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Biswas R, Chen Y, Vela J, Rossini AJ. Relativistic DFT Calculations of Cadmium and Selenium Solid-State NMR Spectra of CdSe Nanocrystal Surfaces. ACS OMEGA 2023; 8:44362-44371. [PMID: 38027327 PMCID: PMC10666156 DOI: 10.1021/acsomega.3c07680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 10/11/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023]
Abstract
Solid-state NMR spectra have been used to probe the structure of CdSe nanocrystals and propose detailed models of their surface structures. Density functional theory (DFT)-optimized cluster models that represent probable molecular structures of carboxylate-coordinated surface sites have been proposed. However, to the best of our knowledge, 113Cd and 77Se chemical shifts have not been calculated for these surface models. We performed relativistic DFT calculations of cadmium and selenium magnetic shielding tensors on model compounds with previously measured solid-state NMR spectra with (i) the four-component Dirac-Kohn-Sham (DKS) Hamiltonian and (ii) the scalar and (iii) spin-orbit levels within the ZORA Hamiltonian. Molecular clusters with Cd and Se sites in varying bonding environments were used to model CdSe (100) and CdSe(111) surfaces capped with carboxylic acid ligands. Our calculations identify the observed 113Cd isotropic chemical shifts δ(iso) of -465, -318, and -146 ppm arising from CdSeO3, CdSe2O2, and CdSe3O surface groups, respectively, with very good agreement with experimental measurements. The 113Cd chemical shifts linearly decrease with the number of O-neighbors. The calculated spans (δ11 - δ33) encompass the experimental values for CdSe3O and CdSe2O2 clusters but are slightly larger than the measured value for CdSeO3 clusters. Relativistic DFT calculations predicted a one-bond 113Cd-77Se scalar coupling of 258 Hz, which is in good agreement with the experimental values of 250 Hz. With a dense coverage of carboxylic acid ligands, the CdSe (100) surface shows a distribution of Cd-Se bond lengths and J-couplings. Relativistic DFT simulations thus aid in interpretation of NMR spectra of CdSe nanocrystals and related nanomaterials.
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Affiliation(s)
- Rana Biswas
- U.S.
Department of Energy Ames National Laboratory, Ames, Iowa 50011. United States
- Department
of Physics and Astronomy; Electrical & Computer Engineering; Microelectronics
Research Center, Iowa State University, Ames, Iowa 50011. United States
| | - Yunhua Chen
- U.S.
Department of Energy Ames National Laboratory, Ames, Iowa 50011. United States
- Department
of Chemistry, Iowa State University, Ames, Iowa 50011. United States
| | - Javier Vela
- U.S.
Department of Energy Ames National Laboratory, Ames, Iowa 50011. United States
- Department
of Chemistry, Iowa State University, Ames, Iowa 50011. United States
| | - Aaron J. Rossini
- U.S.
Department of Energy Ames National Laboratory, Ames, Iowa 50011. United States
- Department
of Chemistry, Iowa State University, Ames, Iowa 50011. United States
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2
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Chen Y, Dorn RW, Hanrahan MP, Wei L, Blome-Fernández R, Medina-Gonzalez AM, Adamson MAS, Flintgruber AH, Vela J, Rossini AJ. Revealing the Surface Structure of CdSe Nanocrystals by Dynamic Nuclear Polarization-Enhanced 77Se and 113Cd Solid-State NMR Spectroscopy. J Am Chem Soc 2021; 143:8747-8760. [PMID: 34085812 DOI: 10.1021/jacs.1c03162] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Dynamic nuclear polarization (DNP) solid-state NMR (SSNMR) spectroscopy was used to obtain detailed surface structures of zinc blende CdSe nanocrystals (NCs) with plate or spheroidal morphologies which are capped by carboxylic acid ligands. 1D 113Cd and 77Se cross-polarization magic angle spinning (CPMAS) NMR spectra revealed distinct signals from Cd and Se atoms on the surface of the NCs, and those residing in bulk-like environments, below the surface. 113Cd cross-polarization magic-angle-turning (CP-MAT) experiments identified CdSe3O, CdSe2O2, and CdSeO3 Cd coordination environments on the surface of the NCs, where the oxygen atoms are presumably from coordinated carboxylate ligands. The sensitivity gain from DNP enabled natural isotopic abundance 2D homonuclear 113Cd-113Cd and 77Se-77Se and heteronuclear 113Cd-77Se scalar correlation solid-state NMR experiments which revealed the connectivity of the Cd and Se atoms. Importantly, 77Se{113Cd} scalar heteronuclear multiple quantum coherence (J-HMQC) experiments were used to selectively measure one-bond 77Se-113Cd scalar coupling constants (1J(77Se, 113Cd)). With knowledge of 1J(77Se, 113Cd), heteronuclear 77Se{113Cd} spin echo (J-resolved) NMR experiments were used to determine the number of Cd atoms bonded to Se atoms and vice versa. The J-resolved experiments directly confirmed that major Cd and Se surface species have CdSe2O2 and SeCd4 stoichiometries, respectively. Considering the crystal structure of zinc blende CdSe and the similarity of the solid-state NMR data for the platelets and spheroids, we conclude that the surface of the spheroidal CdSe NCs is primarily composed of {100} facets. The methods outlined here will generally be applicable to obtain detailed surface structures of various main group semiconductor nanoparticles.
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Affiliation(s)
- Yunhua Chen
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Rick W Dorn
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Michael P Hanrahan
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Lin Wei
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | | | | | - Marquix A S Adamson
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Anne H Flintgruber
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States
| | - Javier Vela
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Aaron J Rossini
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
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3
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Xing B, Ge S, Zhao J, Yang H, Song J, Geng Y, Qiao Y, Gu L, Han P, Ma G. Alloyed Crystalline CdSe 1-xS x Semiconductive Nanomaterials - A Solid State 113Cd NMR Study. ChemistryOpen 2020; 9:1018-1026. [PMID: 33072471 PMCID: PMC7549000 DOI: 10.1002/open.202000216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/03/2020] [Indexed: 01/14/2023] Open
Abstract
Solid‐state NMR analysis on wurtzite alloyed CdSe1−xSx crystalline nanoparticles and nanobelts provides evidence that the 113Cd NMR chemical shift is not affected by the varying sizes of nanoparticles, but is sensitive to the S/Se anion molar ratios. A linear correlation is observed between 113Cd NMR chemical shifts and the sulfur component for the alloyed CdSe1−xSx (0<x<1) system both in nanoparticles and nanobelts (δCd=169.71⋅XS+529.21). Based on this correlation, a rapid and applied approach has been developed to determine the composition of the alloyed nanoscalar materials utilizing 113Cd NMR spectroscopy. The observed results from this system confirm that one can use 113Cd NMR spectroscopy not only to determine the composition but also the phase separation of nanomaterial semiconductors without destruction of the sample structures. In addition, some observed correlations are discussed in detail.
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Affiliation(s)
- Baoyan Xing
- College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.,Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Sai Ge
- Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Jianguo Zhao
- College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.,Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Hui Yang
- Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Jie Song
- Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Yu Geng
- Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Yuying Qiao
- Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Ling Gu
- Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Peide Han
- College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Guibin Ma
- Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
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4
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Holmes ST, Schurko RW. A DFT/ZORA Study of Cadmium Magnetic Shielding Tensors: Analysis of Relativistic Effects and Electronic-State Approximations. J Chem Theory Comput 2019; 15:1785-1797. [PMID: 30721042 DOI: 10.1021/acs.jctc.8b01296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Theoretical considerations are discussed for the accurate prediction of cadmium magnetic shielding tensors using relativistic density functional theory (DFT). Comparison is made between calculations that model the extended lattice of the cadmium-containing solids using periodic boundary conditions and pseudopotentials with calculations that use clusters of atoms. The all-electron cluster-based calculations afford an opportunity to examine the importance of (i) relativistic effects on cadmium magnetic shielding tensors, as introduced through the ZORA Hamiltonian at either the scalar (SC) or spin-orbit (SO) levels and (ii) variation in the class of the DFT approximation. Twenty-three combinations of pseudopotentials or all-electron methods, DFT functionals, and relativistic treatments are assessed for the prediction of the principal components of the magnetic shielding tensors of 30 cadmium sites. We find that the inclusion of SO coupling can increase the cadmium magnetic shielding by as much as ca. 1100 ppm for a certain principal values; these effects are most pronounced for cadmium sites featuring bonds to other heavy atoms such as cadmium, iodine, or selenium. The best agreement with experimental values is found at the ZORA SO level in combination with a hybrid DFT method featuring a large admixture of Hartree-Fock exchange such as BH&HLYP. Finally, a theoretical examination is presented of the magnetic shielding tensor of the Cd(I) site in Cd2(AlCl4)2.
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Affiliation(s)
- Sean T Holmes
- Department of Chemistry and Biochemistry , University of Windsor , Windsor , ON , Canada N9B 3P4
| | - Robert W Schurko
- Department of Chemistry and Biochemistry , University of Windsor , Windsor , ON , Canada N9B 3P4
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5
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Grigoropoulos A, Maganas D, Symeonidis D, Giastas P, Cowley AR, Kyritsis P, Pneumatikakis G. Synthesis of Chalcogenidoimidodiphosphinato–Rh
I
Complexes and DFT Investigation of Their Catalytic Activation in Olefin Hydroformylation. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201200921] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Alexios Grigoropoulos
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis 15771, Athens, Greece, Fax: +30‐210‐7274782, http://www.chem.uoa.gr/
| | - Dimitrios Maganas
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis 15771, Athens, Greece, Fax: +30‐210‐7274782, http://www.chem.uoa.gr/
- Max‐Planck Institute for Chemical Energy Conversion, 45470 Mülheim an der Ruhr, Germany
| | - Dimitrios Symeonidis
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis 15771, Athens, Greece, Fax: +30‐210‐7274782, http://www.chem.uoa.gr/
| | - Petros Giastas
- Laboratory of Structural and Supramolecular Chemistry, NCSR “Demokritos”, Agia Paraskevi 15310, Athens, Greece
| | - Andrew R. Cowley
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Panayotis Kyritsis
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis 15771, Athens, Greece, Fax: +30‐210‐7274782, http://www.chem.uoa.gr/
| | - Georgios Pneumatikakis
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis 15771, Athens, Greece, Fax: +30‐210‐7274782, http://www.chem.uoa.gr/
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6
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Jalilehvand F, Amini Z, Parmar K. Cadmium(II) complex formation with selenourea and thiourea in solution: an XAS and 113Cd NMR study. Inorg Chem 2012; 51:10619-30. [PMID: 23016594 PMCID: PMC3498765 DOI: 10.1021/ic300852t] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The complexes formed in methanol solutions of Cd(CF(3)SO(3))(2) with selenourea (SeU) or thiourea (TU), for thiourea also in aqueous solution, were studied by combining (113)Cd NMR and X-ray absorption spectroscopy. At low temperature (~200 K), distinct (113)Cd NMR signals were observed, corresponding to CdL(n)(2+) species (n = 0-4, L = TU or SeU) in slow ligand exchange. Peak integrals were used to obtain the speciation in the methanol solutions, allowing stability constants to be estimated. For cadmium(II) complexes with thione (C═S) or selone (C═Se) groups coordinated in Cd(S/Se)O(5) or Cd(S/Se)(2)O(4) (O from MeOH or CF(3)SO(3)(-)) environments, the (113)Cd chemical shifts were quite similar, within 93-97 ppm and 189-193 ppm, respectively. However, the difference in the chemical shift for the Cd(SeU)(4)(2+) (578 pm) and Cd(TU)(4)(2+) (526 ppm) species, with CdSe(4) and CdS(4) coordination, respectively, shows less chemical shielding for the coordinated Se atoms than for S, in contrast to the common trend with increasing shielding in the following order: O > N > Se > S. In solutions dominated by mono- and tetra-thiourea/selenourea complexes, their coordination and bond distances could be evaluated by Cd K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy. At ~200 K and high excess of thiourea, a minor amount (up to ~30%) of [Cd(TU)(5-6)](2+) species was detected by an upfield shift of the (113)Cd NMR signal (up to 423 ppm) and an amplitude reduction of the EXAFS oscillation. The amount was estimated by fitting linear combinations of simulated EXAFS spectra for [Cd(TU)(4)](2+) and [Cd(TU)(6)](2+) complexes. At room temperature, [Cd(TU)(4)](2+) was the highest complex formed, also in aqueous solution. Cd L(3)-edge X-ray absorption near edge structure (XANES) spectra of cadmium(II) thiourea solutions in methanol were used to follow changes in the CdS(x)O(y) coordination. The correlations found from the current and previous studies between (113)Cd NMR chemical shifts and different Cd(II) coordination environments are generally useful for evaluating cadmium coordination to thione-containing or Se-donor ligands in biochemical systems or for monitoring speciation in solution.
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Affiliation(s)
- Farideh Jalilehvand
- Department of Chemistry, University of Calgary, Calgary, AB, Canada T2N 1N4.
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7
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Sutrisno A, Lo AY, Tang JA, Dutton JL, Farrar GJ, Ragogna PJ, Zheng S, Autschbach J, Schurko RW. Experimental and theoretical investigations of selenium nuclear magnetic shielding tensors in Se–N heterocycles. CAN J CHEM 2009. [DOI: 10.1139/v09-100] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A preliminary study involving solid-state 77Se NMR spectroscopy and first principles calculations of 77Se NMR parameters in Se–N heterocycles is reported. 77Se CP/MAS NMR spectra of the ring systems reveal expansive selenium chemical shift (CS) tensors, which are extremely sensitive to molecular geometry, symmetry, ligand substitution, and intermolecular contacts. For systems with known crystal structures, hybrid density functional theory (DFT) calculations of selenium nuclear magnetic shielding (NMS) tensors were carried out, and tensor orientations in the molecular frames examined. Additional DFT calculations of selenium NMS tensors are presented, along with a detailed analysis of pairs of occupied and virtual molecular orbitals that give rise to the Se NMS tensors. A new naturalized local molecular orbital (NLMO) analysis under the same DFT framework is also discussed. Collectively, the NMR data and first principles calculations provide understanding of the influences of electronic structure, bonding, and intermolecular interactions on the selenium NMS tensors, allowing for (i) prediction of unknown molecular structures and (ii) insight into the positions of the stereochemically active selenium lone pairs.
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Affiliation(s)
- Andre Sutrisno
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
- Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada
- Department of Chemistry, The State University of New York, Buffalo, NY 14260-3000, USA
| | - Andy Y.H. Lo
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
- Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada
- Department of Chemistry, The State University of New York, Buffalo, NY 14260-3000, USA
| | - Joel A. Tang
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
- Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada
- Department of Chemistry, The State University of New York, Buffalo, NY 14260-3000, USA
| | - Jason L. Dutton
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
- Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada
- Department of Chemistry, The State University of New York, Buffalo, NY 14260-3000, USA
| | - Gregg J. Farrar
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
- Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada
- Department of Chemistry, The State University of New York, Buffalo, NY 14260-3000, USA
| | - Paul J. Ragogna
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
- Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada
- Department of Chemistry, The State University of New York, Buffalo, NY 14260-3000, USA
| | - Shaohui Zheng
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
- Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada
- Department of Chemistry, The State University of New York, Buffalo, NY 14260-3000, USA
| | - Jochen Autschbach
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
- Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada
- Department of Chemistry, The State University of New York, Buffalo, NY 14260-3000, USA
| | - Robert W. Schurko
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
- Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada
- Department of Chemistry, The State University of New York, Buffalo, NY 14260-3000, USA
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Affiliation(s)
- Cecil Dybowski*
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716
| | - Shi Bai
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716
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Robertson SD, Chivers T. Synthesis, NMR characterisation and X-ray structures of mixed chalcogenido PNP ligands containing tellurium: crystal structures of SeiPr2PNP(H)iPr2 and [NaN(EPiPr2)2]infinity (E = Se, Te). Dalton Trans 2008:1765-72. [PMID: 18354775 DOI: 10.1039/b717287g] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Reaction of HN(PiPr2)2 with one equivalent of selenium in hexane at room temperature yields the monoselenide as the P-H tautomer Se=PiPr2-N=P(H)iPr2 (2b). Deprotonation of 2b with n butyllithium in the presence of TMEDA at -78 degrees C followed by addition of tellurium produces the air-sensitive, mixed chalcogenido complex [(TMEDA)Li(SePiPr2)(TePiPr2)N] (8Li) in >97% purity after recrystallisation. Similarly, deprotonation of Te=PiPr2-N=P(H)iPr2 (2c), followed by addition of sulfur, gives the sulfur analogue [(TMEDA)Li(SPiPr2)(TePiPr2)N] (7Li) in >99% purity. The symmetrical complexes [(TMEDA)Li(SePiPr2)2N] (4Li) and [(TMEDA)Li(TePiPr2)2N] (5Li) are produced by similar methods. Compounds 2b, 4Li, 5Li, 7Li and 8Li were characterised in solution by multinuclear (1H, 31P, 77Se and 125Te) NMR spectroscopy and their solid-state structures were determined by X-ray crystallography. The X-ray crystal structures of the polymeric chains [NaN(EPiPr2)2]infinity (4Na, E = Se and 5Na, E = Te) are also reported.
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Affiliation(s)
- Stuart D Robertson
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
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10
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Demko BA, Wasylishen RE. Comparing Main Group and Transition-Metal Square-Planar Complexes of the Diselenoimidodiphosphinate Anion: A Solid-State NMR Investigation of M[N(iPr2PSe)2]2 (M = Se, Te; Pd, Pt). Inorg Chem 2008; 47:2786-97. [DOI: 10.1021/ic7019999] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bryan A. Demko
- Department of Chemistry, Gunning/Lemieux Chemistry Centre, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Roderick E. Wasylishen
- Department of Chemistry, Gunning/Lemieux Chemistry Centre, University of Alberta, Edmonton, AB T6G 2G2, Canada
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