Phosphorus Chain Research Articles

Novel ternary Zintl phosphide halides Ba3P5X (X = Cl, Br) with 1D helical phosphorus chains: synthesis, crystal and electronic structure.

Black single crystals of two novel ternary phosphide halides, Ba3P5Cl and Ba3P5Br, were grown using molten metal Pb-flux high-temperature reactions. These compounds were structurally characterized with the aid of the single-crystal X-ray diffraction (SCXRD) method at 100(2) K. The SCXRD shows that both compounds are isostructural and adopt a new structure type (space group R3̄c, No. 167, Z = 6) with unit cell parameters a = 14.9481(16) Å, c = 7.3954(11) Å and a = 15.045(4) Å, c = 7.537(3) Å for Ba3P5Cl and Ba3P5Br, respectively. Cl- and Br- anions are octahedrally coordinated by Ba2+ cations, thus composing a face-sharing 1D infinite chain 1∞[XBa3]5+ running along the [001] direction. Moreover, the crystal structures feature peculiar one-dimensional disordered infinite helical chains of 1∞P-, composed of partially occupied phosphorous atoms, each being a superposition of three symmetrical copies of the ordered phosphorus chain, with continuity along the c-axis. Ba3P5X (X = Cl, Br) compounds are charge-balanced heteroanionic Zintl phases according to the charge-partitioning scheme (Ba2+)3[P-]5X-. The presumed semiconducting behavior of both compounds corroborates well with the results of the electronic structure calculations performed with the aid of the TB-LMTO-ASA code.

Gradual Coordination and Reversible P-P Bond Activation of a P3 -Unit with Transition Metal Carbonyls.

Coordination of a stereochemically defined P3 -chain to a series of transition metal carbonyls [M(CO)x ]z- (M=Mn (x=5, z=1), Fe (x=4, z=2) or Co (x=4, z=1)) is explored using a [3]ferrocenophane scaffold. A gradual transition from η1 -, η2 - toη3 -coordination is observed where in the η2 -mode the terminal positions of the phosphorus chain are bridged. With an excess of cobalt carbonyl successive P-P bond activation and gradual separation of the central phosphorus atoms from the phosphorus chain has been observed. This process is reversible and with suitable reagents such as methyl lithium, the P3 -unit is regenerated in stereospecific manner. The bonding situation and steps of the gradual P-P bond activation are investigated by DFT calculations as well as experimental methods (e.g., NMR spectroscopy, X-ray crystallography).

Network of Bi2O3–Al2O3–NaPO3 glasses studied by solid‐state nuclear magnetic resonance spectroscopy

AbstractA detailed structural investigation of a series of phosphate laser glasses with composition xBi2O3–yAl2O3–(100 − x–y)NaPO3 (x = 0, 10; y = 0, 5, 10, 15, 20) has been conducted using solid‐state nuclear magnetic resonance (NMR) techniques and X‐ray photoelectron spectroscopy (XPS). 31P MAS NMR spectroscopy demonstrates that the addition of Bi2O3 and Al2O3 leads to the depolymerization of the phosphorus chain in the process of Q2 → Q1 → Q0. The various phosphorus species (Qn, n = 0, 1, 2) are identified by 31P single pulse, 31P{27Al} rotational echo adiabatic passage double resonance, 31P{27Al} J‐coupling‐based heteronuclear multiple‐quantum coherence, and 1D refocused INADEQUATE experiments. The results of 23Na{31P}, 31P{23Na}, 27Al{31P} rotational echo double resonance, and XPS consistently confirm that Na+, Al3+, and Bi3+ ions are all bound by phosphorus tetrahedron [PO4]3−. No bond is formed between these glass modifiers. Based on the complementary evidence from previous experiments, comprehensive local structure models are developed for these Bi2O3–Al2O3–NaPO3 glasses.

"Missing" One-Dimensional Red-Phosphorus Chains Encapsulated within Single-Walled Carbon Nanotubes.

We identify the "missing" 1D-phosphorus allotrope, red phosphorus chains, formed in the interior of tip-opened single-walled carbon nanotubes (SWCNTs). Via a comprehensive experimental and theoretical study we show that in intermediate diameter cavities (1.6-2.9 nm), phosphorus vapor condenses into linear P8]P2 chains and fibrous red-phosphorus type cross-linked double-chains. Thermogravimetric and X-ray photoelectron spectroscopy analysis estimates ∼7 atom % of elemental phosphorus in the sample, while high-resolution energy dispersive X-ray spectroscopy mapping reveals that phosphorus fills the SWCNTs. High-resolution transmission electron microscopy (HRTEM) shows long chains inside the nanotubes with varying arrangement and packing density. A detailed match is obtained between density functional theory (DFT) simulations, HRTEM, and low-frequency Raman spectroscopy. Notably, a signature spectroscopic signal for phosphorus chain cross-linking is identified. When coupled with reinterpretation of literature data and wide-ranging DFT calculations, these results reveal a comprehensive picture of the diameter dependence of confined 1D-phosphorus allotropes.

One-dimensional phosphorus chain and two-dimensional blue phosphorene grown on Au(111) by molecular-beam epitaxy

Single layer (SL) phosphorus (phosphorene) has drawn considerable research attention recently as a two-dimensional (2D) material for application promises. It is a semiconductor showing superior transport and optical properties. Few-layer or SL black phosphorus has been successfully isolated by exfoliation from bulk crystals and extensively studied thereof for its electronic and optical properties. Blue phosphorus (blueP), an allotrope of black phosphorus where atoms are arranged in a more flat atomic configuration, has been recently suggested by theory to exist in the SL form on some substrates. In this work, we report the formation of a blueP-like epilayer on Au(111) by molecular-beam epitaxy. In particular, we uncover by scanning tunneling microscopy (STM) one-dimensional (1D) atomic chains at low coverage, which develop into more compact islands or patches of $(\sqrt{3}\times\sqrt{3})R30^\circ$ structure with increasing coverage before blueP-like islands nucleate and grow. We also note an interesting growth characteristic where the $(\sqrt{3}\times\sqrt{3})R30^\circ$ surface at intermediate coverage tends to phase-separate into locally low-coverage 1D chain and high-coverage blueP-like structures, respectively. This experiment thus not only lends a support of the recently proposed half-layer by half-layer (HLBHL) growth mechanism but also reveals the kinetic details of blueP growth processes.

Structural Studies of Bi2O3–NaPO3 Glasses by Solid State Nuclear Magnetic Resonance and X-ray Photoelectron Spectroscopy

Glasses in the system xBi2O3–(100 – x)NaPO3 were prepared using transitional melting–quenching and characterized using solid state nuclear magnetic resonance (SSNMR), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FT-IR). The addition of Bi2O3 results in the depolymerization of the phosphorus chain and the formation of Q(n) (n = 0, 1, 2) phosphorus species, where n represents the number of P–O–P bonds that can be quantified using 31P magic angle spinning (MAS) NMR and constant-time double-quantum based dipolar recoupling effects nuclear alignment reduction (CT-DQ-DRENAR). The 23Na{31P}, 31P{23Na}, and XPS results consistently prove that both Na+ and Bi3+ ions are bounded by phosphorus tetrahedron [PO4]3–. Unlike other trivalent ions such as Ga3+ and Al3+, which connect with the phosphorus tetrahedron by corner-sharing, Bi3+ ions were first proved to share edge with the phosphorus tetrahedron by the analysis of 31P spectra, taking the charge balance and bond valence consideration into account. Such a difference in connectivity results in significant structural differences.

Pressure-induced zigzag phosphorus chain and superconductivity in boron monophosphide.

We report on the prediction of the zinc-blende structure BP into a novel C2/m phase from 113 to 208 GPa which possesses zigzag phosphorus chain structure, followed by another P42/mnm structure above 208 GPa above using the particle-swarm search method. Strong electron-phonon coupling λ in compressed BP is found, in particular for C2/m phase with the zigzag phosphorus chain, which has the highest λ (0.56–0.61) value among them, leading to its high superconducting critical temperature Tc (9.4 K–11.5 K), which is comparable with the 4.5 K to 13 K value of black phosphorus phase I (orthorhombic, Cmca). This is the first system in the boron phosphides which shows superconductivity from the present theoretical calculations. Our results show that pressure-induced zigzag phosphorus chain in BP exhibit higher superconducting temperature TC, opening a new route to search and design new superconductor materials with zigzag phosphorus chains.

Hydrophosphination with cationic primary phosphine iron complexes: synthesis of P-chiral functionalized phosphines

The synthesis of P-chiral secondary phosphines, characterized by phosphorus and side chain chirality, has been realized via insertion of various organic multiple bond systems into the PH-bond of the primary phosphine complexes {C 5R 5(OC) 2Fe[P(R′)H 2]}BF 4 (R=H, Me; R′=alkyl, aryl). In the case of acetylenedicarboxylic acid dimethylester a double hydrophosphination is observed, leading diastereospecifically to the dinuclear complexes {C 5R 5(OC) 2Fe{P(H)(R′)[C(H)(CO 2Me)]}} 2(BF 4) 2 (R=H, Me; R′= t-Bu, 2-py), bearing four stereogenic centers. The use of p-benzoquinone gives access to secondary 2,5-bis(hydroxy)aryl phosphine ligands, suitable for further derivatizations. α-Hydroxyalkyl phosphine iron complexes can be obtained by hydrophosphination of aldehydes and ketones. Transformation into highly functionalized tertiary phosphine complexes is performed by a further hydrophosphination step using the alkenes H 2CCHX (X=CN, 2-py), diazoacetic ethylester, p-benzoquinone or ethylisocyanate, respectively, in special cases formation of functionalized azaphospholane ligands is observed. Release of the phosphines from the metal is achieved by photoinduced ligand exchange. In addition, primary phosphine iron complexes {C 5H 5(diphos)Fe[P(R)H 2]}BF 4 (diphos=DIOP, CHIRAPHOS) bearing chiral bis(phosphine) ligands have been used to provide the stereocontrol of the hydrophosphination process.

Biological Phosphorus Removal: Effect of Low Temperature

Phosphorus is a key nutrient responsible for eutrophication. Conventional activated sludge process (ASP) removes approximately 30 to 40% phosphorus. Additional phosphorus removal has been achieved by incorporating an anaerobic stage before aerobic ASP. The application of technology, however, in cold-region countries is limited. Temperature is an important consideration in the design of any treatment process in cold regions. In this paper, the performance of biological phosphorus removal (BPR) systems at low temperatures has been reviewed. The mechanism of BPR has been considered to analyze the effect of reduced temperature. Chemical coprecipitation of phosphorus, and acetate and/or short chain fatty acid (SCFA) production may affect BPR efficiency. Both these aspects have been reviewed in systems other than BPR.

Alternative modes of conjugation in one-dimensional polymers

Electronic delocalization may be achieved utilizing unconventional modes of conjugation between unsaturated centers. Spiroconjugation, through-bond coupling, and long-range through-space coupling have been explored as mechanisms for conjugation in one-dimensional semiconductors. Three prototypical systems are examined in order to shed light on the prospects for the actual exploitation of these modes of conjugation in electronically interesting polymers. The stabilizing or destabilizing influence of through-bond coupling and spiroconjugation is examined. A prevalent phosphorus chain system 1∞ [Px−5 ] (0<x<1) is analyzed as an example of an infinite ‘‘laticycle.’’ Through-space apex–apex interactions in this system have profound effects on the protonated derivative, 1∞ [P5H].

Effect of high pressure on the vibrational modes and the energy gap of ZnP2

The pressure dependence of the vibrational modes in ZnP2 has been investigated by Raman Spectroscopy using a diamond anvil cell, up to 150 kbar pressure. The intrachain phosphorus modes exhibit a strong pressure dependence whereas the low frequency Zn-P modes soften very slightly under pressure. For a crystal which is treated as a molecular crystal this is an unexpected result. It is suggested that the behaviour may be due to a buckling of the phosphorus chain, or due to a double bond promotion between P atoms, or a charge transfer under pressure. The shift in the energy gap has also been measured to 100 kbar hydrostatic pressure. There is a small initial blue shift which gradually changes over to a red shift. However the whole shift in 100 kbar is quite small. Combining the (dEg/dP) T with the published (dEg/dT) P the thermal expansion contribution and the electron-phonon interaction contribution were evaluated. The latter dominates the total (dEg/dT) P of ZnP2.

Cyclization of the phosphorus chain of the methylene-bridged analogs of adenosine triphosphate

The phosphorus-containing side chains of two methylene-bridged analogs of adenosine triphosphate have been cyclized to produce the corresponding analogs of monoadenosine-5′-trimetaphosphate: adenosine-5′-O P(O)OP(O)(OH)CH 2P(O)(OH)O and adenosine-5′-O P*(O)CH 2P(O)(OH)OP(O)(OH)O The molecules, which were generated in anhydrous media through a carbodi- imide-mediated condensation, were characterized by 31P nuclear-magnetic resonance, and the white-noise 1H decoupled spectra were simulated. These molecules are quite reactive and readily converted to their corresponding linear forms upon hydrolysis. The second structure contains an asymmetric phosphorus atom, and both of the possible cyclic molecules have been ob- served and the diasteroisometric mixture has been isolated.

Ion Chemistry of Phosphirane and Structure of the Phosphirane Molecular Ion

The mass spectrum and the ion molecule reactions of phosphirane and of mixtures of phosphirane with NH3 , NH2D, NHD2 and ND3 have been studied by ion cyclotron resonance spectrometry. Almost all important product ions are formed by PH-group transfer reactions, where ethene is generated as the neutral particle. Only two of the more abundant ions, the protonated molecule, H2P(CH2)2 + and the ion m/e=63, P2H+, are formed via other reaction pathways. Secondary, tertiary and quarternary product ions with the general formula R(PH)n + (R: phosphirane fragment, n-1, 2, 3) have been detected. The molecular ion is proved to have a cyclic structure. Two possible structures of the product ions with two and three phosphorus atoms are discussed: a structure with an open phosphorus chain, leaving the phosphirane ring intact and a ring extended structure, produced by a ring extension reaction of the PH-group. Several rate constants of the ion molecule reactions of the phosphirane molecular ion are given

Hot-atom chemistry of polyphosphates—III: Reactions of 32P resulting from neutron activation of higher polymer

For the study of the reactions of 32P in polymer phosphate during neutron activation, polyphosphates with mean chain lengths, n ̄ , of 10 and ∞ (Graham's salt) were used as target materials. The yield of recoil 32P monomer was found to be much lower than that for tripolyphosphate. But three oxidation states of radiophosphorus of (+1), (+3) and (+5) were found in the recoil species. However, the distribution of the three states could be varied by changing the irradiation condition and target materials. The specific activity decreased with increase of polymer chain length. Bond breakage of polyphosphate during alkaline hydrolysis occurred in units of four (PO 3) −, and the accumulation of tetramer and the further hydrolysis of this species led to the conclusion that radioactive labelling occured only at the end atom of the long phosphorus chain.