31P CP MAS NMR Research Articles

Co-ordination and conformational isomerism in bis(tricyclohexylphosphine) gold(I) halides

Solid state complexes of bis(tricyclohexylphosphine)gold(I) with halide counter ions, Au(PCy3)2X (X = Cl, Br or I), have been crystallised from solutions of [NBu4][AuX2] and PCy3 in dimethylformamide and characterised by single crystal structure determinations, far-infrared spectroscopy and solid state 31P CP MAS NMR spectroscopy. The results show the complexes crystallise as a unique array of co-ordination and conformational isomers which reflect the conformational flexibility of the tricyclohexylphosphine ligand and the relative preferences of the halide anions for C–H· · ·X–versus Au+· · ·X– bonding interactions. The chloride crystallises as a single ionic complex, [Au(PCy3)2]+Cl–, with the gold two-co-ordinate and the cations and anions well separated in the crystal lattice. The bromide crystallises as three different polymorphs with four distinct molecular structures. The first (α) form crystallises as ionic [Au(PCy3)2]+Br– with the bromide adjacent to but not co-ordinated to the gold. The second (β) form presents two crystallographically independent [Au(PCy3)2Br] molecules with semi-co-ordinated bromide and significant differences in the conformational dispositions of the PCy3 ligands. The third (γ) form crystallises as [Au(PCy3)2Br] with fully co-ordinated bromide. The iodide crystallises with semi-co-ordinated and co-ordinated iodide in [Au(PCy3)2I]·PCy3 and [Au(PCy3)2I] complexes respectively. The study provides an unusual series of molecular ‘vignettes’ in which the response of the [Au(PCy3)2]+ cation to halide anion can be monitored as it passes through the ligand substituents and co-ordinates to the central gold atom.

Solid-state phosphorus-31 NMR study of phosphine- and phosphite-substituted cobaloximes

Solid-state 31P NMR spectra of two phosphiteand 17 phosphine-substituted cobaloximes have been acquired under conditions of magic-angle spinning (MAS) and cross polarization (CP) at two applied magnetic fields. In the majority of cases, eight-peak multiplets are observed in the 31P CPMAS NMR spectra, arising from one-bond indirect spin–spin coupling to cobalt (spin S = 7/2). The spacings between adjacent peaks gradually increase or decrease from low to high frequency, due to the presence of residual dipolar coupling between the cobalt and phosphorus nuclei. Values of 1J(59Co,31P) were estimated from the spacing between the central peaks of the eight-peak multiplets. For the phosphine-substituted cobaloximes, values of 1J(59Co,31P) range from 225 to 372 Hz, while in the phosphite derivatives this coupling is considerably larger, from 420 to 615 Hz. From comparison with cobaloximes for which the cobalt nuclear quadrupole coupling interaction is fully characterized, the residual dipolar shift, d, and sense of the 31P NMR spectrum can be utilized to infer the electric field gradient (EFG) orientations at the cobalt nucleus in cobaloximes for which such data are unavailable. The magnitudes of 1J(59Co,31P) and d, as well as the sense of the spectra, are shown to be dependent upon the nature of the axially-substituted ligands. Phosphorus-31 CPMAS NMR spectra of several cobaloximes exhibit broad peak shapes at room temperature. Variable-temperature 31P NMR experiments reveal that the cobalt nucleus is effectively self-decoupled at room temperature; however, splittings due to 1J(59Co,31P) were observed in spectra acquired at low temperatures.

31P chemical shift anisotropies of trimethyl- and triphenylphosphine-substituted Group 6 metal pentacarbonyl complexes

The 31P chemical shift tensor components and anisotropies of the trimethyl- and triphenylphosphine complexes of the group 6 metal pentacarbonyls, M(CO)5PR3 (M = Cr, Mo, W and R = Me, Ph), have been measured using solid-state CP-MAS 31P NMR spectroscopy. For the trimethylphosphine derivatives, the chemical shift tensors have near axial symmetry and the shift tensor components are in reasonable agreement with the calculated values for the chromium and molybdenum complexes. In the triphenylphosphine complexes, the tensors are asymmetric due to the different torsion angles of the phenyl rings. The trend to higher shielding of the isotropic 31P chemical shifts on descending group 6 arises from changes in the perpendicular components of the shift tensor. The one-bond coupling constants, 1J(95/97Mo-31P), for the trimethyl- and triphenylphosphine complexes are 129 and 133 Hz, respectively.Key words: chemical shift anisotropy, phosphines, chromium, molybdenum, tungsten.

31P CP-MAS NMR, Vibrational, and X-Ray Characterization of the Adducts of Triphenylphosphine Sulfide with ICl and IBr

The reactions between triphenylphosphine sulfide (Ph3PS) and ICl in CCl4 and IBr in CH2Cl2 in 1 : 1 molar ratio give the solid adducts Ph3PS · ICl (I) and Ph3PS · IBr (II) whose structures have been solved by X-ray diffraction. Compounds I and II consist of discrete molecule units and feature the S–I–Cl or S–I–Br linear group. The S–I bond distances in I, II (2.641(1), 2.665(1) A respectively) and in compound 2 Ph3PS · 3 I2 (III) (2.729(2) A) are correlable to the net increase in the I–X (X = Cl, Br, I) bond distance. The structural features of I, II and III are in accordance with 31P CP–MAS NMR, FT-Raman and FT-IR spectral data, and elucidate the nature of the donor (Ph3PS)-acceptor (ICl, IBr, I2) interaction. 31P-CP-MAS-NMR, Schwingungs- und Strukturuntersuchung der Addukte von Triphenylphosphinsulfid mit IBr und ICl Die Reaktion zwischen Triphenylphosphin sulfid (Ph3PS) und ICl in CCl4 bzw. IBr in CH2Cl2 im Molverhaltnis von 1 : 1 ergab die festen Addukte Ph3PS · ICl (I) und Ph3PS · IBr (II), deren Strukturen durch Rontgenstrahlenbeugung bestimmt wurden. I und II bestehen aus isolierten Molekuleinheiten mit linearen S–I–Cl- bzw. S–I–Br-Einheiten. Die S–I-Bindungslangen von I und II (2.641(1) bzw. 2.665(1) A) und in 2 Ph3PS · 3 I2 (III) (2.729(2) A) stehen in Beziehung zu den Bindungslangen von I–X (X = Cl, Br, I). Die strukturellen Eigenschaften von I, II und III sind mit den 31P-CP-MAS-NMR-, FT-Raman- und FT-IR-Daten zu deuten und erklaren die Natur der Donor(Ph3PS)-Akzeptor(ICl, IBr, I2)-Wechselwirkung.

Structural and 31P CP MAS NMR spectroscopic studies of the P2CuN2 copper(I) complexes [Cu(PPh3)2(MeCN)2]X for X = PF6, BF4 and ClO4

The mixed ligand P2CuN2 copper(I) complexes [Cu(PPh3)2(MeCN)2]X have been studied by one- and two-dimensional 31P CP MAS NMR spectroscopy for X = PF6, BF4 or ClO4 and single crystal X-ray diffraction for X = PF6 and ClO4, completing availability of precise structural data for this isomorphous series. The compounds crystallise as discrete cations and anions in space group P21/n with a ≈ 15, b ≈ 27, c ≈ 9 A, β = 95°, Z = 4. The anion is located ca. 6 A from the copper atom and adjacent to a cleft formed between the acetonitrile ligands and phosphine ligand 2 while the crystallographically independent PPh3 ligands adopt staggered three-bladed propeller-type conformations of opposite chirality. The geometric symmetry of the P2CuN2 co-ordination sphere is low with Cu–P(1) 2.276(4)–2.287(2), Cu–P(2) 2.258(4)–2.269(1) A, Cu–N 2.023(9)–2.053(3) A, P–Cu–P 126.82(4)–127.73(5), N–Cu–N 99.5(4)–100.3(1), P(1)–Cu–N 100.87(8)–102.34(9) and P(2)–Cu–N 110.4(1)–111.9(3)°. One- and two-dimensional solid state 31P CP MAS NMR spectra of the compounds at 9.40 T show chemical shift differences of 6 ppm between the signals arising from the two P sites which form part of an ABX spin system with 1J[31P(1)–63Cu] 1.13–1.14 kHz, 1J[31P(2)–63Cu] 1.30 kHz and 2J(31P–31P) 75 Hz. The copper quadrupolar induced distortion of the line spacings is different for the two sites and is postulated to be a consequence of variation in the angle between the Cu–P vectors and the z axis of the electric field gradient tensor. The magnitude of the distortion is relatively small and consistent with small copper quadrupolar coupling constants for the compounds and a balanced electronic charge distribution about the copper(I) site in spite of the low geometric symmetry of the P2CuN2 co-ordination sphere.

Intercalation of Aminomethylcrowns into α-Zirconium Phosphate

The intercalation of (±)-2-aminomethylcrowns into α-zirconium phosphate has been investigated by the batch method and followed by X-ray diffractometry. The reaction was dependent on the solvent, and 1-propanol was employed as a solvent. (±)-2-Aminomethyl-12-crown-4 and -15-crown-5 were taken up in two and three stages, respectively, while the uptake process of (±)-2-aminomethyl-18-crown-6 was complicated. Monolayers and bilayers of aminomethylcrowns might be formed when inserted into the interlayer space. 31P CPMAS-NMR and IR spectra of the intercalates suggest that the amino group is protonated by a proton of the phosphate group and/or proton transfer from the phosphate group to the amino group occurred.

Structural Alternatives in R2(Cl)P:GaCl3 Systems (R = Alkyl, Phenyl), Including Examples of Intermolecular P → P Coordination

Systematic NMR studies of (dialkyl/diaryl)chlorophosphine−gallium chloride reaction mixtures reveal three structural alternatives, which are related by equilibria in solution, and their relative stability is dependent on the nature of the substituent (R = Me, Et, iPr, tBu, Ph) and the reaction stoichiometry. The coordination complex R2(Cl)P→GaCl3 is observed in all cases, and a derivative (R = iPr) has been crystallographically characterized. Tetrachlorogallate salts of the diphosphorus cations [R2(Cl)P−PR2]+ are observed for smaller R substituents (R = Me, Et, iPr, Ph), consistent with a previous report. Solid-state 31P CP-MAS NMR spectra distinguish the methyl derivative from the novel salt [Me2(Cl)P−P(Me2)−GaCl3][GaCl4], containing a phosphine−phosphenium−gallium chloride cation, which has been crystallographically characterized. Factors governing the relative stabilities of the structural alternatives are discussed, and comparisons are made between the isomeric forms for R2(Cl)P:GaCl3.

Synthesis and characterization of a fluorinated anionic aluminophosphate framework UT-6, and its high-temperature dehydrofluorination to AlPO4-CHA

The structure of an anionic aluminophosphate molecular sieve UT-6 has been determined by single-crystal X-ray diffraction and 19 F MAS NMR, 31 P CP MAS NMR and 27 Al MQ MAS spectroscopy. Large crystals were grown in a non-aqueous synthesis system when hydrogen fluoride was used in trace amounts. The title compound, [Al 3 P 3 O 12 F] - [C 5 H 5 NH] + ·0.15H 2 O, crystallizes in the triclinic space group P (no. 2), with Z=2, a=9.118(1), b=9.161(1), c=9.335(1) A, α=85.98(1), β=77.45(1), γ=89.01(1)°, V=759.25(14) A 3 , R 1 =0.0280 and wR 2 =0.0830. UT-6 is a small pore material that has a three-dimensional network of channels running through the structure. The structure is closely related to that of chabazite. In addition to alternating tetrahedral phosphorus and aluminium atoms connected by bridging oxygens, there are also isolated pairs of octahedral aluminiums in the four-membered rings of the UT-6 framework that share two bridging fluorine atoms. The resulting negative charge on the framework is balanced by pyridinium cations that reside in the chabazite cages. Upon thermal treatment of UT-6, pyridine molecules and HF are removed from the structure and the material transforms into rhombohedral AlPO 4 -CHA, as evidenced by in situ high-temperature powder X-ray diffraction, thermogravimetry and mass spectrometry. This represents the first solid-state transformation of an anionic aluminophosphate molecular sieve framework to an entirely neutral one.

CRYSTAL STRUCTURE, SOLID-STATE NMR STUDIES AND IGLO CALCULATIONS OF 1-HYDROXYCYCLOHEXANEPHOSPHONIC ACID

Abstract X-ray diffraction of 1-hydroxycyclohexanephosphonic acid, C6H13O4P, gives the following crystal data: orthorhombic, P212121 (no. 19), a = 6.558(1), b = 7.644(2), c = 16.271(1) A, V = 815.65 A3, Z = 4, and Dx = 1.467 g/cm3. The molecular structure shows a chair conformation of the cyclohexane ring with the phosphonate group in equatorial position. The asymmetric unit consists of the formula unit. Solid-state 31P CP MAS NMR spectroscopy of different crystallization fractions of the title compound gives two sets of principal values of the nuclear magnetic shielding tensor caused by different modifications of the acid. According to IGLO caculations the most shielded component is almost along the P[dbnd]O bond. The results are compared with the principal values of some other C6 phosphonic acids.

Protons in the magnesium phosphates phosphoellenbergerite and holtedahlite; an IR and NMR study

Other| April 01, 1996 Protons in the magnesium phosphates phosphoellenbergerite and holtedahlite; an IR and NMR study Fabrice Brunet; Fabrice Brunet Universitaet Bayreuth, Bayerisches Geoinstitut, Bayreuth, Federal Republic of Germany Search for other works by this author on: GSW Google Scholar Torsten Schaller Torsten Schaller Search for other works by this author on: GSW Google Scholar American Mineralogist (1996) 81 (3-4): 385–394. https://doi.org/10.2138/am-1996-3-413 Article history first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Fabrice Brunet, Torsten Schaller; Protons in the magnesium phosphates phosphoellenbergerite and holtedahlite; an IR and NMR study. American Mineralogist 1996;; 81 (3-4): 385–394. doi: https://doi.org/10.2138/am-1996-3-413 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search nav search search input Search input auto suggest search filter All ContentBy SocietyAmerican Mineralogist Search Advanced Search Abstract Two structurally related magnesium phosphates, phosphoellenbergerite (P63mc) and holtedahlite (P63), have been investigated using a combination of high-frequency IR and 1H MAS, 31P MAS, and 31P CP MAS NMR spectroscopy on synthetic material. For phosphoellenbergerite, the two proton sites, H1 and H2, detected in single-crystal XRD studies, are confirmed. The protons on the first site, H1, delocalized around the threefold axis, form OH groups with the unshared apical O atom of PO4 tetrahedra. Those on the second site, H2, belong to Mg2O8OH dimers of face-sharing Mg octahedra, which form double chains. The spectroscopic data reveal additional protons (H3) in phosphoellenbergerite. By combining both crystallographic and spectroscopic data, it can be inferred that the H3 protons are associated with Mg vacancies in the single chains of face-sharing Mg octahedra. Furthermore, a quantitative inspection of signal intensities indicates that the proton sites in synthetic phosphoellenbergerite are not all saturated. Therefore, the substitution P5+ = Si4+ + H+ might account for part of the Si-P replacement in the silicate-to-phosphate ellenbergerite series. The results obtained for the proton distribution in holtedahlite, Mg2PO4OH, were used as a reference to facilitate the interpretation of the IR and NMR spectra of phosphoellenbergerite. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not currently have access to this article.

Chalcogeno Methylene Phosphoranes 2,4,6-tBu3C6H2-P(=X)=C(Sime3)2, X = O, S, Se Crystal Structure, 31P CP Mas NMR and IGLO Calculations

Abstract Chalcogeno methylene phosphoranes 2,4,6-tBu3C6H2P(=X)=C(SiMe3)2 with X = O, S or Se were synthesized and their crystal structures characterized by means of X-ray structure analysis. 31P CP MAS NMR measurements and IGLO calculations of model compounds C6H5P(=X)(=CH2) allow to study the influence of the chalcogeno substituent X on the principal values of the nuclear magnetic shielding tensor σii.

Novel Pillared Layer Structure of the Organically Templated Indium Phosphate [In8(HPO4)14(H2O)6](H2O)5(H3O)(C3N2H5)3

An imidazole encapsulating indium phosphate with an In:P ratio of 4:7 and a new pillared layer structure has been synthesized under solvothermal conditions and characterized by single-crystal X-ray diffraction, 31P CPMAS NMR, and thermogravimetric analysis. [Crystal data: [In8(HPO4)14(H2O)6](H2O)5(H3O)(C3N2H5)3, Mr = 2686.72, trigonal, space group P−3c1 (No. 165), a =13.859(2) Å, c =19.186(8) Å, V = 3193(4) Å3, Z = 2, R = 3.6%, Rw = 3.7% (1650 observed data with I > 3σ(I))]. The structure consists of layers assembled from InO6 and InO5(OH2) octahedra and PO3(OH) tetrahedra which are pillared through additional InO6 octahedra to produce a three-dimensional framework. The framework contains a two-dimensional array of channels in which imidazolium cations, hydroxonium ions, and water molecules reside. Within the channels are 16-membered rings of alternating In and P polyhedra which have dimensions ∼8.6 × 9.7 Å.

Spectroscopic and structural studies on 1 : 1 adducts of silver(I) salts with tricyclohexylphosphine

The 1 : 1 adducts of silver(I) halides (AgX; X = Cl, Br or I) with tricyclohexylphosphine have been prepared and their room-temperature single-crystal structures, solid-state cross polarization magic angle spinning (CP MAS)31P NMR, solution 31P NMR and far-IR spectra determined. The solid-state structures of the chloride and bromide complexes recrystallized from pyridine are unsolvated, isomorphous, centrosymmetric dihalide-bridged dimers, [{AgX[P(C6H11)3]}2], with three-co-ordinate metal centres. Crystals are triclinic, space group P, a≈8.8, b≈9.4, c≈13.3 Å, α≈100, β≈92, γ≈115°. Recrystallization of the iodide complex from pyridine (py) yielded a novel dimer consisting of [{AgI(py)0.5[P(C6H11)]3]}2] units in which the silver and phosphorus atoms are folded around the I ⋯ I vector and towards a bridging pyridine ligand in a ‘crevice’ co-ordination mode. Recrystallization of the iodide from substituted pyridine bases did not yield further examples of such complexes but rather crystals of an unsolvated ‘cubane’ tetramer, [{AgI[P(C6H11)3]}4]. The far-IR spectra of the complexes exhibit bands due to v(AgX) vibrational modes at 225, 143 cm–1 for X = Cl, 189, 167, 135, 114 cm–1 for X = Br, 113, 83 cm–1 for X = I and at 115, 90 cm–1 for [{AgI(py)0.5[P(C6H11)3]}2]. These spectra are interpreted in terms of idealized C2h Ag(µ-X)2Ag and Td Ag4I4 structures of the silver halide cores. The separation between the bands in the spectra of the dimeric species is a sensitive function of the extent of distortion of the cores from D2h symmetry. The solid-state CP MAS 31P NMR spectra of the dimers exhibit simple doublets with average 1J(P–Ag) coupling constants of 648 Hz for [{AgCl[P(C6H11)3]}2], 612 Hz for [{AgBr[P(C6H11)3]}2] and 552 Hz for [{AgI(py)0.5[P(C6H11)3]}2]. Solution 31P NMR spectra of the chloride and bromide complexes show well resolved sets of doublets due to 1J(P–107,109Ag) coupling at 25 and 0 °C respectively with average 1J(P–Ag) coupling constants of 642 and 627 Hz. The solution spectra of both the tetrameric and crevice iodide complexes are similar, showing broad signals at room temperature and doublets at –60 °C [δ 12, 1J(P–Ag)= 544 Hz]. These structural and spectroscopic results are compared with those for other 1 : 1 AgX : phosphine complexes.

SOLID-STATE NMR STUDIES AND CRYSTAL STRUCTURE OF THE LAWESSON-REAGENT

Abstract X-ray diffraction of the toluene solvate of the Lawesson reagent, C14H14O2P2S4.C7H3, gives the following crystal data: triclinic, PT (no. 2). a = 6.831 (2), b = 9.393 (3), c = 9.793 (3) A, α = 70.33 (2), β = 83.28 (2). γ = 71.35 (2)°, V = 560.6 A3, Z = 1, and D2 = 1.471 Mg m−3. The bond lengths and angles are very close to those observed in the solvent-free crystals. The toluene molecule is disordered over two positions related by an inversion center. The asymmetric unit consists of half the formula unit. This is consistent with the fact that the solid-state 31P CP MAS NMR spectrum gives one set of principal values of the nuclear magnetic shielding tensor. Similar values were obtained for solvates of other aromatic compounds such as benzene, o-dichlorobenzene, methoxybenzene and p-dimethoxybenzene. A comparison with the data for the solvent-free Lawesson reagent shows that the nuclear shielding depends not only on the molecular structure but can also be influenced by short intermolecular S==S dis...

Separating subspectra from cross-polarization magic-angle spinning nuclear magnetic resonance spectra by proton spin relaxation editing

Differences in proton spin relaxation time constants can be exploited to edit cross-polarization magic-angle spinning nuclear magnetic resonance (CP-MAS NMR) spectra of heterogeneous mixtures of different types of organic matter. This paper describes an extension of the editing procedure from two-component to three-component mixtures. Clean separation of 13C NMR subspectra was achieved for three synthetic polymers mixed as powders. Applying the procedure to both 13C and 31P CP-MAS NMR spectra of solid dairy pond sludge provided clues to the location of the phosphorus relative to different types of organic matter, and provided estimates of the proportions of organic matter in categories labeled “plant fragments”, “partly degraded residues” and “recalcitrant structures”. The editing procedure increased noise levels by factors between 2 and 11 in these worked examples, depending on the degree of difficulty involved in distinguishing differences in proton spin relaxation time constants.

The solid state structure of the cation bis[1,3-dioxane-2-ylmethyl) diphenylphosphine- P; O′, P′]-(pentamethylcyclopentadienyl) ruthenium(II)

Cationic, monochelated bis[(1,3-dioxane-2-ylmethyl)diphenylphosphine- P; O′, P′](pentamethylcyclopentadienyl)ruthenium(II) ( 2) was obtained by chloride abstraction from Cp ∗RuCl(P ∼ O) 2 ( 1) with NaBPh 4. 31P CP MAS NMR investigations together with an X-ray crystal structure analysis of 2 were carried out to determine the diastereomeric composition of the complex in the solid state. These results are compared with the spectroscopic data of 2 in solution. 2 crystallizes in the monoclinic space group P2 1/ c with Z = 4. The cell dimensions are: a = 1387(2), b = 2235(2), c = 1836(2) pm, β = 100.8(1)°, R 1 = 0.093 and wR 2 = 0.229.

Studies of the sorption of triethyl phosphate by ion-exchanged smectite clays

The binding of triethyl phosphate (TEP) to smectites containing Bu4N+, Mg2+ or Al3+ as the counter-ion has been studied. Solid-state 31P and 13C CPMAS and SPE-MAS NMR were used to observe both mobile and motion-restricted phases. Magnesium complexes of TEP and dimethylmethyl phosphonate (DMMP) have been prepared and used as models for the complexes formed in the clay matrix. These compounds were also investigated by solid-state 31P NMR and FTIR spectroscopies. TG, XRD and FTIR spectroscopy have also been used to study the sorbed TEP species. A number of sorption sites have been detected; one important mechanism of sorption involves coordination to the interlamellar cation.

Structural and solid-state 31P nuclear magnetic resonance studies on 1 : 1 : 1 mixed nitrogen and phosphine base complexes with copper(I) halides

1 : 1 : 1 Adducts of copper(I) halides with phosphine and amine donor ligands, [{CuX[PPh2(C6H4Me-o)](cpy)}2] and [{CuX(PPh3)(pip)}2](cpy = 4-cyanopyridine, pip = piperidine; X = Cl, Br or I) have been synthesized as crystalline dihalide-bridged binuclear complexes and characterized by single-crystal structure determinations and solid-state 31P cross-polarization magic angle spinning (CPMAS) NMR spectroscopy. The [{CuX[PPh2(C6H4Me-o)](cpy)}2] complexes are isomorphous with their PPh3 analogues, crystallizing as centrosymmetric dimers in space group P21/n with a≈ 15.5, b≈ 8.0, c≈ 18.7 Å, β≈ 104°(Z= 2 dimers). Introduction of the o-tolyl group into the phosphine ligand increases all of the Cu–p, Cu–N and Cu–X bond distances by 1–2% with the increase in Cu–X accommodated primarily by an increase in the Cu ⋯ Cu distances by 2–6%. For [{CuX(PPh3)(pip)}2] the chloride and bromide complexes are isomorphous, crystallizing in space group Pbca with a≈ 16.5, b≈ 18.0, c≈ 14.6 Å(Z= 4 dimers). The monomer/asymmetric units are disposed close to a centre of symmetry but the two Cu–X distances at each copper site differ by over 0.3 Å and the resultant ‘dimers’ are better described as associated monomers with three- rather than four-co-ordinate copper. The iodide complex crystallizes in space group P, with a= 17.442(9), b= 16.532(6), c= 13.801(3)Å, α= 92.78(2), β= 112.08(3), γ= 112.65(3)°(Z= 3 dimers). The unit cell contains independent centro- and non-centro-symmetric dimers with significant differences in the geometric parameters of the two. Differences in the Cu–X distances are much smaller than for the X = Cl and Br complexes. The piperidine ligand co-ordinates through the nitrogen lone pair with the Cu–N bond approximately perpendicular to the Cu2X2 plane and is disposed away from the Cu2X2 plane and towards the phosphine ligand for all dimers except the centrosymmetric iodide dimer. The Cu ⋯ Cu distances are 7–11% longer than those of the corresponding pyridine base complexes, but are shorter than those in complexes with acetonitrile as the base. The solid-state 31P CP MAS NMR spectra of the complexes at B= 9.4 T show well resolved asymmetric quartets arising from a combination of scalar and dipolar coupling between the quadrupolar spin 3/2; copper and the spin ½ phosphorus nuclei. The structural and spectroscopic data are discussed in relation to steric and electronic properties of the donor ligands and the influence of these on the size and shape of the Cu2X2 core.

High-resolution NMR studies of (diphosphine)(diene) rhodium complexes in the solid state

Well-resolved resonances are observed in the 31P-CPMAS NMR spectra of (2S,4S)-2,4-bis(diphenylphosphino)pentane or ( S, S)-BDPP ( 1) and its cationic complexes [(Rh{( S, S)-BDPP}(NBD)]BF 4 ( 2a), [Rh{( S, S)-BDPP}(NBD)]PF 6 ( 2b), [Rh{( S, S)-BDPP}(NBD)]ClO 4 ( 2c) and [Rh{( S, S)-BDPP}(COD)]BF 4 ( 3). Packing forces split the single resonance observed for these systems in solution. The spectral parameters depend remarkably on the counterion in 2a, 2b, and 2c. Complex 3 showed a splitting of every resonance due to the presence of two independent molecules in the unit cell. The complex [Rh{( S, S)-BDPP}(NBD)Cl] ( 4) showed two broad 31P resonances which are ascribed to a number of closely related structures based on the expected trigonal bipyramidal geometry.

Diphenylphosphin-substituiertes, chirales Polyepichlorhydrin, ein Träger für die heterogene, asymmetrische Katalyse / Diphenylphosphine-Substituted, Chiral Polyepichlorohydrin, a Support for the Heterogeneous, Asymmetric Catalysis

Chiral polyepichlorohydrin was obtained as a crystalline, optically active powder by coordinative polymerization of S(+)-epichlorohydrin. Subsequent reaction with lithium diphenylphosphide in THF resulted in substitution of about 90% of the chlorine atoms by the P(C6H5)2 group to give an insoluble polymer, which was characterized by elemental analysis, 31P CP MAS NMR, and IR spectroscopy. On addition of solutions of bis(1.5-cyclooctadiene)-rhodium tetrafluoroborate to the polymer “heterogenization” of the complex occurred. The reason for the as yet short operational life time during the hydrogenation of α-acetamido cinnamic acid is the leaching of the metal complex moiety. The rhodium atom is coordinated to only one phosphorus atom of the polymer in the side group and rather weakly to one oxygen atom of the polymer chain.