The first cobalt molecule to function as a single-molecule magnet, [Co4(hmp)4(MeOH)4Cl4], where hmp- is the anion of hydroxymethylpyridine, reported. core consists four Co(II) cations and oxygen atoms ions at corners cube. Variable-field variable-temperature magnetization data have been analyzed establish that has S=6 ground state with considerable negative magnetoanisotropy. Single-ion zero-field interactions (DSz2) each ion are origin A single-crystal compound was studied by means...

A Raman spectroscopic evaluation of numerous crystalline solvates with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI or LiN(SO2CF3)2) has been conducted over a wide temperature range. Four new solvate structures—(PHEN)3:LiTFSI, (2,9-DMPHEN)2:LiTFSI, (G3)1:LiTFSI and (2,6-DMPy)1/2:LiTFSI phenanthroline, 2,9-dimethyl[1,10]phenanthroline, triglyme, 2,6-dimethylpyridine, respectively—have determined to aid in this study. The data have correlated varying modes TFSI–···Li+ cation coordination...

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,...

The homoleptic complexes [Ph(4)P](2)[Co[N(CN)(2)](4)] and [Ph(4)P][M[N(CN)(2)](3)] [M = Co, Mn] have been structurally as well magnetically characterized. containing [M[N(CN)(2)](4)](2-) form 1-D chains, which are bridged via a common dicyanamide ligand in [M[N(CN)(2)](3)](-) to 2-D structure. five-atom [NCNCN](-) bridging ligands lead weak magnetic coupling along chain. six (4)T(1g) ground state for Co(II) has an unquenched spin-orbit that is reflected the properties. Long-range ordering...

The water/ZnCl2 phase diagram in the vicinity of 75 mol % water composition is reported, demonstrating existence a congruently melting phase. Single crystals this 3-equiv hydrate were grown, and crystal structure [Zn(OH2)6][ZnCl4] was determined. Synchrotron X-ray neutron diffraction IR Raman spectroscopy along with reverse Monte Carlo modeling demonstrate that CsCl-type packing molecular ions persists into liquid state. Consistent crystalline structural data, demonstrates O–H bonds...

We report four photocatalytically active cobaloxime complexes for light-driven hydrogen evolution. The catalysts are sensitized by different meso-pyridyl boron dipyrromethene (BODIPY) chromophores, bearing either two bromo- or iodo-substituents on the BODIPY core. pyridine linker between and is further modified a methyl substituent pyridine, influencing stability electronic properties of catalyst thus photocatalytic efficiency each system. Four three novel chromophores synthesized...

Partially and fully aromatic molecular spacers bearing two symmetrically bound terpyridyl chelators have been prepared. These spacer-chelators were constructed to dispose the ligands their complexes with square planar metals cofacially a separation of about 7 Å between metals. Dipalladium(II) these prepared characterized. palladium readily form large rectangles linear linker such as 4,4'-dipyridyl. The dichlorodipalladium complex partially reduced spacer-chelator is capable incarcerating...

The preparation and characterization of three new donor–bridge–acceptor biradical complexes are described. Using variable-temperature magnetic susceptibility, EPR hyperfine coupling constants, the results X-ray crystal structures, we evaluate both exchange electronic couplings as a function bridge length for two quintessential molecular bridges: oligo(para-phenylene), β = 0.39 Å–1 oligo(2,5-thiophene), 0.22 Å–1. This report represents first direct comparison exchange/electronic distance...

A series of four anti-disposed dinuclear platinum(II) complexes featuring metal–metal-to-ligand charge-transfer (MMLCT) excited states, bridged by either 2-hydroxy-6-methylpyridine or 2-hydroxy-6-phenylpyridine and cyclometalated with 7,8-benzoquinoline 2-phenylpyridine, are presented. The 2-hydroxypyridine bridging ligands control intramolecular d8–d8 metal–metal σ interactions, affecting the frontier orbitals' electronic structure, resulting in marked changes to ground- excited-state...

Copper(I)−dioxygen interactions are of great interest due to their role in biological O2-processing as well importance industrial oxidation processes. We describe here the study systems which lead new insights concerning factors govern Cu(II)-μ-η2:η2 (side-on) peroxo versus Cu(III)−bis-μ-oxo species formation. Drastic differences O2-reactivity Cu(I) complexes differ only by a single −CH3 −H substituent on central amine tridentate ligands employed observed. [Cu(MeAN)]B(C6F5)4 (1) (MeAN =...

The di-Co(2+) complex, [Co(2+)(mu-OH)(oxapyme)Co(2+)(H(2)O)](+), contains an unsymmetrical binucleating ligand (oxapyme) which provides five- and six-coordinate metal sites when a hydroxide bridge is introduced. This complex absorbs 1 equiv of O(2) irreversibly in solution, producing unstable di-Co(3+) oxygenated product. product has been studied at low temperatures, where its electronic absorption (1)H NMR spectra were recorded. It probable that the oxygenation reaction involves one-site...

Syntheses, crystal structures, and polymerization data for new isospecific metallocenes (heterocenes) having cyclopentenyl ligands b-fused to substituted thiophenes (Tp) pyrroles (Pyr) are reported. The C2- C1-symmetric heterocenes dimethylsilyl bridged, have methyl groups adjacent the bridgehead carbon atoms, aryl substituents protruding in front. rac-Me2Si(2,5-Me2-3-Ph-6-Cp[b]Tp)2ZrCl2/MAO (MAO = alumoxanes) is most active metallocene catalyst polypropylene reported date....

The ligand TMPA (tris(2-pyridylmethyl)amine) and its copper complexes have played a prominent role in recent (bio)inorganic chemistry studies; the copper(I) complex [CuI(TMPA)(CH3CN)]+ possesses an extensive dioxygen reactivity, it is also known to effect reductive dechlorination of substrates such as dichloromethane benzyl allyl chlorides. In this report, we describe set new analogues TMPA, 6TMPAOH, binucleating Iso-DO, trinucleating SYMM. Copper(I) with these ligands previously described...

The complex bis-5,5'-(1,3-propanediyldiimino)-2,2-dimethyl-4-hexen-3-onato samarium bis(trimethylsilyl)amido is a solvent- and halide-free anhydrous, monomeric lanthanide Schiff base complex. It was synthesized from triflate-derived homoleptic Sm[N(TMS)2]3 isolated in excellent yields analytical purity. For larger rare earths, only dimers were observed using analogous reaction pathways.

Elemental sulfur (S8) was found to react with [(TMPA)CuI(CH3CN)]+ form the trans-μ-1,2 end-on disulfide complex [(TMPA)Cu−S−S−Cu(TMPA)]2+. The X-ray structure of this centrosymmetric shows a Cu(1)−S(1) bond length 2.280(2) Å and S(1)−S(1A) 2.044(4) Å.

The chiral Pd(0) trans-stilbene complexes Pd(diphos*)(trans-stilbene) (diphos* = (R,R)-Me-Duphos, (R,R)-Et-Duphos, (R,R)-i-Pr-Duphos, (R,R)-Me-BPE, (S,S)-Me-FerroLANE, (S,S)-Me-DuXantphos, (S,S)-Et-FerroTANE, (R,S)-CyPF-t-Bu, (R,S)-PPF-t-Bu, (R,S)-BoPhoz) and Ni((R,R)-Me-Duphos)(trans-stilbene) were prepared by NaBH(OMe)3 reduction of the corresponding M(diphos*)Cl2 compounds in presence trans-stilbene. rate oxidative addition phenyl iodide to stilbene complexes, which gave...

The reaction of oxorhenium complexes that incorporate diamidopyridine (DAP) ligands with B(C6F5)3 results in the formation classical Lewis acid-base adducts. adducts effectively catalyze hydrogenation a variety unactivated olefins at 100 °C. Control reactions these or alone did not yield any hydrogenated products under conditions. Mechanistic studies suggest frustrated pair is generated between DAP and B(C6F5)3, which effective olefin hydrogenation. Thus, we demonstrate for first time...

Methanol formation from [Cp*Ir(III)(NHC)Me(CD2Cl2)](+) occurs quantitatively at room temperature with air (O2) as the oxidant and ethanol a proton source. A rare example of diiridium bimetallic complex, [(Cp*Ir(NHC)Me)2(μ-O)][(BAr(F)4)2], 3, was isolated shown to be an intermediate in this reaction. The electronic absorption spectrum 3 features broad observation ∼660 nm, which is primarily responsible for its blue color. In addition, diamagnetic can characterized by NMR spectroscopy. Complex...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTDirect Synthesis of β-Mannans. A Hexameric [→3)-β-d-Man-(1→4)-β-d-Man-(1]3 Subunit the Antigenic Polysaccharides from Leptospira biflexa and Octameric (1→2)-Linked β-d-Mannan Candida albicans Phospholipomannan. X-ray Crystal Structure a Protected TetramerDavid Crich, Hongmei Li, Qingjia Yao, Donald J. Wink, Roger D. Sommer, Arnold L. RheingoldView Author Information Department Chemistry, University Illinois at Chicago 845 West Taylor Street,...

The complexes Pd(diphos)(o-An)(I) (o-An = o-MeOC6H4; diphos dppe (3), (S,S)-Chiraphos (4), (R,R)-Me-Duphos (5), (R,S)-t-Bu-Josiphos (6), (R)-Tol-Binap (7)) were prepared. Complex 6 catalyzed the coupling of PH(Me)(Ph)(BH3) (2) with o-AnI in presence base to yield PAMP−BH3 (P(Me)(Ph)(o-An)(BH3) (1)) low enantiomeric excess. course stoichiometric reactions 3−7 2 and NaOSiMe3 depended on diphosphine ligand. Complexes 7 gave (1) Pd(0) species; no intermediates observed. With 3, intermediate...

The front end of any modern ion accelerator includes a radio frequency quadrupole (RFQ). While many pulsed linacs successfully operate RFQs, several accelerators worldwide have significant difficulties operating continuous wave (CW) RFQs to design specifications. In this paper we describe the development and results beam commissioning CW RFQ designed built for National User Facility: Argonne Tandem Linac Accelerator System (ATLAS). Several innovative ideas were implemented in RFQ. By...

The ability to quickly generate and identify crystalline solids for organic compounds in a parallel fashion requires rapid, adaptable crystallization screening strategy that delivers reliable, valuable, consistent results. key the system is standard platform small-scale (0.5–2 mg) crystallizer array reproducibly crystallizes facilitates presentation of samples both an automated polarized light microscope instrument capable PXRD analysis. Data science technologies were leveraged streamline...

Growing high-quality crystals remains a necessary part of crystallography and many other techniques. This article tabulates describes several techniques variations that will help individuals grow in preparation for crystallographic endeavors, such as form screening. The discussion is organized to focus on low-tech approaches available any laboratory.

Treatment of Pd((S,S)-Chiraphos)(o-An)(I) (3, o-An = o-MeOC6H4) with either enantiomer highly enantioenriched PH(Me)(Ph)(BH3) (1) gave the phosphido-borane complex Pd((S,S)-Chiraphos)(o-An)(P(Me)(Ph)(BH3)) (4) retention configuration at phosphorus, as shown by X-ray crystal structure determinations for both diastereomers 4. Heating diastereomer 4 diphenylacetylene Pd((S,S)-Chiraphos)(PhCCPh) (5) and P(o-An)(Me)(Ph)(BH3) (2) phosphorus.