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Sutter K, Autschbach J. Computational study and molecular orbital analysis of NMR shielding, spin-spin coupling, and electric field gradients of azido platinum complexes. J Am Chem Soc 2012; 134:13374-85. [PMID: 22794134 DOI: 10.1021/ja3040762] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
(195)Pt, (14)N, and (15)N NMR data for five azido (N(3)(-)) complexes are studied using relativistic density functional theory (DFT). Good agreement with experiment is obtained for Pt and N chemical shifts as well as Pt-N J-coupling constants. Calculated (14)N electric field gradients (EFGs) reflect experimentally observed trends for the line broadening of azido (14)N NMR signals. A localized molecular orbital analysis of the nitrogen EFGs and chemical shifts is performed to explain some interesting trends seen experimentally and in the first-principles calculations: (i) (14)N NMR signals for the Pt-coordinating (N(α)) nuclei in the azido ligands are much broader than for the central (N(β)) or terminal (N(γ)) atoms. The N(β) signals are particularly narrow; (ii) compared to N(γ), the N(α) nuclei are particularly strongly shielded; (iii) N(β) nuclei have much larger chemical shifts than N(α) and N(γ) ; and (iv) The Pt-N(α) J-coupling constants are small in magnitude when considering the formal sp hybridization of N(α). It is found that for N(α) a significant shielding reduction due to formation of the dative N(α)-Pt bond is counterbalanced by an increased shielding from spin-orbit (SO) coupling originating at Pt. Upon coordination, the strongly delocalized π system of free azide localizes somewhat on N(β) and N(γ). This effect, along with rehybridization at N(α) upon bond formation with Pt, is shown to cause a deshielding of N(γ) relative to N(α) and a strong increase of the EFG at N(α). The large 2p character of the azide σ bonds is responsible for the particularly high N(β) chemical shifts. The nitrogen s-character of the Pt-N(α) bond is low, which is the reason for the small J-coupling. Similar bonding situations are likely to be found in azide complexes with other transition metals.
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Affiliation(s)
- Kiplangat Sutter
- Department of Chemistry, State University of New York at Buffalo, Buffalo, New York 14260-3000, USA
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52
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Michaelis VK, Markhasin E, Daviso E, Herzfeld J, Griffin RG. Dynamic Nuclear Polarization of Oxygen-17. J Phys Chem Lett 2012; 3:2030-2034. [PMID: 23024834 PMCID: PMC3459188 DOI: 10.1021/jz300742w] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Oxygen-17 detected DNP NMR of a water/glycerol glass enabled an 80-fold enhancement of signal intensities at 82 K, using the biradical TOTAPOL. The >6,000-fold savings in acquisition time enables (17)O-(1)H distance measurements and heteronuclear correlation experiments. These experiments are the initial demonstration of the feasibility of DNP NMR on quadrupolar (17)O.
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Affiliation(s)
- Vladimir K Michaelis
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA, 02139
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53
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Bonhomme C, Gervais C, Folliet N, Pourpoint F, Coelho Diogo C, Lao J, Jallot E, Lacroix J, Nedelec JM, Iuga D, Hanna JV, Smith ME, Xiang Y, Du J, Laurencin D. 87Sr Solid-State NMR as a Structurally Sensitive Tool for the Investigation of Materials: Antiosteoporotic Pharmaceuticals and Bioactive Glasses. J Am Chem Soc 2012; 134:12611-28. [DOI: 10.1021/ja303505g] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Christian Bonhomme
- Laboratoire Chimie de la Matière
Condensée de Paris, UMR CNRS 7574, UPMC Université Paris 06, Collège de France, 11 place Marcelin
Berthelot, 75231 Paris Cedex 05, France
| | - Christel Gervais
- Laboratoire Chimie de la Matière
Condensée de Paris, UMR CNRS 7574, UPMC Université Paris 06, Collège de France, 11 place Marcelin
Berthelot, 75231 Paris Cedex 05, France
| | - Nicolas Folliet
- Laboratoire Chimie de la Matière
Condensée de Paris, UMR CNRS 7574, UPMC Université Paris 06, Collège de France, 11 place Marcelin
Berthelot, 75231 Paris Cedex 05, France
| | - Frédérique Pourpoint
- Laboratoire Chimie de la Matière
Condensée de Paris, UMR CNRS 7574, UPMC Université Paris 06, Collège de France, 11 place Marcelin
Berthelot, 75231 Paris Cedex 05, France
| | - Cristina Coelho Diogo
- IMPC, Institut des Matériaux
de Paris Centre, FR2482, UPMC Université Paris 06, Collège de France, 11 place Marcelin Berthelot,
75231 Paris Cedex 05, France
| | - Jonathan Lao
- Clermont Université, Université
Blaise Pascal, CNRS/IN2P3, Laboratoire de Physique
Corpusculaire, BP 10448, 63000 Clermont-Ferrand, France
| | - Edouard Jallot
- Clermont Université, Université
Blaise Pascal, CNRS/IN2P3, Laboratoire de Physique
Corpusculaire, BP 10448, 63000 Clermont-Ferrand, France
| | - Joséphine Lacroix
- Clermont Université, Université
Blaise Pascal, CNRS/IN2P3, Laboratoire de Physique
Corpusculaire, BP 10448, 63000 Clermont-Ferrand, France
| | - Jean-Marie Nedelec
- Clermont Université, ENSCCF, ICCF, BP 10448, F-63000 Clermont-Ferrand, France
- CNRS, UMR
6296, ICCF, F-63177 Aubière
| | - Dinu Iuga
- Department of Physics, University of Warwick, CV4 7AL Coventry, U.K
| | - John V. Hanna
- Department of Physics, University of Warwick, CV4 7AL Coventry, U.K
| | - Mark E. Smith
- Department of Physics, University of Warwick, CV4 7AL Coventry, U.K
- Vice-Chancellor’s Office,
University House, Lancaster University,
LA1 4YW, Lancaster, U.K
| | - Ye Xiang
- Department
of Materials Science and
Engineering, CASCaM, University of North Texas, Denton, Texas 76203, United States
| | - Jincheng Du
- Department
of Materials Science and
Engineering, CASCaM, University of North Texas, Denton, Texas 76203, United States
| | - Danielle Laurencin
- Institut Charles Gerhardt de Montpellier,
UMR 5253, CNRS UM2 UM1 ENSCM, CC 1701 Université de Montpellier 2, Place E. Bataillon, 34095 Montpellier
cedex 5, France
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54
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Perras FA, Widdifield CM, Bryce DL. QUEST-QUadrupolar Exact SofTware: a fast graphical program for the exact simulation of NMR and NQR spectra for quadrupolar nuclei. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2012; 45-46:36-44. [PMID: 22763585 DOI: 10.1016/j.ssnmr.2012.05.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 05/15/2012] [Accepted: 05/16/2012] [Indexed: 05/28/2023]
Abstract
We present a new program for the exact simulation of solid-state NMR spectra of quadrupolar nuclei in stationary powdered samples which employs diagonalization of the combined Zeeman-quadrupolar Hamiltonian. The program, which we call QUEST (QUadrupolar Exact SofTware), can simulate NMR spectra over the full regime of Larmor and quadrupolar frequency ratios, which encompasses scenarios ranging from high-field NMR to nuclear quadrupole resonance (NQR, where the Larmor frequency is zero) and does not make use of approximations when treating the quadrupolar interaction. With the use of the fast powder averaging scheme of Alderman, Solum, and Grant, exact NMR spectral simulations are only marginally slower than the second-order perturbation theory counterpart. The program, which uses a graphical user interface, also incorporates chemical shift anisotropy and non-coincident chemical shift and quadrupolar tensor frames. The program is validated against newly-acquired experimental data through several examples including: the low-field (79/81)Br NMR spectra of CaBr(2), the (14)N overtone NMR spectrum of glycine, the (187)Re NQR spectra of Re(2)(CO)(10), and lastly the (127)I overtone NQR spectrum of SrI(2), which, to the best of our knowledge, represents the first direct acquisition of an overtone NQR spectrum for a powdered sample.
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Affiliation(s)
- Frédéric A Perras
- Department of Chemistry and Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario, Canada
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O’Dell LA, Ratcliffe CI, Kong X, Wu G. Multinuclear Solid-State Nuclear Magnetic Resonance and Density Functional Theory Characterization of Interaction Tensors in Taurine. J Phys Chem A 2012; 116:1008-14. [DOI: 10.1021/jp210844t] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Luke A. O’Dell
- Steacie Institute for Molecular Sciences, National Research Council, 100
Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada
| | - Christopher I. Ratcliffe
- Steacie Institute for Molecular Sciences, National Research Council, 100
Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada
| | - Xianqi Kong
- Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston,
Ontario, K7L 3N6, Canada
| | - Gang Wu
- Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston,
Ontario, K7L 3N6, Canada
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56
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57
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O'Dell LA. Direct detection of nitrogen-14 in solid-state NMR spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2011; 59:295-318. [PMID: 22027340 DOI: 10.1016/j.pnmrs.2011.04.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 04/07/2011] [Indexed: 05/31/2023]
Affiliation(s)
- Luke A O'Dell
- Steacie Institute for Molecular Sciences, National Research Council, 100 Sussex Drive, Ottawa, Ontario, Canada K1N 5A2.
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58
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Penner GH, Webber R, O’Dell LA. A multinuclear NMR and quantum chemical study of solid trimethylammonium chloride. CAN J CHEM 2011. [DOI: 10.1139/v11-034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The solid salt, trimethylammonium chloride (TMAC), is investigated by a combination of NMR spectroscopic techniques and quantum chemical calculations. Chemical shift and nuclear quadrupolar interaction parameters have been measured for 35Cl, 1H/2H, and 15N/14N. These parameters have also been calculated as a function of the hydrogen position in the N···H···Cl fragment. Overall, the measured parameters are consistent with a structure in which the hydrogen is completely transferred to the nitrogen (i.e., N–H···Cl). The high hydrogen chemical shift (10.9 ppm by 2H CP/MAS) and relatively small deuterium quadrupolar coupling constant (127 kHz) indicate a moderately strong N–H···Cl hydrogen bond. A pronounced deuterium isotope effect on the 35Cl quadrupolar coupling constant is observed.
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Affiliation(s)
- Glenn H. Penner
- Department of Chemistry, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Renee Webber
- Department of Chemistry, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Luke A. O’Dell
- Steacie Institute for Molecular Sciences, National Research Council, 100 Sussex Drive, Ottawa, ON K1A 0R6, Canada
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60
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Jakobsen HJ, Bildsøe H, Gan Z, Brey WW. Experimental aspects in acquisition of wide bandwidth solid-state MAS NMR spectra of low-γ nuclei with different opportunities on two commercial NMR spectrometers. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 211:195-206. [PMID: 21704544 DOI: 10.1016/j.jmr.2011.05.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 05/25/2011] [Accepted: 05/26/2011] [Indexed: 05/31/2023]
Abstract
The acquisition and different appearances observed for wide bandwidth solid-state MAS NMR spectra of low-γ nuclei, using (14)N as an illustrative nucleus and employing two different commercial spectrometers (Varian, 14.1T and Bruker, 19.6T), have been compared/evaluated and optimized from an experimental NMR and an electronic engineering point of view, to account for the huge differences in these spectra. The large differences in their spectral appearances, employing the recommended/standard experimental set-up for the two different spectrometers, are shown to be associated with quite large differences in the electronic design of the two types of preamplifiers, which are connected to their respective probes through a 50Ω cable, and are here completely accounted for. This has led to different opportunities for optimum performances in the acquisition of nearly ideal wide bandwidth spectra for low-γ nuclei on the two spectrometers by careful evaluation of the length for the 50Ω probe-to-preamp cable for the Varian system and appropriate changes to the bandwidth (Q) of the NMR probe used on the Bruker spectrometer. Earlier, we reported quite distorted spectra obtained with Varian Unity INOVA spectrometers (at 11.4 and 14.1T) in several exploratory wide bandwidth (14)N MAS NMR studies of inorganic nitrates and amino acids. These spectra have now been compared/evaluated with fully analyzed (14)N MAS spectra correspondingly acquired at 19.6T on a Bruker spectrometer. It is shown that our upgraded version of the STARS simulation/iterative-fitting software is capable of providing identical sets for the molecular spectral parameters and corresponding fits to the experimental spectra, which fully agree with the electronic measurements, despite the highly different appearances for the MAS NMR spectra acquired on the Varian and Bruker spectrometers.
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Affiliation(s)
- Hans J Jakobsen
- Instrument Centre for Solid-State NMR Spectroscopy and Interdisciplinary Nanoscience Center (iNANO), Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.
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61
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Lucier BE, Reidel AR, Schurko RW. Multinuclear solid-state NMR of square-planar platinum complexes — Cisplatin and related systems. CAN J CHEM 2011. [DOI: 10.1139/v11-033] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Multinuclear solid-state nuclear magnetic resonance (SSNMR) experiments have been performed on cisplatin and four related square-planar compounds. The wideband uniform rate smooth truncation – Carr–Purcell–Meiboom–Gill (WURST–CPMG) pulse sequence was utilized in NMR experiments to acquire 195Pt, 14N, and 35Cl ultra-wideline NMR spectra of high quality. Standard Hahn-echo and magic-angle spinning 195Pt NMR experiments are also performed to refine extracted chemical shielding (CS) tensor parameters. Platinum magnetic shielding (MS) tensor orientations are calculated using both plane-wave density functional theory (DFT) and standard DFT methods. The tensor orientations are shown to be highly constrained by molecular symmetry elements, but also influenced to some degree by intermolecular interactions. 14N WURST–CPMG experiments were performed on three compounds and electric field gradient (EFG) parameters (the quadrupolar coupling constant, CQ, and the asymmetry parameter, ηQ) are reported. First principles calculations of the 14N EFG tensor parameters and orientations and affirm their dependence on the local hydrogen bonding environment. 35Cl WURST–CPMG experiments on cisplatin and transplatin are reported, using two different static magnetic fields to extract EFG and CS tensor parameters, and 35Cl EFG tensor magnitudes and orientations are predicted using first principles calculations. Transverse (T2) relaxation data for all nuclei are used to investigate heteronuclear dipolar relaxation mechanisms, as well as the nature of the local hydrogen bonding environments.
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Affiliation(s)
- Bryan E.G. Lucier
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - Alex R. Reidel
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - Robert W. Schurko
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
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