Excited-State Dynamics Leading Either to Triplet Formation or Coordinative Expansion following Photolysis of Cu(II)-Porphyrins: A DFT, TD-DFT, Luminescence and Femtosecond Time-Resolved Absorbance Study

Round 1

Reviewer 1 Report

This paper of McGarry et al. reports an in depth study on the photophysical properties of a couple of Cu(II) complexes containing different porphyrins as ligands. Specifically, luminescence and femtosecond time-resolved absorbance methods, supported by DFT and TD-DFT theoretical calculations have been employed in this study. The importance of a charge-transfer state, whose energy can be affected by the solvent and/or the nature of the substituents on the macrocyclic ligands, in directing the photophysics of these porphyrin-containing copper(II) complexes is highlighted, and the possible use of this kind of copper porphyrins to identify the location of the porphyrin when interacting with DNA fragments is concluded from the work.  In general, the aim of the manuscript is attractive, although, from my point of view, the paper is highly “physics and theoretical”. For me, the study sounds and looks to be done properly and in accurate way, and the conclusions are supported by the studies reported in the paper. Moreover, the manuscript is well structured and written, so from my viewpoint, it merits to be published in Molecules in its actual form.

Author Response

The authors are grateful to Reviewer 1 for the care and diligence taken with the review of our manuscript.  We are happy that the reviewer recommended publication of the work and we are pleased that the reviewer found the manuscript acceptable in its current form.

Reviewer 2 Report

The manuscript of Ross McGarry et al. “Excited-state Dynamics Leading either to Triplet Formation or 2 Coordinative Expansion …” is devoted to the theoretical and experimental study of photophysical behavior of Cu(II) porphyrins. The results obtained well explain many peculiarities of this class of metal-organic compounds. These experiments were designed to answer several important questions, such as which excited-state or states react with the Lewis base to form the five-coordinate species, and why the lifetime of different five-coordinate complexes depends on the nature of the axial ligand. The manuscript is well written, with very rich citation of previous works. My opinion is that the manuscript can be helpful for a wide audience in molecular biophysics and spectroscopy and can be published as it is, without any further modifications.

Author Response

The authors wish to than this reviewer for the care and attention taken in reviewing our manuscript.  We are grateful that the reviewer recognised the contribution this work makes to a better understanding of the photophysics and photochemistry of this important class of copper complex.  We are delighted that the reviewer recommended publication of the manuscript in its current form.