Trioctylphosphine oxide

The O or S atoms in P=0 and P=S groups may act as electron donors although these groups form relatively weak complexes with electron acceptor compounds such as nonpolarizable, more electropositive (ie, hard) acids, including protons (14). Use is made of this property in the recovery of uranium from wet-process phosphoric acid by extractants such as trioctylphosphine oxide [78-50-2] and di(2-ethylhexyl) hydrogen phosphate [298-07-7]. 

Thorium, tetrakis(4,4,4-trifluoro-l-thienyl-l, 3-butanedione)(trioctylphosphine oxide)-structure, 1, 98 Thorium, triaquatetranitrato-structure, 1, 99... 

PBE dendrons coordinate to the surface of II-VI semiconductor nanocrystals (e.g., CdSe [33] and CdSe/ZnS core/shell structure [34, 35]) to modulate the photoluminescence of the nanocrystals [32]. Trioctylphosphine oxide (TOPO)-capped II-VI semiconductor nanocrystals of several-nanometers diameter have been synthesized by a pyrolysis reaction of organometallics in TOPO [33-35]. The capping ligand (TOPO) can be replaced by stronger ligands such as thiol compounds [36], suggesting that dendrons bearing sulfur atom(s) at the focal point replace TOPO as well. 

Talapin, D. V., Rogach, A. L, Kornowski, A., Haase, M. and Weller, H. (2001) Highly luminescent monodisperse CdSe and CdSe/ZnS nanocrystals synthesized in a hexadecylamine-trioctylphosphine oxide-trioctylphospine mixture. Nano Lett., 1, 207-211. 

Inoue, K. Nagamatsu, I. Baba, Y. Yoshizuka, K. Solvent extraction of platinum(TV) by trioctylphosphine oxide. Solvent Extr. Ion Exch. 1989, 7, 1111-1119. 

Hasegawa, Y. Kobayashi, I. Okuda, A. Solvent-extraction behavior of platinum(TV) and palladium(II) as chlorocomplex acids with trioctylphosphine oxide. Anal. Sci. 1991, 7, 377-381. 

Another study of the surface structure of CdSe NCs of 3.7 nm size used 31P MAS-NMR and 31P/77Se rotational-echo double-resonance (REDOR) to identify overlapping broad peaks from two surface species trioctylphosphine oxide (TOPO) at 29.3 ppm and trioctylphosphine selenide (TOPSe) at 22.2 ppm [343]. Both the isotropic chemical shift and CSA of the surface-bound TOPO were substantially different from those of the free ligand. Spin-echo experiments on 31P were stated to indicate an average P-P distance of 8-10 A at the surface, consistent with capping at alternate atomic sites (all Cd but not Se). 

Korkisch and Koch [106,107] determined low concentrations of uranium in seawater by extraction and ion exchange in a solvent system containing trioctyl phosphine oxide. Uranium is extracted from the sample solution (adjusted to be 1 M in hydrochloric acid and to contain 0.5% of ascorbic acid) with 0.1 M trioctylphos-phine oxide in ethyl ether. The extract is treated with sufficient 2-methoxyethanol and 12 M hydrochloric acid to make the solvent composition 2-methoxyethanol-0.1 M ethereal trioctylphosphine acid-12 M hydrochloric acid (9 10 1) this solution is applied to a column of Dowex 1-X8 resin (Cl" form). Excess of trioctylphosphine oxide is removed by washing the column with the same solvent mixture. Molybdenum is removed by elution with 2-methoxyethanol-30% aqueous hydrogen peroxide-12 M hydrochloric... 

The reactions used for synthesis of II-VI (CdSe, CdTe), III-V (InP, InAs), and IV-VI (PbS, PbSe, PbTe) semiconductor nanocrystals are outlined by Schemes 3-5.4,17,30-32 The syntheses are carried out at high temperatures, and in the presence of long-chain alkylphosphines (trioctylphosphine,TOP), alkyl-phosphine oxides (trioctylphosphine oxide, TOPO), alkylamines (hexadecyl-amine, HD A), and alkylphosphonic acids as the stabilizing agents. 

DEPA-TOPO [di (2-ethylhexyl) phosphoric acid and trioctylphosphine oxide] A process for recovering uranium from wet-process phosphoric acid, by solvent extraction with a mixture of the two named reagents. Developed at Oak Ridge National Laboratory and first commercialized in 1978 by Freeport Minerals Corporation and Wyoming Mineral Corporation. 

Tri-O-acylglycerols (TAGs), 70 281 Trioctylphosphine oxide (TOPO), 79 66 Triode gauge, 20 660-661 Triols, phosphine oxide, 77 501 Triorganohydridosilanes, in silicone chemistry, 22 555... 

A comparison of the basicities of Group VA element organic derivatives in nitro-methane solution showed that trioctylphosphine oxide (165 R = octyl) is a much weaker base than the corresponding amine oxide or hexamethylphosphoric triamide. 

Li+ Trioctylphosphine oxide + neutral carrier Lithium in blood serum and pharmaceuticals 136... 

Transmission electron microscopy (TEM) has been an underutilized yet valuable too in particle size characterization of MC particles in LB films. Monolayer films of trioctylphosphine oxide-capped CdSe (18), spread as a monolayer on an aqueous subphase, were transferred to a TEM grid. A close-packed hexagonal arrangement of 5.3-nm (cr —4%) crystallites was found. TEM images were also obtained for HMP-stabilized CdS incorporated in BeH/octadecylamine films (79) and for CdS formed under an amine-based surfactant monolayer and transferred to a TEM grid (14). In one study, direct viewing of CdS and CdSe particles made from Cd2+-FA films on TEM grids was not possible due to poor phase contrast between the particles and the film (30). Diffraction patterns were observed, however, that were consistent with crystalline (3-CdS or CdSe. Approximately spherical particles of CdSe could... 

Considerable practical difficulties arise in making quantum dots of a regular size and shape, and in preventing the dots, once made, from coalescing into a larger crystal. CdSe quantum dots are currently made by dissolving selenium and dimethylcadmium ((CH3)2Cd) in hot trioctylphosphine oxide (TOPO), from whence large quantities of CdSe... 

Most popular schemes used to collect analytes are based on coordination reactions and electrostatic attraction. Common examples include the accumulation of nickel onto dimethylglyoxime-containing surfaces [39], the uptake and voltammetry of mercury on a diphenylcarbazide-carbon paste electrode [40], the use of surface-bound crown ethers for the collection and measurements of lead [41], or of trioctylphosphine oxide for the preconcentration of uranium [42], and the utility of polyelectrolyte-coated electrodes for the electrostatic collection of counterionic reactants [43,44], Bioaccumulation through binding to surface-bound microorganisms [45] or biocatalytic processes [46] can also offer the desired sensitivity and selectivity enhancements. 

Quantum dots used in liquid crystal systems (ranging in size from a few to tens of nanometers) are usually from the II-VI group, and include CdS, CdSe, and CdTe capped with trioctylphosphine/trioctylphosphine oxide (TOP/TOPO) [101-103], CdS as well as CdTe stabilized with thiols [104], and CdSe protected with amines [105]. 

Note TBPO, tributylphosphine oxide. TOPO, trioctylphosphine oxide. TPPO, triphenylphosphine oxide, acac, acetyl acetone. HDEHP, di(2-ethylhexyl)phosphoric acid. MIBK, methylisobutyl ketone. DMDOHEMA, N,iV-diniethyl-iV,iV-dioctylhexylethoxymalonamide. 

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