Ab initio calculation of NMR shielding in phosphaalkenes X—PCY2

Rozhenko, Alexander; Schoeller, Wolfgang W.; Povolotskii, M. I.

doi:10.1002/(sici)1097-458x(199908)37:8<551::aid-mrc503>3.0.co;2-3

Cited by 21 publications

(30 citation statements)

References 63 publications

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“…Table 5 shows the bond lengths and bond angles around the PdC core calculated with several methods and the 6-311++G** basis set for the series XPdC(CH 3 ) 2 (X ) H, F, Cl, Br, and OH). The Hartree-Fock data are from Rozhenko et al, 43 and the other data are from a The HF data are from reference 43; the other data are from this work. b C 1 and C 2 are trans and cis to X, respectively.…”

Section: Resultsmentioning

confidence: 99%

Theoretical Study of the Tautomerism, Structures, and Vibrational Frequencies of the Phosphaalkenes XP═C(CH₃)₂(X = H, F, Cl, Br, OH, Ar_F(Ar_F= 2,6-(CF₃)₂C₆H₃))

Watts

Huang

2009

J. Phys. Chem. A

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Ab initio theoretical calculations have been used to study the influence of phosphorus substituents, Y, on the tautomerism between the vinylphosphine XP(H)C(CH(3))=CH(2) and the phosphaalkene XP=C(CH(3))(2) (X = H, F, Cl, Br, OH, and Ar(F); Ar(F) = 2,6-(CF(3))(2)C(6)H(3)) and on the acidity of the aforementioned vinylphosphine. The stabilization of the phosphaalkene and the increased acidity of the vinylphosphine by Ar(F) are possible factors in the successful synthesis of certain isolable phosphaalkenes. In this work, the properties of Ar(F) are assessed theoretically. Density functional theory using the B3LYP functional has been used for all substituents. In addition, coupled-cluster singles and doubles with noniterative triples (CCSD(T)) has been used for X = H, F, Cl, Br, and OH. The phosphaalkene is favored over the vinylphosphine for all substituents, with F having the strongest stabilizing effect. Cl, Br, and OH have stronger stabilizing effects than Ar(F). In contrast, the most acidic vinylphosphine is that with Ar(F). To aid in the interpretation and analysis of future experimental work, CCSD(T) calculations were used to provide structures and vibrational frequencies for the series XP=C(CH(3))(2) (X = H, F, Cl, Br). The influence of the substituent on geometries and C=P and X-P stretching frequencies was examined, and comparisons were made with the CH(2)=PX series.

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Section: Resultsmentioning

confidence: 99%

Theoretical Study of the Tautomerism, Structures, and Vibrational Frequencies of the Phosphaalkenes XP═C(CH₃)₂(X = H, F, Cl, Br, OH, Ar_F(Ar_F= 2,6-(CF₃)₂C₆H₃))

Watts

Huang

2009

J. Phys. Chem. A

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“…Nevertheless, the available data attract considerable interest, taking into account exceptionally broad range of variation of phosphorus chemical shifts (up to 500 ppm) and important structural information that could be obtained therefrom. Analysis of various factors affecting the accuracy of calculation of δ P values for organophosphorus compounds was performed only in some recent studies [9][10][11]; in particular, comparison of different electron density functionals, basis sets, and methods for consideration of gauge invariance.In the present work we estimated the accuracy in the calculation of 31 P shielding constants (chemical shifts), depending on the calculation method (level of theory) and basis set (primarily its size and flexibility) for effective and appropriate use of these parameters in stereochemical studies on organophosphorus compounds. As subjects for study we selected nine simplest organophosphorus compounds of different natures: phosphines R 3 P (I-III), phosphine oxides R 3 P=O (IV-VI), and phosphine sulfides R 3 P=S (VII-IX) containing methyl, ethyl, and methoxy groups on the phosphorus (I, IV, VII, R = Me; II, V, VIII, R = Et; III, VI, IX, R = MeO).…”

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Quantum-chemical calculations of NMR chemical shifts of organic molecules: I. Phosphines, phosphine oxides, and phosphine sulfides

Chernyshev

Krivdin

2010

Russ J Org Chem

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The accuracy in the calculation of 31 P NMR chemical shifts in the series of the simplest phosphines, phosphine oxides, and phosphine sulfides was estimated in terms of the Hartree-Fock self-consistent final perturbation theory and density functional theory with different basis sets. The best agreement between the calculated and experimental data was achieved at the DFT/B3LYP/IGLO-III level of theory.NMR spectroscopy is one of the most important experimental tools for studying steric and electronic structures of molecules. In this connection, development of theoretical methods for the calculation of NMR parameters, in particular chemical shifts, becomes significant. Such methods could provide invaluable help both in assignment of signals in the spectra of complex organic molecules and determination of their structure and in conformational analysis, configurational assignment, studying intra-and intermolecular interactions, and prediction of the reactivity of organic compounds [1,2]. The present communication opens a new series of our theoretical works on the calculation of NMR shielding constants (chemical shifts) of nuclei in organic molecules at a high level of modern quantum chemistry.At present, most studies concerned with calculations of magnetic shielding constants make use of approaches based on the density functional theory (DFT) which ensures fairly good results for 1 H, 13 C, and 15 N chemical shifts of natural compounds [3, 4] and organometallic complexes [5,6]. These results are very useful for studying tautomeric equilibria and proving formation of intramolecular hydrogen bonds [7,8]. On the other hand, calculations on shielding constants of nuclei belonging to the third and higher Periods of the Periodic Table, e.g., 31 P, were reported in a few publications. Nevertheless, the available data attract considerable interest, taking into account exceptionally broad range of variation of phosphorus chemical shifts (up to 500 ppm) and important structural information that could be obtained therefrom. Analysis of various factors affecting the accuracy of calculation of δ P values for organophosphorus compounds was performed only in some recent studies [9][10][11]; in particular, comparison of different electron density functionals, basis sets, and methods for consideration of gauge invariance.In the present work we estimated the accuracy in the calculation of 31 P shielding constants (chemical shifts), depending on the calculation method (level of theory) and basis set (primarily its size and flexibility) for effective and appropriate use of these parameters in stereochemical studies on organophosphorus compounds. As subjects for study we selected nine simplest organophosphorus compounds of different natures: phosphines R 3 P (I-III), phosphine oxides R 3 P=O (IV-VI), and phosphine sulfides R 3 P=S (VII-IX) containing methyl, ethyl, and methoxy groups on the phosphorus (I, IV, VII, R = Me; II, V, VIII, R = Et; III, VI, IX, R = MeO).All calculations of 31 P chemical shifts were performed for the most favora...

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“…Also, the 31 P nuclear magnetic shielding constants and chemical shifts have been obtained in different molecules. 17,[22][23][24][25][26] Recent findings indicate that our understanding of methods and basis sets is incomplete. The advantages of computational studies in many fields of chemistry showed that the optimal calculation is the most important, and choosing the methods and basis sets is an essential step in computational studies.…”

Section: Introductionmentioning

confidence: 99%

Prediction of ³¹P-NMR Chemical Shifts Using Empirical Models with Modest Methods and Optimally Selected Basis Sets

Tafazzoli

Ebrahimi

2011

Phosphorus, Sulfur, and Silicon and the Related Elements

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The performance of the ab initio and density functional theory (DFT) functional, B3LYP and PBEPBE, in conjunction with selected basis sets for the prediction of 31 P shielding constants for small phosphorous-containing molecules is assessed. The effects of applied factors are discussed. By including the electron correlation treatment, B3LYP and PBEPBE are the most accurate methods to compute the chemical shielding for a set of small phosphines that was studied. Also, additional improvements of DFT were obtained by empirical scaling of basis sets in calculation of chemical shifts. For molecules containing only phosphorous and carbon atoms with sp 3 hybridization, the PBEPBE/6-311G(d,p) level of theory has been shown to provide reliable 31 P chemical shifts.

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Ab initio calculation of NMR shielding in phosphaalkenes X—PCY2

Cited by 21 publications

References 63 publications

Theoretical Study of the Tautomerism, Structures, and Vibrational Frequencies of the Phosphaalkenes XP═C(CH₃)₂(X = H, F, Cl, Br, OH, Ar_F(Ar_F= 2,6-(CF₃)₂C₆H₃))

Theoretical Study of the Tautomerism, Structures, and Vibrational Frequencies of the Phosphaalkenes XP═C(CH₃)₂(X = H, F, Cl, Br, OH, Ar_F(Ar_F= 2,6-(CF₃)₂C₆H₃))

Quantum-chemical calculations of NMR chemical shifts of organic molecules: I. Phosphines, phosphine oxides, and phosphine sulfides

Prediction of ³¹P-NMR Chemical Shifts Using Empirical Models with Modest Methods and Optimally Selected Basis Sets

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Ab initio calculation of NMR shielding in phosphaalkenes X—PCY2

Cited by 21 publications

References 63 publications

Theoretical Study of the Tautomerism, Structures, and Vibrational Frequencies of the Phosphaalkenes XP═C(CH3)2(X = H, F, Cl, Br, OH, ArF(ArF= 2,6-(CF3)2C6H3))

Theoretical Study of the Tautomerism, Structures, and Vibrational Frequencies of the Phosphaalkenes XP═C(CH3)2(X = H, F, Cl, Br, OH, ArF(ArF= 2,6-(CF3)2C6H3))

Quantum-chemical calculations of NMR chemical shifts of organic molecules: I. Phosphines, phosphine oxides, and phosphine sulfides

Prediction of 31P-NMR Chemical Shifts Using Empirical Models with Modest Methods and Optimally Selected Basis Sets

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Theoretical Study of the Tautomerism, Structures, and Vibrational Frequencies of the Phosphaalkenes XP═C(CH₃)₂(X = H, F, Cl, Br, OH, Ar_F(Ar_F= 2,6-(CF₃)₂C₆H₃))

Theoretical Study of the Tautomerism, Structures, and Vibrational Frequencies of the Phosphaalkenes XP═C(CH₃)₂(X = H, F, Cl, Br, OH, Ar_F(Ar_F= 2,6-(CF₃)₂C₆H₃))

Prediction of ³¹P-NMR Chemical Shifts Using Empirical Models with Modest Methods and Optimally Selected Basis Sets