(2,2‐Dimethylpropylidyne)Phosphine

Becker, Gerd; Schmidt, Helmut; Uhl, G.; Uhl, Werner; Regitz, Manfred; Rösch, Wolfgang; Vogelbacher, Uwe‐Josef

doi:10.1002/9780470132586.ch49

Cited by 38 publications

(8 citation statements)

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“…Fluorescence spectra were acquired on a Horiba FL3–21tau fluorescence spectrometer. P(SiMe 3 ) 3 and ODPA were prepared according to literature procedures. ,− …”

Section: Methodsmentioning

confidence: 99%

Two-Step Nucleation and Growth of InP Quantum Dots via Magic-Sized Cluster Intermediates

et al. 2015

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We report on the role of magic-sized clusters (MSCs) as key intermediates in the synthesis of indium phosphide quantum dots (InP QDs) from molecular precursors. Heterogeneous growth from the MSCs directly to InP QDs was observed without intermediate sized particles. These observations suggest that previous efforts to control nucleation and growth by tuning precursor reactivity have been undermined by formation of these kinetically persistent MSCs prior to QD formation. The thermal stability of InP MSCs is influenced by the presence of exogenous bases as well as choice of the anionic ligand set. Addition of a primary amine, a common additive in previous InP QD syntheses, to carboxylate terminated MSCs was found to bypass the formation of MSCs, allowing for homogeneous growth of InP QDs through a continuum of isolable sizes. Substitution of the carboxylate ligand set for a phosphonate ligand set increased the thermal stability of one particular InP MSC to 400 °C. The structure and optical properties of the MSCs with both carboxylate and phosphonate ligand sets were studied by UV-Vis absorption spectroscopy, powder XRD analysis, and solution 31 P{ 1 H} and 1 H NMR spectroscopy. Finally, the carboxylate terminated MSCs were identified as effective single source precursors (SSPs) for the synthesis of high quality InP QDs. Employing InP MSCs as SSPs for QDs effectively decouples the formation of MSCs from the subsequent second nucleation event and growth of InP QDs. The concentration dependence of this SSP reaction, as well as the shape uniformity of particles observed by TEM suggests that the stepwise growth from MSCs directly to QDs proceeds via a second nucleation event rather than an aggregative growth mechanism.

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“…Fluorescence spectra were acquired on a Horiba FL3–21tau fluorescence spectrometer. P(SiMe 3 ) 3 and ODPA were prepared according to literature procedures. ,− …”

Section: Methodsmentioning

confidence: 99%

Two-Step Nucleation and Growth of InP Quantum Dots via Magic-Sized Cluster Intermediates

et al. 2015

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“…This synthesis was adapted from literature procedures. , Warning: This reaction uses Na/K alloy, which is highly pyrophoric and should be handled with absolute exclusion of both oxygen and water . Certain byproducts and unreacted starting materials remaining at the end of this reaction may be pyrophoric and should be quenched as described below.…”

Section: Methodsmentioning

confidence: 99%

Investigation of Indium Phosphide Quantum Dot Nucleation and Growth Utilizing Triarylsilylphosphine Precursors

2014

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We have developed a two-phosphine strategy to independently tune nucleation and growth kinetics based on the relative reactivity of each precursor in the synthesis of indium phosphide (InP) quantum dots (QDs). This approach was allowed by the exploration of the synthesis and reactivity of a series of sterically encumbered triarylsilylphosphines substituted at the para position of the aryl group, P(Si(C 6 H 4 -X) 3 ) 3 (X = H, Me, CF 3 , or Cl), as a contrast to P(SiMe 3 ) 3 , the P 3− source commonly employed in such syntheses. UV−vis absorption spectroscopy of aliquots taken during InP QD growth revealed a stark contrast between triarylsilylphosphines with electron-donating and electron-withdrawing groups in both the rate of InP formation and the final particle size. 31 P{ 1 H} nuclear magnetic resonance spectroscopy confirmed that precursor conversion remains rate-limiting throughout the nanocrystal synthesis when P(SiPh 3 ) 3 is incorporated as the sole phosphorus precursor; however, this is insufficient for effective separation of nucleation and growth in this system because of the slow nucleation rates that result. In all cases, syntheses that employ a single chemical species as the P 3− source were found to suffer from a poor match in reactivity with In(O 2 C(CH 2 ) 12 CH 3 ) 3 as they either fail to separate nucleation from growth because of slow precursor conversion rates [P(SiPh 3 ) 3 and P(Si(C 6 H 4 -Me) 3 ) 3 ] or preclude size selective growth from rapid precursor conversion [P(SiMe 3 ) 3 , P(Si(C 6 H 4 -Cl) 3 ) 3 , and P(Si(C 6 H 4 -CF 3 ) 3 ) 3 ]. To balance these two extreme cases, we developed a novel approach in which two different P 3− sources were introduced to segregate nucleation and growth based on the relative reactivity of each precursor.

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“…Literature Preparations . [Ti(N t Bu)(COT)] ( 1 ), [Ti(N t Bu)(COT‘ ‘)] ( 2 ), [Ti(NAr)(COT)] ( 3 ), and t BuC⋮P were prepared using literature methods.…”

Section: Methodsmentioning

confidence: 99%

Reactions of^tBuC⋮P with Cyclooctatetraene-Supported Titanium Imido Complexes

et al. 2006

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Reaction of the pseudo two-coordinate titanium imido complexes [Ti(N t Bu)(COT)] (1; COT ) η 8 -C 8 H 8 ) and [Ti(N t Bu)(COT′′)] (2; COT′′ ) η 8 -1,4-C 8 H 6 (SiMe 3 ) 2 ) with 2 equiv of t BuCtP generated the new complexes [Ti{N( t Bu)PC( t Bu)PC( t Bu)}(COT)] ( 4) and [Ti{N( t Bu)PC( t Bu)PC( t Bu)}(COT′′)] (5), respectively. Complex 4 was crystallographically characterized, and a density functional theory (DFT) study combined with photoelectron (PE) spectroscopy revealed this apparently 20-valence-electron species to contain a HOMO which is almost entirely ligand-based. In contrast, the organic compound N(Ar)-P 2 C 2 t Bu 2 (6), which incorporates a 1,2,4-azadiphosphole ring, was the only isolated product from the reaction of the arylimido species [Ti(NAr)(COT)] (3; Ar ) 2,6-i Pr 2 C 6 H 3 ) with an excess of t BuCtP. DFT studies indicated that the mechanisms for the formation of compounds 4-6 are similar. Initially, one molecule of t BuCtP undergoes a [2 + 2] cycloaddition with [Ti(NR)(COT)] to form [Ti{N(R)PC-( t Bu)}(COT)], which contains a Ti-C bond. Subsequently, a second molecule of t BuCtP reacts with [Ti{N(R)PC( t Bu)}(COT)] to form [Ti{N(R)PC( t Bu)PC( t Bu)}(COT)]. When R ) 2,6-i Pr 2 C 6 H 3 or a substituent which is less sterically bulky, the formation of a heterocyclic ring such as N(Ar)P 2 C 2 t Bu 2 (6) is favored. However, when R ) t Bu, it is sterically unfavorable to form such a ring and thus compound 4 is stable.

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(2,2‐Dimethylpropylidyne)Phosphine

Cited by 38 publications

References 10 publications

Two-Step Nucleation and Growth of InP Quantum Dots via Magic-Sized Cluster Intermediates

Two-Step Nucleation and Growth of InP Quantum Dots via Magic-Sized Cluster Intermediates

Investigation of Indium Phosphide Quantum Dot Nucleation and Growth Utilizing Triarylsilylphosphine Precursors

Reactions of^tBuC⋮P with Cyclooctatetraene-Supported Titanium Imido Complexes

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(2,2‐Dimethylpropylidyne)Phosphine

Cited by 38 publications

References 10 publications

Two-Step Nucleation and Growth of InP Quantum Dots via Magic-Sized Cluster Intermediates

Two-Step Nucleation and Growth of InP Quantum Dots via Magic-Sized Cluster Intermediates

Investigation of Indium Phosphide Quantum Dot Nucleation and Growth Utilizing Triarylsilylphosphine Precursors

Reactions oftBuC⋮P with Cyclooctatetraene-Supported Titanium Imido Complexes

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Reactions of^tBuC⋮P with Cyclooctatetraene-Supported Titanium Imido Complexes