Molecular level ceramic/polymer composites. 3. Synthesis of polymer-trapped cadmium and copper sulfides starting from the elements and the structure of the intermediate, soluble, cadmium sulfide precursor

Polymers doped with small semiconductor and conductor clusters represent a new class of materials with novel combinations of properties. Cadmium sulfide (CdS) and copper sulfide (CuS) are two metal sulfides that show such useful properties as photoconductivity and nonlinear optical response. However, in many practical applications, the ability to form films and fibers is an important requirement. This is most easily achieved by forming composites in which the sulfide cluster are embedded in a processable polymeric matrix. A further advantage of synthesizing such composites is that the polymer matrix will physically prevent the agglomeration of the clusters-a persistent problem in size-selective cluster synthesis. The synthesis of polymer-trapped metal sulfides generally begins with discrete, soluble, precursor compounds that act as sources for the metal ion and the sulfide ion. A synthetic procedure that directly uses the elements would, however, eliminate the need for the preparation of the precursor compounds and would, therefore, be of significant practical advantage. Herein, the authors report the synthesis of poly(4-vinylpyridine)-trapped CdS and CuS clusters starting directly from the respective metallic element and sulfur. Additionally, the structure of the intermediate CdS precursor is described.