal X-ray diffraction. Rubrenes 5–7 maintain orthorhombic features parent (1) in solid-state structures. Control structure provided first series systematically manipulated...

Raman spectroscopy is a powerful method for identifying ion–ion interactions, but only if the vibrational band signatures anion coordination modes can be accurately deciphered. The present study characterizes PF6– P–F symmetric stretching evaluating PF6–···Li+ cation interactions within LiPF6 crystalline solvates to create characterization tool liquid electrolytes. To facilitate this, crystal structures two new solvates—(G3)1:LiPF6 and (DEC)2:LiPF6 with triglyme diethyl carbonate,...

In an effort to gain more insight into the factors controlling formation of low-spin non-heme FeIII−peroxo intermediates in oxidation catalysis, such as activated bleomycin, we have synthesized a series iron complexes based on pentadentate ligand N4Py (N4Py = N,N-bis(2-pyridylmethyl)-N-(bis-2-pyridylmethyl)amine). The following been prepared: [(N4Py)FeII(CH3CN)](ClO4)2 (1), [(N4Py)FeIICl](ClO4) (2), [(N4Py)FeIIIOMe](ClO4)2 (3), and [(N4Py)2Fe2O](ClO4)4 (4). Complexes 1 2 low- high-spin FeII...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Thiolate-Bridged, Fully Delocalized Mixed-Valence Dicopper(I,II) Complex That Models the CuA Biological Electron-Transfer SiteRobert P. Houser, Victor G. Young, and William B. TolmanView Author Information Department of Chemistry, University Minnesota 207 Pleasant Street SE, Minneapolis, 55455Cite this: J. Am. Chem. Soc. 1996, 118, 8, 2101–2102Publication Date (Web):February 28, 1996Publication History Received9 November 1995Published...

The enhanced stability provided by two triphenylphosphane oxide ligands has enabled the first crystal structure analysis of a non-heme diironO2 adduct (1) (structure core is shown on right). Complexes this type can be activated introducing more electron-donating carboxylate ligand. These observations rationalize carboxylate-rich active sites diiron oxygen-activating enzymes such as methane monooxygenase and ribonucleotide reductase. [Fe2(μ-1,2,O2)(N-Et-hptb)(Ph3PO)2](BF4)3 1

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Flexible Germanate Structure Containing 24-Ring Channels and with Very Low Framework DensityJacques Plévert, Travis M. Gentz, Aaron Laine, Hailian Li, Victor G. Young, Omar Yaghi, Michael O'KeeffeView Author Information Department of Chemistry Biochemistry Arizona State University, Tempe, 85287-1604 Chemistry, University Minnesota Minneapolis, 55455 Michigan Ann Arbor, 48109-1055 Cite this: J. Am. Chem. Soc. 2001, 123, 50,...

The synthesis, structures, and reactivity of cationic aluminum complexes containing the N,N'-diisopropylaminotroponiminate ligand ((i)Pr(2)-ATI(-)) are described. reaction ((i)Pr(2)-ATI)AlR(2) (1a-e,g,h; R = H (a), Me (b), Et (c), Pr (d), (i)Bu (e), Cy (g), CH(2)Ph (h)) with [Ph(3)C][B(C(6)F(5))(4)] yields ((i)()Pr(2)-ATI)AlR(+) species whose fate depends on properties ligand. 1a 1b react 0.5 equiv to produce dinuclear monocationic [([(i)Pr(2)-ATI] AlR)(2)(mu-R)][(C(6)F(5))(4)] (2a,b)....

In our efforts to model high-valent intermediates in the oxygen activation cycles of nonheme diiron enzymes such as methane monooxygenase (MMOH-Q) and ribonucleotide reductase (RNR R2-X), we have synthesized spectroscopically characterized a series bis(μ-oxo)diiron(III,IV) complexes, [Fe2(μ-O)2(L)2](ClO4)3, where L is tris(2-pyridylmethyl)amine (TPA) or its ring-alkylated derivatives. We now report crystal structure [Fe2(μ-O)2(5-Et3-TPA)2](ClO4)3 (2), first example structurally reactive...

Crystal structures of glyme solvates with LiTFSI and LiBETI (TFSI- = bis(trifluoromethanesulfonyl)imide, BETI- bis(perfluoroethanesulfonyl)imide) have been determined including (monoglyme)1:LiBETI, (diglyme)2:LiTFSI, (diglyme)1/2:LiTFSI, low-temperature (triglyme)1:LiBETI. These solvates, combined the phase behavior salts various glymes from DSC analysis, provide insight into molecular interactions lithium in ethoxy solvents commonly used for solid polymer liquid electrolytes. Many appear to...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTCationic Aluminum Alkyl Complexes Incorporating Aminotroponiminate LigandsEiji Ihara, Victor G. Young,, and Richard F. JordanView Author Information Department of Chemistry, University Iowa City, 52242 Minnesota Minneapolis, 55455 Cite this: J. Am. Chem. Soc. 1998, 120, 32, 8277–8278Publication Date (Web):July 29, 1998Publication History Received19 May 1998Published online29 July inissue 1 August...

The reactivity of dicopper(I) complexes the ligands α,α'-bis(4,7-diisopropyl-1,4,7-triazacyclononan-1-yl)-p- and m-xylene (p- m-XYLiPr4) with dioxygen was examined by spectroscopic rapid stopped-flow kinetics methods. Only bis(μ-oxo)dicopper(III) core formation observed p-XYLiPr4, but both (μ-η2:η2-peroxo)dicopper(II) species were generated in m-XYLiPr4 case, their relative proportions being dependent on solvent, concentration precursor, temperature. Subsequent decomposition under conditions...