scholarly journals Experimental and computational evidence for a stabilising C–Cl(lone-pair)⋯π(chelate-ring) interaction

CrystEngComm ◽  
2021 ◽  
Vol 23 (1) ◽  
pp. 119-130
Author(s):  
Sang Loon Tan ◽  
See Mun Lee ◽  
Kong Mun Lo ◽  
A. Otero-de-la-Roza ◽  
Edward R. T. Tiekink

Stabilising C–Cl(lone-pair)⋯π(chelate ring) interactions are described.

2020 ◽  
Author(s):  
Olivier Charles Gagné

The scarcity of nitrogen in Earth’s crust, combined with challenging synthesis, have made inorganic nitrides a relatively-unexplored class of compounds compared to their naturally-abundant oxide counterparts. To facilitate exploration of their compositional space via <i>a priori</i> modeling, and to help <i>a posteriori</i> structure verification not limited to inferring the oxidation state of redox-active cations, we derive a suite of bond-valence parameters and Lewis-acid strength values for 76 cations observed bonding to N<sup>3-</sup>, and further outline a baseline statistical knowledge of bond lengths for these compounds. We examine structural and electronic effects responsible for the functional properties and anomalous bonding behavior of inorganic nitrides, and identify promising venues for exploring uncharted compositional spaces beyond the reach of high-throughput computational methods. We find that many mechanisms of bond-length variation ubiquitous to oxide and oxysalt compounds (e.g., lone-pair stereoactivity, the Jahn-Teller and pseudo Jahn-Teller effects) are similarly pervasive in inorganic nitrides, and are occasionally observed to result in greater distortion magnitude than their oxide counterparts. We identify inorganic nitrides with multiply-bonded metal ions as a promising venue in heterogeneous catalysis, e.g. in the development of a post-Haber-Bosch process proceeding at milder reaction conditions, thus representing further opportunity in the thriving exploration of the functional properties of this emerging class of materials.<br>


2017 ◽  
Author(s):  
Arpita Yadav ◽  
Dasari L V K Prasad ◽  
Veejendra Yadav

<p>The torquoselectivity, the inward or outward ring opening of 3-substituted cyclobutenes, is conventionally guided by the donor and/or acceptor ability of the substituent (S). It is typically predicted by estimating the respective ring opening transition state (TS) barriers. While there is no known dissent in regard to the outward rotation of electron-rich substituents from the approaches of TS calculations, the inward rotation was predicted for some electron-accepting substituents and outward for others. To address this divergence in predicting the torquoselectivity, we have used reliable orbital descriptors through natural bond orbital theoretical calculations and demonstrated that (a) interactions <i>n</i><i><sub>S</sub></i>→s*<sub>C3C4</sub> for a lone pair containing substituent, s<sub>S</sub>→s*<sub>C3C4</sub> for a s-donor substituent, s<sub>C3C4</sub>→p*<sub>S</sub> for a resonance-accepting substituent and s<sub>C3C4</sub>→s*<sub>S</sub> for a s-acceptor substituent constitute the true electronic controls of torquoselectivity, and (b) reversibility of the ring opening event is an additional important contributor to the observed product distribution.</p>


Author(s):  
Olivier Charles Gagné ◽  
Frank Christopher Hawthorne

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.


Author(s):  
Olivier Charles Gagné ◽  
Frank Christopher Hawthorne

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.


Author(s):  
Olivier Charles Gagné ◽  
Frank Christopher Hawthorne

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 O<sup>2-</sup> is discussed, as well as the polymerization of the PO<sub>4</sub> group.


2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Mircea Braban ◽  
Ionel Haiduc

The paper describes the solid state structure of a compound of composition [Cu(bipy)3][Cu(bipy)(ala) (ClO4)2]ClO4, in which both the cation and anion are octahedral complex species with copper(II) as coordination center. The cation contains three chelate rings formed by bipy; the anion contains in the quatorial plane a CuONC2 chelate ring formed by the alaninato ligand and a CuN2C2 chelate ring formed by bipy, with two monodentate perchorato ligands in axial positions completing the six-coordination. In the crystal p-p stackings lead to a supramolecular self-assembled structure.


1990 ◽  
Vol 55 (6) ◽  
pp. 1427-1434 ◽  
Author(s):  
František Pavelčík ◽  
Eva Luptáková

The conformational surface of the Co(en) chelate ring was studied by the method of structural correlation. The reduction of dimensionality of the conformation problem was achieved by employing the pseudorotation concept. The empirical potential surface was obtained by statistical treatment of 743 independent conformations from the Cambridge Structural Database. The theoretical potential surface was obtained by molecular mechanics. The minimal-energy conformation is gauche with the Co atom on the two-fold axis. Conformational flexibility also includes an envelope conformation with the N atom bent out of the plane. The transition between the mirror-image symmetrical conformations can occur by a pseudorotation pathway and is accompanied by increased planarity of the ring. The transition state is an envelope conformation with an out-plane Co atom.


2021 ◽  
Author(s):  
Anna A Mukhacheva ◽  
Tatyana Asanova ◽  
Maxim R. Ryzikov ◽  
Taisiya Sergeevna Sukhikh ◽  
Nikolay B. Kompankov ◽  
...  
Keyword(s):  

Bi3+ and Pb2+ uptake by [PW11O39]7– monolacunary Keggin-type anion leads to the formation of [PW11O39Bi]4– and [PW11O39Pb]5– complexes with stereochemically active lone pair at the incorporated heterometal. Both complexes were...


2021 ◽  
Vol 23 (15) ◽  
pp. 9121-9129
Author(s):  
Weixing Li ◽  
Imanol Usabiaga ◽  
Camilla Calabrese ◽  
Luca Evangelisti ◽  
Assimo Maris ◽  
...  
Keyword(s):  

Stronger and more flexible lone pair⋯π–hole interaction of ammonia with respect to water in complexes with perfluorinated arenes.


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