Synthesis and Characterization of Hydrogen-Bonded Assemblies of W6S8L6 Clusters
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- 作者：Catherine M. Oertel ; Ryan D. Sweeder ; Sonal Patel ; Craig M. Downie ; and Francis J. DiSalvo
- 刊名：Inorganic Chemistry
- 出版年：2005
- 出版时间：April 4, 2005
- 年：2005
- 卷：44
- 期：7
- 页码：2287 - 2296
- 全文大小：392K
- 年卷期：v.44,no.7(April 4, 2005)
- ISSN：1520-510X
文摘
Ligand-exchange reactions involving octahedral W6S8 clusters and a family of pyridine-based ligands (isonicotinicacid, isonicotinamide, 4-hydroxypyridine, 4-aminopyridine, 4-pyridineacetamide) have been explored with the goalof preparing compounds that crystallize in hydrogen-bonded arrays. Two new compounds, W6S8(4-pyridineacetamide)6·DMF·4-pyridineacetamide (1) and W6S8(4-aminopyridine)6·4DMF (2), were isolated and characterized by single-crystal X-ray diffraction. Both compounds crystallize in the P21/c space group with a = 16.461(1), b = 33.08(2),c = 13.165(10) Å, 
= 103.270(15)
for 1 and a = 13.8988(5), b = 13.2791(5), c = 15.6293(6) Å, =108.5410(10) for 2. Each compound was further characterized by 1H NMR spectroscopy, elemental (CHN) analysis,and thermogravimetric analysis. Examination of the structures shows that 1 forms a three-dimensional hydrogen-bonded network in which each 4-pyridineacetamide ligand interacts with ligands on neighboring clusters or with thefree ligand of crystallization. This is the first hydrogen-bonded network formed from W6S8 clusters. In 2, the aminogroups act as hydrogen-bond donors toward DMF molecules of crystallization, but an extended array is not formed.In addition, the binding strengths of these pyridine-based ligands to the W6S8 cluster were studied through quantitative1H NMR studies of ligand-exchange reactions. A qualitative relationship was found between ligand binding strengthsand Hammett substituent constants for this group of ligands.
= 103.270(15) for 1 and a = 13.8988(5), b = 13.2791(5), c = 15.6293(6) Å, =108.5410(10) for 2. Each compound was further characterized by 1H NMR spectroscopy, elemental (CHN) analysis,and thermogravimetric analysis. Examination of the structures shows that 1 forms a three-dimensional hydrogen-bonded network in which each 4-pyridineacetamide ligand interacts with ligands on neighboring clusters or with thefree ligand of crystallization. This is the first hydrogen-bonded network formed from W6S8 clusters. In 2, the aminogroups act as hydrogen-bond donors toward DMF molecules of crystallization, but an extended array is not formed.In addition, the binding strengths of these pyridine-based ligands to the W6S8 cluster were studied through quantitative1H NMR studies of ligand-exchange reactions. A qualitative relationship was found between ligand binding strengthsand Hammett substituent constants for this group of ligands.