Solid state 31P NMR spectroscopic studies of tertiary phosphines and their complexes (original) (raw)
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Inorganic Chemistry, 1991
High-resolution, solid-state ,IP NMR spectra of PPhJ and its oxide, sulfide, and selenide and PCy3 and its oxide, sulfide, and selenide are presented and interpreted in terms of reported space group information from X-ray crystallographic studies. The spectra of Ph2PCH2CHzPPh2 and Ph2PCH2PPh2 are similarly described. In order to fully interpret the NMR spectra, the X-ray crystal structures of PCy, (l), OPC 3 (2). and SePCy3 (3) were determined. Data are as follows: 1, fw = 280.44, trigonal, P31, u = 9.893 (2) A, c = 15.446 (3) K, V = 1309.2 A3, 2 = 3,Da = 1.07 g cmq3, X(Mo Kal) = 0.70930 A, p = 1.4 cm-l, F(o00) = 468, T = 294 (I) K, R = 0.045 for 1092 unique reflections with P > 3u(P); 2, fw = 296.44, triclinic, Pi, u = 9.799 (4) A, b = 16.402 (6) A, c = 17.067 (6) A, a = 101.30 (3)O, B = 90.39 (3)O, y = 99.86 (3)O, V = 2647.8 A', Z = 6, Da = 1.23 g 6111-3, h(Mo Ka) = 0.71073 A, p = 1.6 cm-l, F(OO0) = 1086, T = 294 (I) K, R = 0.051 for 4939 unique reflections with P > 3u(P); 3, fw = 359.40, orthorhombic, Pnmcl, u = 11.1 10 (1) A, b = 15.803 (2) A, c = 10.364 (1) A, V = 1819.6 A3, Z = 4, 0, = 1.31 g cm-), X(Mo Kn) 0.71073 A, p = 21.2 cm-I, F(OO0) = 760, T = 294 (I) K, R = 0.034 for 1308 unique reflections with P > 3u(P). 'All solution 'IP('H] NMR data were measured in CDC13 at room temperature and referenced to external 85% HIPOI. b1J(31P,77Se) = 728 Hz. r1J(31P,"Se) = 737 Hz. dlJ(31P,77Se) = 673 Hz. 'IJ-(31P,' 7Se) = 684 Hz. f2J(31P,31P) = 210 Hz. of the important results. Considering CP/MAS ,IP NMR and high-resolution solution 31P or 31P[1H) NMR methods as repre-(2) Fyfe. C. A.
High resolution 31P solid state NMR in phosphorus-transition metal compounds
Materials Chemistry and Physics, 1991
The use of a high resolution solid state 31P NMR technique to investigate the coordination of phopshorus ligands bound to transition metal atoms is reviewed using examples which include information on molecular structure and crystallographic sites in organometallic solids, and characterization of supported transition metal complexes on surfaces. Moreover 31P CPMAS (cross polarization magic angle spinning) experiments can afford a wealth of information such as chemical shift anisotropy, isotropic coupling constants with quadrupolar nuclei and quadrupole coupling constants that are often obscured in solution state due to the rapid isotropic motion of the molecules.
Solid-state 31P NMR vs. solution study of bis(tertiary phosphines)
Solid State Nuclear Magnetic Resonance, 1993
Solid-state 31P and 13C CP/MAS results of several diphosphines are compared with solution phase data. Non-equivalence of the P atoms are observed in the solid state for the less flexible derivatives (including all chiral diphosphines studied), whereas the more flexible compounds with a linear alkyl chain such as the 1,2-ethane and the 1,Cbutane derivatives give only rise to a single resonance. For the more strained bis(diphenylphosphino)methane contradictory data have been reported. Our experiments confirm the existence of an AB spin system, i.e., two different P atoms in solid state. Substantial chemical shift difference between P atoms have been observed in the solid state but not in solution of the chiral compounds. A possible explanation is suggested in terms of the concerted anisotropic effect of the phenyl rings attached to the phosphorus atom.
Practical Interpretation of P‐31 NMR Spectra and Computer Assisted Structure Verification
2006
Organophosphorus chemistry is of increasing importance as a field that can provide new compounds with practical value in agriculture, medicine, catalysis, etc. Furthermore, natural phosphorus compounds are well recognized to play vital roles in living systems. Chemists and biochemists working with these compounds are very fortunate to be dealing with a central atom that has outstanding properties for nuclear magnetic resonance spectral characterization. The 31P isotope is 100% naturally abundant, and has a spin quantum number of 1/2. It is a simple matter to record a 31P NMR spectrum with modern spectrometers, and many thousands of phosphorus compounds have been characterized by their chemical shifts. Indeed, a great majority of the research papers now being published on phosphorus compounds include 31P NMR shift data. The 31P shift is not just a physical constant like a melting point, however; it is a definite statement about the bonding at phosphorus and the nature of the groups attached to this nucleus. Anyone reporting 31P chemical shifts should rationalize the data with the structure at phosphorus and avoid assignment errors, and they should be observant about any unusual effects that might be operating on the shielding phenomenon. This book is designed to aid the researcher, especially students or newcomers to the field, in these tasks, and to help in developing an understanding of the factors that lead to a certain shift. Chemists no longer find themselves isolated to the bench. Modern chemists more frequently find themselves in front of a computer screen performing online searches, computer-based structure design, processing and analyzing their analytical data or compiling their research into an appropriate report or publication. Software tools which were once only the domain of a specialist are now available to the masses. Content databases and, in relation to this text, NMR prediction tools are starting to play a more influential role in the structural verification and elucidation processes of the chemist. While the existing literature contains many fine reviews on 31P NMR, an introductory yet comprehensive survey of the chemical shift effects for the various functional groups, written in an instructional mode, is not available. In this text one of us applies our through knowledge of phosphorus chemistry to provide a through grounding for the chemist in the NMR properties of the nucleus (Chapters 1 to 15, LQ). Coupling this capability with a review and validation of the value of software tools to aid in the interpretation of 31P NMR (Chapter 16, AW), we hope that this book will fulfill this need.
Inorganic Chemistry, 1997
The molecular structure of (5-methyldibenzophosphole)pentacarbonylmolybdenum(0), 1, has been determined by X-ray crystallography. The crystal is monoclinic C2/c, Z ) 8, with unit cell dimensions of: a ) 31.113(2) Å, b )7.7917(5) Å, c ) 17.9522(12) Å, and ) 122.135(4)°. Least-squares refinement converged to R(F) ) 0.0245 for 2407 independent reflections. The molecular structure is typical of phosphine-substituted metal carbonyls. It contains an approximate mirror plane which bisects the dibenzophosphole framework. Phosphorus-31 NMR spectra of powder and single-crystal samples of 1 have been obtained with cross-polarization and 1 H high-power decoupling. The 31 P CP/MAS NMR spectra exhibit exceptionally well-resolved satellites due to spin-spin coupling interactions with 95,97 Mo (I ) 5 / 2 ). Using first-order perturbation theory, the multiplets have been analyzed to yield 1 J( 95,97 Mo, 31 P) ) 123(2) Hz and estimates of the molybdenum nuclear quadrupolar coupling constants, ( 95 Mo) ) -0.87 MHz and ( 97 Mo) ) 10.1 MHz. Phosphorus-31 NMR spectra of a large single crystal of 1 have been investigated as a function of orientation about three orthogonal axes in the applied magnetic field. Analysis of the data yields the three principal components of the phosphorus chemical shift tensor, δ 11 ) 112 ppm, δ 22 ) -23 ppm, and δ 33 ) -40 ppm; δ 22 lies close to the Mo-P bond (8°), while δ 11 lies in the approximate mirror plane. The phosphorus chemical shift tensor determined for 1 is compared with the limited anisotropic phosphorus shift data available in the literature.
Inorganic Chemistry, 1992
The synthesis and characterization of a new platinum(1) phosphine complex, [Pt,(p-dppm)(q'-dppm)dppeCl]Cl, is reported. This unique complex is the fmt example of a stable Pt(1) dimer in which all three types of coordination possible for a diphosphine ligand are observed. To structurally characterize this complex, we have employed one-and two-dimensional 31P NMR spectroscopy. Using 14 other structurally simpler platinum phosphine complexes, it is established that the 31P homonuclear shift correlated spectroscopy (COSY) technique provides valuable information about both the phosphorus-phosphorus and platinum-phosphorus couplings, especially when the rtSOnanceS in the onedimensional spectra are poorly resolved. The ,JRP and 3JR-p coupling constants are obtained from the relative positions of the observed cross-correlations with respect to the main phosphorus resonances. From the analysis of the coupling patterns observed and the coupling constants measured from the two-dimensional data sets, determination of the geometrical arrangement of the phosphine ligands is demonstrated. The structural assignment of the new Pt complex is based on the analysis of its ,IP COSY map and further supported by the COSY studies of the other platinum complexes.
Annals of The New York Academy of Sciences, 1980
Because of the complicated (and sometimes unusual) nature of these polyphosphinc ligands, a glossary of formulae and corresponding abbreviations is given here for reference: ttp = PhP(CHzCH2CHzPPhz)z ; Cyttp = PhP(CHzCHzCHzPCyz)z ; PPH = PhzPCHzCHzCHzP(Ph)H; dmetp = PhP(CHZCHzPMe,), ; eptp = PhzPCHzCHzP(Ph)CH2CHzCHzPPh2 ; tripod = CH3C(CHZPPhz), ; ppol= PhzPCHzCHzCHzP(Ph)CHzCH2CHECHz ; PP, = P(CHzCH,PPhz)3 ; etp = PhP(CH,CHzPPh,)z ; dppp = PhzPCH,CHzCHzPPhz ; d p p = PhZPCHzCH,PPh,.