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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 29, Number 6
JKCSEZ 29(6)
December 20, 1985 

 
Title
The Effects of Solvent Composition and Pressure on the Rate of Solvolysis of trans-[Co(en)2Cl2]+, trans-[Co(N-eten)2Cl2]+, trans-[Co(N-meen)2Cl2]+ and trans-[Co(tn)2Cl2]+ in Aceton-Water Mixture. Excess Free Energy & Free Energy Cycle and Reaction Mecha

아세톤-물 혼합용매에서 trans-[Co(en)2Cl2]+, trans-[Co(N-eten)2Cl2]+, trans-[Co(N-meen)2Cl2]+, trans-[Co(tn)2Cl2]+ 착이온의 가용매 분해반응에 대한 압력과 용매조성의 영향. 반응메카니즘과 자유에너지 변화사이클 및 Excess 자유에너지
Author
Yu-Chul Park, Young-Je Cho

박유철, 조영제
Keywords
Abstract
아세톤-물 혼합용매에서 trans-[Co(AA)2Cl2]+ 착이온의 가용매분해반응속도를 전도도법과 분광광도법을 사용하여 1~2000bar의 압력범위ㅣ에서 측정하였다. 여기서 AA는 에틸렌디아민(en), N-에틸에틸렌디아민(N-eten), N-메틸에틸렌디아민(N-meen)과 트리메틸렌디아민(tn)을 각각 의미한다. 속도상수에 대한 압력의 영향으로부터 구한 활성화 체적은 AA가 en, N-eten, N-meen 및 tn 일때 각각 -0.2∼0.9 cm3mole-1, -0.2∼0.6 cm3mole-1, -0.8∼6.0 cm3mole-1, 0.7∼7.0cm3mole-1이었다. 이들 착이온의 가용매분해반응성은 excess 자유에너지와 자유에너지 사이클로부터 얻을 결과를 비교하여 검토하였다. 가용매분해반응성은 압력이 감소할수록, 그리고 아세톤의 함량이 증가할수록 SN1 경향성이 증가하였다. 또한 가용매 분해반응의 메카니즘에 미치는 하전분리 효과도 고찰하였다.

The rates of solvolysis of trans-[Co(AA)2Cl2]+ in which AA indicates ethylenediamine(en), N-ethylethylenediamine (N-eten), N-methylethylenediamino (N-meen) and trimethylenediamine(tn) respectively have been investigated using conductometric and spectrophotometric methods at various pressure up to 2,000 bar in acetone-water mixture. The activation volumes (ΔV≠) obtained from the pressure effect on rate constants were -0.2∼0.9 cm3mole-1 for en, -0.2∼0.6 cm3mole-1 for N-eten, -0.8∼6.0 cm3mole-1 for N-meen and 0.7∼7.0cm3mole-1 for tn. The rates of solvolysis of these complexes were analyzed by comparing with the results obtained from excess free energy (GE) and free energy cycle. It was found that SN1 character was increased with decreasing the pressure and increasing the content of acetone in the mixture solvent. In addition to that, the effect of charge separation on the mechanism of solvolysis was discussed.

Page
629 - 636
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