Labeling primary amine groups in peptides and proteins with N-hydroxysuccinimidyl ester modified Fe3O4@SiO2 nanoparticles containing cleavable disulfide-bond linkers.

The surface of superparamagnetic silica coated iron oxide (Fe3O4@SiO2) nanoparticles was functionalized with a disulfide bond linked N-hydroxysuccinimidyl (NHS) ester group in order to develop a method for labeling primary amines in peptides/proteins. The nanoparticle labeled proteins/peptides formed after NHS ester reaction with the primary amine groups were isolated using a magnet without any additional purification step. Nanoparticle moieties conjugated to peptides/proteins were then trimmed by cleavage at the disulfide linker with a reducing agent. The labeled peptides were analyzed by LC-MS/MS to determine their sequences and the sites of NHS ester labeling. This novel approach allowed characterization of lysine residues on the solvent accessible surface of native bovine serum albumin. Low cost, rapid magnetic separation, and specificity toward primary amine groups make NHS ester coated Fe3O4@SiO2 nanoparticles a potential labeling probe to study proteins on living cell surfaces.

Bilateral staghorn kidney stones in Megacalycosis: Non operative management of complex kidney stone disease.

What happens when kidney stone clearance is not feasible? We report the case of a 46-year-old male who presented for review with bilateral congenital non-obstructive calyceal dilatation (megacalycosis) and high volume bilateral renal calculi in the setting of stage four chronic kidney disease. Since complete stone clearance was deemed futile, thus a consensus was made between Urology and Nephrology, and treatment goals were focused on addressing symptoms, preserving renal function and preventing urinary tract infections until renal transplantation is needed. This case highlights that for some patients with severe complex kidney stone disease, an alternative management plan is needed.

Water-dispersible iron oxide magnetic nanoparticles with versatile surface functionalities.

We report a simple one-pot strategy to prepare surface-function-alized, water-dispersible iron oxide nanoparticles. Small organic molecules that have desired functional groups such as amines, carboxylics, and thiols are chosen as capping agents and are injected into the reaction medium at the end of the synthesis. A diversity of functionalities are effectively introduced onto the surface of the nanoparticles with a minimal consumption of solvents and chemical resources by simply switching the capping ligand to form the ligand shell. The resulting nanocrystals are quasi-spherical and narrowly size-distributed. Energy-dispersive X-ray analysis and Fourier transform infrared spectroscopy studies suggest a successful surface modification of iron oxide nanoparticles with selected functionalities. The colloidal stabilities are characterized by dynamic light scattering and zeta potential measurements. The results imply that functionalized nanoparticles are very stable and mostly present as individual units in buffer solutions. The pedant functional groups of the capping ligand molecules are very reactive, and their availabilities are investigated by covalently linking fluorescent dyes to the nanoparticles through the cross-linking of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. The quenched quantum yield and shortened lifetime of the dyes strongly indicate a direct bonding between the functional group of the nanoparticles and the fluorescent molecules.

Solid-state coordination chemistry of copper(II) tetrazolates: anion control of frameworks constructed from trinuclear copper(II) building blocks.

The products of the reactions of copper(II) starting materials with 4-pyridyltetrazole (4-Hpt) in N,N-dimethylformamide (DMF)/methanol solutions are determined by the anion identity and concentration. In the absence of chloride, the 3-D open-framework material [Cu(3)(OH)(3)(4-pt)(3)(DMF)(4)].5DMF.3MeOH (1.5DMF.3MeOH) is isolated, while variations in the chloride concentration yield the 2-D and 3-D materials, 2 and 3, respectively. All three structures exhibit trinuclear copper(II) building blocks: the triangular {Cu(3)(mu(3)-OH)}(5+) core in 1 and {Cu(3)Cl(4)(4-pt)(4)(4-Hpt)(2)}(2-) and {Cu(3)Cl(2)(4-pt)(8)}(4-) chains in 2 and 3, respectively. All three materials display microporosity, which is highly dependent on the method of sample preparation.

Construction of metal-organic oxides from molybdophosphonate clusters and copper-bipyrimidine building blocks.

A series of organic-inorganic hybrid materials of the copper(II)-molybdophosphonate family have been prepared using conventional hydrothermal conditions. The reactions of MoO(3), copper(II) acetate, bipyrimidine (bpyr), a phosphonic acid, and water at temperatures below 160 degrees C and in the presence of a mineralizer such as acetic acid or HF provided crystalline samples of materials of the general class {Cu(2)(bpyr)}(4+)/Mo(x)O(y)-phosphonate. The recurrent themes of the structures are the presence of the binuclear {Cu(2)(bpyr)}(4+) and pentanuclear {Mo(5)O(15)(O(3)PR)(2)}(4-) building blocks. For the alkylphosphonate-containing materials, [{Cu(2)(bpyr)(2)}Mo(5)O(15)(O(3)PCH(3))(2)].2.5H(2)O (1.2.5H(2)O) is two-dimensional and exhibits {Cu(bpyr)}(n)(2n+) chains, while [{Cu(2)(bpyr)(H(2)O)}Mo(5)O(15)(O(3)PCH(2)CH(3))(2)] (2) is three-dimensional. The diphosphonate series of materials {{Cu(2)(bpyr)}(4+)[Mo(5)O(15){O(3)P(CH(2))(n)PO(3)}](4-) with n = 2-6 (4, 5, 7-9) in all cases contain the characteristic [Mo(5)O(15){O(3)P(CH(2))(n)PO(3)}](n)(2n+) chains, linked through {Cu(2)(bpyr)}(4+) rods into three-dimensional frameworks. When n = 1, the three-dimensional phase [{Cu(2)(bpyr)}MoO(2)(HO(3)PCH(2)PO(3))(2)].2H(2)O (3.2H(2)O) is obtained, the exclusive example of a structure constructed from isolated {MoO(6)} polyhedra rather than pentamolybdate clusters. The Ni(II)-containing phase [{Ni(2)(bpyr)(H(2)O)(4)}Mo(5)O(15){O(3)P(CH(2))(3)PO(3)}].9H(2)O (6.9H(2)O) was also prepared and compared to the structure of the Cu(II) analogue, [{Cu(2)(bpyr)(H(2)O)(4)}Mo(5)O(15){O(3)P(CH(2))(3)PO(3)}].3H(2)O (5.3H(2)O). Magnetic susceptibility studies of the compounds revealed that the magnetic behavior was consistent in all cases with antiferromagnetically coupled dimers. However, the magnitude of the exchange coupling was clearly dependent on the orientation of the M(II) mean equatorial or basal planes relative to the bipyrimidine plane. Thus, when the metal and bipyrimidine planes are nearly coplanar, the J values are in the -77 to -87 cm(-1) range, while J values of -2 to -5 cm(-1) are observed for the compounds with out-of-plane orientations.

The hydrothermal and structural chemistry of oxovanadium-arylphosphonate networks and frameworks.

The hydrothermal reactions of NH4VO3 with the aromatic phosphonate ligands 1,4-, 1,3-, and 1,2-phenylenediphosphonic acids (H4L1, H4L3, H4L4, respectively); biphenyl-4,4'-diyldiphosphonic acid (H4L2); and 1,3,5-tris(phenyl)-4,4'-triphosphonic acid (H6L5) yielded materials of the V(x)O(y)/organophosphonate family [VO(H2L1)] (1), [VO(H2L2)] (2), [V2O2(H2O)2(L3)] x 1.5 H2O (3 x 1.5 H2O), [V2O2(H2O)2(L4)] x 2 H2O (4 x 2 H2O), and [V3O3(OH)(H3L5)2] x 7.5 H2O (6 x 7.5 H2O). The reactions were carried out in the presence of HF, and in one case, fluoride was incorporated to provide [V2F(OH)(H2O)3(L4)] x 2.25 H2O (5 x 2.25 H2O). The materials exhibit diverse structural chemistry, including the prototypical buttressed layer architecture for 1 and 2, a complex three-dimensional structure for 3, and unique two-dimensional structures for 4, 5, and 6. The structures of this oxovanadium-arylphosphonate family are quite distinct from those previously described for the V(x)O(y)/alkyldiphosphonate series.

Poly(vinylpyrrolidone) coated iron nanoparticles in polar aprotic solvent.

Poly(vinylpyrrolidone) (PVP) coated iron nanoparticles which show well-defined core-shell structures have been successfully synthesized in a polar aprotic solvent. In this approach, PVP was employed not as capping agent, but as coating polymer directly applied to the metallic (iron) core nanoparticles. The morphologies, structures, compositions and magnetic properties of the products were investigated by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), energy dispersive X-ray spectroscopy (EDXS), SQUID magnetometry and FTIR spectroscopy.

Preparation and characterization of silica-coated indium oxide nanoparticles.

Silica-coated Indium oxide nanoparticles have been successfully synthesized by a modified reverse microemulsion method and characterized by TEM, XRD, EDS and luminescence spectrometer; the single crystal particles are encapsulated by a smooth and uniform silica shell (average size approximately 35 nm in diameter) and show photoluminescence property. The size of the particles and the thickness of the shells can be controlled by adjust the ratio of the reaction agents. The physical structure and optical property of Indium oxide particles remain same during the silica coating process.

Gold-magnetite nanocomposite materials formed via sonochemical methods.

Treatment of preformed magnetite nanoparticles with ultrasound in aqueous media with dissolved tetrachloroauric acid resulted in the formation of gold-magnetite nanocomposite materials. These materials maintained the morphology of the original magnetite particles. The loading of gold particles could be controlled by adjusting experimental parameters, including the addition of small amounts of solvent modifiers such as methanol, diethylene glycol, and oleic acid. The nanocomposite materials were magnetic and exhibited optical properties similar to pure gold nanoparticles.

Synthesis and characterization of a polyoxovanadate cluster representing a new topology.

A new type of mixed-valence polyoxoanionic cluster, [V(V)13V(IV)3O42(Cl)]8-, composed of 14 {VO5} square pyramids and 2 {VO4} tetrahedral units, hosting a chloride ion has been synthesized and characterized.

Drug-loaded, magnetic, hollow silica nanocomposites for nanomedicine.

Magnetic, hollow silica nanocomposites (MHSNC), including nanospheres and nanotubes, have been successfully synthesized using a coating of Fe(3)O(4) magnetic nanoparticles (NPs) ( approximately 10 nm) and silica on nanosized spherical and nanoneedle-like calcium carbonate (CaCO(3)) surfaces under alkaline conditions. The nanosized CaCO(3) surfaces were used as nanotemplates, and tetraethoxysilane and magnetic NPs were used as precursors. The as-synthesized MHSNC were immersed in an acidic solution to remove the CaCO(3), forming magnetic, hollow silica nanospheres and nanotubes. The MHSNC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray powder diffraction, and superconducting quantum interference device (SQUID) magnetometer. SEM and TEM results showed that a smooth surface of MHSNC and a thin layer of silica ( approximately 10 nm) embedded with the magnetic NPs were successfully formed, and that the CaCO(3) nanotemplates appeared to be dissolved. SQUID measurement demonstrated that magnetization of MHSNC was dependent on temperature, exhibiting superparamagnetism. The MHSNC were immersed in ibuprofen solution. The amount of the loaded drug was determined to be 12 wt% for nanospheres, and 8 wt% for nanotubes by UV measurement, respectively. Drug-loaded MHSNC have potential applications in nanomedicine.

A building block approach to the synthesis of organic-inorganic oxide materials: the hydrothermal synthesis and network structure of [[Ni4(tpypyz)3][Mo5O15(O3PCH2CH2PO3)]2] x 23H2O (tpypyz = tetra-2-pyridylpyrazine).

The hydrothermal reaction of MoO3, [Ni(CH3CO2)2] x 4H2O, tpypyz, ethylenediphosphonic acid and water yields the 2D material [[Ni4(tpypyz)3][Mo5O15(O3PCH2CH2PO3)]2] x 23H2O (1 x 23H2O), constructed from [Mo5O15(O3PCH2CH2PO3)]4- clusters linked in one-dimension through the ethylene tethers of the diphosphonate component; these molybdodiphosphonate chains are in turn linked into a 2D network through the tetranuclear secondary metal-ligand subunit [Ni4(tpypyz)3]8+.

High-Valent Manganese in Polyoxotungstates. 3. Dimanganese Complexes of gamma-Keggin Anions.

Dimanganese-substituted gamma-Keggin heteropoly tungstates have been synthesized by reaction of the lacunary species gamma-[(SiO(4))W(10)O(32)](8)(-) with appropriate mixtures of Mn(II) and MnO(4)(-). The crystal structure of [(CH(3))(3)(C(6)H(5))N](4)[(SiO(4))W(10)Mn(III)(2)O(36)H(6)].2CH(3)CN.H(2)O (anion 1) was determined by X-ray diffraction. Crystallographic data: space group P&onemacr;, a = 12.951(3) Å, b = 14.429(3) Å, c = 20.347(4) Å, alpha = 81.95(3) degrees, beta = 88.92(3) degrees, gamma = 67.48(3) degrees, V = 3475.2(13) Å(3), and Z = 2. The final R value is 7.29% for 15861 reflections with I > 2sigma(I). The anion has the anticipated gamma-Keggin structure with virtual C(2)(v)() symmetry. The two Mn cations occupy adjacent, edge-shared octahedra with bridging hydroxo and terminal aqua ligands. Anion 1 can be oxidized and reduced to the corresponding Mn(III)Mn(IV) (2) and Mn(II)(2) (3) species respectively. The magnetic susceptibility of 1 between 2 and 300 K indicates that the Mn(III) cations are antiferromagnetically coupled, with J = -17.0 cm(-)(1) and g = 1.965. No simple magnetic behavior was observed for 2 or 3.

Magnetic Susceptibility Trends in Oxo-Bridged, Dinuclear Chromium(III) Complexes. Crystal Structure of [(tmpa)Cr(&mgr;-O)(&mgr;-CO(3))Cr(tmpa)](ClO(4))(2).2H(2)O.

The synthesis and physical characterization of oxo-bridged [Cr(2)(tmpa)(2)(&mgr;-O)(X)](n)()(+) complexes (tmpa = tris(2-pyridylmethyl)amine) containing a variety of complementary ligands (X = CO(3)(2)(-), PhPO(4)(2)(-), HS(-)) are described, with the objective of understanding factors underlying variations in the antiferromagnetic coupling constant J. We also present the crystal structure of [(tmpa)Cr(&mgr;-O)(&mgr;-CO(3))Cr(tmpa)](ClO(4))(2).2H(2)O, for comparison with previous findings on [(tmpa)Cr(&mgr;-O)(&mgr;-CH(3)CO(2))Cr(tmpa)](ClO(4))(3). The carbonate-bridged complex crystallizes in the monoclinic space group P2(1)/c with a = 11.286(10) Å, b = 18.12(2) Å, c = 20.592(12) Å, beta = 95.99(5) degrees, and V = 4190 Å(3) and Z = 4. Asymmetric tmpa ligation pertains, with apical N atoms situated trans to bridging oxo and acido O atoms. Key structural parameters include Cr-O(b) bond lengths of 1.818(6) and 1.838(6) Å, Cr-OCO(2) distances of 1.924(7) and 1.934(7) Å, and a bridging bond angle of 128.3(3) degrees. Several attempts to prepare oxo, amido-bridged dimers were unsuccessful, but the nearlinear [Cr(tmpa)(N(CN)(2))](2)O(ClO(4))(2).3H(2)O complex was isolated from the reaction of dicyanamide ion with [Cr(tmpa)(OH)](2)(4+). In contrast to the behavior of analogous diiron(III) complexes, antiferromagnetic coupling constants of [Cr(2)(tmpa)(2)(&mgr;-O)(X)](n)()(+) dinuclear species are highly responsive to the X group. Considering the complexes with X = CO(3)(2)(-), PhPO(4)(2)(-), HS(-), SO(4)(2)(-), and RCO(2)(-) (10 R substituents), we find a reasonably linear, empirical relationship between J and oxo bridge basicity, as measured by pK(a) (Cr(OH)Cr) values in aqueous solution. While there is no theoretical basis for such a correlation between solid-state and solution-phase properties, this relationship demonstrates that CrOCr pi-bonding contributes significantly to antiferromagnetic exchange. Thus, J tends to become less negative with increasing &mgr;-O(2)(-) basicity, showing that greater availability of a bridging oxo group lone pair toward the proton, with decreasing CrOCr pi-interaction, reduces the singlet-triplet gap.

Synthesis and Characterization of Novel V/O/SO(4) Chains Incorporating 2,2'-Bipyridine Ligands: Crystal Structure of [V(2)O(2)(OH)(2)(SO(4))(2,2'-bpy)(2)].

The hydrothermal reaction of a mixture of vanadyl acetylacetonate (VO(acac)(2)), Na(2)SO(4), 2,2'-bipyridine (2,2'-bpy), and H(2)O for 48 h at 160 degrees C gives brown crystals of [V(2)O(2)(OH)(2)(SO(4))(2,2'-bpy)(2)] (1) in 70% yield. The structure of 1 consists of ribbons constructed from the infinite inorganic chains, [-{V(2)O(2)(OH)(2)}-&mgr;(2)-SO(4){V(2)O(2)(OH)(2)}-SO(4)](infinity), incorporating organic (2,2'-bipyridine) ligands. The inorganic chains are composed of the pairs of edge-sharing octahedra joined by {SO(4)} tetrahedra through octahedral-tetrahedral corner sharing. The octahedral geometry around each vanadium(IV) ion is defined by {VO(2)(OH)(2)N(2)} with each V(IV) center coordinated to a terminal oxo group, two &mgr;(2)-OH groups, two nitrogen donor atoms from a chelating 2,2'-bipyridine ligand, and an oxygen donor atom from a &mgr;(2)-SO(4)(2)(-) ligand. Crystal data for 1: monoclinic space group P2(1)/n (No. 14), a = 11.7937(2) Å, b = 12.1161(3) Å, c = 15.5763(2) Å, beta = 93.750(2) degrees, Z = 4. 1 constitutes the first example of a fully reduced vanadosulfate (V/O/SO(4)) based solid incorporating both the organic and inorganic ligands. The novel solid exhibits Curie-Weiss paramagnetism at high temperature (T > 140 K) and short-range antiferromagnetic coupling between the V(IV) centers at lower temperature.

Synthesis and Characterization of a Series of Edge-Sharing Octahedral-Tetrahedral-Octahedral Linear Trinuclear Complexes [M(3)(L1O)(4)](2+), Where M = Mn(2+), Co(2+), Ni(2+), Cu(2+), and Zn(2+) and L1OH Is the "Heteroscorpionate" Ligand (2-Hydroxyphenyl)bis(pyrazolyl)methane.

The mixed functionality pyrazole/phenol ligand (2-hydroxyphenyl)bis(pyrazolyl)methane, L1OH, has been used to prepare a series of linear trimetallic systems with the general structural motif [M(3)(L1O)(4)](2+), where M = Mn(2+), Co(2+), Ni(2+), Cu(2+), and Zn(2+). Each of these complexes has been structurally characterized by X-ray crystallography giving the following structural parameters: [Zn(3)(L1O)(4)][BF(4)](2).H(2)O, C(52)H(44)N(16)B(2)F(8)O(5)Zn(3), monoclinic, a = 18.572(4) Å, b = 22.400(5) Å, c = 15.921(3), beta = 112.439(8) degrees, space group C2/c, Z = 4; [Cu(3)(L1O)(4)] [BF(4)](2).2MeCN, C(56)H(44)N(18)B(2)Cu(3)F(8)O(4), monoclinic, a = 40.574(2) Å, b = 16.701(1) Å, c = 19.841(2) Å, beta = 111.388(5) degrees, space group C2/c, Z = 8; [Ni(3)(L1O)(4)][ClO(4)](2).MeCN.0.5H(2)O, C(54)H(44)N(17)Cl(2)Ni(3)O(12.5), monoclinic, a = 12.324(4) Å, b = 26.537(2) Å, c = 18.829(3) Å, beta = 102.78(1) degrees, space group C2/c, Z = 4; [Co(3)(L1O)(4)][BF(4)](2).MeCN, C(54)H(44)N(17)B(2)Co(3)F(8)O(4), monoclinic, a = 12.395(2) Å, b = 26.483(3) Å, c = 18.703(4) Å, beta = 103.22(2) degrees, space group C2/c, Z = 4; [Mn(3)(L1O)(4)(MeCN)][ClO(4)](2).1.4MeCN, C(56.68)H(44)N(18.34)Cl(2)Mn(3)O(12), orthorhombic, a = 15.471(2) Å, b = 17.364(2) Å, c = 24.216(2) Å, space group Pbcn, Z = 4. For Zn(2+), Cu(2+), Ni(2+), and Co(2+) the central metal atom of the linear trimetallic [M(3)(L1O)(4)](2+) unit is four coordinate and has a pseudotetrahedral geometry with a dihedral angle, omega, between the two M(central)O(2)M(terminal) planes of 79.9 degrees (Zn), 61.2 degrees (Co), 60.4 degrees (Ni), and 46.8 degrees (Cu). The central Mn(2+) atom of [Mn(3)(L1O)(4)(MeCN)][ClO(4)](2).1.4MeCN is five-coordinate, with a trigonal bipyramidal stereochemistry, the result of an equatorially coordinated MeCN solvent molecule. Variable-temperature magnetic data indicate that the Ni, Cu, and Mn complexes display modest antiferromagnetic coupling between the metal centers, while the Co derivative is strongly ferromagnetically coupled.

Anionic Halomolybdate(III) Chemistry. Tetrahydrofuran Loss from [MoX(3)Y(THF)(2)](-) (X, Y = Cl, Br, I), Preparation and Properties of [Mo(3)X(12)](3)(-) (X = Br, I), and Crystal Structure of the Edge-Sharing Trioctahedral [PPh(4)](3)[Mo(3)I(12)].

By interaction of MoX(3)(THF)(3) with [Cat]X in THF, the salts [Cat][MoX(4)(THF)(2)] have been synthesized [X = I, Cat = PPh(4), NBu(4), NPr(4), (Ph(3)P)(2)N; X = Br, Cat = NBu(4), PPh(4) (Ph(3)P)(2)N]. Mixed-halide species [MoX(3)Y(THF)(2)](-) (X, Y = Cl, Br, I) have also been generated in solution and investigated by (1)H-NMR. When the tetraiodo, tetrabromo, and mixed bromoiodo salts are dissolved in CH(2)Cl(2), clean loss of all coordinated THF is observed by (1)H-NMR. On the other hand, [MoCl(4)(THF)(2)](-) loses only 1.5 THF/Mo. The salts [Cat](3)[Mo(3)X(12)] (X = Br, I) have been isolated from [Cat][MoX(4)(THF)(2)] or by running the reaction between MoX(3)(THF)(3) and [Cat]X directly in CH(2)Cl(2). The crystal structure of [PPh(4)](3)[Mo(3)I(12)] exhibits a linear face-sharing trioctahedron for the trianion: triclinic, space group P&onemacr;; a = 11.385(2), b = 12.697(3), c = 16.849(2) Å; alpha = 76.65(2), beta = 71.967(12), gamma = 84.56(2) degrees; Z = 1; 431 parameters and 3957 data with I > 2sigma(I). The metal-metal distance is 3.258(2) Å. Structural and magnetic data are consistent with the presence of a metal-metal sigma bond order of (1)/(2) and with the remaining 7 electrons being located in 7 substantially nonbonding orbitals. The ground state of the molecule is predicted to be subject to a Jahn-Teller distortion, which is experimentally apparent from the nature of the thermal ellipsoid of the central Mo atom. The [Mo(3)X(12)](3)(-) ions reacts with phosphines (PMe(3), dppe) to form products of lower nuclearity by rupture of the bridging Mo-X bonds.

Synthesis and Characterization of Novel Oxo-Bridged Dinuclear and Hydroxo-Bridged Trinuclear Chromium(III) Assemblies.

The structural and spectroscopic properties of a novel dinuclear chromium-oxo and a trinuclear chromium-hydroxo complex are reported. The dinuclear assembly, [Cr(2)(&mgr;-O)(2)(&mgr;-O(2)CMe)(bpy)(2)(H(2)O)(2)]ClO(4).bpy.[bpyH]ClO(4) (1), crystallizes in the monoclinic space group Cc with a = 16.8259(8) Å, b = 21.9622(11) Å, c = 14.6056(8) Å, beta = 122.1830(10) degrees, V = 4568.0(4) Å(3), and Z = 4. The structure was refined with 4378 observed reflections having F > 2.0sigma(F), giving final R factors of 0.0721 and 0.1305 for R and R(w2), respectively. The [Cr(2)(&mgr;-O)(2)(&mgr;-O(2)CMe)](+) core is structurally akin to those of recently reported isoelectronic [Mn(2)(&mgr;-O)(2)(&mgr;-O(2)CMe)](3+) complexes. The trinuclear assembly, [Cr(3)(&mgr;-OH)(2)(&mgr;-O(2)CMe)(4)(O(2)CMe)(2)(bpy)(2)]ClO(4) (2).5CHCl(3) crystallizes in the triclinic space group P&onemacr; with a = 16.104(5) Å, b = 17.623(5) Å, c = 12.236(3) Å, alpha = 93.33(1) degrees, beta = 92.81(1) degrees, gamma = 64.84(1) degrees, V = 3136.68 Å(3), and Z = 2. The structure was refined with 6732 observed reflections having F > 2.33sigma(F), giving final R factors of 0.0602 and 0.0616 for R and R(w), respectively. Results of electronic, (1)H and (2)H NMR, and EPR spectroscopy, fast atom bombardment mass spectrometry, and variable-temperature magnetic susceptibility studies of these materials and the use of Cr-oxo assemblies as isoelectronic models of the photosynthetic manganese assembly in high-S states are discussed.

Synthesis of one-dimensional magnetic Co nanoparticles in a novel solution system.

Magnetic Co nanoparticles with different morphologies were synthesized in a novel solution system using a UV irradiation technique. By adjusting the compositions in the solution, long nanowires with different aspect ratios as well as spherical nanoparticles with controllable particle size could be obtained.