Materials Data on P(CN)3 by Materials Project
(CN)3P crystallizes in the tetragonal I-42d space group. The structure is zero-dimensional and consists of forty-eight hydrogen cyanide molecules and sixteen phosphine molecules.
36 MATERIALS SCIENCE↗
SEARCH · Engineering Papers
Results for “P(CN)3”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Catalytic Reduction of Cyanide to Ammonia and Methane at a Mononuclear Fe Site
Nitrogenase enzymes catalyze nitrogen reduction (N 2 R) to ammonia and also the reduction of non-native substrates, including the 7H + /6e – reduction of cyanide to CH 4 and NH 3 . CN – and N 2 are isoelectronic, and it is hence fascinating to compare the mechanisms of synthetic Fe catalysts capable of both CN – and N 2 reduction. Here, we describe the catalytic reduction of CN – to NH 3 and CH 4 by a highly selective (P 3 Si )Fe(CN) catalyst (P 3 Si represents a tris(phosphine)silyl ligand). Catalysis is driven in the presence of excess acid ([Ph 2 NH 2 ]OTf) and reductant ((C 6 H 6 ) 2 Cr), with turnover as high as 73 demonstrated.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Controlling P–C/C–H Bond Cleavage in Nickel Bis(diphosphine) Complexes: Reactivity Scope, Mechanism, and Computations
The synthesis of heteroleptic [Ni(P 2 N 2 )(diphosphine)][BF 4 ] 2 complexes and the cleavage of P–C and C–H bonds of the P 2 N 2 ligand in those complexes are reported here. The products are five-coordinate complexes in which Ni–C and P–H bonds have formed to give a cyclic moiety containing Ni–CH$=$NR 2 . The reactivity of [Ni(P 2 N 2 )(diphosphine)][BF 4 ] 2 complexes is influenced by the rigidity of the diphosphine, the steric effect of the substituents, and length of the carbon linker of the diphosphine ligands. Diphosphine ligands bearing a rigid backbone (e.g., dmpbz, 1,2-bis(dimethylphosphino)benzene) or aromatic substituents (e.g., dppe, 1,2-bis(diphenylphosphino)ethane) react with [Ni(P t Bu 2 N Bn 2 )(CH 3 CN) 2 ][BF 4 ] 2 to give P–C/C–H bond cleavage products. Both [Ni(P t Bu 2 N Bn 2 )(dmpe)(MeCN)][BF 4 ] 2 and [Ni(P t Bu 2 N Bn 2 )(dmpm)(MeCN)][BF 4 ] 2 (dmpm = 1,2-bis(dimethylylphosphino)methane) were prepared by the reaction of [Ni(P t Bu 2 N Bn 2 )(CH 3 CN) 2 ][BF 4 ] 2 with the corresponding diphosphine ligands. [Ni(P t Bu 2 N Bn 2 )(dmpe)(MeCN)][BF 4 ] 2 readily undergoes P–C/C–H bond cleavage in nitromethane. In sharp contrast, [Ni(P t Bu 2 N Bn 2 )(dmpm)][BF 4 ] 2 is stabilized by dmpm, a diphosphine with small bite angle, and does not show P–C/C–H bond cleavage reactivity. Computational results show that for complexes bearing less bulky diphosphine ligands, such as dmpm, the barriers for the rate-determining transition states are in some examples higher than 30 kcal/mol with the M06 functional, higher than those for complexes bearing more rigid or more bulky ligands, consistent with experimental studies. The calculated barriers for the first transition state correlated with increased values of the dihedral angle formed by the two NiP 2 planes.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Circumventing Kinetic Barriers to Metal Hydride Formation with Metal–Ligand Cooperativity
We report the two-electron, one-proton mechanism of cobalt hydride formation for the conversion of [Co III Cp(P Ph 2 N Bn 2 )(CH 3 CN)] 2+ to [HCo III Cp(P Ph 2 NBn 2 )] + . This complex catalytically converts CO 2 to formate under CO 2 reduction conditions, with hydride formation as a key elementary step. Through a combination of electrochemical measurements, digital simulations, theoretical calculations, and additional mechanistic and thermochemical studies, we outline the explicit role of the P Ph 2 N Bn 2 ligand in the proton-coupled electron transfer (PCET) reactivity that leads to hydride formation. We reveal three unique PCET mechanisms, and we show that the amine on the P Ph 2 N Bn 2 ligand serves as a kinetically accessible protonation site en route to the thermodynamically favored cobalt hydride. Cyclic voltammograms recorded with proton sources that span a wide range of pK a values show four distinct regimes where the mechanism changes as a function of acid strength, acid concentration, and timescale between electrochemical steps. Peak shift analysis was used to determine proton transfer rate constants where applicable. Furthermore, this work highlights the astute choices that must be made when designing catalytic systems, including the basicity and kinetic accessibility of protonation sites, acid strength, acid concentration, and timescale between electron transfer steps, to maximize catalyst stability and efficiency.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Impact of Pendant Amine Basicity on Electrochemically-Promoted Cobalt Hydride Formation: Kinetic and Mechanistic Analysis
Here, we report the role of pendant amine basicity on the proton-coupled electron transfer (PCET) reactivity for the conversion of [Co III Cp(P Ph 2 N R 2 )(CH 3 CN)] 2+ complexes to [HCo III Cp(P Ph 2 N R 2 )] + , which is a key transformation involved in catalytic CO 2 conversion to formate and in H 2 evolution. Three complexes were studied, where the amine substituent (R) varies from benzyl, methoxyphenyl, or phenyl. In previous work on the benzyl system, we showed that the amine on the P Ph 2 N Bn 2 ligand serves as a kinetically accessible protonation site and enables three participating hydride formation mechanisms. In this work, a combination of electrochemical measurements and theoretical calculations were used to show that the electronic donation at the pendant amine influences the accessible PCET mechanism and proton transfer kinetics related to cobalt hydride formation under analogous reaction conditions. Notably, the amine with the most electron-donating substituent correlates to the lowest barrier for amine protonation, and specific cobalt hydride formation mechanisms can be shut off for the amine with the least electron-donating substituent. The mechanistic and kinetic changes upon modulation of the amine substituent have great implications for overall catalytic efficiency and selectivity, especially to generate the cobalt hydride intermediate involved in selective CO 2 reduction to formate. This work shows how to exploit kinetic basicity using ligand-cooperative design to facilitate PCET reactions involved in energy related transformations.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Materials Data on Cd2Ru(CN)6 by Materials Project
Ru(Cd(CN)3)2 crystallizes in the trigonal P-3 space group. The structure is two-dimensional and consists of one ruthenium molecule and one Cd(CN)3 sheet oriented in the (0, 0, 1) direction. In the Cd(CN)3 sheet, Cd2+ is bonded to six equivalent N3- atoms to form edge-sharing CdN6 octahedra. There are three shorter (2.40 Å) and three longer (2.41 Å) Cd–N bond lengths. C+1.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. N3- is bonded in a distorted trigonal planar geometry to two equivalent Cd2+ and one C+1.33+ atom.
36 MATERIALS SCIENCE↗
Materials Data on Mn2Ru(CN)6 by Materials Project
Ru(Mn(CN)3)2 crystallizes in the trigonal P-3 space group. The structure is two-dimensional and consists of one ruthenium molecule and one Mn(CN)3 sheet oriented in the (0, 0, 1) direction. In the Mn(CN)3 sheet, Mn2+ is bonded to six equivalent N3- atoms to form edge-sharing MnN6 octahedra. There are three shorter (2.25 Å) and three longer (2.26 Å) Mn–N bond lengths. C+1.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.19 Å. N3- is bonded in a distorted trigonal planar geometry to two equivalent Mn2+ and one C+1.33+ atom.
36 MATERIALS SCIENCE↗
Materials Data on Cd2Fe(CN)6 by Materials Project
Fe(Cd(CN)3)2 crystallizes in the trigonal P-3 space group. The structure is two-dimensional and consists of one iron molecule and one Cd(CN)3 sheet oriented in the (0, 0, 1) direction. In the Cd(CN)3 sheet, Cd2+ is bonded to six equivalent N3- atoms to form edge-sharing CdN6 octahedra. There are three shorter (2.38 Å) and three longer (2.39 Å) Cd–N bond lengths. C+1.83+ is bonded in a distorted single-bond geometry to one N3- atom. The C–N bond length is 1.19 Å. N3- is bonded in a distorted trigonal planar geometry to two equivalent Cd2+ and one C+1.83+ atom.
36 MATERIALS SCIENCE↗
Materials Data on Tl4Fe(CN)6 by Materials Project
Fe(Tl2(CN)3)2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional and consists of two iron molecules and one Tl2(CN)3 framework. In the Tl2(CN)3 framework, there are four inequivalent Tl1+ sites. In the first Tl1+ site, Tl1+ is bonded in a 2-coordinate geometry to five N3- atoms. There are a spread of Tl–N bond distances ranging from 2.84–3.50 Å. In the second Tl1+ site, Tl1+ is bonded to six N3- atoms to form distorted edge-sharing TlN6 octahedra. There are a spread of Tl–N bond distances ranging from 2.91–3.18 Å. In the third Tl1+ site, Tl1+ is bonded to six N3- atoms to form distorted edge-sharing TlN6 octahedra. There are a spread of Tl–N bond distances ranging from 2.92–3.32 Å. In the fourth Tl1+ site, Tl1+ is bonded in a 6-coordinate geometry to six N3- atoms. There are a spread of Tl–N bond distances ranging from 2.83–3.61 Å. There are six inequivalent C+1.83+ sites. In the first C+1.83+ site, C+1.83+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.19 Å. In the second C+1.83+ site, C+1.83+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.19 Å. In the third C+1.83+ site, C+1.83+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.19 Å. In the fourth C+1.83+ site, C+1.83+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.19 Å. In the fifth C+1.83+ site, C+1.83+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.19 Å. In the sixth C+1.83+ site, C+1.83+ is bonded in a distorted single-bond geometry to one N3- atom. The C–N bond length is 1.19 Å. There are six inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted single-bond geometry to four Tl1+ and one C+1.83+ atom. In the second N3- site, N3- is bonded in a single-bond geometry to four Tl1+ and one C+1.83+ atom. In the third N3- site, N3- is bonded in a distorted single-bond geometry to four Tl1+ and one C+1.83+ atom. In the fourth N3- site, N3- is bonded in a distorted single-bond geometry to four Tl1+ and one C+1.83+ atom. In the fifth N3- site, N3- is bonded in a distorted single-bond geometry to four Tl1+ and one C+1.83+ atom. In the sixth N3- site, N3- is bonded in a distorted single-bond geometry to three Tl1+ and one C+1.83+ atom.
36 MATERIALS SCIENCE↗
Copper Clusters Containing Hydrides in Trigonal Pyramidal Geometry
Structurally precise copper hydrides [Cu 11 H 2 {S 2 P(O i Pr) 2 } 6 (C≡CR) 3 ], R = Ph (1), C 6 H 4 F (2), and C 6 H 4 OMe (3), were first synthesized from the polyhydrido copper cluster [Cu 20 H 11 {S 2 P(O i Pr) 2 } 9 ] with nine equivalents of terminal alkynes. Later, their isolated yields were significantly improved by direct synthesis from [Cu(CH 3 CN) 4 ](PF 6 ), [NH 4 ][S 2 P(O i Pr) 2 ], NaBH 4 , and alkynes along with NEt 3 in THF. 1, 2, and 3 were fully characterized by single-crystal X-ray diffraction, ESI-MS, and multinuclear NMR spectroscopy. All three clustershave 11 copper atoms, adopting 3,3,4,4,4-pentacapped trigonal prismatic geometry, with two hydrides inside the Cu 11 cage, the position of which was ascertained by a single-crystal neutron diffraction structure of cluster 1 co-crystallized with a [Cu 7 (H){S 2 P(O i Pr) 2 } 6 ] (4) cluster. Six dithiophosphate and three alkynyl ligands stabilize the Cu 11 H 2 core in which the two hydrides adopt a trigonal pyramidal coordination mode. This coordination mode is so far unprecedented for hydride. The 1 H NMR resonance frequency of the two hydrides appears at 4.8 ppm, a value further confirmed by 2 H NMR spectroscopy for their deuteride derivatives [Cu 11 (D) 2 {S 2 P(O i Pr) 2 } 6 (C≡CR) 3 ]. A DFT investigation allows understanding the bonding within this new type of copper(I) hydrides.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Mechanistic Studies of Ligand Substitution, Linkage Isomerism, and Insertion Reactions in Electron Rich Pd(II) Complexes of a Zwitterionic Diimine Ligand
We have prepared cationic palladium complexes possessing a new zwitterionic ligand bis-N,N’–1-(2,4,6-triphenylpyridyl) oxalamide [(N ^ N)Pd(Me)(L)] + [BArF] - , (BArF=3,5-(CF 3 ) 2 C 6 H 3 , L=NCMe, CO). The structure of [(N ^ N)Pd(Me)(CO)] + [BArF] - was determined by X-ray diffraction analysis. Energy Decomposition Analysis (EDA) indi-cates this N ^ N zwitterionic ligand is more electron-donating relative to bidentate diimine ligands. Low temperature NMR analysis shows the existence of linkage isomers with the N ^ N isomer the most stable. Structures were assigned using NMR and DFT analysis. Barriers to interconversion of isomers are ΔG ‡ = 10-12 kcal/mol. Kinetics of acetoni-trile displacement from [(N ^ N)Pd(Me)(NCCH 3 )] + [BArF] - by CD 3 CN, ethylene and t Bu 3 P were measured and mechanisms of exchange determined. The ethylene complex, [(N ^ N)Pd(Me)(C 2 H 4 )] + was generated at -45 °C, and the barrier of migrato-ry insertion determined at 0 °C (ΔG ‡ = 23.4 kcal/mol) and compared to related diimine complexes. The methyl carbonyl complex undergoes migratory insertion in the presence of CO at -70 to -55 °C (ΔG ‡ = ca. 15.7 kcal/mol) to yield the acyl carbonyl complex. Furthermore, the neutral bis-trimethylsilylmethyl complex [(N ^ N)Pd(CH 2 SiMe 3 ) 2 was prepared and characterized by X-ray diffraction analysis. It displays dynamic behavior at very low temperatures in the NMR spectrum (-90 °C, ΔG ‡ =7.9 kcal/mol) which, supported by DFT analysis, is ascribed to rotation of the bulky -CH 2 SiMe 3 groups.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Materials Data on Al(CN)3 by Materials Project
Al(CN)3 is Modderite-derived structured and crystallizes in the tetragonal P-42_1m space group. The structure is zero-dimensional and consists of two Al(CN)3 clusters. Al3+ is bonded in a T-shaped geometry to three N3- atoms. There is one shorter (1.96 Å) and two longer (1.97 Å) Al–N bond length. There are two inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.16 Å. In the second C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a linear geometry to one Al3+ and one C2+ atom. In the second N3- site, N3- is bonded in a linear geometry to one Al3+ and one C2+ atom.
36 MATERIALS SCIENCE↗
Materials Data on CoAg3(CN)6 by Materials Project
Co(Ag(CN)2)3 crystallizes in the trigonal P-31m space group. The structure is zero-dimensional and consists of one cobalt molecule and three Ag(CN)2 clusters. In each Ag(CN)2 cluster, Ag1+ is bonded in a linear geometry to two equivalent N3- atoms. Both Ag–N bond lengths are 2.05 Å. C+2.33+ is bonded in a distorted single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a linear geometry to one Ag1+ and one C+2.33+ atom.
36 MATERIALS SCIENCE↗
Materials Data on CoH3(CN)6 by Materials Project
Co(H(CN)2)3 crystallizes in the trigonal P-31m space group. The structure is zero-dimensional and consists of one cobalt molecule and three H(CN)2 clusters. In each H(CN)2 cluster, C+2.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a linear geometry to one C+2.33+ and one H1+ atom. The N–H bond length is 1.27 Å. H1+ is bonded in a linear geometry to two equivalent N3- atoms.
36 MATERIALS SCIENCE↗
Materials Data on FeAg3(CN)6 by Materials Project
Fe(Ag(CN)2)3 crystallizes in the trigonal P-31m space group. The structure is zero-dimensional and consists of one iron molecule and three Ag(CN)2 clusters. In each Ag(CN)2 cluster, Ag1+ is bonded in a linear geometry to two equivalent N3- atoms. Both Ag–N bond lengths are 2.04 Å. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a linear geometry to one Ag1+ and one C2+ atom.
36 MATERIALS SCIENCE↗
Observation of CH A->X, Cn B->X, and NH A->X Emissions in Gas-phase Collisions of Fast O ((sup 3)P) Atoms with Hydrazines
Optical emissions in single-collision reactions of fast (20 eV laboratory translational energy) O((sup 3)P) atoms with hydrazine, methylhydrazine, and 1,1-dimethylhydrazine have been measured in a crossed-beams geometry. The emissions were observed in the wavelength range 325-440 nm, and were identified as the CH (A 2(sub A))-->X(sup 2)pi(sub r), (for methylhydrazine), CN (B sup 2) Sigma(sup +) --> X(sup 2) Sigma(sup +) (for methylhydrazine)and NH(A(sup 3)pi --> X(sup3 Sigma) transitions (for all three hydraz vibration-rotation bands were fit to a synthetic spectrum of CH, CN and NH with given vibrational and rotational temperatures.
chemical reactions↗
Directed Gas-Phase Formation of the 1-Cyanovinyl Radical (H 2 CCCN, X 2 A′) in the Interstellar Medium
The formation pathways to nitrogen-containing molecules and radicals are crucial to the understanding of the carbon–nitrogen chemistry in interstellar and atmospheric environments. While over 65 nitrogen-containing neutral species have been observed in deep space to date, their formation mechanisms─in particular, those of radical species─remain largely speculative. The crossed molecular beam technique in conjunction with electronic structure and statistical calculations was utilized to offer a detailed overview of the fundamental pathways in the gas-phase bimolecular reaction of ground-state atomic carbon (C, 3 P) with acetonitrile-d 3 (CD 3 CN, X 1 A 1 ) under single-collision conditions leading to the formation of the 1-cyanovinyl radical (D 2 CCCN, X 2 A′) coupled with deuterium atom loss. Here, the indirect reaction was initiated by barrierless carbon-atom addition, with the most probable route involving carbon addition across the carbon–nitrogen nitrile triple bond of acetonitrile, forming a three-membered ring intermediate followed by ring-opening and unimolecular decomposition via atomic deuterium loss from the C3 carbon atom. The reaction was overall exoergic, and intermediates and transition states lie lower in energy than the separated reactants, unlocking the reaction of carbon with acetonitrile in low-temperature environments such as cold molecular clouds, e.g., Taurus Molecular Cloud (TMC-1), and planetary atmospheres, e.g., Saturn’s moon Titan. In these environments, the 1-cyanovinyl radical may act as a building block for cyano-substituted polycyclic aromatic hydrocarbons and N-heterocycles, thus furthering our understanding of the complex carbon–nitrogen chemistry in deep space.
Chemical reactions↗