Maja Šumar-Ristović a , Vlada Blagojević b , Maja Gruden-Pavlović a , Katarina Anđelković a , Dejan Poleti c , Dragica M. Minić b a Faculty of Chemistry, University of Belgrade, Serbia b Faculty of Physical Chemistry, University of Belgrade, Serbia c Faculty of Technology and Metallurgy, University of Belgrade, Serbia The most stable conformation of starting complex (E a = 714 kJ/mol) Calculated enthalpies changes indicate one step decomposition of intermediate. Calculated E a of intermediate [Zn(OOCCH 2 NHC · O) 2 ] is 458 kJ/mol. Changes of the activation energies with conversion degree indicate complex processes involving more than one step Structure Fragment ΔH 175 , ΔH 297 Two step mechanism Step 1 [Zn(N-Boc-gly) 2 ] C 6 H 5 CH 2 O · 797.6, 790.7 Step 2 [Zn(N-Boc-gly) (OOCCH 2 NHC · O] C 6 H 5 CH 2 O · -83.1, - 82.2 One step mechanism [Zn(N-Boc-gly) 2 ] 2 C 6 H 5 CH 2 O · 713.8, 714.7 Thermal Stability Kinetics and Mechanism First Principle Calculations 0 200 400 600 800 1000 20 40 60 80 100 = 15 o C min -1 T / o C m /% -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 T / % 0 200 400 600 800 1000 0.0 0.5 1.0 1.5 2.0 = 15 o C min -1 D erivative mass /% o C -1 T / o C 0.0 0.2 0.4 0.6 0.8 1.0 60 80 100 120 140 160 180 200 Step 3 F riedm an KAS E a /kJ m ol -1 0.0 0.2 0.4 0.6 0.8 1.0 280 300 320 340 360 380 400 420 440 460 E a /kJ m ol -1 S tep 2 Friedm an KAS 0.0 0.2 0.4 0.6 0.8 1.0 0 100 200 300 400 500 600 700 800 S tep 1 F riedm an KAS E a /kJ m ol -1

Maja Šumar - Ristović a , Vlada Blagojević b , Maja Gruden-Pavlović a , Katarina Anđelković a ,

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Kinetics and mechanism of thermal degradation of Zn(II) complex with N - benzyloxycarbonyl glycinato ligand. Maja Šumar - Ristović a , Vlada Blagojević b , Maja Gruden-Pavlović a , Katarina Anđelković a , Dejan Poleti c , Dragica M. Minić b a Faculty of Chemistry, - PowerPoint PPT Presentation

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Page 1: Maja Šumar - Ristović a , Vlada Blagojević b , Maja Gruden-Pavlović a , Katarina Anđelković a ,

Maja Šumar-Ristovića Vlada Blagojević b Maja Gruden-Pavlovića Katarina Anđelkovića Dejan Poletic Dragica M Minićb

aFaculty of Chemistry University of Belgrade SerbiabFaculty of Physical Chemistry University of Belgrade SerbiacFaculty of Technology and Metallurgy University of Belgrade Serbia

The most stable conformation of starting complex (Ea = 714 kJmol)

Calculated enthalpies changes indicate one step decomposition of intermediate Calculated Ea of

intermediate [Zn(OOCCH2NHCmiddotO)2] is 458 kJmol

Changes of the activation energies with conversion degree indicate complex processes involving more than one step

Structure Fragment ΔH175 ΔH297

Two step mechanismStep 1 [Zn(N-Boc-gly)2] C6H5CH2O 7976 7907

Step 2 [Zn(N-Boc-gly)(OOCCH2NHCO] C6H5CH2O -831 -822

One step mechanism [Zn(N-Boc-gly)2] 2 C6H5CH2O 7138 7147

Thermal Stability

Kinetics and Mechanism

First Principle Calculations

0 200 400 600 800 1000