Far infra-red spectra and metal-ligand force constants of metal ammine complexes☆
01 Apr 1966-Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy (Elsevier)-Vol. 22, Iss: 4, pp 759-775
TL;DR: In this article, a normal co-ordinate analysis of these complex ions has been made, including all the ligand atoms, in order to check the vibration assignments made experimentally and to clarify the normal modes of vibration for the observed bands.
About: This article is published in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy.The article was published on 1966-04-01. It has received 93 citations till now. The article focuses on the topics: Ligand & Molecular vibration.
Citations
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TL;DR: In this article, the Urey-Bradley force constants for the corresponding metal-nitrogen stretching modes are estimated to be 0.553, 0.662, and 0.760 mdyn/A, respectively.
Abstract: The infrared spectra of porphin and its metal complexes with 64Zn, 68Zn, Cu, and Ni have been obtained from 4000 to 100 cm−1. Normal coordinate analyses have been carried out on the D4h model of the porphin complexes with 64Zn, 68Zn, Cu, and Ni. Only the eighteen in‐plane vibrations have been calculated. The results indicate that the bands between 1700 and 950 cm−1 are due to CC stretching, CN stretching, CH in‐plane bending, CCN in‐plane bending or coupled vibrations between these modes, and that the largest contribution of the metal‐nitrogen stretching coordinate is found in the vibrations at ≈ 203, 246, and 295 cm−1 of the Zn, Cu, and Ni complexes, respectively. The Urey‐Bradley force constants for the corresponding metal‐nitrogen stretching modes are estimated to be 0.553, 0.662, and 0.760 mdyn/A, respectively.
112 citations
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TL;DR: In this paper, a normal coordinate analysis was performed on chloro complexes employing a Urey-Bradley force field with resonance parameter and suitable general valence force field terms about the metal site.
89 citations
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78 citations
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TL;DR: In this article, the metal-nitrogen in-plane bending vibrations were measured in the frequency region from 300 to 200 cm −1 and the metal out-of-planar bending vibrations from 250 to 180 cm−1.
49 citations
References
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TL;DR: In this article, a general rule for writing down the coefficients of the transformation to symmetry coordinates is derived together with a method of obtaining the kinetic energy reciprocal matrix (G) in terms of symmetry coordinates with a minimum of algebra.
Abstract: Developments which reduce the labor of calculating the vibration frequencies of complex molecules are described. In particular a vectorial scheme is given for obtaining the reciprocal of the matrix of the kinetic energy in terms of valence‐type coordinates. A general rule for writing down the coefficients of the transformation to symmetry coordinates is derived together with a method of obtaining the kinetic energy reciprocal matrix (G) in terms of symmetry coordinates with a minimum of algebra. A treatment of redundant coordinates is developed. In addition, reduction of the secular equation by the splitting out of high frequencies, a new type of isotope product rule, and the determination of normal coordinates are discussed. The molecule CH3Cl is worked out as an illustration.
685 citations
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TL;DR: In this paper, a method for obtaining the secular equation for the vibration frequencies of a molecule directly in expanded form, i.e. as an algebraic rather than a determinantal equation, is described.
Abstract: A method is described for obtaining the secular equation for the vibration frequencies of a molecule directly in expanded form, i.e. as an algebraic rather than a determinantal equation. The force constants occur literally and the masses may occur either literally or numerically, as desired. The symmetry may be employed as usual to factor the secular equation. Several methods of obtaining approximate roots are described for which the expanded form is particularly suitable. Finally, an example, the nonlinear general triatomic molecule, is worked out algebraically.
651 citations
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230 citations
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TL;DR: In this article, the Urey-Bradley force field has been applied to more than one hundred molecules and the assignments based on these calculations have been shown to be reliable and transferable force constants.
Abstract: The calculations ofnormal vibrations have two aspects. One is the use of calculated frequencies for the assignments of observed vibrational bands. In this case a deviation of several percent is permissible. Mizushima together with the author and co-workers have applied the Urey-Bradley force field to more than one hundred molecules and the assignments based on these calculations have been shown to be reliabJ.el, 2, The second aspect is to obtain accurate force constants. During the past few years the author and co-workers* have tried to obtain reliable and transferable force constants. This paper will review results so far obtained. Recently, Crawford, Overend, Scherer, Hisatsune et al. have madeextensive studies ~m the U rey-Bradley field. I t is a pleasure for the author to include these results in this review. For the potential function of molecules we started from the Urey-Bradley force field3 (UBFF) and tried to classify various molecules according to whether this type of force field is adequate or not.
182 citations