Topic
Tetrahedral molecular geometry
About: Tetrahedral molecular geometry is a research topic. Over the lifetime, 1795 publications have been published within this topic receiving 30706 citations.
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TL;DR: As anticipated, the weakly coordinating nitromethane ligands in 1 are easily displaced by a variety of donors, including Et(2)O, MeCN, and piperidine, and more surprisingly, the addition of mesitylene to 1 results in the formation of an η(6)-coordinated nickel arene complex, suggesting a relatively weak Ni-arene interaction.
Abstract: The reaction of [NO][PF6] with excess Ni powder in CH3NO2, in the presence of 2 mol % NiI2, results in the formation of [Ni(NO)(CH3NO2)3][PF6] (1), which can be isolated in modest yield as a blue crystalline solid. Also formed in the reaction is [Ni(CH3NO2)6][PF6]2 (2), which can be isolated in comparable yield as a pale-green solid. In the solid state, 1 exhibits tetrahedral geometry about the Ni center with a linear nitrosyl ligand [Ni1–N1–O1 = 174.1(8)°] and a short Ni–N bond distance [1.626(6) A]. As anticipated, the weakly coordinating nitromethane ligands in 1 are easily displaced by a variety of donors, including Et2O, MeCN, and piperidine (NC5H11). More surprisingly, the addition of mesitylene to 1 results in the formation of an η6-coordinated nickel arene complex, [Ni(η6-1,3,5-Me3C6H3)(NO)][PF6] (6). In the solid state, complex 6 exhibits a long Ni–Ccent distance [1.682(2) A], suggesting a relatively weak Ni–arene interaction, a consequence of the strong π-back-donation to the nitrosyl ligand. Th...
17 citations
TL;DR: The voltage-gated proton channel (Hv1/VSOP) is inhibited by Zn2+, of which the binding site is located in the extracellular region and the most probable coordination structure was proposed as a tetrahedral geometry with ligands of carboxylate and imidazole groups in addition to a water molecule
Abstract: The voltage-gated proton channel (Hv1/VSOP) is inhibited by Zn2+, of which the binding site is located in the extracellular region. We utilized attenuated total reflection–Fourier transform infrared (ATR-FTIR) spectroscopy to examine the coordination structure by monitoring protein structural changes induced by Zn2+-binding. The Zn2+-induced difference ATR-FTIR spectra of Hv1 showed IR features that can be assigned to the histidine C5–N1 and carboxylate-COO– stretches as well as amide I changes likely in α-helical peptide bonds. Analysis of vibrational frequencies indicated that the Zn2+ is coordinated by the anionic carboxylate with monodentate mode and by the histidine at N1 (Nτ) position of the neutral imidazole form. Combined with quantum chemical calculations, the most probable coordination structure was proposed as a tetrahedral geometry with ligands of carboxylate and imidazole groups in addition to a water molecule.
17 citations
TL;DR: The simulations indicate that water preferentially associates with borohydride on the tetrahedral corners and edges, causing transitions to excited states with p character to become more intense and a sharp feature, uncharacteristic of tetrahed molecules, to emerge.
Abstract: Borohydride salts have been considered as good prospects for transportable hydrogen storage materials, with molecular hydrogen released via hydrolysis. We examine details of the hydration of sodium borohydride by the combination of X-ray absorption spectroscopy and first principles' theory. Compared to solid sodium borohydride, the aqueous sample exhibits an uncharacteristically narrow absorption feature that is shifted to lower energy, and ascribed to the formation of dihydrogen bonds between borohydride and water that weaken the boron–hydrogen covalent bonds. Water also acts to localize the highly excited molecular orbitals of borohydride, causing transitions to excited states with p character to become more intense and a sharp feature, uncharacteristic of tetrahedral molecules, to emerge. The simulations indicate that water preferentially associates with borohydride on the tetrahedral corners and edges.
17 citations
TL;DR: In this article, the reaction of 1-hydroxypyridine-2-thione (HpyOS) with Ag2CO3 suspended in CHCl3 under magnetic stirring followed by addition of PPh3 yields a product of stoichiometry: Ag(pyOS)(PPh3), where each Ag atom acquires a distorted tetrahedral geometry by co-ordinating to one oxygen, two sulphur and one phosphorus atoms.
Abstract: Reaction of 1-hydroxypyridine-2-thione (HpyOS) in CHCl3 with Ag2CO3 suspended in CHCl3 under magnetic stirring followed by addition of PPh3 yields a product of stoichiometry: Ag(pyOS)(PPh3). The compound adopts a dimeric structure [Ag(pyOS)(PPh3)]2 (1) where each Ag atom acquires a distorted tetrahedral geometry by co-ordinating to one oxygen, two sulphur and one phosphorus atoms. The Ag2S2 core forms a parallelogram [Ag—S 2.507(1), 2.822(1)A] with Ag—S—Ag and S—Ag—S angles of 74.8(1) and 105.2(1)°, respectively.
17 citations
TL;DR: In this article, the synthesis, spectral characterisation of the zinc(II) pyrrolecarboxylates, [Zn(2-Hpyrrc)2(H2O)] (1) and Zn(1-methylimidazole)2] (2) (2H2pyrr = 2-pyrrole-carboxylic acid) is reported as well as the X-ray structure determination of the latter compound.
17 citations