Six-coordinate Phosphorus Research Articles

Silylimidazolium Hexafluorophosphate Salts as Synthetic Precursors to N-Heterocyclic Carbene Pentafluorophosphorus Adducts.

N-Heterocyclic carbene pentafluorophosphorus (NHC-PF5) adducts are six-coordinate phosphorus(v) compounds with emerging applications but poor synthetic accessibility. We have developed a simple and high yielding protocol for synthesizing imidazolylidene NHC-PF5 adducts from silylimidazolium hexafluorophosphate salts. Using this methodology, we have prepared a series of NHC-PF5 adducts in high yields, including new NHC-PF5 building blocks amenable to subsequent synthetic diversification. We also demonstrate that a similar approach enables access to analogous, synthetically elusive NHC-BF3 and NHC-SbF5 adducts.

Tuning Chemical and Physical Properties of Phosphorus Corroles for Advanced Applications.

Although the affinity of metallocorroles to axial ligands is quite low, this is not the case when the chelated element is phosphorus. This work is hence focused on the mechanism of ligand exchange of six-coordinate phosphorus corroles as a tool for affecting their chemical and physical properties. These fundamental investigations allowed for the development of facile methodologies for the synthesis of a large series of complexes and the establishment of several new structure/activity profiles that may be used to understand and predict spectroscopic features and for tailor-made modification of photophysical and electrochemical properties. This is exemplified by the facile access to complexes with terminal groups that are of large potential for practical applications based on click chemistry, optical imaging, and surface science.

Adducts of Donor-Functionalized Ar3P with the Soft Lewis Acid I2: Probing Simultaneous Lewis Acidity and Basicity at Internally Solvated P(III) Centers.

The enhancement of donor strength of ortho-functionalized triarylphosphanes is shown to occur via different mechanisms for O- and N-donor substituents, with internal solvation of the phosphorus center observed for N donors. Nevertheless, the steric congestion about the P center is shown to significantly oppose the increase in donor ability, leading to donation weaker than that expected. A series of mono- and bis-aryl-substituted Ar3PI2 adducts (Ph3-n(o-OMe-C6H4)nPI2, Ph3-n(o-NMe2-C6H4)nPI2, Ph3-n(o-CH2NMe2-C6H4)nPI2 (n = 1, 2)) have been synthesized via the 1:1 reaction of donor-functionalized phosphanes with diiodine. These soft Lewis acid/base adducts exhibit apparent internal solvation of the donor phosphorus by the pendant donor moieties, giving rise to five- or six-coordinate phosphorus atoms acting as both Lewis base and Lewis acid; the first neutral six-coordinate simultaneous P(III) Lewis acid and Lewis base adduct is reported. Single-crystal X-ray diffraction studies reveal unexpectedly weak donor strength for one of the phosphanes, indicating significant steric hindrance as a consequence of internal solvation. Crystallographic interrogation of the corresponding iodophosphonium salts [Ar3PI]X (X = I3, BArF) shows that the cationic complexes experience a still greater influence of the steric bulk of the donor moieties than their neutral precursors. The steric and electronic contributions to bonding have been analyzed through computational studies, determining the factors governing the basicity of these donor-functionalized phosphanes, and show that enhancement of P-centered donor strength occurs by conjugation of lone pairs through the arene rings for oxygen substituents and via internal solvation for the nitrogen donors.

A water-soluble phosphite derived from sulfonated calix[4]arene. The remarkable stability of its rhodium complexes and two phase hydroformylation studies

The reaction of tetrasulfonated calix[4]arene (trioctylammonium salt) with P(NMe2)3 followed by treatment with gaseous NMe2H gave a zwitterionic six-coordinate phosphorus(V) species 1 containing a P(H)(NHMe2) group which can be stored for months without decomposition. In water, 1 loses NHMe2 and rearranges to form the water soluble phosphite Lcc. Phosphite Lcc has a half-life in water of ca. 5 h decomposing to H3PO3 and free tetrasulfonated calix[4]arene. Compound 1 serves as a convenient precursor to Lcc and complexes of Lcc are formed by dissolving 1 in water in the presence of labile metal complexes. The products have been identified by comparison of their 31P NMR data with well established analogues of calix[4]arene derived phosphites. In this way the water soluble complexes [Rh(acac)(CO)(Lcc)2] (2c) [Rh2Cl2(CO)2(Lcc)2] (3c), [Pt2Cl4(Lcc)2] (4c) and [PtCl2(Lcc)2] have been tentatively identified. The rhodium complex 3c has a half-life in water of 4 months. Two-phase (water/toluene) hydroformylation of 2-methylpentenoate with 2c as a catalyst has been investigated and the results compared with the same reaction in toluene with lipophilic analogues of 2c. Under mild conditions, with 2ccatalyst, branched aldehydes are the only products of hydroformylation and one of the branched aldehydes is selectively hydrogenated to give the lactone derivative.

Conversion of tricoordinate to hexacoordinate phosphorus. Formation of a phosphorane-phosphatrane system.

Reaction of RPCl(2) with tris(2-hydroxy-3-tert-butyl-5-methylbenzyl)amine (4) led to the formation of a tricoordinated phosphonite (1) when R = Ph and to a hexacoordinated phosphorane-phosphatrane (2) when R = Et. The X-ray structures showed that the unreacted hydroxyl group in 1 oxidatively added to phosphorus in 2 leading to the formation of three additional bonds, a P[bond]O, a P[bond]H, and a P[bond]N linkage. In solution, (31)P measurements assisted by solid-state (31)P measurements revealed that each of the compounds existed in both structural forms. VT (31)P established equilibria where the solid-state structures predominated in each case. This is the first example of a conversion of three-coordinate to six-coordinate phosphorus on going from the solid to the solution state and the existence of these two disparate geometries in equilibrium with one another in solution. In the absence of steric protection with the use of an analogous amine (5) without tert-butyl groups, a hydrolysis reaction occurred with PhPCl(2). X-ray analysis revealed an anionic phenylphosphinate structure (3) hydrogen bonded in a cage-like arrangement with the protonated amine. Similar hydrolysis reactions take place with 1 and 2 but much more slowly.

A Cationic, Macrocyclic, Six-Coordinate Phosphorus(V) Compound Containing a Mixed Valence PIII-PV-PIII Linear Chain

In the highly symmetrical environment of the PV center in the cation [P{P(o-C6 H4 O)2 Ph}2 ]+ of 1 the two PV -PIII bonds are relatively short (2.2023(10) Å) for compounds of this type. Compound 1 was obtained from the reaction of PCl5 with two equivalents of [(o-OSiMe3 )C6 H4 ]2 PPh.

A Cationic, Macrocyclic, Six-Coordinate Phosphorus(V) Compound Containing a Mixed Valence PIII-PV-PIII Linear Chain

A Cationic, Macrocyclic, Six-Coordinate Phosphorus(V) Compound Containing a Mixed Valence PIII-PV-PIII Linear Chain

Reaction mechanisms of phosphorus fluorides: An ab initio study

Reaction mechanisms of phosphorus fluorides may be analyzed on the basis of the coordination model of reaction mechanisms. Some of the intermediates and mechanistic details arising out of such an analysis have been investigated by ab initio molecular orbital calculations. The rapid equilibrium between five- and six-coordinate phosphorus fluorides, and exchange of axial and equatorial fluorines in PF 5, is investigated by calculating the structures of adducts of phosphorus pentafluoride, i.e. D-PF 5 where D = NH 3, H 2O, CH 3F, HF, PF 5 and PF 6. Bond cleavage in phosphorus fluorides is investigated by calculating the structure of a fluorine-bridged anion P 2F 11 −. A reaction pathway is proposed for the fluoride-catalyzed oxidation of phosphorus (III) to phosphorus(V) fluorides which involves the known species PF 3, PF 4 −, PF 4 and PF 5.

AB INITIO TREATMENT OF A PHOSPHORUS COORDINATE, TRIGONAL BIPYRAMIDAL TO PENTAFLUORIDE-PYRIDINE REACTION SQUARE PYRAMIDAL TO OCTAHEDRAL

Ab initio calculations of the interaction of pyridine with PF5 show that the initial trigonal bipyramidal geometry isomerizes to a square pyramid before forming an octahedron as pyridine enters the coordination sphere. The calculated reaction trajectory mimics that found for sulfur donor actions in cyclic pentaoxyphosphoranes where X-ray studies show a range of geometries toward increasing octahedral character from a square pyramid as the P-S interaction increases. It is concluded that inclusion of the donor atom as part of a cyclic system does not control the observed geometrical changes on going from five- to six-coordinate phosphorus.

Six-coordinate phosphorus compounds. Crystal structures and dynamic NMR studies of phosphoranes containing chelating ligands

Hexacoordination of the neutral phosphorus compounds 4–6 is evidenced by their high field 31P NMR chemical shifts and is further substantiated by the crystal structure of 5 and 6.5 contains the potentially bis-chelating ligand Ar = (C 6H 3(CH 2NMe 2) 2-2,6) and 6 the same ligand with a protonated amino group. In both cases the compounds exhibit slightly distorted octahedral geometry. In compound 5, only one NMe 2 group is coordinated to the phosphorus atom with an N → P bond of 2.063 Å. In compound 6, the NMe 2 group is coordinated to the phosphorus atom with an N → P bond of 2.007 Å while the dimethylammonium substituent is pointing away from the phosphorus atom forming a hydrogen bridge with two oxygen atoms. The fluxional behavior of these three novel six-coordinate phosphorus compounds was studied by dynamic 1H NMR spectroscopy.

Hexacoordinate Phosphorus. 7. Synthesis and Characterization of Neutral Phosphorus(V) Compounds Containing Divalent Tridentate Diphenol Imine, Azo, and Thio Ligands.

The reactions of bis(trimethylsilyl)ated forms of the Schiff base ligands N-(2-hydroxyphenyl)salicylideneamine {(HO)C(6)H(4)N(CH)C(6)H(4)(OH)}, N-(4-tert-butyl-2-hydroxyphenyl)salicylideneamine {(HO)((t)Bu)C(6)H(3)N(CH)C(6)H(4)(OH)}, N-(2-hydroxy-4-nitrophenyl)salicylideneamine {(HO)(O(2)N)C(6)H(3)N(CH)C(6)H(4)(OH)}, and the structurally related ligand 2,2'-azophenol with halogeno- and (trifluoromethyl)halogenophosphoranes yield a series of neutral hexacoordinate phosphorus(V) compounds by means of trimethylsilyl halide elimination. In all of these cases the ligands chelate in a meridional conformation in which bicyclic five- and six-membered chelate rings are formed through structures containing two phenolic P-O bonds and one N-P bond. The hexacoordinate nature of these compounds is evidenced by their high-field (31)P NMR chemical shifts and their characteristic J(PF) coupling patterns and is further substantiated by the crystal structures of {O((t)Bu)C(6)H(3)N(CH)C(6)H(4)O}PCl(3) and {OC(6)H(4)N=NC(6)H(4)O}PF(3). Crystal data for {O((t)Bu)C(6)H(3)N(CH)C(6)H(4)O}PCl(3): triclinic, space group P&onemacr; (No. 2), a = 11.167(1) Å, b = 15.684(1) Å, c = 17.047(2) Å, V = 2840(1) Å(3), Z = 2. Final R and R(w) values were 0.051 and 0.079, respectively. Crystal data for {OC(6)H(4)N=NC(6)H(4)O}PF(3): monoclinic, space group P2(1)/c (No. 14), a = 6.9393(8) Å, b = 12.450(2) Å, c = 13.907(2) Å, V = 1190.7(6) Å(3), Z = 4. Final R and R(w) values were 0.045 and 0.056, respectively. The molecular structures of {O((t)Bu)C(6)H(3)N(CH)C(6)H(4)O}PCl(3) and {OC(6)H(4)N=NC(6)H(4)O}PF(3) show that in both cases the Schiff base ligand chelates occupy the meridional plane about the six-coordinate phosphorus atom. In the case of {OC(6)H(4)N=NC(6)H(4)O}PF(3) the equivalent nitrogen atoms in the chelate rings are disordered to form half-occupancy pairs. The silylated form of the related thiobis(phenol), 2,2'-thiobis(4,6-tert-butylphenol), reacted similarly with pentavalent halides to form the six-coordinate complex [{2-O-3,5-((t)Bu)(2)C(6)H(2)}(2)S]PCl(3) which was also verified by a crystal structure. Crystal data for [{2-O-3,5-((t)Bu)(2)C(6)H(2)}(2)S]PCl(3): monoclinic P2(1)/n, a = 13.989(2), b = 13.594(2), c = 16.483(2) Å, beta = 97.98(2) degrees, V = 3104(2) Å(3), Z = 4; final R and R(w)() values were 0.039 and 0.052, respectively. In contrast to the above six coordinate complexes, this compound possesses a facial structure in which two phenoxy substituents form planar chelates centered on the bridging sulfur and intersecting at the P-S axis. The P-S bond length, 2.331(1) Å, is slightly shorter than has been previously observed in the example wherein the ligand possesses two tert-butyl groups and the phosphorus carries three OCH(2)CF(3 )substituents indicating stronger interaction between P and S in the present case.

Hypercoordinate phosphorus in gold clusters: novel species [P(AuL)6]3+(BF4–)3

Treatment of (Me3Si)3P with a solution of six equivalents of a (triorganophosphine)gold(I) tetrafluoroborate LAu+BF4–(L = But3P, Pri3P) in tetrahydrofuran, in the presence of an excess of KF, leads to high yields of the title compounds 1a, b as stable microcrystalline solids; the products, which contain interstitial six-coordinate phosphorus, have been characterized by a detailed NMR study and on the basis of elemental and mass spectrometric analysis.

The Richness of Structures Available to P2N2Inorganic Heterocycles: A Topological and Molecular' Orbital (EHMO) Analysis

Abstract A topological analysis, based upon Polya's theorem, was used to calculate all possible isomers of P2N2 ring derivatives, as a function of the number of substituents attached to phosphorus and nitrogen. The analysis considered four-, five- and six-coordinate phosphorus, and two-, three- and four-coordinate nitrogen. EHMO calculations established the HOMO-LUMO orbitals and the charges of variously substituted P2N2 heterocycles.

ChemInform Abstract: Hexacoordinate Phosphorus. Part 6. Synthesis and Characterization of Neutral Six‐Coordinate Phosphorus(V) Compounds Derived from 2‐ Pyridinol and Related Heteroatomic Pyridine Ligands.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Hexacoordinate phosphorus. 6. Synthesis and characterization of neutral six-coordinate phosphorus(V) compounds derived from 2-pyridinol and related heteroatomic pyridine ligands

The reaction of the silylated of the substituted pyridine ligands 2-(methylamino)pyridine, 2-hydroxypyridine, 2-mercapto-pyridine, and 2,2'-dipyridylamine with λ 5 -halogenophosphoranes yields, via trimethylsilyl halide elimination, a series of neutral hexacoordinate λ 6 -phosphorus compounds, in which a four-membered chelate structure is achieved by donation of the electron pair from the pyridine nitrogen to phosphorus in addition to formation of P−O,; P−N, or P−S bonds

Encapsulated phosphides: Ru8(CO)21(.mu.6-P)(.mu.4-PPh)(.mu.2-PPh2), a molecule with a six-coordinate phosphorus atom in a condensed cluster

Encapsulated phosphides: Ru8(CO)21(.mu.6-P)(.mu.4-PPh)(.mu.2-PPh2), a molecule with a six-coordinate phosphorus atom in a condensed cluster

The Structure of o-Hydroxyaryloxy-bis-(o-arylenedioxy)-phosphoranes and their Acid-Base Properties

1. We have obtained crystalline phosphoranes with o-hydroxyphenyl substituent and we have studied their vibrational, electronic, and NMR spectra, and also the spectra of the products of their reaction with nitrogen bases. 2. The molecular structure with a five-coordinate phosphorus atom corresponds to the investigated phosphoranes; and the ionic structure with a six-coordinate phosphorus atom corresponds to the phosphorates. 3. A new type of acid-base interaction has been established, connected with the fact that the process of proton transfer is accomplished by phosphorane-phosphorate conversions; in this case the hydroxyl group in the phosphorane molecule displays enhanced acidity, and yields products of complete proton transfer with different bases.

New Six-Coordinate Phosphorus Compounds. Synthesis and Stereochemistry

Abstract Synthesis and stereochemistry of several new six-coordinate organophosphorus compounds are discussed.

The 31P NMR chemical shifts of four-, five- and six-coordinate phosphorus(V) compounds

There appears to be a correlation between the 31P chemical shift differences between A + and AX (Δ 1), and between A + and AX 2 − (Δ 2), where A + is a phosphonium ion and X is an anionic ligand. This relationship holds for a wide range of substituents on phosphorus, despite the expected changes in hybridisation along the series, and is very useful for predicting the shifts of new or unknown species.

Crystalline six-coordinate phosphorus compounds derived from spiropentaoxyphosphoranes

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystalline six-coordinate phosphorus compounds derived from spiropentaoxyphosphoranesFausto Ramirez, Vidyanatha A. V. Prasad, and James F. MarecekCite this: J. Am. Chem. Soc. 1974, 96, 23, 7269–7275Publication Date (Print):November 1, 1974Publication History Published online1 May 2002Published inissue 1 November 1974https://doi.org/10.1021/ja00830a016RIGHTS & PERMISSIONSArticle Views122Altmetric-Citations38LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (801 KB) Get e-Alerts Get e-Alerts