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Structure and Bonding of Alkenes

Structure and Bonding of Alkenes

Olefins, which are unsaturated hydrocarbons containing one or more carbon–carbon double bonds, are broadly divided into alkenes and cycloalkenes. The general chemical formula of an alkene is CnH2n.
Doubly bonded carbons are sp2 hybridized and have a trigonal planar geometry. The double bond is composed of a σ bond formed by the overlap of hybrid orbitals and a π bond produced by the lateral overlap of unhybridized 2p orbitals on both the carbons. Each carbon atom is...

Structure of Alkanes

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The formation of carbon-carbon bonds leading to the creation of the carbon chain is the basis of organic chemistry. August Kekulé and Archibald Scott Couper independently developed this idea of carbon chain formation.
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Structure and Physical Properties of Alkynes

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Introduction:
In nature, compounds containing both carbon and hydrogen are known as "hydrocarbons". Aliphatic hydrocarbons are compounds whose molecules contain saturated single bonds (i.e., alkanes) or unsaturated double or triple bonds. Alkenes contain carbon–carbon double bonds and have a structural formula CnH2n. Unsaturated hydrocarbons containing carbon–carbon triple bonds are called "alkynes" and are structurally represented by the formula CnH2n-2.
The...

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Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.

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The molecular ions of linear alkanes prefer to fragment at the carbon-carbon bond away from the end of the chain since the cleavage of an inner bond creates a stable carbocation and a stable radical. Consequently, the mass signals of linear alkanes feature intense peaks in the middle of the mass-to-charge ratio plot with weaker peaks on either end. The fragmentation of each carbon-carbon bond with the release of a methyl group in each splitting leads to prominent peaks in the mass spectra...

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Preparation of SNS CobaltII Pincer Model Complexes of Liver Alcohol Dehydrogenase

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Characterisation of alkane σ-complexes.

Rowan D Young¹

¹Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543 (Singapore). rowan.young@nus.edu.sg.

Chemistry (Weinheim an Der Bergstrasse, Germany)

|September 9, 2014

Summary

This summary is machine-generated.

Metal alkane σ-complexes are increasingly studied. This review details their bonding metrics, binding modes, selectivity, and stability, advancing understanding of these intermediates.

Keywords:

CH activation alkanes coordination modes rhenium

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Area of Science:

Organometallic Chemistry
Coordination Chemistry
Chemical Bonding

Background:

Alkane σ-complexes have transitioned from curiosities to key intermediates in chemical research.
Historically, geometric characterization was limited, leading to assumptions based on related complexes or C-H activation products.

Purpose of the Study:

To review and illuminate the bonding metrics of alkane-metal bonds.
To critically analyze the binding modes, selectivity, and stability of metal alkane complexes.

Main Methods:

Literature review of studies employing UV/Vis, IR, NMR spectroscopy, and X-ray and neutron diffractometry.
Assembly of data illuminating alkane-metal bonding metrics.
Critical analysis of binding characteristics.

Main Results:

Detailed characterization of metal alkane complexes has advanced significantly over the past fifteen years.
Established metrics for alkane-metal bonding are now available.
Insights into binding modes, selectivity, and stability have been elucidated.

Conclusions:

The understanding of metal alkane σ-complexes has matured due to advanced characterization techniques.
This review provides a critical analysis of their bonding, selectivity, and stability.
Further research is fueled by the growing interest in these important chemical intermediates.