Sains  Malaysiana 37(2): 195-199(2008)

Synthesis and Characterisation of Tetraalkylammonium Tetrathiotungstate Complexes: X-ray Crystal Structure of Tetrapropylammonium Tetrathiotungstate, [{(C₃H₇)₄N}₂WS₄]
(Sintesis dan Pencirian Kompleks Tetraalkilamonium Tetratiotungstat:

Struktur Kristalografi Sinar-X bagi Tetrapropilamonium

Tetratiotungstat, [{(C₃H₇)₄N}₂WS₄] )

Fadhli Hadana Rahman, Khuzaimah, Rusli Daik & Mohammad B. Kassim

School of Chemical Sciences and Food Technology

Faculty of Science and Technology, Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor, Malaysia

Wan Ramli Wan Daud

Department of Chemical and Process Engineering

Faculty of Engineering, Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor, Malaysia

Diserahkan:  4 April 2007 / Diterima:  15 July 2007

ABSTRACT

The metathesis reaction of aqueous solutions of tetraethylammonium chloride [(C₂H₅)₄NCl], tetrapropylammonium bromide [(C₃H₇)₄NBr] and tetrabutylammonium iodide [(C₄H₉)₄NI] with ammonium tetrathiotungstate in the absence of oxidizing agent afforded the mononuclear tetraethylammonium tetrathiotungstate [{(C₂H₅)₄N}₂WS₄] (1), tetrapropylammonium tetrathiotungstate [{(C₃H₇)₄N}₂WS₄] (2) and tetrabutylammonium tetrathiotungstate [{(C₄H₉)₄N}₂WS₄] (3). Yields obtained for the complexes were 17, 21 and 14 % respectively. The characteristic of W-S stretching mode was detected at 451, 448, 453 cm^-1 for 1, 2 and 3. UV-Vis spectra showed three peaks for each complex. The complex 2 has been crystallographically and spectroscopically characterized. The crystal adopted a monoclinic system with a = 15.4246(2) Å, b = 29.7390(1) Å, c = 16.5056(2) Å and β = 114.11° and belong to the P2(1)/n space group. The crystal structure showed a highly disordered tetrapropylammonium molecule involving the position of the C and N atoms. Complexes 1 and 3 were not characterized crystallographically due to its difficulty to form a single crystal.

Keywords: photocatalyst; hydrogen; photolysis; tungsten; tris(dithiolene)

ABSTRAK

Tindak balas metatesis larutan akueus tetraetilamonium klorida [(C₂H₅)₄NCl], tetrapropilamonium bromida [(C₃H₇)₄NBr] dan tetrabutilamonium iodida [(C₄H₉)₄NI] dengan amonium tetratiotungstat tanpa kehadiran agen pengoksida telah menghasilkan tetraetilamonium tetratiotungstat [{(C₂H₅)₄N}₂WS₄] (1), tetrapropilamonium tetratiotungstat [{(C₃H₇)₄N}₂WS₄] (2) dan tetrabutilamonium tetratiotungstat [{(C₄H₉)₄N}₂WS₄] (3). Peratus hasil kompleks yang diperoleh ialah masing-masing 17, 21 dan 14 %. Spektrum inframerah kompleks yang diperoleh menunujukkan ciri regangan W-S masing-masing pada 451, 448, 453 cm^-1. Manakala, spektra UV-Vis menunjukkan 3 puncak serapan yang menjadi ciri utama spektra kompleks tetrahedron. Struktur kristalografi sinar-X kompleks 2 menunjukkan hablur mempunyai sistem monoklinik dengan a = 15.4246(2) Å, b = 29.7390(1) Å, c = 16.5056(2) Å dan β = 114.11° dan tergolong di dalam kumpulan ruang P2(1)/n. Struktur yang diperoleh menunjukkan molekul tetrapropilamonium mengalami pengherotan yang melibatkan kedudukan atom C dan N pada salah satu molekul kompleks tersebut. Usaha untuk medapatkan struktur X-ray bagi kompleks 1 dan 3 tidak berhasil kerana sukar untuk mendapatkan hablur yang sesuai.

Kata kunci: fotomangkin; hidrogen; fotolisis; tungsten; tris(dithiolena)

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