Home R & D Chem Metal-Stabilized Triborane Compounds: Synthesis and Structure

Metal-Stabilized Triborane Compounds: Synthesis and Structure

Metal-Stabilized Triborane Compounds: Synthesis and Structure

🔬 This study focuses on the synthesis and characterization of metal-stabilized triborane compounds, specifically arachno-[2-{CpRu(PPh3)B3H8}] (2) and heterometallic triborane [{CpRu(PPh3)}(μ3-η1:η2:η2-B3H6){Fe2(CO)7}] (3). The researchers investigated their structures, bonding interactions, and stability.

  • Compound 2 was obtained from the reaction of [Cp*Ru(PPh3)2Cl] with monoborane reagent [BH3·THF] at 60 °C.
  • Compound 3 was synthesized by reacting arachno-2 with [Fe2(CO)9] at room temperature.
  • Compound 3 has a trimetallic triborane(6) structure stabilized by Cp*Ru(PPh3) and Fe(CO)3 fragments.
  • DFT calculations revealed the electronic and bonding characteristics of compounds 2 and 3.

In an attempt to synthesize arachno-[2-{CpRu(PPh3)B3H8}] (2), researchers reacted [CpRu(PPh3)2Cl] with monoborane reagent [BH3·THF] at elevated temperature. Compound 2 was obtained in 12% yield and characterized using various spectroscopic techniques. Additionally, heterometallic triborane [{Cp*Ru(PPh3)}(μ3-η1:η2:η2-B3H6){Fe2(CO)7}] (3) was synthesized by reacting arachno-2 with [Fe2(CO)9]. Compound 3 was structurally characterized, and its stability and bonding interactions were explored through various analyses.

The researchers observed that compound 2 has characteristics of metal-B3H8 compounds, indicating stabilization by the CpRu(PPh3) fragment. Compound 3, a trimetallic triborane(6), features a stabilized triborane(6) unit [{CpRu(PPh3)}(μ3-η1:η2:η2-B3H6){Fe2(CO)7}]. The structural analysis and computational studies suggest strong bonding interactions between the metal fragments and the boron centers, leading to stability.

🔬 In this study, researchers aimed to synthesize and characterize metal-stabilized triborane species using various reactions involving metal complexes and borane reagents.

🔬 Molecular Structure: The synthesized compound, arachno-[2-{CpRu(PPh3)B3H8}], was characterized by its molecular structure, which revealed the attachment of the CpRu(PPh3) fragment to a B3H8 unit, stabilizing the triborane species. 🔬 Spectroscopic Evidence: NMR spectra, including 1H, 11B, 13C, and 31P NMR, provided insights into the bonding interactions and chemical shifts within the compound. 🔬 Crystallographic Analysis: Single-crystal diffraction analysis confirmed the compound’s structure, revealing the coordination of metal and boron atoms and their spatial arrangement. 🔬 Metal-Boron Bonds: The research showed that the metal-boron bonds within the compound were consistent with other known metal-stabilized triborane species, and computational analysis supported these findings. 🔬 Bonding Interactions: Molecular orbital analysis and natural bond orbital analysis shed light on the bonding interactions between metal and boron atoms within the compound.

Compound 2 possesses a wingtip isomer geometry where the Cp* ligand is at the exo-position, while the PPh3 ligand is at the endo-position. Its core geometry resembles other known arachno metal-B3H8 compounds. Compound 3 has a unique structure with a flattened FeB3 core, stabilized by Cp*Ru(PPh3) and Fe(CO)3 fragments. The research suggests that the stability of these metal-stabilized triborane compounds arises from the strong metal-boron interactions.

📚 This study sheds light on the synthesis, structure, and stability of metal-stabilized triborane compounds, providing valuable insights into their bonding interactions and potential applications in various fields.

  • 🔬 Reaction Attempts: The researchers initially attempted to synthesize a specific triborane species, but the reaction of a metal complex with a borane reagent at room temperature led to compound decomposition.
  • 🔬 Successful Reaction: A different reaction involving thermolysis at 60°C resulted in the successful synthesis of a new triborane compound, arachno-[2-{Cp*Ru(PPh3)B3H8}], with a yield of 12%.
  • 🔬 Previous Analogue: The PMe3 analogue of the synthesized compound had been previously reported and characterized by a different research group, and alternate synthetic procedures were also described for related compounds.
  • 🔬 Characterization Methods: The synthesized triborane compound was characterized using various techniques, including NMR spectroscopy, mass spectrometry, single-crystal diffraction analysis, and theoretical calculations.

Diborane and Triborane Species in the Coordination Sphere of Group-8 Transition Metals

  • Alaka Nanda Pradhan, Subhash Bairagi, and Sundargopal Ghosh*
  • Researchers attempted to synthesize a specific triborane species using metal complexes and borane reagents.
  • Successful synthesis of arachno-[2-{Cp*Ru(PPh3)B3H8}] occurred through thermolysis, yielding a new compound.
  • Characterization methods included NMR spectroscopy, mass spectrometry, single-crystal diffraction, and theoretical calculations.
  • Molecular structure analysis revealed metal-boron bonding interactions and spatial arrangement.
  • Computational analysis supported the findings of the study, enhancing understanding of metal-stabilized triborane compounds.


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