Self-assembled wire-like and honeycomb-like osmium nanoclusters (NCs) in DNA with pronounced catalytic and SERS activities

Enhanced catalytic and SERS activities of CTAB stabilized interconnected osmium nanoclusters

“…We recently reported that self-assembled Os NCs in DNA having a wire-like morphology can generate a SPR peak at 594 nm whereas a honey-comb like structure can generate a peak at 602 nm. 22 In our present study, the appearance of a peak at a much higher wavelength region (at 639 nm) is probably attributed to plasmon oscillation originating for the formation of coupled NPs as observed in the TEM microscopy images. Similar types of explanation were drawn by Sampath and co-workers as they also observed a peak at 540 nm for their Os nano-chain aggregates.…”

“…2 In our previous report taking Os NCs in DNA as scaffold, we observed the first order catalytic reaction rate 3.87 Â 10 À2 min À1 for first 6 min and 0.45 min À1 for later 8 min. 22 In the present study we observed that the reaction rate was 0.26 min À1 which was the highest ever reported for Os NPs as a catalyst and much superior to other noble metals like Au or Ag. 2,22,43,44,[48][49][50][51] Apart from 4-NA, we also checked our catalysis reaction with other nitro compounds like 4-NP, 2-NP, 2-NA, etc., and in all cases the expected catalysis reduction taking place and the reaction were completed in different time scales.…”

“…Very recently, Os nanostructures were also tested in SERS studies. 21,22 As we observed, the plasmon resonance of our synthesized Os particles falls in the visible region, so we believed that Os NPs can also act as a potential SERS substrate. Keeping that idea in mind, we performed a SERS study of Os NPs taking Rose Bengal (R Be) as a model anionic dye molecule.…”

“…The wet chemical synthesis of Os metal NPs in the literature is very limited. 21,22 Recently, Chakrapani and Sampath reported the synthesis of small Os NPs by ascorbic acid reduction at 95 1C. 21 Very recently, we synthesized wire-like and honey-comb like Os nanoclusters (NCs) using deoxyribonucleic acid (DNA) as a scaffold using microwave heating.…”

“…As the surface plasmon resonance (SPR) band of Os metal falls in the visible region like Au, Ag etc., it is assumed that it can also be used as a potential substrate in a SERS study and in catalysis reactions. In recent reports as described above, 21,22 authors observed that Os NPs can be used as potential SERS substrate while they used Rhodamine 6 G (R6G) and Methylene Blue (MB) as a potential SERS probe.…”