On the nature of metal-carbon bonding: AIM and ELF analyses of MCH(n) (n = 1-3) compounds containing early transition metals.

The journal of physical chemistry. A · 2005 · No effect · Insufficient evidence

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No effectInsufficient evidencePaper 3584

Study snapshot

PublicationThe journal of physical chemistry. A · 2005

Study typein_vitro

Reported directionNo effect

Evidence ratingInsufficient

Abstract

Ab initio and DFT calculations have been performed on a series of organometallic compounds, according to the formula MCH(n), where M = K, Ca, Sc, Ti, V, Cr, or Mn and n = 1-3. Various theoretical methods are compared, the B3LYP level yielding the same agreement with the experimental geometries available as the correlated MP2 and CISD methods, with the 6-311++G(3df,2p) basis set for C and H and Wachter's (15s11p6d3f1g)/[10s7p4d3f1g] basis set for transition metals. The main geometric and electronic features of the molecules studied are described, analyzing the M-C bonding characteristics in terms of the atoms in molecules theory (AIM) and the electron localization function (ELF). Although multiple bonding is expected from the Lewis bonding scheme, the results indicate an almost pure ionic bond for all of the systems studied. The net charge transfer from the metal to the carbon atom ranges from 0.5 to 1 e(-), and the electronic structure of the CH(n)(-) moiety is unaltered after the interaction with the metal cation, showing little or no effect on the shape of the electron pairing. The bond paths corresponding to a possible alpha-agostic bond for these systems are not present.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typein_vitro

Effect directionno_effect

PopulationNot supplied

Sample sizeNot supplied

ExposureNot supplied

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

Ab initio and DFT calculations (including B3LYP, MP2, and CISD) on MCH(n) (M = K, Ca, Sc, Ti, V, Cr, Mn; n = 1–3) indicate the M–C bond is almost purely ionic across all systems studied. Net charge transfer from metal to carbon is reported to range from 0.5 to 1 e−, the CH(n)− moiety electronic structure is described as largely unaltered upon interaction with the metal cation, and bond paths corresponding to a possible α-agostic bond are reported as absent.

Outcomes measured

M–C bonding characteristics (AIM analysis)
Electron localization function (ELF) features
Net charge transfer (metal to carbon)
Presence/absence of bond paths consistent with α-agostic bonding

Limitations

Computational/theoretical study; no EMF exposure assessed
No biological or health outcomes reported
No sample size stated (molecules/systems analyzed not quantified in abstract)

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": null,
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "M–C bonding characteristics (AIM analysis)",
    "Electron localization function (ELF) features",
    "Net charge transfer (metal to carbon)",
    "Presence/absence of bond paths consistent with α-agostic bonding"
  ],
  "main_findings": "Ab initio and DFT calculations (including B3LYP, MP2, and CISD) on MCH(n) (M = K, Ca, Sc, Ti, V, Cr, Mn; n = 1–3) indicate the M–C bond is almost purely ionic across all systems studied. Net charge transfer from metal to carbon is reported to range from 0.5 to 1 e−, the CH(n)− moiety electronic structure is described as largely unaltered upon interaction with the metal cation, and bond paths corresponding to a possible α-agostic bond are reported as absent.",
  "effect_direction": "no_effect",
  "limitations": [
    "Computational/theoretical study; no EMF exposure assessed",
    "No biological or health outcomes reported",
    "No sample size stated (molecules/systems analyzed not quantified in abstract)"
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "ab initio",
    "DFT",
    "B3LYP",
    "MP2",
    "CISD",
    "organometallic",
    "metal-carbon bonding",
    "AIM",
    "atoms in molecules",
    "ELF",
    "electron localization function",
    "charge transfer",
    "agostic bond"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1021/jp050146q
PubMed: 16834119

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