Abstract
The first-order hyperpolarizability, β, has been calculated for a group of marine natural products, the makaluvamines. These compounds possess a common cationic pyrroloiminoquinone structure that is substituted to varying degrees. Calculations at the MP2 level indicate that makaluvamines possessing phenolic side chains conjugated with the pyrroloiminoquinone moiety display large β values, while breaking this conjugation leads to a dramatic decrease in the calculated hyperpolarizability. This is consistent with a charge-transfer donor-π-acceptor (D−π–A) structure type, characteristic of nonlinear optical chromophores. Dynamic hyperpolarizabilities calculated using resonance-convergent time-dependent density functional theory coupled to polarizable continuum model (PCM) solvation suggest that significant resonance enhancement effects can be expected for incident radiation with wavelengths around 800 nm. The results of the current work suggest that the pyrroloiminoquinone moiety represents a potentially useful new chromophore subunit, in particular for the development of molecular probes for biological imaging. The introduction of solvent–solute interactions in the theory is conventionally made in a density matrix formalism, and the present work will provide detailed account of the approximations that need to be introduced in wave function theory and our program implementation. The program implementation as such is achieved by a mere combination of existing modules from previous developments, and it is here only briefly reviewed.
Original language | English |
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Pages (from-to) | 5368-5376 |
Number of pages | 9 |
Journal | Journal of Physical Chemistry A |
Volume | 119 |
Issue number | 21 |
Early online date | 13 Jan 2015 |
DOIs | |
Publication status | Published - 28 May 2015 |
Externally published | Yes |
Bibliographical note
AcknowledgmentFinancial support from the Swedish Research Council (Grant No. 621-2010-5014) as well as a grant for computing time at the Swedish National Supercomputer Centre (NSC) are acknowledged. B.F.M. thanks the Portuguese Foundation for Science and Technology (project PTDC/FIS/103587/2008), the Donostia International Physics centre, and the Centre de Fisica de Materiales, University of the Basque Country, for financial support. B.F.M. acknowledges the provision of computer resources, technical support, and assistance from the Laboratory for Advanced Computing of the University of Coimbra, Portugal.
Keywords
- Chromophores
- Nonlinear optics
- Optical properties
- polarizability
- quantum mechanics