maja Šumar - ristović a , vlada blagojević b , maja gruden-pavlović a , katarina anđelković...

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

20

40

60

80

100

= 15 oC min-1

T oC

m

-30

-25

-20

-15

-10

-05

00

05

10

T

0 200 400 600 800 1000

00

05

10

15

20 = 15 oC min-1

Der

ivat

ive

mas

s

o C-1

T oC

00 02 04 06 08 1060

80

100

120

140

160

180

200 Step 3

Friedman KAS

E a kJ m

ol-1

00 02 04 06 08 10

280

300

320

340

360

380

400

420

440

460

E a kJ m

ol-1

Step 2 Friedman KAS

00 02 04 06 08 100

100

200

300

400

500

600

700

800 Step 1 Friedman KAS

E a kJ m

ol-1