Trialkylphosphine-Stabilized Copper(I) Dialkylaluminum(III) Ethanedithiolate Complexes: Single-Source Precursors and a Novel Modification of Copper Aluminum Disulfide

Four types of trialkylphosphine-stabilized
copper dialkylaluminum ethanedithiolate complexes with the compositions
[iPr3PCuSC2H4SAlR2]2 (R = Me, Et, iPr, tBu, vinyl), [(iPr3PCu)3(SC2H4S)2AlR2] (R = Et), [(Me3P)3CuSC2H4SAlR2] (R = Me, Et),
and [(Me3P)4Cu]­[SC2H4SAlR2] (R = Me, Et, iPr) have been
synthesized and structurally characterized by X-ray diffraction. The
first series features an eight-membered (CuSAlS)2 ring
as the core structure. The trimethylphosphine complexes can be distinguished
as nonionic and ionic compounds, depending on the amount of trimethylphosphine.
In systematic thermogravimetric studies, the complexes were converted
into the ternary semiconductor CuAlS2. In this process,
a novel wurtzite-type CuAlS2 phase was identified. Binary
copper sulfide is observed as a minor side product in thermolysis
reactions when volatile trialkylaluminum is released. The thermolysis
reactions are completed at temperatures between 330 and 470 °C,
depending on the aluminum alkyls. The Cu/Al ratio and phase purity
of the thermolysis products were determined by Rietveld analysis of
the powder X-ray diffraction patterns and by inductively coupled plasma
optical emission spectroscopy measurements. To our knowledge, this
is the first study of molecular single-source precursors for CuAlS2.

本研究合成了四类三烷基膦稳定（trialkylphosphine-stabilized）的二烷基铝乙二硫醇酸铜配合物，其组成分别为：[iPr₃PCuSC₂H₄SAlR₂]₂（R = Me、Et、iPr、tBu、乙烯基）、[(iPr₃PCu)₃(SC₂H₄S)₂AlR₂]（R = Et）、[(Me₃P)₃CuSC₂H₄SAlR₂]（R = Me、Et）以及[(Me₃P)₄Cu]­[SC₂H₄SAlR₂]（R = Me、Et、iPr），并通过X射线衍射（X-ray diffraction）对其结构进行了表征。第一类配合物以八元(CuSAlS)₂环作为核心结构。根据三甲基膦（trimethylphosphine）的用量，三甲基膦配位的配合物可区分为离子型与非离子型两类。在系统的热重分析研究中，上述配合物可转化为三元半导体CuAlS₂，过程中首次发现了一种新型纤锌矿型（wurtzite-type）CuAlS₂物相。当挥发性三烷基铝逸出时，热解反应中会伴随少量二元硫化铜作为副产物生成。根据铝烷基取代基的差异，热解反应可在330至470 ℃的温度范围内完成。通过粉末X射线衍射（powder X-ray diffraction）图谱的里特维尔德分析（Rietveld analysis）以及电感耦合等离子体发射光谱（inductively coupled plasma optical emission spectroscopy）测试，可确定热解产物的Cu/Al比例与相纯度。据我们所知，本研究是首例针对CuAlS₂的分子基单源前驱体（single-source precursors）研究。