Reduction of the cationic Ge(II) complex [dimpyrGeCl][GeCl3] (dimpyr=2,6-(ArN=CMe)2NC5H3, Ar=2,6-iPr2C6H3) with potassium graphite in benzene affords an air sensitive, dark green compound of Ge(0), [dimpyrGe], which is stabilized by a bis(imino)pyridine platform. This compound is the first example of a complex of a zero-valent Group 14 element that does not contain a carbene or carbenoid ligand. This species has a singlet ground state. DFT studies revealed partial delocalization of one of the Ge lone pairs over the π*(C=N) orbitals of the imines. This delocalization results in a partial multiple-bond character between the Ge atom and imine nitrogen atoms, a fact supported by the X-ray crystallography and IR spectroscopy data.
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http://dx.doi.org/10.1002/anie.201309421 | DOI Listing |
Nat Commun
September 2024
National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, China.
Metavalent bonding is a unique bonding mechanism responsible for exceptional properties of materials used in thermoelectric, phase-change, and optoelectronic devices. For thermoelectrics, the desired performance of metavalently bonded materials can be tuned by doping foreign atoms. Incorporating dopants to form solid solutions or second phases is a crucial route to tailor the charge and phonon transport.
View Article and Find Full Text PDFACS Appl Mater Interfaces
July 2024
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, Hubei 430070, People's Republic of China.
The coupling of charge and phonon transport in solids is a long-standing issue for thermoelectric performance enhancement. Herein, two new narrow-gap semiconductors with the same chemical formula of GeSeTe (GST) are rationally designed and synthesized: one with a layered hexagonal structure (H-GST) and the other with a non-layered rhombohedral structure (R-GST). Thanks to the three-dimensional (3D) network structure, R-GST possesses a significantly larger weighted mobility than H-GST.
View Article and Find Full Text PDFChemistry
April 2024
Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3 A1, Canada.
The germylone dimNHCGe (5, dimNHC=diimino N-heterocyclic carbene) undergoes a [2+2] cycloaddition with isocyanates RNCO (R=4-tolyl or 3,5-xylyl) to furnish novel alkyl carboxamido germylenes 7 (R=4-tolyl) and 8 (R=3,5-xylyl), featuring a C-C bond between the former carbene carbon and the isocyanate moiety. Heating a mixture of 8 with 4-tolyl isocyanate to 100 °C results in isocyanate metathesis, demonstrating reversible C-C bond formation on the reduced germanium compound. DFT calculations suggest that this process occurs via the reductive dissociation of isocyanate from 8 that regenerates the parent Ge(0) compound 5.
View Article and Find Full Text PDFChemistry
February 2024
Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India.
Researchers have successfully isolated Si /Ge species, termed silylone and germylone, with two lone pairs of electrons on them. These elusive compounds have been stabilised in singlet ground states by using different donor base ligands. Driess et al.
View Article and Find Full Text PDFInnovation (Camb)
November 2023
College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China.
In thermoelectrics, phase engineering serves a crucial function in determining the power factor by affecting the band degeneracy. However, for low-symmetry compounds, the mainstream one-step phase manipulation strategy, depending solely on the valley or orbital degeneracy, is inadequate to attain a high density-of-states effective mass and exceptional . Here, we employ a distinctive two-step phase manipulation strategy through stepwise tailoring chemical bonds in GeSe.
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