An isolable, crystalline complex of square-planar silicon(IV)

Chem, Год журнала: 2021, Номер 7(8), С. 2151 - 2159

Опубликована: Июнь 9, 2021

The structure and reactivity of silicon(IV), the second most abundant element in our Earth's crust, is determined by its invariant tetrahedral coordination geometry. Silicon(IV) with a square-planar configuration (ptSiIV) represents transition state. Quantum theory supported feasibility stabilizing ptSiIV structural constraint, but isolation has not been achieved yet. Here, we present synthesis full characterization first coordinated silicon(IV). planarity provokes an extremely low-lying unoccupied molecular orbital that induces unusual silicon redox chemistry CH-agostic interactions. small separation frontier orbitals enables visible-light ligand-element charge transfer bond-activation reactivity. Previously, such characteristics have reserved for d-block metals or low-valent p-block elements. Planarization transfers them, time, to normal valence

Язык: Английский

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Ligand-enforced geometric constraints and associated reactivity in p-block compounds

Chemical Society Reviews, Год журнала: 2023, Номер 53(2), С. 764 - 792

Опубликована: Дек. 15, 2023

This review presents a group-wise summary of ligand enforced non-VSEPR geometries in compounds the p-block elements and discusses emergent consequences for reactivity.

Язык: Английский

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Synthesis and Reactivity of an Anti-van’t Hoff/Le Bel Compound with a Planar Tetracoordinate Silicon(II) Atom

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(13), С. 7084 - 7089

Опубликована: Март 21, 2023

For a long time, planar tetracoordinate carbon (ptC) represented an exotic coordination mode in organic and organometallic chemistry, but it is now useful synthetic building block. In contrast, realization of silicon (ptSi), heavier analogue ptC, still challenging. Herein we report the successful synthesis unusual reactivity first ptSi species divalent present 3, supported by chelating bis(N-heterocyclic silylene)bipyridine ligand, 2,2'-{[(4-tBuPh)C(NtBu)]2SiNMe}2(C5N)2, 1]. The compound resulted from direct reaction 1 with Idipp-SiI2 [Idipp = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene]. Alternatively, can also be synthesized two-electron reduction corresponding Si(IV) precursor 2 molar equiv KC10H8. Density functional theory calculations show that lone pair at ptSi(II) resides almost completely its 3pz orbital, very different known four-coordinate silylenes. Oxidative addition MeI to atom affords pentacoordinate 4, methyl group located apical position. Remarkably, [CuOtBu] leads regeneration bis(silylene) arms via Si-Si bond scission induces Si(II) → oxidation central concomitant bipyridine moiety form neutral bis(silylene)silyl Cu(I) complex 5.

Язык: Английский

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Exploring the Use of “Honorary Transition Metals” To Push the Boundaries of Planar Hypercoordinate Alkaline-Earth Metals

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(24), С. 16689 - 16697

Опубликована: Июнь 6, 2024

The quest for planar hypercoordinate atoms (phA) beyond six has predominantly focused on transition metals, with dodecacoordination being the highest reported thus far. Extending this bonding scenario to main-group elements, which typically lack d orbitals despite their larger atomic radius, posed significant challenges. Intrigued by potentiality of covalent formation using heavier alkaline-earth metals (Ae = Ca, Sr, Ba), so-called "honorary metals", we aim push boundaries hypercoordination. By including rings formed 12–15 boron–carbon and Ae centers, propose a design scheme 180 candidates phA. Further systematic screening, structural examination, stability assessments identified 10 potential clusters metal (phAe) as lowest-energy form. These unconventional structures embody dodeca-, trideca-, tetradeca-, pentadecacoordinate atoms. Chemical analyses reveal important role in facilitating interactions between central atom surrounding rings, thereby establishing new record coordination numbers two-dimensional realm.

Язык: Английский

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Planar pentacoordinate s-block metals

Chemical Science, Год журнала: 2023, Номер 14(33), С. 8785 - 8791

Опубликована: Янв. 1, 2023

The presence of a delocalized π-bond is often considered an essential criterion for achieving planar hypercoordination. Herein, we show that σ-delocalization could be sufficient to make the configuration most stable isomer in series pentacoordinate s-block metals. High-level ab initio computations reveal global minimum interalkali and interalkali-alkaline earth clusters (LiNa5, Li5Mg+, Na5Mg+, K5Ca+, CaRb5+, Rb5Sr+, SrCs5+) adopts singlet D5h structure with lithium or alkaline metal (AE = Mg, Ca, Sr). These are unusual combinations stabilize atom, as all their constituents electropositive. Despite absence π-electrons, Hückel's rule fulfilled by six σ-electrons. Furthermore, systems exhibit diatropic ring current response external magnetic field strong shielding, so they might classified σ-aromatic. Therefore, multicenter σ-bonds resulting these clusters, even though lack π-aromaticity.

Язык: Английский

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Planar tetracoordinate fluorine in FMg4Se4– cluster

Physical Chemistry Chemical Physics, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

Through bridging chalcogens, a star-like cluster FMg 4 Se − featuring planar tetracoordinate fluorine is designed theoretically. The configuration of attributed to electrostatic interactions and covalent interactions.

Язык: Английский

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Calix[4]pyrrolato-germane-(thf)₂: Unlocking the Anti-van’t Hoff–Le Bel Reactivity of Germanium(IV) by Ligand Dissociation

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(32), С. 17746 - 17754

Опубликована: Авг. 7, 2023

Anti-van't Hoff-Le Bel configured p-block element species possess intrinsically high reactivity and are thus challenging to isolate. Consequently, numerous elements in this configuration, including square-planar germanium(IV), remain unexplored. Herein, we follow a concept reach anti-van't by ligand dissociation from rigid calix[4]pyrrole germane its bis(thf) adduct. While the macrocyclic assures coordination uncomplexed form, labile thf donors provide robustness for isolation on multigram scale. Unique properties of low-lying acceptor orbital imparted germanium(IV) can be verified, e.g., isolating an elusive anionic hydrido germanate exploiting it bond activations. Aldehydes, water, alcohol, CN triple activated first time germanium-ligand cooperativity. Unexpected behaviors against fluoride ion disclose critical interferences putative redox-coupled transfer during experimental determination Lewis acidity. Overall, showcase how lability grants access uncharted chemistry line up as member emerging class structurally constrained elements.

Язык: Английский

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Heavier tetrylene- and tetrylyne-transition metal chemistry: it's no carbon copy

Chemical Society Reviews, Год журнала: 2024, Номер 53(19), С. 9738 - 9831

Опубликована: Янв. 1, 2024

Developments in synthetic methods for and reactivity of heavier tetrylene tetrylyne complexes the d-block elements are summarised, with a view towards cooperative bond activation utilisation catalysis.

Язык: Английский

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Transition Metal Carbide Complexes

Chemical Reviews, Год журнала: 2021, Номер 122(1), С. 830 - 902

Опубликована: Ноя. 19, 2021

Carbide complexes remain a rare class of molecules. Their paucity does not reflect exceptional instability but is rather due to the generally narrow scope synthetic procedures for constructing carbide complexes. The preparation typically revolves around generating LnM–CEx fragments, followed by cleavage C–E bonds coordinated carbon-based ligands (the alternative being direct C atom transfer). Prime examples involve deoxygenation carbonyl and deprotonation methyl ligands, several other p-block fragments can be cleaved off afford ligands. This Review outlines strategies toward terminal complexes, bridging as well carbide–carbonyl cluster It then surveys reactivity covering stoichiometric reactions where act C1 reagents, engage in cross-coupling reactions, enact Fischer–Tropsch-like chemistry; addition, we discuss context catalysis. Finally, examine spectroscopic features which helps establish presence functionality address its electronic structure.

Язык: Английский

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Bare and ligand protected planar hexacoordinate silicon in SiSb₃M₃⁺ (M = Ca, Sr, Ba) clusters

Chemical Science, Год журнала: 2022, Номер 13(27), С. 8045 - 8051

Опубликована: Янв. 1, 2022

The occurrence of planar hexacoordination is very rare in main group elements. We report here a class clusters containing hexacoordinate silicon (phSi) atom with the formula SiSb

Язык: Английский

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