Grundlagen und Hauptgruppenelemente

Holleman, A. F.

doi:10.1515/9783110495850

Cited by 20 publications

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“…The phosphorus atom P1 of 2‐benzyl‐1‐mesityl‐5,7‐dimethyl‐2,3‐dihydrophosphindole ( 2 ) is in a trigonal pyramidal environment with an angle sum of 302.1°. In unstrained PH 3 an angle sum of 280.3° (H–P–H 93.42°) [ 4 ] has been observed which is commonly explained by lack of sp 3 hybridization of the phosphorus atom leading to a P–H bond by interaction of a P‐centered p ‐orbital with the hydrogen atom. Increasingly bulky substituents induce steric strain and enhance the bond angles at the phosphorus atom.…”

Section: Resultsmentioning

confidence: 99%

“…Increasing electronegativity differences (ΔEN) of P and E strengthen the ionic picture whereas small ΔEN values reduce the heteropolar nature of the P–E bonds. With Allred‐Rochow electronegativity values of 2.06 for phosphorus on the one hand and EN values of 3.50, 2.44, and 2.48 for oxygen, sulfur, and selenium [ 10 ] on the other, the by far most ionic P–E bond is expected for 2‐benzyl‐1‐mesityl‐5,7‐dimethyl‐2,3‐dihydrophosphindole 1‐oxide ( 2‐O , ΔEN PO = 1.44). The very similar and smaller electronegativity of S and Se leads to rather similar P–C bond lengths for 2‐S and 2‐Se (ΔEN PS = 0.38, ΔEN PSe = 0.42).…”

Section: Resultsmentioning

confidence: 99%

“…[ 3 ] Chirality of phosphanes is a consequence of the rather large inversion barrier at the phosphorus atom, leading to enantiomers that can be isolated [contrary to amines with very low energy barriers for the inversion at the nitrogen atom; compare the inversion barriers of ammonia (24.5 kJ · mol –1 ) and PH 3 (155 kJ · mol –1 )]. [ 4 ] This barrier is enhanced in small phosphacycles because the trigonal planar transition state becomes even more disadvantageous due to the fact that three C–P–C bond angles of 120° cannot be realized due to ring strain. Due to the importance of secondary and tertiary phosphanes and their phosphane oxides numerous protocols have been developed to reduce phosphane oxides.…”

Section: Introductionmentioning

confidence: 99%

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Sterically Encumbered 2,3‐Dihydrophosphindole and Its Chalcogenides

Fener

Görls

Krieck

et al. 2020

Zeitschrift anorg allge chemie

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Reduction of 2‐benzyl‐1‐mesityl‐5,7‐dimethyl‐2,3‐dihydrophosphindole 1‐oxide (2‐O), which was prepared by catalytic addition of dimesitylphosphane oxide across phenylacetylene via dimesityl‐phenylethenylphosphane oxide (1), with excess of trichlorosilane in toluene yielded 2‐benzyl‐1‐mesityl‐5,7‐dimethyl‐2,3‐dihydrophosphindole (2). Straightforward oxidation of 2 with sulfur and selenium in toluene at 110 °C allowed the isolation of crystalline colorless 2‐benzyl‐1‐mesityl‐5,7‐dimethyl‐2,3‐dihydrophosphindole 1‐sulfide (2‐S) and 1‐selenide (2‐Se). The hindered rotation of the P‐bound mesityl group around the P–C bond is indicative of significant intramolecular steric strain. Despite this strain, the P–E bond lengths (E = S, Se) lie in expected ranges.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Sterically Encumbered 2,3‐Dihydrophosphindole and Its Chalcogenides

Fener

Görls

Krieck

et al. 2020

Zeitschrift anorg allge chemie

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“…Notably, S5 not only bridges the two Ni2 centers, but also interacts with the potassium counter ion (S5-K1: 3.378(2) Å). This distance is very close to the sum of their covalent radii (3.39 Å [53]) and it will take away at least some electron density from the Ni2-S5 bonds, thereby weakening them. With regard to assigning the two oxidation states (+2 and +3) to the inner and outer nickel centers, metrical structural parameters of the C-S and C=C bonds in the three dithiolene ligands of the asymmetric unit are also of interest.…”

Section: Bond Lengthsmentioning

confidence: 94%

“…This might contribute to elongation of the Ni-S bonds, despite a higher oxidation state. Notably, the longer ones of the Ni-S bonds, i.e., those which surpass 2.3 Å, mean that the Ni and S atoms have distances which are longer than the sum of their covalent radii (2.29 Å [53]), suggesting only comparably weak attraction/interaction. While Ni1 is clearly strongly coordinated by all four sulfur donor atoms of its two dithiolene ligands, three out of the five Ni-S interactions of Ni2 are significantly weakened beyond a typical Ni-S single bond.…”

Section: Bond Lengthsmentioning

confidence: 99%

A Mixed-Valence Tetra-Nuclear Nickel Dithiolene Complex: Synthesis, Crystal Structure, and the Lability of Its Nickel Sulfur Bonds

et al. 2020

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In this study, by employing a common synthetic protocol, an unusual and unexpected tetra-nuclear nickel dithiolene complex was obtained. The synthesis of the [Ni4(ecpdt)6]2− dianion (ecpdt = (Z)-3-ethoxy-3-oxo-1-phenylprop-1-ene-1,2-bis-thiolate) with two K+ as counter ions was then intentionally reproduced. The formation of this specific complex is attributed to the distinct dithiolene precursor used and the combination with the then coordinated counter ion in the molecular solid-state structure, as determined by X-ray diffraction. K2[Ni4(ecpdt)6] was further characterized by ESI-MS, FT-IR, UV-Vis, and cyclic voltammetry. The tetra-nuclear complex was found to have an uncommon geometry arising from the combination of four nickel centers and six dithiolene ligands. In the center of the arrangement, suspiciously long Ni–S distances were found, suggesting that the tetrameric structure can be easily split into two identical dimeric fragments or two distinct groups of monomeric fragments, for instance, upon dissolving. A proposed variable magnetism in the solid-state and in solution due to the postulated dissociation was confirmed. The Ni–S bonds of the “inner” and “outer” nickel centers differed concurrently with their coordination geometries. This observation also correlates with the fact that the complex bears two anionic charges requiring the four nickel centers to be present in two distinct oxidation states (2 × +2 and 2 × +3), i.e., to be hetero-valent. The different coordination geometries observed, together with the magnetic investigation, allowed the square planar “outer” geometry to be assigned to d8 centers, i.e., Ni2+, while the Ni3+ centers (d7) were in a square pyramidal geometry with longer Ni–S distances due to the increased number of donor atoms and interactions.

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Post‐Synthetic Modification: Systematic Study on a Simple Access to Nitridophosphates

et al. 2020

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Nitridophosphates are a well‐studied class of nitrides with diverse materials properties, such as luminescence or ion conductivity. Despite the growing interest in this compound class, their synthesis mostly works through direct combination of starting materials. Herein, we present a systematic study on a promising method for post‐synthetic modification by treating pre‐synthesized nitridophosphates with halides under elevated pressures and temperatures. Herein, we focus on the applicability of this approach to P/N compounds with different degrees of condensation. Accordingly, BaP2N4, Ba3P5N10Br, SrH4P6N12, CaP8N14, and Ca2PN3 are investigated as model compounds for framework‐, layer‐, and chain‐type nitridophosphates. The formation of structurally related, as well as, completely unrelated compounds, compared to the starting materials, shows the great potential of the approach, which increases the synthetic possibilities for nitridophosphates significantly.

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Grundlagen und Hauptgruppenelemente

Cited by 20 publications

References 0 publications

Sterically Encumbered 2,3‐Dihydrophosphindole and Its Chalcogenides

Sterically Encumbered 2,3‐Dihydrophosphindole and Its Chalcogenides

A Mixed-Valence Tetra-Nuclear Nickel Dithiolene Complex: Synthesis, Crystal Structure, and the Lability of Its Nickel Sulfur Bonds

Post‐Synthetic Modification: Systematic Study on a Simple Access to Nitridophosphates

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