Isolation of uranium(III) primary phosphido complexes.

Low-valent uranium(III) primary phosphido complexes supported by hydrotris(3,5-dimethylpyrazolyl)borate (Tp*) were synthesized with phosphines of varying steric and electronic profiles. Compounds were characterized by multinuclear NMR spectroscopy (1H, 11B, 31P NMR), infrared spectroscopy, electronic absorption spectroscopy, X-ray crystallography, and quantum chemical calculations.

Synthesis of Non-Aqueous Neptunium(III) Halide Solvates from NpO2.

Two Np(III) halides, NpI3 (THF)4 and NpBr3 (THF)4 , have been prepared and isolated in high yields as described in this work. Starting with neptunia (NpO2 ), NpCl4 (DME)2 was first generated in an updated, higher yielding synthesis than what was previously reported by using HCl/HF. This material was then reduced with KC8 , followed by subsequent ligand exchange, to generate NpBr3 (THF)4 and NpI3 -(THF)4 . Full characterization by single-crystal X-ray crystallography, 1 H NMR spectroscopy and electronic absorption spectroscopy confirmed the molecular formulas and oxidation states. These trivalent materials are straightforward to synthesize and can be used as starting materials for non-aqueous Np(III) chemistry, obviating the need for rare and restricted Np metal and elemental halogens.

Organophosphorus-Modified Lanthanide Nitrates as Potential Actinide Oxide Aerosol Surrogates.

In search of suitable simulants for aerosol uranium waste products from Plutonium Uranium Redox Extraction (PUREX) process burns, a series of lanthanide nitrate hydrates ([Ln(κ2-NO3)3·nH2O]) were dissolved in the presence of tributylphosphate (O═P(O(CH2)3CH3)3) referred to as TBP) in kerosene or triphenylphosphate (O═P(O(C6H5) referred to as TPhP) in acetone. The crystal structure of the TPhP derivatives of the lanthanide nitrate series and uranium nitrate were solved as [Ln(κ2-NO3)3(TPhP)3] (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and [U(O)2(κ2-NO3)2(TPhP)2] (U), respectively. The lanthanide-TBP, Ln, and U were further characterized using FTIR spectroscopy, 31P NMR spectroscopy, thermogravimetric analysis, and X-ray fluorescence spectroscopy. Further, thermal treatment of the lanthanide-TBP, Ln, and U using a box furnace to mimic pyrolysis conditions was found by PXRD analyses to generate a phosphate phase [LnP3O9 or UP2O7) for all systems. The resultant nuclear waste fire contaminant particulates will impact both aerosol transport and toxicity assessments.

Conversion of Trivalent Uranium Anilido to Tetravalent Uranium Imido Species via Oxidative Deprotonation.

Two uranium(III) anilido complexes were synthesized, Tp*2U(NH-C6H4-p-terpyridine) (2-terpy) and Tp*2U(NH-C6H4-p-CH3) (2-ptol), where Tp* = hydrotris(3,5-dimethylpyrazolyl)borate, by protonation of Tp*2UBn (1-Bn; Bn = benzyl) with 4-[2,6-di(pyridin-2-yl)pyridin-4-yl]benzenamine or p-toluidine, respectively. Conversion to the respective uranium(IV) imido species was possible by oxidation and deprotonation, forming Tp*2U(N-C6H4-p-terpyridine) (3-terpy) and Tp*2U(N-C6H4-p-CH3) (3-ptol). These compounds were characterized by multinuclear NMR spectroscopy, IR spectroscopy, electronic absorption spectroscopy, and X-ray crystallography.

Synthesis, Characterization, and Nanomaterials Generated from 6,6'-(((2-Hydroxyethyl)azanediyl)bis(methylene))bis(2,4-di- tert-butylphenol) Modified Group 4 Metal Alkoxides.

The impact on the morphology nanoceramic materials generated from group 4 metal alkoxides ([M(OR)4]) and the same precursors modified by 6,6'-(((2-hydroxyethyl)azanediyl)bis(methylene))bis(2,4-di- tert-butylphenol) (referred to as H3-AM-DBP2 (1)) was explored. The products isolated from the 1:1 stoichiometric reaction of a series of [M(OR)4] where M = Ti, Zr, or Hf; OR = OCH(CH3)2(OPr i); OC(CH3)3(OBu t); OCH2C(CH3)3(ONep) with H3-AM-DBP2 proved, by single crystal X-ray diffraction, to be [(ONep)Ti( k4( O,O',O'',N)-AM-DBP2)] (2), [(OR)M(µ( O)- k3( O',O'',N)-AM-DBP2)]2 [M = Zr: OR = OPr i, 3·tol; OBu t, 4·tol; ONep, 5·tol; M = Hf: OR = OBu t, 6·tol; ONep, 7·tol]. The product from each system led to a tetradentate AM-DBP2 ligand and retention of a parent alkoxide ligand. For the monomeric Ti derivative (2), the metal was solved in a trigonal bipyramidal geometry, whereas for the Zr (3-5) and Hf (6, 7) derivatives a symmetric dinuclear complex was formed where the ethoxide moiety of the AM-DBP2 ligand bridges to the other metal center, generating an octahedral geometry. High quality density functional theory level gas-phase electronic structure calculations on compounds 2-7 using Gaussian 09 were used for meaningful time dependent density functional theory calculations in the interpretation of the UV-vis absorbance spectral data on 2-7. Nanoparticles generated from the solvothermal treatment of the ONep/AM-DBP2 modified compounds (2, 5, 7) in comparison to their parent [M(ONep)4] were larger and had improved regularity and dispersion of the final ceramic nanomaterials.

Synthesis and Characterization of Tris(trimethylsilyl)siloxide Derivatives of Early Transition Metal Alkoxides That Thermally Convert to Varied Ceramic-Silica Architecture Materials.

In an effort to generate single-source precursors for the production of metal-siloxide (MSiO x) materials, the tris(trimethylsilyl)silanol (H-SST or H-OSi(SiMe3)3 (1) ligand was reacted with a series of group 4 and 5 metal alkoxides. The group 4 products were crystallographically characterized as [Ti(SST)2(OR)2] (OR = OPr i (2), OBu t (3), ONep (4)); [Ti(SST)3(OBu n)] (5); [Zr(SST)2(OBu t)2(py)] (6); [Zr(SST)3(OR)] (OR = OBu t (7), ONep, (8)); [Hf(SST)2(OBu t)2] (9); and [Hf(SST)2(ONep)2(py) n] ( n = 1 (10), n = 2 (10a)) where OPr i = OCH(CH3)2, OBu t = OC(CH3)3, OBu n = O(CH2)3CH3, ONep = OCH2C(CH3)3, py = pyridine. The crystal structures revealed varied SST substitutions for: monomeric Ti species that adopted a tetrahedral ( T-4) geometry; monomeric Zr compounds with coordination that varied from T-4 to trigonal bipyramidal ( TBPY-5); and monomeric Hf complexes isolated in a TBPY-5 geometry. For the group 5 species, the following derivatives were structurally identified as [V(SST)3(py)2] (11), [Nb(SST)3(OEt)2] (12), [Nb(O)(SST)3(py)] (13), 2[H][(Nb(µ-O)2(SST))6(µ6-O)] (14), [Nb8O10(OEt)18(SST)2·1/5Na2O] (15), [Ta(SST)(µ-OEt)(OEt)3]2 (16), and [Ta(SST)3(OEt)2] (17) where OEt = OCH2CH3. The group 5 monomeric complexes were solved in a TBPY-5 arrangement, whereas the Ta of the dinculear 16 was solved in an octahedral coordination environment. Thermal analyses of these precursors revealed a stepwise loss of ligand, which indicated their potential utility for generating the MSiO x materials. The complexes were thermally processed (350-1100 °C, 4 h, ambient atmosphere), but instead of the desired MSiO x, transmission electron microscopy analyses revealed that fractions of the group 4 and group 5 precursors had formed unusual metal oxide silica architectures.

Synthesis and characterization of thallium-salen derivatives for use as underground fluid flow tracers.

A pair of thallium salen derivatives was synthesized and characterized for potential use as monitors (or taggants) or as models for Group 13 complexes for subterranean fluid flows. These precursors were isolated from the reaction of thallium ethoxide with N,N'-bis(3,5-di-tert-butylsalicylidene)-ethylenediamine (H2-salo-But), or N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-phenylenediamine (H2-saloPh-But). The products were identified by single crystal X-ray diffraction as: [((µ-O)2,κ1-(N)(N')salo-But)Tl2] (1) and {[((µ-O)2saloPh-But)Tl2][((µ-O)2,κ1-(N)(N')saloPh-But)Tl2]} (2). Both structures are similar, wherein each O atom of the salo moiety bridges the two Tl atoms, leading to a TlTl interaction, which is further stabilized by an intramolecular π-bond with neighboring phenyl rings. For 1, an additional TlN interaction was solved for each metal center; whereas, for 2, one of the two molecules in the matrix has a weak TlN interaction but no bonding noted in the other molecule. Both Density Functional Theory (DFT) calculations and variable temperature solution 205Tl NMR studies of 1 and 2 further confirmed the TlTl interaction. The UV-vis absorbance spectra of these compounds had an absorbance peak at 392 nm for 1 and a broad absorbance peak centered at 469 nm for 2, which were found to be in good agreement with the DFT calculated spectra that were dominated by the singlet state. Fluorescence emission and excitation studies reveal absorptions at 360 and 380 nm for 1 and 2, respectively, which are attributed to the TlTl metal centers. To demonstrate practicality, fluorescence spectra of 1 and 2 were obtained using a handheld 405 nm cw laser pointer and portable spectrometer where compound 1 was found to glow 15 times brighter than compound 2. Only compound 1 was found to survive the simulated deep-well conditions explored, which was attributed to the TlN interaction noted for 1 but not for 2.

Synthesis and Characterization of Structurally Diverse Alkaline-Earth Salen Compounds for Subterranean Fluid Flow Tracking.

A family of magnesium and calcium salen-derivatives was synthesized and characterized for use as subterranean fluid flow monitors. For the Mg complexes, di- n-butyl magnesium ([Mg(Bu n)2]) was reacted with N, N'-ethylene bis(salicylideneimine) (H2-salen), N, N'-bis(salicylidene)-1,2-phenylenediamine (H2-saloPh), N, N'-bis(3,5-di- t-butylsalicylidene)-ethylenediamine (H2-salo-Bu t), or N, N'-bis(3,5-di- t-butylsalicylidene)-1,2-phenylenediamine (H2-saloPh-Bu t), and the products were identified by single-crystal X-ray diffraction as [(κ3-(O,N,N'),µ-(O')saloPh)(µ-(O),(κ2-(N,N'),µ-(O')saloPh)2(µ-(O),κ3-(N,N',O')saloPh')Mg4]·2tol (1·2tol; saloPh' = an alkyl-modified saloPh derivative generated in situ), [(κ4-(O,N,N',O')saloPh)Mg(py)2]·py (2·py), [(κ4-(O,N,N',O')salo-Bu t)Mg(py)2] (3), [(κ4-(O,N,N',O')saloPh-Bu t)Mg(py)2]·tol (4·tol), and [(κ3-(O,N,N'),µ-(O')saloPh-Bu t)Mg]2 (5), where tol = toluene; py = pyridine. For the Ca species, a calcium amide was independently reacted with H2-salo-Bu t and H2-saloPh-Bu t to generate the crystallographcially characterized compounds: [(κ4-(O,N,N',O')salo-Bu t)Ca(py)3] (6), [(κ4-(O,N,N',O')saloPh-Bu t)Ca(py)3]·py (7·py). The bulk powders of these compounds were further characterized by a number of analytical tools, where 2-7 were found to be distinguishable by Fourier transform infrared and resonance Raman spectroscopies. Structural properties obtained from quantum calculations of gas-phase analogues are in good agreement with the single-crystal results. The potential utility of these compounds as taggants for monitoring subterranean fluid flows was demonstrated through a series of experiments to evaluate their stability to high temperature and pressure, interaction with mineral surfaces, and elution behavior from a loaded proppant pack.

Evolución favorable de trillizos prematuros con candidiasis sistémica neonatal tratados con caspofungina / Successfully evolution of premature triplets with systemic neonatal candidiasis treated with caspofungin

Introducción: Las infecciones por especies de Candida son un problema que se ha incrementado de manera importante en pacientes de las unidades de cuidados intensivos neonatales (UCIN) y son una causa común de morbi-mortalidad en dicha población. La anfotericina B ha sido considerada como el principal agente terapéutico antifúngico; sin embargo, se ha asociado con efectos adversos como la fungemia persistente debido al aumento en la resistencia a Candida, particularmente especies no albicans, a menudo resistentes también a otros antifúngicos, como el fluconazol. Casos clínicos: Se trata de recién nacidos trillizos de 29 semanas de gestación, quienes recibieron soporte avanzado en la UCIN, incluyendo ventilación mecánica (VM), inserción de catéteres venosos centrales, nutrición parenteral total (NPT) y varios esquemas de antibióticos de amplio espectro, desarrollando sepsis por Candida parapsillosis en los tres casos; la terapia antifúngica fue iniciada con fluconazol, posteriormente con anfotericina B convencional y anfotericina B liposomal, sin mejoría clínica y con hemocultivos positivos. El deterioro fue revertido después del inicio de caspofungina (2 mg/kg/día) añadida a la anfotericina B liposomal. Los tres pacientes se recuperaron totalmente, sin ningún efecto adverso y con adecuada tolerancia. Conclusiones: La caspofungina resultó ser efectiva y bien tolerada en los pacientes tratados a dosis de 2 mg/kg/ día, por lo que se puede considerar una alternativa de tratamiento de la candidiasis invasiva en neonatos prematuros, aunque la dosis óptima no se ha determinado.

Background: Infections caused by Candida sp. have been significantly increasing in patients in neonatal intensive care units (NICU) and are the most common causes of morbi-mortality in this population group. Amphotericin B has been considered to be the standard antifungal therapy. However, it has been associated with adverse effects such as persistent fungemia due to the increase of Candida resistance, in particular the non-albicans species, similar to the resistance shown by other antifungals such as fluconazol. Clinical cases: Triplets of gestational age of 29 weeks received advanced life support in the NICU, including mechanical ventilation (MV), insertion of venous catheters, total parenteral nutrition (TPN) and multiple regimes of broad-spectrum antibiotics. The three patients developed C. parapsilosis sepsis. Antifungal therapy was initiated with fluconazol prior to the use of conventional amphotericin B and liposomal amphotericin B. There was no clinical improvement and blood cultures remained positive. Clinical improvement was noted after the initiation of caspofungin (2 mg/kg/day) in addition to the use of liposomal amphotericin B. The triplets recovered completely with adequate tolerance to the medication and without adverse effects. Conclusion: Use of caspofungin proved to be an effective and well-tolerated therapy in these patients (2 mg/ kg/day). It can be considered an alternative treatment for invasive candidiasis in premature neonates, although optimal dosage remains undetermined.