Infrared Spectra of Metal‐Chelate Compounds. I. A Normal Coordinate Treatment on Bis‐(Acetylacetonato)‐Cu(II)

A normal coordinate treatment on the chelate ring of bis‐(acetylacetonato)‐Cu(II) gives calculated frequencies in good agreement with the observed ones in the 1700 and 350 cm—1 range obtained with NaCl, KBr, and CsBr optics. In order to assign the observed bands and to see the coupling between various vibrational modes, the L matrices and the potential energy distribution, Lii2Fi were calculated for all the in‐plane vibrations. The results reveal that (1) the band at 1580 cm—1 previously assigned to asym. CO stretching is asym. CC stretching, (2) the bands at 684 and 654 cm—1 formerly suggested to be metal‐oxygen stretching modes are metal‐oxygen stretching vibrations coupled with ring deformation and CCH3 bending modes, respectively, and (3) a new band found at 455 cm—1 is the sym. Cu–O stretching mode. By comparing the force constants of the Cu–O stretching vibration with those of metal‐nitrogen and metal‐carbon bonds of other compounds, it is suggested that the Cu–O bond in this compound has double bon...

[1]  F. Cotton,et al.  Spectral Investigations of Metal Complexes of β-Diketones. I. Nuclear Magnetic Resonance and Ultraviolet Spectra of Acetylacetonates1 , 1958 .

[2]  R. West.  Notes - Structures of Silyl Derivatives of Ethyl Acetoacetate , 1958 .

[3]  A. Winston,et al.  The Infrared Spectra of Some metal Chelates of β-Diketones , 1958 .

[4]  R. West,et al.  The infra-red spectra of metal acetylacetonates in the sodium chloride region , 1958 .

[5]  J. Collman,et al.  Infrared Absorption of Metal Chelate Compounds of 1,3-Diketones1 , 1957 .

[6]  R. Roof.  The crystal structure of ferric acetylacetonate , 1956 .

[7]  I. Wender,et al.  Spectra and Structures of Cobalt Carbonyls1 , 1955 .

[8]  Y. Kakiuti.  The Normal Vibrations of Some Silicon Tetrahalides as Calculated by Urey-Bradley Field , 1953 .

[9]  Yonezo Morino,et al.  A Note on the Classification of Normal Vibrations of Molecules , 1952 .

[10]  G. Spicer,et al.  908. Compounds of curcumin and boric acid. Part III. Infra-red studies of rosocyanin and allied compounds , 1952 .

[11]  J. Lecomte.  Infra-red adsorption spectra of metallic acetyl-acetonates , 1950 .

[12]  T. Simanouti.  The Normal Vibrations of Polyatomic Molecules as Treated by Urey‐Bradley Field , 1949 .

[13]  Walter Gordy,et al.  A Relation between Bond Force Constants, Bond Orders, Bond Lengths, and the Electronegativities of the Bonded Atoms , 1946 .

[14]  M. Calvin,et al.  Stability of Chelate Compounds , 1945 .

[15]  L. Pauling.  The Nature Of The Chemical Bond , 1939 .