Journal ArticleDOI
A study of transition-metal organometallic complexes combining 35Cl solid-state NMR spectroscopy and 35Cl NQR spectroscopy and first-principles DFT calculations.
Karen E. Johnston,Christopher A. O’Keefe,Régis M. Gauvin,Julien Trébosc,Laurent Delevoye,Jean-Paul Amoureux,Nicolas Popoff,Mostafa Taoufik,Konstantin Oudatchin,Robert W. Schurko +9 more
TLDR
The combination of (35)Cl’s solid-state NMR and NQR spectroscopy and DFT calculations is shown to be a promising and simple methodology for the characterization of all manner of chlorine-containing transition-metal complexes, in pure, impure bulk and supported forms.Abstract:
A series of transition-metal organometallic complexes with commonly occurring metal-chlorine bonding motifs were characterized using (35)Cl solid-state NMR (SSNMR) spectroscopy, (35)Cl nuclear quadrupole resonance (NQR) spectroscopy, and first-principles density functional theory (DFT) calculations of NMR interaction tensors. Static (35)Cl ultra-wideline NMR spectra were acquired in a piecewise manner at standard (9.4 T) and high (21.1 T) magnetic field strengths using the WURST-QCPMG pulse sequence. The (35)Cl electric field gradient (EFG) and chemical shielding (CS) tensor parameters were readily extracted from analytical simulations of the spectra; in particular, the quadrupolar parameters are shown to be very sensitive to structural differences, and can easily differentiate between chlorine atoms in bridging and terminal bonding environments. (35)Cl NQR spectra were acquired for many of the complexes, which aided in resolving structurally similar, yet crystallographically distinct and magnetically inequivalent chlorine sites, and with the interpretation and assignment of (35)Cl SSNMR spectra. (35)Cl EFG tensors obtained from first-principles DFT calculations are consistently in good agreement with experiment, highlighting the importance of using a combined approach of theoretical and experimental methods for structural characterization. Finally, a preliminary example of a (35)Cl SSNMR spectrum of a transition-metal species (TiCl4) diluted and supported on non-porous silica is presented. The combination of (35)Cl SSNMR and (35)Cl NQR spectroscopy and DFT calculations is shown to be a promising and simple methodology for the characterization of all manner of chlorine-containing transition-metal complexes, in pure, impure bulk and supported forms.read more
Citations
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Cooperative Effect of Monopodal Silica-Supported Niobium Complex Pairs Enhancing Catalytic Cyclic Carbonate Production.
Valerio D'Elia,Hailin Dong,Aaron J. Rossini,Cory M. Widdifield,Sai V. C. Vummaleti,Yury Minenkov,Albert Poater,Edy Abou-Hamad,Jérémie D. A. Pelletier,Luigi Cavallo,Lyndon Emsley,Lyndon Emsley,Jean-Marie Basset +12 more
TL;DR: With the support of a systematic DFT study carried out on model silica surfaces, the observed differences in catalytic efficiency were correlated with an unprecedented cooperative effect between two neighboring Nb centers on the surface of 2a, in an excellent agreement with previous discoveries regarding the mechanism of NbCl5-catalyzed cycloaddition in the homogeneous phase.
Journal ArticleDOI
New methods and applications in solid-state NMR spectroscopy of quadrupolar nuclei.
Sharon E. Ashbrook,Scott Sneddon +1 more
TL;DR: A brief overview of the quadrupolar interaction is provided, some of the basic experimental approaches used for acquiring high-resolution NMR spectra are described, and the information that these spectra can provide are discussed.
Journal ArticleDOI
Recent NMR developments applied to organic-inorganic materials.
TL;DR: The article is divided in two main parts: in the first one, recent NMR methodological/instrumental developments are presented in connection with hybrid materials, and an exhaustive overview of the major classes of O/I materials and their NMR characterization is presented.
Journal ArticleDOI
35Cl dynamic nuclear polarization solid-state NMR of active pharmaceutical ingredients
TL;DR: A new protocol is reported, called spinning-on spinning-off (SOSO) acquisition, where MAS is applied during part of the polarization delay to increase the DNP enhancements and then the MAS rotation is stopped so that a wideline 35Cl NMR powder pattern free from the effects of spinning sidebands can be acquired under static conditions.
Journal ArticleDOI
Unravelling the Structure of Magnus¿ Pink Salt
Bryan E. G. Lucier,Karen E. Johnston,Wenqian Xu,Jonathan C. Hanson,Sanjaya D. Senanayake,Siyu Yao,Megan W. Bourassa,Monika Srebro,Monika Srebro,Jochen Autschbach,Robert W. Schurko +10 more
TL;DR: High-resolution NMR spectra of select regions of the broad (195)Pt powder patterns, in conjunction with an array of (14)N and (35)Cl spectra, reveal clear structural differences between all compounds, which offers much promise for future investigation and characterization of Pt-containing systems.
References
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