Tracer Experiments on Alkaline Hydrolysis of Some Oxalate Ammonia Cobalt(III) Complexes

Kinetics and mechanism of aquation and formation reactions of carbonato complexes. 14. Base-catalyzed carbonato ring opening of carbonato (.beta.,.beta.',.beta."-triaminotriethylamine) cobalt(III) perchlorate and spontaneous decarboxylation of aquobicarbonato (.beta.,B',B"-triaminotriethylamine) cobalt(III)

“…The base-catalyzed hydrolysis of Co(en)2(C03)+ has been studied in several laboratories.7,9,21 There is some disagreement concerning the value of kx at high [OH"], but a figure of about 3 X 10™3 M'1 s'1 at 25 °C with AH* « 22 kcal/mol and * = 3 cal deg™1 mol™1 is consistent with all data in the base concentration range of our study and not widely different from our figures for the Co(tren)(C03)+ complex of kx = 3.6 X 10™3 M™1 s™1 at 25 °C, AH* = 17.2 ± 1.9 kcal/mol, and AS* = -12 ± 6 cal deg™1 mol™1. A further comparison is possible by use of the estimate given by Scheidegger for the ratio kx/k"x of 100 at 20 °C, i.e., the ratio of the rates of ring opening of Co(tren)(C03)+ by OH™ ion to ring closure of the hydroxo-carbonato product.…”

“…Studies in our laboratory of the acid hydrolysis of Co-(tren)(C03)+ have yielded the reasonably accurate value2 for ka at 25 °C of (1.7 ± 0.2) X 10-4 s™1 in satisfactory agreement with the value obtained in the present base-hydrolysis study of (2.6 ± 0.6) X 10™4 M™1 s'1. Some very limited flow-system data due to Scheidegger5 indicate a value for kx of about 13 X 10'"3 M"1 s'1 at 20 °C and I = 0.1 M (NaClG4), severalfold greater than the figure of 2.2 X 10"3 M™1 s'1 (extrapolated to 20 °C from data in Table V).…”

Reaction of allylic boron and aluminum "ate" complexes with organic halides and carbonyl compounds. Trialkylboranes as regio-, stereo-, and chemoselective control elements

“…The reaction of various allylic halides with several allylic boron ate complexes was examined to establish a high generality of control of regiochemistry (Table II). As mentioned later, 13C NMR spectra of lithium crotyl-9-BBN ate complex clearly indicate that 1-methylallyl isomer is not involved (entries [7][8][9][10][11].26…”

Peptide‐ or Protein‐Cleaving Agents Based on Metal Complexes

“…For example, metal-bound carboxylate ion can be hydrolyzed through the attack of hydroxide ion at the acyl carbon of the bound carboxylate ion (E) accompanied by CÀ ÀO bond cleavage instead of metal-O (38)(39)(40). The oxide ion is much more basic than the hydroxide ion, with the leaving group ability being extremely low.…”