LEGISLACIÓN NACIONAL
C.- Código Procesal Penal
108
The "buffer was observed to be operating perfectly and, between pH 3 4, the reaction was f ir s t order in hydrogen ion concentration, and, between pH 2 and 3, the reaction was zeroth order in hydrogen ion concentration. A mechanism has been postulated (scheme 1) where there is a rapid undirectional reaction of the origin al nitrosylpentacyano- manganate(l) anion with acid to produce an intermediate; th is reacts further in a slow rate determining step producing the nitrosylpentacyano- manganate(ll) anion and hydrogen.
The compound (product) is extremely air unstable and a good sample was d if ficu lt to prepare. It was fin a lly isolated as a cobalt s a lt for an alytical purposes. But the calcu lation o f zeroth law rate constants ^ requires an accurate ex tin ctio n c o -e ffic ie n t o f the pure product which
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was found to be im possible. Manoharan gives a value ( £max 1,700 385 nm) which was subsequently used to give the values shown in tab le 5»
Figure 5 shows a negative Intercept, which is im possible. Three, d ifferen t explanations can be given for th is. ^
(a) Manoharan’s ex tin ction c o -e ffic ie n t is low; producing a mathematical tran slation o f the graphical resu lts producing a negative in tercep t. I f his preparation was also contaminated by the a ir reaction th is would explain why he should have a low
resu lt.
(b) There could be a slow reaction at neutral pH's where the k in etics would probably change. This claim is im possible to prove as the reaction at th is pH would be far too long for study and, the compound would probably react with low concentrations o f hydroxide at th is pH.
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(c) The reaction put forward in scheme 1 is incorrect; figure 4 could be interpreted as a. ca ta ly tic process (sim ilar to
enzymes), Reaction in A lkali
Gotton^^, in h is simple study, mentioned that the nitrosylpentacyano* manganate(l) anion reacted with hydroxide to produce KnC^* This
reaction was found to be on a stopped-flow sca le , but the manganese- dioxide produced coated the glass and produced flo c u la n ts. Attempts to keep the manganese dioxide in solution using KGl and KF electro ly tes fa iled and k in etic stud ies were im possible. Using the cyanide
< sensitive electrode on a basic solution o f the n itro sy l complex
produced no su bstan tial evidence for cyanide production. Only 10^ o f the cyanide in the complex was detected in so lutio n , whereas 95% o f the manganese was accounted for as MnO^.
The nitrosylpentacyanomanganate(l) anion does not react with amines, hydrogen sulphide, and th io ls.
Phptpchemistry_of the Nitrp8%l2entaGjanoman^nate(l)_Anipn
The compound is unstable in its so lid form; a brown mixture (MnOg)
resu lts from prolonged exposure to l i ^ t . In solution at pH ?.2 the complex is also photo la b ile with respect to potassium cyanide but in the dark is sta b le . (There may be a slow reaction with OH and/or H^ in the dark but neither resu lts in the production o f cyanide anion.) S ta b ility in the dark is to be expected as the complex is d^ low spin
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su bstitution inert. The ph o to la b ility is due to the two bands
(tab le 4) d^-—►■TY^NO at 540 nm and ^xz*^yz TV at 405 which would be expected to produce NO sim ilar to the nitroprusside anion (figure 6 ).
The Photo Decomposition of Nitrosylpentacyano; Kanganate and Ferrate Anions
(GN)^Kn^NO^“ (CN)^hn^^3" + kG
d^ su bstitution inert d-^ su bstitution la b ile
(CN)^Fe“^N02- (C N )^ e™ 2- ^
(figure 6)
The compound was tested for hypertensive a c tiv ity at Ninewells Hospital in Dundee. The resu lts were negative and nitrosylpentacyano- manganate has no therapeutic value. Although th is complex exhibits nitroprusside-type chemistry i t does not react with amines and th io ls ,
which are believed to be the important groups for hypertensive"activity (as mentioned prev io usly ).