# Dihydrogen bonding vs metal-σ interaction in complexes between H2 and metal hydride.
> 金属水素化物とH2錯体におけるジヒドロゲン結合と金属σ相互作用の理論的解析


## Abstract

Quantum chemical calculations at the MP2/aug-cc-pVTZ, MP2/aug-cc-pVQZ, and CCSD(T)/aug-cc-pVTZ levels were used to investigate complexes formed between molecular hydrogen and a series of metal hydrides including LiH, NaH, BeH2, MgH2, BH3, AlH3, Li2H2, Na2H2, Be2H4, and Mg2H4. The H2 molecule was found to function either as a Lewis acid or a Lewis base depending on the system. Lewis acid behavior produces dihydrogen-bonded complexes, whereas Lewis base behavior results in σ-bond donation from H2 into vacant metal orbitals. Intermolecular interactions were characterized using the quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analyses. Cooperativity effects in selected complexes containing two H2 molecules, where both interaction types coexist, were also examined.

### Mechanism

H2 acts as a Lewis acid to form dihydrogen bonds or as a Lewis base by donating σ-bond electron density into empty metal orbitals, with cooperativity observed when both modes occur simultaneously in complexes containing two H2 molecules.

## Bibliographic

- **Authors**: Alkorta I, Elguero J, Solimannejad M, Grabowski SJ
- **Journal**: J Phys Chem A
- **Year**: 2011 (2011-01-20)
- **PMID**: [21155597](https://pubmed.ncbi.nlm.nih.gov/21155597/)
- **DOI**: [10.1021/jp1100544](https://doi.org/10.1021/jp1100544)
- **Study type**: other
- **Delivery route**: not specified
- **Effect reported**: not assessed

## Delivery context

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

## Safety notes

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)

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> **Cite as**: H2 Papers — PMID 21155597. https://h2-papers.org/en/papers/21155597
> **Source**: PubMed PMID [21155597](https://pubmed.ncbi.nlm.nih.gov/21155597/)