The flash photolysis of C O ( N H~)~C O~+ in aqueous solution generates the C03-radical which is characterized by its absorption spectrum with A, , , 600 nm and its second-order decay kinetics. The radical is also generated from Co(NH3)&03+ and, to a lesser extent, from Co(en)zC03+. By monitoring the decay of the C03-absorption as a function of the concentration of added scavenger solutes, values of k(CO3-+ S) have been obtained for some organic and inorganic solutes. In particular, k(C03-+ indole-3-propionic acid) was determined as a function of ionic strength and pH; at pH 7, k is independent of ionic strength while a t pH 12 there is a positive dependence of log k us. &*. From the data it is concluded that a t pH 7 the radical must exist in its acidic form, C03H, with a pK, = 9.6 f 0.3. The dependence of k on pH at constant ionic strength for N-acetyltryptophan and P,P'-dithiodipropionic acid supports the model presented as does the lack of a pH dependence for indole.(24) S. -N. Chen and M. Z. Hoffman, to be submitted for publication.

The 254-nm irradiation of neutral, buffered, solutions of Co(NH3)4C03+ and Co(en)2C03+ produces Coaq2+ with a relatively low quantum yield (0.06 and 0.02, respectively); Co(NH3)6CQ3+ also is photoreduced. The irradiation of Co(NH3)4C03+ also generates Co(NH3)4(OH2)23+ with a quantum yield of 0.11 ± 0.03. The flash photolysis of the three complexes yields a transient intermediate which has 600 nm and which is identified as the C03~radical. The flash photolysis of the bidentate carbonato complexes also reveals a long-lived tail absorption in the 300-nm region which decays via pH-dependent first-order kinetics. The behavior of this intermediate is identical with that of the aquocarbonato species proposed as an intermediate in the acid-catalyzed aquation of the bidentate carbonato complexes. It is proposed that photochemical excitation of these complexes in the intense ligand-to-metal charge-transfer band produces the charge-transfer singlet state (1CT) which generates, via

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l. Nutritional balances for calories, glucose, water, nitrogen, Na+, K+, Ca2+, and Mg2+ have been estimated for free-flying cedar waxwings feeding on Washington hawthorn fruits.2. Birds assimilate 39.9 calories/fruit ( = 20.0% of available calories) and a net loss of 155 mg of water/fruit.3. Reducing sugars account for 74.5% of assimilated calories ( = 66.0% assimilation efhciency). 4. While feeding on these fruits, birds exhibit positive nitrogen and caloric balance, and negative Na+, K+, Mg2+, Ca2+, and water balances.

Rate constants for the reaction of C03H radicals in neutral and mildly acidic aqueous solution with labile aquo ions (Coaq2+, Znaq2+, Niaq2+, Cuaq2+, Mnaq2+, and two Co(II) diaquo-macrocyclic complexes) and 19 substitution-inert amine complexes of Cr(III), Co(III), Rh(III), Ir(III), and Ru(III) have been measured at 23 °C using the flash photolysis technique. The value of k for the labile ions depends upon the oxidation potential of the complex and rate of exchange of the aquo ligands. Complexes of the form ( 3)5 2+ are more reactive than their conjugate acid and, generally, than their Min(NH3)6Cl2+ analogue. Complexes with an accessible higher oxidation state (Ir(NH3)Cl2+) or an easily oxidizable ligand (Co(NH3)5N022+) have high rates (>107 M'1 s'1). The reaction of C03H with Co(NH3)6C12+ (k = 2.0 X 106 M'1 s'1) and Co(NH3)6Br2+ (k = 5.7 X 10ß M"1 s'1) leads to ligand substitution; in contrast, the reaction of these complexes with OH radicals leads solely to the formation of Coaq2+.It is suggested that C03H and OH radicals react with these complexes by initially coupling with the halide ligand; subsequent intraand intermolecular processes lead to the final products.