Kraftkonstanten und Bindungsgrade von Stickstoffverbindungen

Goubeau, J.

doi:10.1002/ange.19660781103

Cited by 57 publications

(2 citation statements)

References 86 publications

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“…Meanwhile, various efficient syntheses for the archetypal transition metal nitrides (M = Mo, W) NMCl 3 , 1 , have appeared − (Chart ). From the calculation of the force constants a bond order of 2.2 could be deduced for the related Mo⋮N bond. When the central atom M is a heavier d 6 transition metal (M = Mo, W), ring structures are observed. , The matter has been now summarized in recent reviews. − The best-known ring system is the tetramer, 2 , characterized for M = Mo and W. − Meanwhile, trimer structures, 3 , have also become known. , Of the higher homologues, the pentamers and hexamers have not been reported so far.…”

Section: Introductionmentioning

confidence: 99%

Ring Structure Formation in Transition-Metal Nitrido Chlorides by Donor−Acceptor Formation

Schoeller

Sundermann

1998

Inorg. Chem.

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According to quantum chemical calculations, nitrido chlorides constituted from d6 transition metals form ring structures which are best described as weak donor−acceptor complexes between the lone pair at nitrogen and the empty d orbitals at the transition metal. The stabilities of the ring structures increase in the order Cr < Mo < W. The transition metal Cr forms only endothermic ring systems, and these in turn decompose into monomers. A comparison of several homologous oligomers of NMoCl3 shows maximum stability for the tetramer, in agreement with the experimental findings. This particular stability of the tetramer is due to a perfect alignment of the nitrogens between two metal centers. The vibrational analyses reveal that the character of the monomers is nearly conserved in the ring systems. An analysis of the electron densities on the basis of Bader's method of atoms in molecules as well as of the natural bond orbitals (NBO) substantiates the weak ring stabilities.

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Section: Introductionmentioning

confidence: 99%

Ring Structure Formation in Transition-Metal Nitrido Chlorides by Donor−Acceptor Formation

Schoeller

Sundermann

1998

Inorg. Chem.

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“…The present analysis suggests here bond strengths of about 2.5 and 0.5 v.u. Using force constants derived from vibrational spectra, Goubeau (1966) ascribes a Bindungsgrad of 2.2 to the multiple bond in [MoC13N]. For the short terminal monosubstituted alkyl imido moiety with a MoV-N bond length of 1.733 (4) A in [Mo2(r/5-CsHs)2{(CH3)3CN}2 -(p-S)2] (Dahl, Frisch & Gust, 1974), a bond strength of about 1.6 v.u.…”

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confidence: 99%

Molybdenum–nitrogen bond-strength bond-length relationships

Bart¹,

Ragaini²

1980

Acta Crystallogr B Struct Crystallogr Cryst Chem

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Generalization of the Badger Rule Based on the Use of Adiabatic Vibrational Modes

Kraka

Larsson

Cremer

2010

Computational Spectroscopy

117

150

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Empirical relationships relating bond lengths to the corresponding bond stretching frequencies or bond stretching force constants were first derived in 1920s (see Table 4.1 for a summary) and have ever since been a topic of research on the nature of the chemical bond . It is remarkable that in a time of easily accessible quantum chemical results, there remains a need for empirically based estimates of either bond lengths or stretching frequencies. There are three primary reasons why such empirical rules and relationships are still valuable tools for modern research:(1) Established relationships between bond properties add to our understanding of the chemical bond, especially if they can be rationalized on a quantum mechanical basis because bonding between atoms is a quantum mechanical phenomenon.(2) There are experimental situations in which it is relatively easy to measure one bond property but difficult to obtain other bond properties. For example, it is easier to measure the vibrational spectra of a compound than to carry out a structural analysis. This is especially true for solid materials that do not crystallize, molecules on a surface, or molecules in some form of aggregation. If quantum chemical calculations are feasible only for model systems rather than the actual targets of chemical research, then vibrational spectroscopy may be the only tool for obtaining information that provides an insight into bond properties. (3) In the realm of computational chemistry, there is also a need for empirical relationships. They may be used to determine suitable bonding force fields for molecular mechanics utilizing force constant -bond length relationships. For quantum chemical geometry optimization, there is the need to set up a guess matrix of energy second derivatives (the Hessian matrix corresponding to the force constant matrix of a molecule), which is best done with the help of available geometry information and a suitable force constant -bond length relationship. For example, the standard procedure to calculate the geometry of a molecule is based on an initial guess of the energy Hessian derived with the help of the Badger rule [42,55]. It is due to these three reasons that there is ongoing research exploring the relationships between bond length r, bond stretching Computational Spectroscopy: Methods, Experiments and Applications. Edited by J€ org Grunenberg

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Kraftkonstanten und Bindungsgrade von Stickstoffverbindungen

Cited by 57 publications

References 86 publications

Ring Structure Formation in Transition-Metal Nitrido Chlorides by Donor−Acceptor Formation

Ring Structure Formation in Transition-Metal Nitrido Chlorides by Donor−Acceptor Formation

Molybdenum–nitrogen bond-strength bond-length relationships

Generalization of the Badger Rule Based on the Use of Adiabatic Vibrational Modes

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