Kinetics and Mechanism of Aquation and Formation Reactions of Carbonato Complexes: Rate of Decarboxylation of the Bis(carbonato)bis(pyridine)cobalt(III) Complex Ion I Aqueous Pyridine Buffer Solution

Material Information

Title:: Kinetics and Mechanism of Aquation and Formation Reactions of Carbonato Complexes: Rate of Decarboxylation of the Bis(carbonato)bis(pyridine)cobalt(III) Complex Ion I Aqueous Pyridine Buffer Solution
Series Title:: Student Symposium 2015
Creator:: Kaur, Sandeep ( Author, Primary )
Ghosh, Phalguni ( Advisor )
Middlesex College, Department of Natural Sciences ( Sponsor )
Place of Publication:: Edison, NJ
Publisher:: Middlesex College
Publication Date:: 2015 December 23

Subjects / Keywords:: College students -- poster presentations ( lcsh )
Student Works -- Natural Sciences -- poster presentations ( lcsh )
Student Works -- Natural Sciences -- academic theses ( lcsh )
Chemistry ( lcsh )
Middlesex College (Edison, NJ) -- Student works
Middlesex County College (Edison, NJ) ( lcsh )
Temporal Coverage:: Academic Year 2015-2016 ( 2015 - 2016 )
Spatial Coverage:: New Jersey -- Edison

Abstract:: The synthesis of the metal coordination was prepared by dissolving Na3[Co(CO3)3]* 3H2O in aqueous sodium bicarbonate. The reaction of these green solutions with excess pyridine was found to produce only cis-Co(C03)zpyz-(aq), which was isolated as a pale blue, moisture-sensitive hydrateK[Co(CO3)z(py)z].0.5H20 and as the purple crystalline salt K[Co(C03)2(py)2].2HzO. The behavior of these product saltsin water, ethanol, and aqueous acid was investigated. The kinetics of the title reaction wasmonitored by conventional spectrophotometry at 525 and 635 nm over the following concentration ranges: [CoIII] = (5.7-1 1.4) X 10-4 M, [H+] = (0.15-9.52) X 10-9 M, [HCO3-]= 0.14-0.865 M, and [py] = (1.2-29.8) X 10-2 M at 25 “C and ionic strength 1.0 M (NaHCO3, NaC104). The rate law was found to pseudo first order as the green solution turns to a purple solution after adding certain molar concentration of pyridine. Spectral scanning during the course of the reaction showed that the rate-determining steps involve the formation of the first cobalt(III) pyridine bond, followed by rapid addition of pyridine to form the bis(carbonato)bis(pyridine)cobaltate(III) product. Another aspect that was studied throughout this experiment was the decomposition of the cobalt complex in nitric acid. Another result that was observed was that the decomposition of the carbonate ligands forms CO2. The rate of decomposition of the carbonate ligands was also found to be pseudo first order.

Source Institution:: Middlesex County College Institution
Holding Location:: Middlesex County College Institution
Rights Management:: All applicable rights reserved by the source institution and holding location.