A series of chromium(II1)-alkylamine complexes with CrNe skeletons have been synthesized. These complexes have similar electronic properties but different numbers of N-H bonds, ranging from 8 to 18. Measurements of absorption spectra, relative phosphorescence quantum yields, and phosphorescence decay times, obtained at liquid nitrogen temperature, showed that there is a good correlation between the radiationless transition rate and the number of active hydrogen atoms attached to the donor atoms. For the dependence of the electronic relaxation rate on the number of the maximum frequency N-H vibrations a theoretical expression is derived, which includes both the effects of configurational changes and of frequency changes in the first coordination layer. This expression adequately predicts the dependence of the nonradiative rate from the vibrational degeneracy and the displacement of the maximum frequency modes.
In all tests performed using antibiotic test medium No. 1, APHA standard reference, BBL standard methods, violet red bile, and desoxycholate lactose agars, the overall mean values of pH readings were significantly higher (p<0.01) when determined at 25 C than at 45 C. This difference varied between 0.14 and 0.38 pH unit. Whether this difference has practical significance in routine laboratory use of these media was not determined.
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