Bond-length distributions for ions bonded to oxygen: Results for the non-metals and discussion of lone-pair stereoactivity and the polymerization of PO4

Author(s):

Olivier Charles Gagné ◽

Frank Christopher Hawthorne

Keyword(s):

Metal Ions ◽

Bond Length ◽

Lone Pair ◽

Group 14 ◽

Bond-length distributions are examined for three configurations of the H+ ion, sixteen configurations of the group 14-16 non-metal ions and seven configurations of the group 17 ions bonded to oxygen. Lone-pair stereoactivity for ions bonded to O2- is discussed, as well as the polymerization of the PO4 group.

Bond-length distributions for ions bonded to oxygen: Results for the non-metals and discussion of lone-pair stereoactivity and the polymerization of PO4

10.26434/chemrxiv.5410918.v2 ◽

2017 ◽

Author(s):

Olivier Charles Gagné ◽

Frank Christopher Hawthorne

Keyword(s):

Metal Ions ◽

Bond Length ◽

Lone Pair ◽

Group 14 ◽

Bond-length distributions are examined for three configurations of the H+ ion, sixteen configurations of the group 14-16 non-metal ions and seven configurations of the group 17 ions bonded to oxygen. Lone-pair stereoactivity for ions bonded to O2- is discussed, as well as the polymerization of the PO4 group.

Bond-length distributions for ions bonded to oxygen: Metalloids and post-transition metals

10.26434/chemrxiv.5410921.v2 ◽

2017 ◽

Author(s):

Olivier Charles Gagné ◽

Frank Christopher Hawthorne

Keyword(s):

Transition Metal ◽

Transition Metals ◽

Metal Ions ◽

Bond Length ◽

Lone Pair ◽

Transition Metal Ions ◽

Bond-length distributions are examined for thirty-three configurations of the metalloid ions and fifty-six configurations of the post-transition-metal ions bonded to oxygen. Lone-pair stereoactivity is discussed.

Bond-length distributions for ions bonded to oxygen: Metalloids and post-transition metals

10.26434/chemrxiv.5410921 ◽

2017 ◽

Author(s):

Olivier Charles Gagné ◽

Frank Christopher Hawthorne

Keyword(s):

Transition Metal ◽

Transition Metals ◽

Metal Ions ◽

Bond Length ◽

Lone Pair ◽

Transition Metal Ions ◽

Bond-length distributions are examined for thirty-three configurations of the metalloid ions and fifty-six configurations of the post-transition-metal ions bonded to oxygen. Lone-pair stereoactivity is discussed.

Bond-length distributions for ions bonded to oxygen: Metalloids and post-transition metals

10.26434/chemrxiv.5410921.v1 ◽

2017 ◽

Author(s):

Olivier Charles Gagné ◽

Frank Christopher Hawthorne

Keyword(s):

Transition Metal ◽

Transition Metals ◽

Metal Ions ◽

Bond Length ◽

Lone Pair ◽

Transition Metal Ions ◽

Bond-length distributions are examined for thirty-three configurations of the metalloid ions and fifty-six configurations of the post-transition-metal ions bonded to oxygen. Lone-pair stereoactivity is discussed.

Acta Crystallographica Section B Structural Science Crystal Engineering and Materials ◽

Bond-length distributions for ions bonded to oxygen: results for the non-metals and discussion of lone-pair stereoactivity and the polymerization of PO4

10.1107/s2052520617017541 ◽

2018 ◽

Vol 74 (1) ◽

pp. 79-96 ◽

Cited By ~ 9

Author(s):

Olivier Charles Gagné ◽

Frank Christopher Hawthorne

Keyword(s):

Metal Ions ◽

Bond Length ◽

Oxidation State ◽

Lone Pair ◽

Bond Valence ◽

Group 14 ◽

Coordination Polyhedra ◽

Bond Lengths ◽

Secondary Bonds ◽

Lone Pair Electrons

Bond-length distributions are examined for three configurations of the H+ ion, 16 configurations of the group 14–16 non-metal ions and seven configurations of the group 17 ions bonded to oxygen, for 223 coordination polyhedra and 452 bond distances for the H+ ion, 5957 coordination polyhedra and 22 784 bond distances for the group 14–16 non-metal ions, and 248 coordination polyhedra and 1394 bond distances for the group 17 non-metal ions. H...O and O—H + H...O distances correlate with O...O distance (R 2 = 0.94 and 0.96): H...O = 1.273 × O...O – 1.717 Å; O—H + H...O = 1.068 × O...O – 0.170 Å. These equations may be used to locate the hydrogen atom more accurately in a structure refined by X-ray diffraction. For non-metal elements that occur with lone-pair electrons, the most observed state between the n versus n+2 oxidation state is that of highest oxidation state for period 3 cations, and lowest oxidation state for period 4 and 5 cations when bonded to O2−. Observed O—X—O bond angles indicate that the period 3 non-metal ions P3+, S4+, Cl3+ and Cl5+ are lone-pair seteroactive when bonded to O2−, even though they do not form secondary bonds. There is no strong correlation between the degree of lone-pair stereoactivity and coordination number when including secondary bonds. There is no correlation between lone-pair stereoactivity and bond-valence sum at the central cation. In synthetic compounds, PO4 polymerizes via one or two bridging oxygen atoms, but not by three. Partitioning our PO4 dataset shows that multi-modality in the distribution of bond lengths is caused by the different bond-valence constraints that arise for Obr = 0, 1 and 2. For strongly bonded cations, i.e. oxyanions, the most probable cause of mean bond length variation is the effect of structure type, i.e. stress induced by the inability of a structure to follow its a priori bond lengths. For ions with stereoactive lone-pair electrons, the most probable cause of variation is bond-length distortion.

Acta Crystallographica Section B Structural Science Crystal Engineering and Materials ◽

Bond-length distributions for ions bonded to oxygen: metalloids and post-transition metals

10.1107/s2052520617017437 ◽

2018 ◽

Vol 74 (1) ◽

pp. 63-78 ◽

Cited By ~ 23

Author(s):

Olivier Charles Gagné ◽

Frank Christopher Hawthorne

Keyword(s):

Transition Metal ◽

Metal Ions ◽

Bond Length ◽

Coordination Number ◽

Lone Pair ◽

Transition Metal Ions ◽

Length Variation ◽

Coordination Polyhedra ◽

Bond Lengths ◽

Lone Pair Electrons

Bond-length distributions have been examined for 33 configurations of the metalloid ions and 56 configurations of the post-transition metal ions bonded to oxygen, for 5279 coordination polyhedra and 21 761 bond distances for the metalloid ions, and 1821 coordination polyhedra and 10 723 bond distances for the post-transition metal ions. For the metalloid and post-transition elements with lone-pair electrons, the more common oxidation state between n versus n+2 is n for Sn, Te, Tl, Pb and Bi and n+2 for As and Sb. There is no correlation between bond-valence sum and coordination number for cations with stereoactive lone-pair electrons when including secondary bonds, and both intermediate states of lone-pair stereoactivity and inert lone pairs may occur for any coordination number > [4]. Variations in mean bond length are ∼0.06–0.09 Å for strongly bonded oxyanions of metalloid and post-transition metal ions, and ∼0.1–0.3 Å for ions showing lone-pair stereoactivity. Bond-length distortion is confirmed to be a leading cause of variation in mean bond lengths for ions with stereoactive lone-pair electrons. For strongly bonded cations (i.e. oxyanions), the causes of mean bond-length variation are unclear; the most plausible cause of mean bond-length variation for these ions is the effect of structure type, i.e. stress resulting from the inability of a structure to adopt its characteristic a priori bond lengths.

Long-term stability in γ-CsPbI3 perovskite via an ultraviolet-curable polymer network

Communications Materials ◽

10.1038/s43246-021-00134-1 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Nam-Kwang Cho ◽

Hyun-Jae Na ◽

Jeeyoung Yoo ◽

Youn Sang Kim

Keyword(s):

Polymer Network ◽

Lone Pair ◽

Ambient Conditions ◽

Absorption Properties ◽

Term Stability ◽

Long Term Stability ◽

Ultraviolet Curable ◽

Oxygen Lone Pair ◽

Lone Pair Electrons

AbstractBlack-colored (α, γ-phase) CsPbI3 perovskites have a small bandgap and excellent absorption properties in the visible light regime, making them attractive for solar cells. However, their long-term stability in ambient conditions is limited. Here, we demonstrate a strategy to improve structural and electrical long-term stability in γ-CsPbI3 by the use of an ultraviolet-curable polyethylene glycol dimethacrylate (PEGDMA) polymer network. Oxygen lone pair electrons from the PEGDMA are found to capture Cs+ and Pb2+ cations, improving crystal growth of γ-CsPbI3 around PEGDMA. In addition, the PEGDMA polymer network strongly contributes to maintaining the black phase of γ-CsPbI3 for more than 35 days in air, and an optimized perovskite film retained ~90% of its initial electrical properties under red, green, and blue light irradiation.

Photoelectron Spectroscopy of Heterocycles. Phenyloxiranes

Zeitschrift für Naturforschung A ◽

10.1515/zna-1984-1215 ◽

1984 ◽

Vol 39 (12) ◽

pp. 1230-1234 ◽

Author(s):

H. Güsten ◽

L. Klasinc ◽

I. Novak ◽

M. Sanjek

Keyword(s):

Double Bond ◽

Ethylene Oxide ◽

Photoelectron Spectroscopy ◽

Lone Pair ◽

Photoelectron Spectra ◽

Ionization Energies ◽

Perpendicular Orientation ◽

Trans Stilbene ◽

The Hel photoelectron spectra of 2-phenyloxirane, 2,2-diphenyloxirane, trans-2.3-diphenyloxirane, 2,2,3-triphenyloxirane, and 2,2,3,3-tetraphenyloxirane are reported. Comparison with the spectra of ethylene oxide (oxirane), benzene, and the following phenylethenes-styrene (1). I,1-diphenylethene (2), cis-stilbene (3), trans-stilbene (4), triphenylethene (5), and tetraphenylethene (6) - allowed to assign the lower ionization energies of the phenyloxiranes. Splitting of the lowest energy benzene π-orbitals is qualitatively the same in both classes of compounds. Because of the perpendicular orientation of the oxygen lone-pair in comparison to the π-electrons of the ethylene double bond this splitting is considerably smaller in phenyloxiranes.

Unsaturated and Benzannulated N-Heterocyclic Carbene Complexes of Titanium and Hafnium: Impact on Catalysts Structure and Performance in Copolymerization of Cyclohexene Oxide with CO2

Molecules ◽

10.3390/molecules25194364 ◽

2020 ◽

Vol 25 (19) ◽

pp. 4364

Author(s):

Lakshmi Suresh ◽

Ralte Lalrempuia ◽

Jonas B. Ekeli ◽

Francis Gillis-D’Hamers ◽

Karl W. Törnroos ◽

...

Keyword(s):

Density Functional ◽

Lone Pair ◽

Catalytic Performance ◽

Nbo Analysis ◽

Cyclohexene Oxide ◽

Group 4 ◽

Low Co2 ◽

And Performance ◽

High Yields ◽

Tridentate, bis-phenolate N-heterocyclic carbenes (NHCs) are among the ligands giving the most selective and active group 4-based catalysts for the copolymerization of cyclohexene oxide (CHO) with CO2. In particular, ligands based on imidazolidin-2-ylidene (saturated NHC) moieties have given catalysts which exclusively form polycarbonate in moderate-to-high yields even under low CO2 pressure and at low copolymerization temperatures. Here, to evaluate the influence of the NHC moiety on the molecular structure of the catalyst and its performance in copolymerization, we extend this chemistry by synthesizing and characterizing titanium complexes bearing tridentate bis-phenolate imidazol-2-ylidene (unsaturated NHC) and benzimidazol-2-ylidene (benzannulated NHC) ligands. The electronic properties of the ligands and the nature of their bonds to titanium are studied using density functional theory (DFT) and natural bond orbital (NBO) analysis. The metal–NHC bond distances and bond strengths are governed by ligand-to-metal σ- and π-donation, whereas back-donation directly from the metal to the NHC ligand seems to be less important. The NHC π-acceptor orbitals are still involved in bonding, as they interact with THF and isopropoxide oxygen lone-pair donor orbitals. The new complexes are, when combined with [PPN]Cl co-catalyst, selective in polycarbonate formation. The highest activity, albeit lower than that of the previously reported Ti catalysts based on saturated NHC, was obtained with the benzannulated NHC-Ti catalyst. Attempts to synthesize unsaturated and benzannulated NHC analogues based on Hf invariably led, as in earlier work with Zr, to a mixture of products that include zwitterionic and homoleptic complexes. However, the benzannulated NHC-Hf complexes were obtained as the major products, allowing for isolation. Although these complexes selectively form polycarbonate, their catalytic performance is inferior to that of analogues based on saturated NHC.