pH dependent molecular self-assembly of octaphosphonate porphyrin of nanoscale dimensions: nanosphere and nanorod aggregates
Authors: Santosh V Nalage
Cecilia H Lalander
Sidhanath V Bhosale
Mohan B Kalyankar
Ruth F Oliver
Steven J Langford
Sheshanath V Bhosale
Journal: International Journal of Molecular Sciences (2011)
Discipline: CHEMISTRY
Keywords: AFM; TEM; aggregation; molecular self-assembly; porphyrin.
Affiliations: School of Chemistry, Monash University, Wellington road, Clayton Victoria 3800, Australia; E-Mails: kalyankar.mb@rediffmail.com (M.B.K.); cecilia.lalander@monash.edu (C.H.L.);  (S.J.L.);  (R.F.O.).

Abstract:  Self-assembled nanostructures of zwitterionic octaphosphanatoporphyrin 1, of either nanoparticles or nanorods, depending on small changes in the pH, is demonstrated based on the J-aggregates. Porphyrin 1 self-assembled into nanosphere aggregates with a diameter of about 70-80 nm in the pH range 5-7, and nanorod aggregates were observed at pH 8.5. Hydrogen bonding, π-π stacking and hydrophilic interactions play important roles in the formation of this nanostructure morphology. Nanostructures were characterized by UV/Vis absorbance, fluorescence, atomic force microscopy (AFM) and transmission electron microscopy (TEM). This interesting pH dependent self-assembly phenomenon could provide a basis for development of novel biomaterials. 

Retracted: Yes

PubPeer comments:
 Figure 5b appears to include repetitive features. Some examples identified. *** False color ![file] *** ![file] , 
 Respected Sir, These are images of self-assembled nanorods. Dr. Sheshanath Bhosale as a corresponding author already responded to the concern Editor. , 
 #2 Thank you for your reply. Could the authors offer readers an explanation for the apparent cut and pasting of these nanorods? How could this occur by accident? , 
 ![file] , 
 Discussions with the editorial team have taken place after their enquiry from Pubpeer and their questions have been answered and the matter resolved. , 
 #5 Could the authors share that correspondence here or provide the contact information used to discuss this with the journal? I am eager to hear the explanation requested in #3. , 
 Figure 5a seems to have similar issues. *** ![file] , 
 Mr. Actinopolyspora Biskrensis, When I came across your pub peer post and got surprised that on the theory of colour you are stating that the image had issues. Then I went through the publication and the Image you posted carefully. Based on my observations I would put the following points. 1) In the published paper authors claimed pH-dependent self-assembly of chromophoric systems and characterized by employing AFM TEM techniques. They observed rod and particle assembly. 2) I monitored the image carefully and the marks you made such as square and oval in different colours for the TEM image. I noticed that in the orange colour rectangles the rods have completely different turns and shape with distinct colour patterns. In the blue colour oval the rods have different length, turn and colour pattern. The red colour rectangles also had a distinct colour pattern. Based on these observations I would say this image doesnu2019t have any issue. 3) Wen I look through the magnifying lens and follow dot to dot in your marked areas I observed completely distinct colour pattern. 4) As an expert in the TEM analysis, I would say carbon grid always has rough surface but constantly spread carbon on the surface and when put light all carbon shows the same reflection with angle. Which is not as like gold silicon surface. 5) One interesting thing I noticed that this paper was published over ten years back (open access) and in recent years you found interest in it. It might be related to your research field. If it is related to my research field I would prefer to write authors. Anyway itu2019s your choice for constructive science. , 
 #8 Thank you for your comment. I agree that the rods outlined in orange do appear different in parts of those rods, and withdraw that particular concern. There are still similarities that are unexpected in those two and many other areas as identified by Hoya and myself. , 
 I hope the attached image is not too busy . The point I m trying to make here is that the rods have a curiously **modular** nature, so there are recurring heads and tails - variously marked with yellow and pink circles, light blue rhomboids, and orange boxes - but the intervening sections of rod can vary in length. Thus accounting for the variation among the rods that Actinopolyspora Biskrensis marked with red and blue. ![file] , 
 Received today: u201cDear Researcher, Thank you for raising your concerns with Monash University. We will certainly investigate this further at our end but as your complaint has been received anonymously, we will not be providing you with an outcome of our findings. Should you wish to receive a formal update on the matter, please provide us with your name and contact details so we can send this to you once available.u201d , 
 Dear Scientists, I went through the arguments of all you three and thought to put my input, the concern raised by reviewer 1 and Hoya is completely wrong, as indicated by the Albana. As an expert in imaging, I would say both the TEM and AFM does not show any disturbances. I see that author s work was focus on rods but Hoya also showing small background also copy-paste. From images, I would say these are background color and self-assembled structures should look similar from organic molecules. From images and concern of 1 and Hoya, it seems they doesn t have an organic chemistry background and seems they, may have a personal interest. As an expert, it looks images are perfect to me , 
 2021 retraction. https: www.mdpi.com 1422-0067 22 3 1327 htm Retraction: Bhosale, S.V., et al. pH Dependent Molecular Self-Assembly of Octaphosphonate Porphyrin of Nanoscale Dimensions: Nanosphere and Nanorod Aggregates. Int. J. Mol. Sci. 2011, 12, 1464u20131473 by International Journal of Molecular Sciences Editorial Office MDPI, St. Alban-Anlage 66, 4052 Basel, Switzerland Int. J. Mol. Sci. 2021, 22(3), 1327; https: doi.org 10.3390 ijms22031327 Received: 22 January 2021 Accepted: 27 January 2021 Published: 29 January 2021 (This article belongs to the Special Issue Molecular Self-Assembly 2011) The journal retracts the article, u201cpH Dependent Molecular Self-Assembly of Octaphosphonate Porphyrin of Nanoscale Dimensions: Nanosphere and Nanorod Aggregatesu201d [1], cited above. Following publication, concerns were brought to the attention of the publisher regarding the figures. Compared with the raw data, Figure 5a appears to have been manipulated. This has brought about uncertainty regarding the scientific conclusions. In addition, this paper [1] was submitted without the permission of all the co-authors. Therefore, this paper [1] is retracted and shall be marked accordingly. The Editor-in-Chief of the International Journal of Molecular Sciences has approved this retraction. We apologize to our readership that this went undetected until now. Reference Bhosale, S.V.; Kalyankar, M.B.; Nalage, S.V.; Lalander, C.H.; Bhosale, S.V.; Langford, S.J.; Oliver, R.F. pH Dependent Molecular Self-Assembly of Octaphosphonate Porphyrin of Nanoscale Dimensions: Nanosphere and Nanorod Aggregates. Int. J. Mol. Sci. 2011, 12, 1464u20131473. ,