含五苯荑之全同配位炔基金(I)團簇的刺激響應性質與多重光色變化研究

Abstract

超分子自組裝為現今當紅的議題，其中金(I)受到相對論效應影響，使其具有強的親金屬作用力，這也使金(I)錯合物在光物理性質上有豐富的表現。其中，依靠親金作用力所以引導出的金團簇廣受關注，已經有許多文獻深入探討這些金團簇的結構與性質。然而，全同配位炔基金(I)團簇(AuC2R)n研究至今僅四篇文獻提出明確的金(I)團簇結構，主要是因為(AuC2R)n通常具有強烈的分子作用力，使其難溶於溶劑中，因此結構鮮少被鑑定。儘管如此，全同配位炔基金(I)團簇在合成不同金(I)錯合物中卻被廣泛應用。

本研究將龐大的H形骨架五苯荑配體引入金(I)炔基錯合物系統中，合成出新的多核全同配位炔基金(I)團簇[AuPa]n。通過不同的結晶條件，獲得了多種晶體。第一類晶體由四核金(I)團簇[AuPa]4與六核金(I)團簇[AuPa]6組成，命名為[AuPa]4+6；第二類晶體由兩個不同之六核金(I)團簇[AuPa]6組成，命名為[AuPa]6+6；第三類晶體由三個不同之六核金(I)團簇[AuPa]6組成，命名為[AuPa]6+6+6。

本研究與先前文獻的不同之處在於，引入五苯荑配體後，即可引導出不同金(I)核數排列的晶體，且[AuPa]n 展現了豐富的刺激響應性質及多重光色變化。這些性質可以通過溫度變化、照光誘導、溶劑薰致和機械研磨處理進行顏色上的轉變，這也是第一個具有刺激響應性質的全同配位炔基金(I)團簇，並給予出明確的兩種金(I)核數結構。此外，我們利用拉曼光譜證實，這些變化是由於激發態下金(I)-金(I)作用力增強所致。

Supramolecular self-assembly is currently a popular topic in chemistry. Due to the influence of relativistic effects on gold(I) complexes, they exhibit strong aurophilicity interactions, resulting in rich photophysical properties. Among them, gold clusters with aurophilicity interactions have garnered significant attention. Despite this interest, research on homoleptic alkynyl gold(I) clusters (AuC2R)n has been limited. This limitation is mainly due to the strong aurophilic interactions in (AuC2R)n, resulting in poor solubility in solvents and challenging structural characterization. Consequently, there are only a few studies that have clearly defined the structures of these gold(I) clusters. Nevertheless, homoleptic alkynyl gold(I) clusters are extensively used in synthesizing various gold(I) complexes.

In this study, we introduced a bulky H-shaped pentiptycene ligand into the gold(I) alkynyl complex system, synthesizing new homoleptic alkynyl gold(I) clusters, named as [AuPa]n. Through varying crystallization conditions, we obtained several types of crystals. The first type includes a tetranuclear gold(I) cluster [AuPa]4 and a hexanuclear gold(I) cluster [AuPa]6, termed [AuPa]4+6. The second type consists of two distinct hexanuclear gold(I) clusters [AuPa]6, named [AuPa]6+6. The third type includes three distinct hexanuclear gold(I) clusters [AuPa]6, referred to as [AuPa]6+6+6.

The distinguishing feature of our work, compared to previous studies, lies in the introduction of the pentiptycene ligand, which leads to the formation of crystals with varying size of gold(I). Moreover, [AuPa]n exhibits a wide range of stimulus-responsive properties and multicolor luminochromism. These properties can be triggered by temperature changes, light irradiation, solvent vapor exposure, and mechanical grinding, marking the first instance of stimuli-responsive behavior observed in homoleptic alkynyl gold(I) clusters. Our study provides clear structural determinations of these clusters. Additionally, Raman spectroscopy confirmed that these changes are due to enhanced gold(I)-gold(I) interactions in the excited state.