Addition/Correction Cite This: Langmuir 2018, 34, 13459−13460
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Correction to “Generic and Scalable Method for the Preparation of Monodispersed Metal Sulfide Nanocrystals with Tunable Optical Properties” Abhijit Bera, Debranjan Mandal, Prasenjit N. Goswami, Arup K. Rath,* and Bhagavatula L. V. Prasad* Langmuir 2018, 34 20, 5788−5797. DOI: 10.1021/acs.langmuir.8b00741
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S Supporting Information *
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ecently we published a paper (Langmuir 2018, 34, 5788 5797) describing a generic and scalable method for the preparation of monodispersed metal sulfide nanocrystals with tunable optical properties, where we reported the utilization of octyldithiocarbamic acid (C8DTCA) as the sulfur source for the preparation of different metal sulfide nanocrystals. In this paper we mentioned that the compound octyldithiocarbamic acid was prepared by adding octylamine to carbon disulfide, and the reaction between them is as follows.
However, it has been brought to our attention by Prof. Graeme Hogarth, Kings College London, U.K., that the dithiocarbamic acids are not very stable in the free acid form; rather, they are more stable in the zwitterionic form -[RNHCS2][RNH3] even when excess CS2 is used.1 Following his suggestion we did additional spectroscopic analysis of the product obtained from the above reaction more carefully, which revealed that the product indeed was in the zwitterionic form and not the free acid form. Unfortunately this was not very evident from the 1H NMR spectral analysis (Figure C1) we did initially (and published as Figure S1 in the Supporting Information of our Langmuir paper), but it became clear from the 13C NMR and DEPT (Figures C2 and C3) analyses that we did now. Thus, the actual molecule that we used as sulfur source for the synthesis of metal sulfides is [C8H17NHCS2][C8H17NH3] and not C8H17NHCS2H as claimed. The reaction itself may be represented as
Figure C1. 1H NMR spectra of of the compound [C8H17NHCS2][C8H17NH3]. 1H NMR (200 MHz, chloroform-d) δ 5.44 (s, 2H, N− H, S−H), 3.60−3.48 (m, 1H), 3.02 (t, J = 7.3 Hz, 1H), 1.70−1.59 (m, 2H), 1.27 (m, 10H), 0.88 (t, J = 6.1 Hz, 3H).
all the reactions for the preparation of metal sulfide nanocrystals and their analysis remains the same. Furthermore, as the molecular weight of the product in the zwitterionic form would be different from the free acid form, the ratios of the Pb/S as reported in the paper also need to be corrected. For example, we mentioned in the main paper that we used a Pb/C8DTCA ratio of 6:1 (65 mg of C8DTCA used), which corresponds to a Pb/S ratio of 3:1 (as each C8DTCA molecule contains two sulfur atoms). However, with the correction in the molecular weight the Pb/C8DTCA ratio gets changed to ∼10:1 (page 5790 of the paper and Figure 2 caption), and the Pb/S ratio is changed to ∼5:1. Similarly it may be noted that in the Supporting Information (experimental section for the generic synthesis of different metal sulfides) we mentioned that 75 mg of sulfur source (C8DTCA) was used, which as per the old structure is equivalent to 0.75 mmol of sulfur. But as per the new structure 0.75 mg of C8DTCA (in the zwitterionic form) would be equivalent to 0.45 mmol of sulfur. Finally in Supporting Information Figure
Thus in the paper wherever we mentioned C8DTCA it should be considered as the zwitterionic form [C8H17NHCS2][C8H17NH3]. We wish to add here that apart from this small difference in identification of the structure of the product (the details are provided in the Supporting Information) the rest of © 2018 American Chemical Society
Published: October 22, 2018 13459
DOI: 10.1021/acs.langmuir.8b03395 Langmuir 2018, 34, 13459−13460
Langmuir
Addition/Correction
Figure C2. 13C NMR spectra of the compound [C8H17NHCS2][C8H17NH3]. 13C NMR (50 MHz, chloroform-d) ppm 181.31, 77.63, 76.37, 44.37, 41.29, 31.73, 29.19, 29.12, 28.96, 26.88, 22.60, 14.04.
Figure C3. 13C DEPT spectra of the compound [C8H17NHCS2][C8H17NH3]. 13C NMR (DEPT-135, 50 MHz, chloroform-d) ppm 44.38, 41.31, 31.77, 29.24, 29.18, 29.00, 26.92, 22.64, 14.10.
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S11 in the caption we mentioned the Pb/S ratios as 6:1 (black), 4:1 (red), and 2:1 (blue), which were again calculated as per the old structure. These now should be corrected as ∼5:1 (black), Pb/S ≈ 3.5:1 (red), Pb/S ≈ 1.5:1 (blue), respectively.
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REFERENCES
(1) Hogarth, G. Transition metal dithiocarbamates: 1978−2003. Progress in inorganic chemistry 2005, 53, 71−561.
ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.langmuir.8b03395.
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Synthesis and characterization of octyl ammonium octyl dithiocarbamate and QDs; methods for solar cell device fabrication (PDF)
ACKNOWLEDGMENTS We sincerely thank Prof. G. Hogarth, Kings College, London, for bringing this to our attention. We also thank Dr. Chepuri V Ramana (CSIR-NCL) for his help with the NMR spectra. 13460
DOI: 10.1021/acs.langmuir.8b03395 Langmuir 2018, 34, 13459−13460
