Absorption spectra of complexes

Figure 25 Comparison of the UY-visible absorption spectra of complexes (22), (24), and (43) in ethanol...

Lever, A. B. P. (1984). Inorganic Electronic Spectroscopy, 2nd ed. Elsevier, New York. A monograph that treats all aspects of absorption spectra of complexes at a high level. This is perhaps the most through treatment available in a single volume. Highly recommended. 

Jones jr., E. J. The Ultraviolet Absorption Spectra of Complex Hydroxy... 

Electronic absorption spectra of complexes formed between cyanine dyes 27 with K3[Fe(CN)g] and K2[Ni(CN)4] in acetonitrile were reported <2002MI557>. The overlap of bands produced by electronic transitions of the metals with the bands due to transition with the dyes did not allow for an unambiguous conclusion regarding the coordination polyhedra of iron and nickel in these complexes. 

Figure 7 Ultraviolet-visible absorption spectra of complexes 22 and 37 in ethanol solution at room temperature.

In Chapter 5 the absorption spectra of complexes of interacting atoms were considered. If some or all of the interacting members of a complex are molecular, additional degrees of freedom exist and may be excited in the presence of radiation. As a result, besides the translational profiles discussed in Chapter 5, new spectral bands appear at the rotovibrational transition frequencies of the molecules involved, and at sums and differences of such frequencies - even if the non-interacting molecules are infrared inactive. The theory of absorption by small complexes involving molecules is considered in the present Chapter. 

C. K. Jorgensen, "Absorption Spectra of Complexes of Heavy Metals," Report to II. S. Army, Frankfort am Main, October, 1958,... 

Analysis of the Absorption Spectra of Complex Pentavalent Actinide Halides. LiUF6, o -NaUF6 and CsUFg. H.G. Hecht, J.G. Malm, J. Foropoulus, and W.T. Camall, J. Chem. Phys. 84, 3653-3662 (1986). 

The absorption spectra of complexes 18-20 are dominated by the MLCT transitions in the visible region, and the lowest allowed MLCT bands appearing at 400 and 545 nm. The molar extinction coefficients of these bands are close to 35 000 and 19 000 M 1cm 1, respectively, which are significantly higher than those of the standard sensitizer ris-dithiocyanatobis(4,4 -dicarboxy-2,2/-bipyridine)Ru(II), (2) (Fig. 9). 

Fig. 11 UV-Vis absorption spectra of complexes 24 and 2 (concentration 3.5 x 1CT5 M) and N719 (concentration 2.0 x 10-5 M) measured in ethanol solution and their chemical structures...

The electronic absorption spectra of complex molecules at elevated temperatures in condensed matter are generally very broad and virtually featureless. In contrast, vibrational spectra of complex molecules, even in room-temperature liquids, can display sharp, well-defined peaks, many of which can be assigned to specific vibrational modes. The inverse of the line width sets a time scale for the dynamics associated with a transition. The relatively narrow line widths associated with many vibrational transitions make it possible to use pulse durations with correspondingly narrow bandwidths to extract information. For a vibration with sufficiently large anharmonicity or a sufficiently narrow absorption line, the system behaves as a two-level transition coupled to its environment. In this respect, time domain vibrational spectroscopy of internal molecular modes is more akin to NMR than to electronic spectroscopy. The potential has already been demonstrated, as described in some of the chapters in this book, to perform pulse sequences that are, in many respects, analogous to those used in NMR. Commercial equipment is available that can produce the necessary infrared (IR) pulses for such experiments, and the equipment is rapidly becoming less expensive, more compact, and more reliable. It is possible, even likely, that coherent IR pulse-sequence vibrational spectrometers will... 

In spite of the difficulties, some specific studies involving absorption spectra of complexes such as oxydiacetates of Pr(III), Nd(III), Eu(III) and Er(III), benzoylacetonates of Eu(III) and monodiketonates of Eu(III) have been made with some success [184-186]. The experimental and calculated absorption spectra of oxydiacetate (ODA) complexes of Pr(III) are shown in Fig. 8.36. 

Fig. IS. Absorption spectra of complex [Mn(Salen) (HjO)]-" (a) 0.1 M HNOj, (b) adsorbed onto Nafion film coated on ITO electrode and (c) after the complex was adsorbed on to ITO electrode held at an applied potential of 1.3V/SCE for 10 min. (Reproduced with permission from Elsevier Science Publishers B.V.)...

The corrole-corrole dimers of Schemes 2.1.91 and 2.1.92 each exhibit optical spectra that are similar to those of an octaalkylcorrole, with no significant modifications in either the Soret or Q-band regions." Thus, the corrole dimer system 2.250a, for instance, exhibits a Soret band at 400/410 nm (e = 112 000 and 82 000 M cm respectively) and Q-bands at 542 nm and 597 nm (e = 24 000 and 28 000 M cm , respectively). Similarly, the electronic absorption spectra of complexes 2.253 and 2.254 do not differ significantly from spectra of analogous monomeric cobalt(III) corrole complexes. This leads the authors of this monograph to conclude that little electronic interaction exists between the two subunits. 

If a molecule consists of several weakly coupled chromophores it may be advantageous to speak of intramolecular CT transitions. The MIM method for calculating the absorption spectra of complex molecules, which has been mentioned in the discussion of substituent effects in Section 2.4.2, is based on this idea. 

The problems involved in assignments of the electronic absorption spectra of complex OTM compounds have been formidable, as indicated, for example by the many reported interpretations of the optical absorption spectra of ferrocene (9-14). The spectra of simpler complexes, such as metal carbonyls, however, have been somewhat more successfully interpreted with applications of MO theory (1,3-5,15). In this section very simple considerations are employed to illustrate the various types of electronic transitions in OTM complexes. While qualitative aspects of the spectral... 

Tellurium has been determined in mixtures with Ga, Pb, In, Ba, Cu, and A1 by using a mathematical treatment of the absorption spectra of complexes with nitrophenylfluorone [53,54],... 

Streng LV, Streng AG (1965) Inorg. ChenL 4 1370 Jorgensen CK (1958) Absorption spectra of complexes of heavy metals. ASTIA document 157158, National Technical Information, Springfield VA... 

Sekiguchi T, Maki S, Niwa H, Ikeda H, Hirano T. Metal-ion complexation of imidazo[l,2-a]pyrazin-3(7H)-ones continuous changes in absorption spectra of complexes depending on the Lewis acidity of a metal ion. Tetrahedron Lett 2004 45 1065-9. 

Graddon, D. P. (1960) Absorption spectra of complex salts. III. Cupric ethylaceto-acetate. J. Inorg. Nucl. Chem. 14, 161. 

Previously reported work demonstrated that substituents can be used to tune the energies of excited states responsible for the emission spectra of certain group VIII metal complexes (1) and to modify significantly the absorption spectra of complexes displaying metal-to-ligand charge transfer (MLCT) bands (2). In this presentation, we summarize some recent attempts to use ligand substituents in our studies of transition metal complex photochemical reaction mechanisms. The particular subjects of interest are the metal ammine complexes M(NH3)5L where M is Rh(III) or Ru(II) and L is a meta- or para-substituted pyridine. 

Recent applications of the ligand field theory to the transition metal complexes give logical interpretations of d-d absorption spectra, and the theoretical treatments help to predict band positions in the absorption spectra of complexes. On the other hand, today low-symmetry complexes are synthesized which contain ligands of more than three kinds. Their spectral data are expected to further develop theoretical fields of spectroscopy. 

Absorption spectra of complexes containing more than one d electron are more complicated because a greater number of electronic transitons are possible. 

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