A Novel Synthetic Method for the Preparation of CuS, and CdS Nanochains Gajanan Pandey Department of Applied Chemistry, Madhav Institute of Technology and Science, Gwalior, India S. K. Srivastava Department of Applied Physics, Madhav Institute of Technology and Science, Gwalior, India CuS and CdS nanochains having average particle size 15.4 nm and 16.7 nm have been synthesized by reaction of Na 2 [M(HL) 2 (H 2 O) 2 ] complexes; M5Cu, Cd; NaH 2 L5Eriochrome Black T with in situ formed H 2 S in aqueous solution phase. Na 2 [M(HL) 2 (H 2 O) 2 ] com- plexes, prepared by reacting M(II) ions with NaH 2 L, were treated by H 2 S, formed by heating alkaline solution of thiourea at 808C. The formed suspension was ultracentrifuged, washed with alcohol, air dried and analyzed for TEM. A mechanism for formation of CuS and CdS nanochains has also been proposed here. Keywords nanostructure, chemical synthesis, electron microscopy INTRODUCTION There has been an explosive growth of nanoscience and nanotechnology [1] in the last few years, primarily because of availability of new methods of synthesizing nanomaterials of varying morphologies, the number of methods of characteriz- ation, and manipulations and exploitations of various size- dependent physical, chemical, [1] electrical, optical, [2 – 5] magnetic [6,7] and biological [8] properties. The ultimate goal of nanotechnology is synthesis of isolated nanostructures (building blocks) and their assemblies with the desired proper- ties, to explore and establish nanodevice concepts, to generate a new class of high performance materials, including biolo- gically inspired systems, and to connect nanoscience to mol- ecular electronics and biology. [9,10] Also, the understanding of biological processes on a nanoscale level is a strong driving force behind the development of nanotechnology. [11] Nanoscale particles of group II sulphides have attracted a growing interest during recent years because of their potential size-dependent properties and applications as photonic crystals, IR windows and luminescent materials. [12 – 15] Quantum-size sul- phides (quantum dots) have potential interests with respect to voltaic solar cells, light emitting diodes or again as luminescent materials. [16 – 20] Copper sulphide, which was established long ago for its metal-like electrical conductivity, [21] chemical sensing property [22] and solar absorption, [23] its nanoparticles, nanorod and nanowires have been synthesized by microemul- sion, [24] vesicles, [25] solid crystals, [26] molecular templates, [27] electrochemistry, [28] an organic assisted hydothermal process [29] and thermolysis [30] in solid, liquid, as well as in gaseous phases. Monodisperesed nanocrystalline particles of CdS having various sizes and morphologies have been syn- thesized employing different procedures in liquid phase and gaseous phase. [31 – 34] These applications will be ideally fulfilled if highly crystalline particles with almost monodispersed size dis- tribution and regular morphologies are prepared. Nevertheless liquid-based synthesis of sulphide nanostruc- tures has been applied in reversed micelle technique, [35] capping methods, [36] photoreductions [37 – 39] or electron beam irradiation, [40] but it is virtually unknown to synthesize metal sulphide, MS (M ¼ Cu, Cd) nanochains via reaction of metal complexes with in situ formed H 2 S in solution phase. Here, we report a new synthetic route of preparation of CuS/ CdS nanochains by reaction of azo complexes of Cu/Cd with H 2 S, formed by heating alkaline solution of thiocarbamides. EXPERIMENTAL All the chemicals used in this investigation were reagent grade and used as received. Copper sulphate, cadmium sulphate, eriochrome black T (NaH 2 L), thiourea, NaOH were purchased from Aldrich and Sigma. Doubly distilled water and ethanol were used as solvents. Ethanol was purified by dis- tillation; eriochrome black T was purified by the literature Received 22 May 2006; accepted 14 July 2006. The authors are thankful to DRDE Gwalior for TEM analyses. The authors are also thankful to Prof. K. K. Narang, Department of Applied Chemistry, Institute of Technology, Banaras Hindu Univer- sity, Varanasi, for useful discussion and suggestion. Address correspondence to Gajanan Pandey, Department of Applied Chemistry, Madhav Institute of Technology and Science, Gwalior 474005, India. E-mail: pandeygajanan@rediffmail.com. Synthesis and Reactivity in Inorganic, Metal-Organic and Nano-Metal Chemistry, 36:663–666, 2006 Copyright # 2006 Taylor & Francis Group, LLC ISSN: 0094-5714 print /1532-2440 online DOI: 10.1080/15533170600962455 663