Chromium complexes spectra

Fig. 1. Simulated room-temperature CW-EPR spectrum for an oxo-chromium complex with giso = 1.9803, Craiso= 15.9 x 10-4 cm-1 and H iso,i = 0.84 x 10-4 cm-1 and H<2iso,2 = 0.87 x 10-4 cm-1. (A) Full-field scan and (B) central detail of spectrum. The microwave frequency was set to 9.48 GHz.

Since the 1 1 chromium complexes can easily be converted to 1 2 complexes with complexable azo dyes, it is also possible to produce unsymmetrical chromium complexes. This opens up an extraordinary number of combination options for producing brown and olive shades, along with navy blue, gray, and a variety of black shades, enormously extending the shade spectrum of chromium complexes. Yellow, red, blue, and black are also obtainable with symmetrical complexes. 

The infra-red spectrum of Cr(TPP)py(02) obtained by the oxygenation of a chroinium(II) porphyrin complex suggests the presence of an dioxygen species The photolysis of chromium complexes such as [Cr2(> -C5H5)2(CO)6] in the presence of O2 gives paramagnetic complexes which may be studied by The g-values lie... 

For each solution in the Cr + G series, Table 8.2 (1) measure the UV-vis spectrum to obtain the absorbance A at Aex, and (2) measure an emission spectrum and obtain the integrated emission intensity, I. Also, prepare a solution having [G] the same as the last in your series (Table 8.2), but with no chromium complex. This will serve as a control sample. Save your sample solutions for time-resolved luminescence quenching if you are conducting these experiments (see below). Save all UV-vis and luminescence spectra files that you acquire—they may be useful for data analysis. 

At - 78°C, the one-electron oxidation of the acyl complexes [M(COR)(CO)5]" (M = Cr or W, R = alkyl or aryl) is quasi-reversible the lifetime of [Cr(COPh)(CO)5] is 20 msec. The ESR spectrum of the chromium complex is similar to that of the benzaldehyde anion, shows no metal hyperfine coupling, and suggests the unpaired electron to be largely based on the acyl ligand. 

G.A. Ozin, University of Toronto In our Cr/CO matrix cocondensation experiments (Angew. Chem., Int. Ed. Eng. 1975, 14, 292), we reported evidence for the facile formation of a binuclear chromium carbonyl complex Cr2(CO)i0 or Cr2 (CCOi x which could be described as square pyramidal Cr(CO)5 weakly interacting with either a Cr(CO)5 or Cr(CO)6 moiety in the vacant (sixth) site. As a result, the infrared spectrum of this "weakly-coupled" binuclear species closely resembled that of the mononuclear fragment Cr(CO)5. I would like to ask you, whether or not you have any evidence for the existence of such a binuclear species in your Cr(CO)6 /Xe cryogenic solutions following various photolysis treatments. 

Spectra of a variety of chromium compoimds in the +3 valence state are included in Fig. 16. The principal peak is centered at about 22-25 ev. in all cases. The CrjOa spectrum is almost identical to that of Mn02 of Fig. 5. Spectra of the oxalato complex and the ammonia complex are almost identical to spectra of the corresponding cobalt compounds of Figs. 13 and 11. 

No significant pseudo-contact shifts could be induced in the spectra of dibenzothiophene, its sulfoxide, or its sulfone, with Eu(dpm)3 although a marked shielding of the protons of one ring was observed in the spectrum of the chromium tricarbonyl complex of dibenzothiophene,presumably due to a contact shift mechanism. 

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