Global minimum and a heap of low-lying isomers with planar tetracoordinate carbon in the CAl3MgH2− system

Malhan, Abdul Hamid; Thirumoorthy, Krishnan

doi:10.1039/d3cp05841g

Cited by 3 publications

(1 citation statement)

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“…However, the emergence of planar tetracoordinate carbon (ptC) challenges this fundamental paradigm, offering novel insights into unconventional bonding configurations. , Building upon the pioneering concepts of Hoffmann, Alder, and Wilcox in 1970, a systematic computational inquiry led by Schleyer, Pople, and collaborators culminated in the discovery of 1,1-dilithiocyclopropane, the seminal molecule favoring ptC geometry relative to the tetrahedrally coordinated alternative. To date, theoretical designs of ptC structures led to some emerging as thermodynamically favored global minima, − and a few were realized in the gas phase and laboratory. − These developments underscore the critical importance of meticulous adherence to geometric and electronic criteria. ,, Remarkably, the concept of a planar hypercoordinate atom extends beyond carbon, enveloping all main-group elements within the second period, except Ne, − and progressively extending into higher periods. − This robust expansion markedly enriches the planar hypercoordinate family, representing a pivotal leap forward in advancing our comprehension of atomic bonding. , …”

Section: Introductionmentioning

confidence: 99%

In_nTl_4–nH⁺ (n = 0∼4): Tetracoordinate Hydrogen in a Planar Fashion?

Cui,

Liu,

Zhang

et al. 2024

Inorg. Chem.

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The recent report of planar tetracoordinate hydrogen (ptH) in In 4 H + is very intriguing in planar hypercoordinate chemistry. Our high-level CCSD(T) calculations revealed that the proposed D 4h -symmetric ptH In 4 H + is a first-order saddle point with an imaginary frequency in the out-of-plane mode of the hydrogen atom. In fact, at the CCSD(T)/aug-cc-pV5Z/aug-cc-pV5Z-PP level, the C 4v isomer, with the H atom located 0.70 Å above the In 4 plane, is 0.5 kcal/mol more stable than the D 4h isomer. However, given the small perturbation from planarity and essentially barrierless C 4v ↔ D 4h ↔ C 4v transition, the vibrationally averaged structure can still be considered as a planar. Extending our exploration to the In n Tl 4−n H + (n = 0−3) systems, we found all these ptH structures, except for In 2 Tl 2 H + , to be the putative global minimum. The single σ-delocalized interaction between the central hydrogen atom and In n Tl 4−n ligand rings proves pivotal in establishing planarity and aromaticity and conferring substantial stability upon these rule-breaking ptH species.

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Section: Introductionmentioning

confidence: 99%

In_nTl_4–nH⁺ (n = 0∼4): Tetracoordinate Hydrogen in a Planar Fashion?

Cui,

Liu,

Zhang

et al. 2024

Inorg. Chem.

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FeC₄H₂: A Potential Astrophysical Molecule Featuring Planar Tetracoordinate Iron to Unveil the Mystery of Missing Iron in Interstellar Medium

Shajan,

Thirumoorthy

2024

ACS Earth Space Chem.

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The exploration of iron-containing species represents a prominent area in contemporary astrochemical investigations. Iron in the interstellar medium exhibits predominantly low concentrations, hinting at the potential presence of missing iron in either a condensed or molecular state. The FeC 4 H 2 neutral system has been investigated using computational calculations, emphasizing the hypothesis that missing iron may exist as iron−carbon hydride compounds or their higher order. A total of 61, 46, and 36 stationary points have been identified on the potential energy surface (PES) of the FeC 4 H 2 in the singlet, triplet, and quintet electronic states, respectively, showcasing the existence of a planar tetracoordinate iron (ptFe). A linear geometry represents the global minimum on the PES of FeC 4 H 2 as observed in the quintet ground electronic state. Meanwhile, the ptFe geometry is identified as the second most stable isomer in the quintet electronic state, which is the lowest energy solely in the singlet electronic state. Further, the observed ptFe geometry closely resembles the experimentally detected FeC 4 molecule in the gas phase. In light of its similarity to FeC 4 and the recent detection of FeC in the interstellar medium, the ptFe would be a potential astrophysical molecule that will also be identified in the gas phase. From that point of view, a comprehensive examination of the nature of chemical bonding of the ptFe geometry in the singlet, triplet, and quintet electronic states has been characterized, which dictates the stabilization of ptFe through multicenter bonding with surrounding carbon atoms. Ab initio molecular dynamics simulations revealed the dynamic stability of the system. Understanding the interstellar species with its structure and chemical bonding is an important aspect that would shed light on new insights into the experimental observations in the future.

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FeC4H22+ Encompassing Planar Tetracoordinate Iron: Structure and Bonding Patterns

Shajan,

Thirunavukkarsu,

Chandrasekaran

et al. 2024

Atoms

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The singlet, triplet, and quintet electronic states of the FeC4H22+ system are theoretically explored using quantum chemical methods, and 39 isomers are identified in the singlet electronic state and 4 isomers in both triplet and quintet electronic states. A molecule with a planar tetracoordinate iron (ptFe) is found on the potential energy surface of singlet and triplet electronic states. The bonding features of ptFe in the singlet electronic state are analyzed with natural bond orbital (NBO) analysis, adaptive natural density partitioning (AdNDP), and molecular orbital analysis. The resultant data delineate that the ptFe is stabilized through electron delocalization in the ptFe system.

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Global minimum and a heap of low-lying isomers with planar tetracoordinate carbon in the CAl₃MgH₂⁻ system

Abstract: A global minimum and a heap of low-lying isomers with planar tetracoordinate carbon (ptC) are identified in the CAl3MgH2– system by computational quantum chemical investigations. The nature of the chemical...

Cited by 3 publications

References 66 publications

In_nTl_4–nH⁺ (n = 0∼4): Tetracoordinate Hydrogen in a Planar Fashion?

In_nTl_4–nH⁺ (n = 0∼4): Tetracoordinate Hydrogen in a Planar Fashion?

FeC₄H₂: A Potential Astrophysical Molecule Featuring Planar Tetracoordinate Iron to Unveil the Mystery of Missing Iron in Interstellar Medium

FeC4H22+ Encompassing Planar Tetracoordinate Iron: Structure and Bonding Patterns

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Global minimum and a heap of low-lying isomers with planar tetracoordinate carbon in the CAl3MgH2− system

Abstract: A global minimum and a heap of low-lying isomers with planar tetracoordinate carbon (ptC) are identified in the CAl3MgH2– system by computational quantum chemical investigations. The nature of the chemical...

Cited by 3 publications

References 66 publications

InnTl4–nH+ (n = 0∼4): Tetracoordinate Hydrogen in a Planar Fashion?

InnTl4–nH+ (n = 0∼4): Tetracoordinate Hydrogen in a Planar Fashion?

FeC4H2: A Potential Astrophysical Molecule Featuring Planar Tetracoordinate Iron to Unveil the Mystery of Missing Iron in Interstellar Medium

FeC4H22+ Encompassing Planar Tetracoordinate Iron: Structure and Bonding Patterns

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Global minimum and a heap of low-lying isomers with planar tetracoordinate carbon in the CAl₃MgH₂⁻ system

In_nTl_4–nH⁺ (n = 0∼4): Tetracoordinate Hydrogen in a Planar Fashion?

In_nTl_4–nH⁺ (n = 0∼4): Tetracoordinate Hydrogen in a Planar Fashion?

FeC₄H₂: A Potential Astrophysical Molecule Featuring Planar Tetracoordinate Iron to Unveil the Mystery of Missing Iron in Interstellar Medium