Malaysian Journal of Analytical Sciences Vol 21 No 4 (2017): 871 - 879

DOI: https://doi.org/10.17576/mjas-2017-2104-13

 

 

 

PALLADIUM PINCER COMPLEXES AS CATALYSTS FOR SELECTIVE ACTIVATION AND FUNCTIONALIZATION OF 1-PROPANOL

 

(Kompleks Paladium Pincer Sebagai Mangkin untuk Pengaktifan dan Pefungsian Terpilih 1-Propanol)

 

Sri Sugiarti1* and Craig M Jensen2

 

1Department of Chemistry, Faculty of Mathematics and Natural Sciences,

Bogor Agricultural University, 16680 Bogor, Indonesia

2Department of Chemistry,

University of Hawaii at Manoa, Honolulu, 96822 Hawaii, United States

 

*Corresponding author:  sri.sw07@gmail.com

 

 

Received: 20 September 2016; Accepted: 16 May 2017

 

 

Abstract

Selective activation and functionalization of saturated C-H bonds in the original Shilov system used a combination of PtCl42- and PtCl62- in aqueous solution to transform methane into methanol and/or methyl chloride.  On the other hand, palladium phosphinito PCP pincer halides (PdX{C6H3-2,6-(OPri2)2}, X=Cl, Br, I) have been developed for the Heck reactions of aryl halide, and they are believed to operate by an alternative Pd(II)/Pd(IV) mechanism, made this catalyst potentially used for the Shilov type reaction.  Palladium pincer complexes showed selectivity for terminal functionalization of 1-propanol at lower temperature.  Successful substitution of PtCl4 by the less expensive oxidation system, CuCl2 and air was achieved.  In the presence of CuCl2, the Wacker-like oxidation is apparently involved in the reaction.  The phosphorous donor palladium pincer complexes showed better activity and selectivity than other types of palladium pincer complexes such as NCN-Pd-Br and SCS-Pd-Cl.

 

Keywords:  C-H bonds activation, palladium pincer complexes, 1-propanol, selective functionalization, Shilov system

 

Abstrak

Pengaktifan dan pefungsian terpilih ikatan C-H tepu pada sistem asal Shilov menggunakan kombinasi larutan akueus daripada PtCl42- dan PtCl62- untuk mengubah metana menjadi metanol dan/atau metil klorida. Selain itu, paladium fosfinito PCP pincer halida (PdX{C6H3-2,6-(OPri2)2}, X=Cl, Br, I) telah digunakan untuk tindak balas Heck daripada aril klorida, dan dipercayai beroperasi melalui mekanisme alternatif Pd(II)/Pd(IV), menjadikan mangkin ini berpotensi untuk digunakan pada tindak balas jenis Shilov.  Kompleks – kompleks paladium pincer menunjukkan kepilihan terhadap pefungsian terminal 1-propanol pada suhu rendah.  Kejayaan penggantian PtCl4 oleh sistem pengoksidaan yang lebih murah iaitu CuCl2 dan udara telah dicapai. Dengan kehadiran CuCl2, tindak balas pengoksidaan Wacker terlibat secara tidak langsung. Kompleks pincer paladium dengan penderma fosforus menunjukkan aktiviti dan kepilihan yang lebih baik dibandingkan dengan jenis lain dari kompleks paladium pincer, seperti NCN-Pd-Br dan SCS-Pd-Cl.

 

Kata kunci:  pengaktifan ikatan C-H, kompleks paladium pincer, 1-propanol, pefungsian terpilih, sistem Shilov

 

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