The external parameters of solvent, pressure, and temperature were used to study the effects of these agents on the photochemical and photophysical properties of cis-[Cr(cyclam)(NCS)2]ClO4. This study was performed in number of solvents: water, dimethylformamide, acetonitrile and nitromethane. The quantum yield for the release of the thiocyanato ligand was found to be 0.0702 ± 0.005, 0.0635 ± 0.003, 0.0108 ± 0.001 and 0.00537 ± 0.001 for water, dimethy1formamide, acetonitrile and nitromethane at room temperature and pressure. The solvent was found affect the radiative lifetime ([tau]) (2Eg [right arrow] 4A2g, Oh approximation) of the complex. The values were determined to be 11.0, 2.24, 4.09, 7.49, 3.15 and 4.1 microseconds in acidified (pH 3.0) water, dimethylformamide, acetonitrile, nitromethane, hexamethylphosphoramide and acetone respectively. The effect of temperature on the observed radiative lifetime ([tau]) for doublet decay (2Eg) was determined. The temperature behavior is model by the Arrhenius equation with only slight deviations from linearity. Thus for the temperatures studied here, most of the data corresponds to the high temperature (strongly coupled region) of nonradiative decay (Engleman and Jortner). The apparent activation energies were determine to span a short range (i.e.41.2 ± 1.7 to 49.8 ± 1.3 kJ mol-1 for water to nitromethane respectively). The values of the apparent activation energies were compared with the energy spacing between the excited quartet and excited doublet state, as determined by the 5% rule of Fleischauer et al. The values of the estimated energy spacing between the excited states were found to be larger than the apparent activation energies. The effect of temperature on the photochemical quantum yield of thiocyanate, release was determined in 0.001 M HClO4. The temperature has only a marginal effect on the quantum yield. An Arrhenius plot of the data revealed a slope of 3 ± 8 kJ mol-1, which is zero within the error. The effect of pressure on the radiative lifetime and photochemical quantum yield in 0.001 M HClO4, dimethyfformamide, acetonitrile and nitromethane, was determined. The volumes of activation [Delta]V* ([tau]-1 ) are +1.9 ± 0.3, +3.9 ± 0.5, +4.2 ± 0.5 and +4.6 ± 0.6 cm3 mol-1 for 0.001 M HClO4, dimethy1formarnide, acetonitrile and nitromethane, respectively. The volume behavior indicates that the complex undergoes a shift in dominant decay modes as temperature is reduced. The effect of pressure on the photochemical quantum yield was determined and are -2.6 ± 0.7, -8.6 ± 0.7 and 3.2 ± 1.0 cm3 mol-1for 0.001 M HClO4, acetonitrile and dimethylformamide respectively. The sensitivity of excited state lifetime ([tau]) of the cis- and trans-isomers of [Cr(cyclam)(NCS)2]+ towards dioxygen was investigated. Th sensitivity is due to efficient energy transfer from the excited complex to molecular oxygen to form singlet delta (1[Delta]g O2) oxygen. The measurements resulted in intersystem-crossing vields which approached a limiting value of 0.5 suggesting that a statistically limited spin-exchange mechanism may be responsible for the energy transfer in these systems.

<p>Tetraazamacrocycles, such as cyclam (1,4,8,11-tetraazacyclotetradecane), are useful ancillary ligands in the formation of organometallic complexes. Coordination of a 3d metal can lead to the formation of square planar complexes, such as with Ni^II and Cu^II, or octahedral complexes upon coordination of additional ligands, such as with Co^II/III and Cr^II/III. Notably with Cr, a mixture of <i>cis-</i> and <i>trans-</i>octahedral complexes are formed, and the isomerism can be influenced through <i>C</i>-substitution of the cyclam macrocycle. Herein, Cr^III complexes featuring <i>C</i>-substituted cyclam derivatives and either redox-active ligands or alkynyl ligands are reported.</p> <p>Chapter 1 features an introduction to the photophysical processes of Cr(III), an overview of cyclam and its derivatives, and a brief review of Cr^III(cyclam/cyclam’) bis-alkynyl complexes for various applications. Chapter 2 discusses the structural, optical, electronic, and magnetic characterizations of <i>cis</i>-[Cr(HMC)catecholate]⁺ and <i>cis</i>-[Cr(HMC)semiquinonate]²⁺ complexes, which feature redox-active catecholate and semiquinonate ligands. Chapter 3 highlights a series of <i>trans</i>-[Cr(HMC)(C₂Ar)Cl]⁺ complexes, which expands upon prior research on bis-alkynyl complexes. Chapter 4 discusses how a different <i>C</i>-substituted cyclam derivative, MPC, is used to produce <i>trans</i>-[Cr(MPC)Cl₂]⁺ starting material in higher quantity than the HMC derivative. This allows for higher amounts of <i>trans</i>-[Cr(MPC)(C₂Ar)₂]⁺ complexes to be synthesized, making it a more practical macrocycle for the future pursuit of dissymmetric bis-alkynyl complexes.</p>

This thesis work deals with different aspects of the chemistry of La(III) and Gd(III) complexes, their interaction with DNA and proteins, photo-induced cleavage of double-stranded DNA, photocytotoxic effect on cancer cells, cell death mechanism and cellular localization behaviour. Chapter I gives an introduction to the metal-based anticancer agents with special emphasis on clinically used drugs and the growing field of lanthanide therapeutics. An overview of the current strategies of cancer treatment, especially photodynamic therapy (PDT), is presented. Mode of small molecule-DNA interactions and the mechanistic aspects associated with DNA photodamage reactions and PDT effect are discussed with selected examples of compounds that are known to photocleave DNA on exposure to light of different wavelengths. A brief discussion on the various therapeutic applications of the lanthanide compounds is also made. Chapter II presents the synthesis, characterization, DNA binding, BSA binding, photo-induced DNA cleavage activity and photocytotoxicity of La(III) and Gd(III) complexes of phenanthroline bases to explore the UV-A light-induced DNA cleavage activity and photocytotoxicity of the complexes. Chapter III describes the synthesis, characterization, DNA binding, photo-induced DNA cleavage activity and photocytotoxicity of La(III) and Gd(III) complexes of phenanthroline bases with an aim to improve the design of the complexes to achieve better solution stability and DNA binding of the complexes. Chapter IV presents the synthesis, characterization, DNA binding, and UV-A light-induced DNA photocleavage activity and photocytotoxicity of La(III) and Gd(III) complexes of pyridyl phenanthroline bases with an objective to improve the photoactivity of the complexes by introducing an additional pyridyl group. Cell death mechanism and confocal microscopic studies are also carried out to gain more insight into the PDT effect caused by light in the presence of the complex. Chapter V describes the synthesis and characterization of La(III) and Gd(III) complexes of terpyridine bases and acetylacetonate to study the complexes as a new class of photosensitizers to explore their DNA photocleavage activity and photocytotoxicity in HeLa cells. Effect of attaching a glucose moiety to the acetyl acetone (Hacac) ligand has been studied. The cellular uptake behaviour of the La(III) pyrenyl-terpyridine complexes has also been investigated. Finally, Chapter VI presents the synthesis and characterization of curcumin and glycosylated curcumin La(III) and Gd(III) complexes having terpyridine base with an objective to study the photoactivated anticancer activity of the complexes in visible light. This chapter describes the visible light-induced DNA cleavage activity and photocytotoxicity of the complexes by exploiting curcumin and glycosylated curcumin as the photosensitizer ligands. Study on the cellular uptake behavior of curcumin La(III) complexes having pyrenyl terpyridine ligand is also presented. The references have been assembled at the end of each chapter and indicated as superscript numbers in the text. The complexes presented in this thesis are represented by bold-faced numbers. Crystallographic data of the complexes which are characterized structurally by single crystal X-ray crystallography are provided in CIF format in the enclosed CD (Appendix-I). Due acknowledgements have been made wherever the work described is based on the findings of other investigators. Any unintentional omission that might have happened due to oversight or mistake is sincerely regretted.

Photodynamic therapy(PDT) has recently emerged as a promising new non-invasive treatment modality for a large number of neoplastic and non-neoplastic lesions. Photoexcitation of a photosensitizing drug in the tumor tissue causes generation of reactive oxygen species which results in cell death. The current porphyrinic photosensitizers suffer a wide range of drawbacks leading to the development of the chemistry of alternative photosensitizing agents in PDT. Among them, the 4d and 5d transition metal-based photosensitizers have been explored extensively with the exception of the 3d metal complexes. The objective of this thesis work is to design and synthesize photoactive iron(III) abd cobalt(III) complexes and evalutate their photonuclease and photocytotoxic potential. Bioessential 3d metal ions provide an excellent platform for metal-based PDT drug designing as because of its varied spectral, magnetic and redox properties, with its complexes possessing rich photochemical behavior in aqueous and non-aqueous media. We have synthesized binary iron(III) complexes as netropsin mimics using amino acid Schiff bases derived from salicylaldehyde/napthaldehyde and arginine/lysine. The complexes were found to be good AT selective DNA binders and exhibited significant DNA photocleavage activity. To enhance the photodynamic potential, we further synthesized iron(III) complexes of phenolate-based ligand and planar phenanthroline bases. The DNA photocleavage activity of these complexes and their photocytotoxic potential in cancer models were studied. ROS generated by these complexes were found to induce apoptotic cell death. Ternary cobalt(III) complexes were synthesized to study the effect of the central metal atom. The diamagnetic cobalt(III) complexes were structurally dissimilar to their iron(III) analogues. Although the Co(III)/Co(II) redox couple is chemically and photochemically accessible but the Co(III)-dppz complex, unlike its iron(III)-dppz analogue, exhibited selective damage to hTSHR expressing cells but not in HeLa cells. A structure-activity relationship study on iron(III) phenolates having modified dppz ligands was carried out and it was found that electron donating group on the phenazine unit and an increase of the aromatic surface area largely improved the PDT efficiency. Finally, SMVT targeted iron(III) complexes with biotin as targeting moiety were synthesized and the in vitro efficacy of the complexes was tested in HepG2 cells over-expressing SMVTs and compared to HeLa amd HEK293 cells. The complexes exhibited higher phytocytotoxicity in HepG2 than in HeLa and cells and HEK293 cells. An endocytotic mode of uptake took place in HepG2 cells whereas in HEK293 cells, uptake is purely by diffusion. This is expected to reduce the side-effects and have less effect on cells with relatively less SMVTs. In summary, the present research work opens up novel strategies for the design and development of primarily iron-based photosensitizers for their potential applications in PDT with various targeting moieties.

Photodynamic therapy (PDT) is a non-invasive treatment of cancer with an advantage of having localized photo-activation of the drug at the targeted tumor cells leaving the healthy cells unaffected by the photo-toxicity of the PDT agent. Organic molecules and 4d/5d metal complexes have been extensively studied for their DNA cleavage activity and photo-cytotoxicity in UV and/or visible light. The photoactivity of the current PDT drugs is due to reactive singlet oxygen species. To address the hypoxic nature within neoplasia and to get a realistic scenario to build model and potent PDT agents, attempts have been made in this thesis work to design and synthesize new cobalt and copper complexes having a variety of ancillary ligands and planar phenanthroline bases showing efficient visible light-induced anaerobic plasmid DNA cleavage activity. The disulfide and thiol compounds are known to generate thyil radical in anaerobic medium in presence of some electron donating solvent. To exploit this chemistry of the sulfur anion radical as a reactive species damaging DNA under light irradiation, we have prepared copper(II) complexes of bis(2-hydroxybenzylamino-ethyl)disulfide and D-penicillaminedisulfide and characterized. The complexes are moderate binders to calf thymus DNA and exhibit plasmid DNA cleavage activity in red light. Near-IR light-induced double-strand DNA cleavage activity is observed for the complexes having 3,3' -dithiodipropionic acid and phenanthroline bases. These complexes show lethal double strand breaks in SC DNA responsible for the inhibition in DNA repair mechanism in the cells thus becoming potent candidates as transcription inhibitors. The work has been extended to achieve better visible light-induced plasmid DNA cleavage activity and UV light-induced photocytotoxicity using a more bio-compatible metal ion, viz. cobalt(II) with the same ligand system and enhancement in the photocytotoxicity is observed. To investigate the role of the disulfide ancillary ligands, complexes of salicylideneaminothiophenol bound to the copper(II) are prepared and the complexes show significant plasmid DNA cleavage activity in red light. Finally, ternary cobalt(III) phenanthroline base complexes are prepared to study their DNA cleavage activity in red light and photo-cytotoxicity in UV light. The complexes show efficient plasmid DNA cleavage activity in red light, significant cytotoxicity in UV light, low dark cytotoxicity, and protein (BSA, lysozyme) cleavage activity in UV light. The mechanistic aspects of the photo-induced DNA and protein cleavage activity of the complexes have been studied. A dual involvement of the charge transfer and d-d band is observed in the photosensitization process leading to generation of reactive oxygen species. In summary, the thesis work presents cobalt and copper complexes having thiolate and disulfide moieties that are designed and synthesized as new photodynamic therapeutic agents showing anaerobic DNA cleavage activity in red light and photocytotoxicity. The present study opens up new strategies for designing and developing cobalt and copper based photosensitizers for their potential photochemotherapeutic applications under hypoxic reaction conditions. References: Lahiri, D. et al., J Chern. Sci, 2010, 122, 321-333; Inorg. Chern., 2009, 48, 339-349; Dalton Trans. 2010,39,1807-1816; Polyhedron, 2010, 29, 2417-2425.

Este trabalho apresenta a síntese de complexos de ouro(III) com ligante (dietilaminotiocarbonil)benzimidoíla-morfolinil-tiossemicarbazona e co-ligante L variando entre Cl-, CN-, SCN-, C3H5OS2- e C9H13N. Para a caracterização destes complexos foram envolvidas diversas técnicas, como espectroscopia na região do infravermelho e do UV-Vis, ponto de fusão, condutividade, espectroscopia de ressonância magnética nuclear 1H e 13C, espectrometria de massas ESI(+)-MS e análise elementar (C,H,N). O estudo consiste na avaliação da influência do ligante L frente a atividade antitumoral e anti-Trypanossoma cruzi, assim como na avaliação de sua influência em interações com possíveis alvos biológicos (DNA e albumina). Nos experimentos biológicos foi verificada a potencial atividade antitumoral destes complexos em células HepG2, HeLa, DU-145 e MDA-MB-231, dando destaque aos resultados obtidos para os complexos do tipo [AuCl(dmstc)] (IC50 = 8,05 ?molL-1) e [Au(xant)(dmstc)] (IC50 = 28,5 ?molL-1) frente à célula MDA-MB-231, ao complexo [AuCl(dmstc)] (IC50 = 8,37 ?molL-1) frente à célula DU-145 e ao complexo [AuSCN(dmstc)] o qual apresentou resultados promissores para todas as linhagens celulares tumorais avaliadas. Os ensaios in vitro contra cepas Tulahuen LacZ de Trypanossoma cruzi apresentaram resultados promissores, demonstrando uma elevada atividade contra o parasita e citotoxicidade geral negligenciável frente à células de baço de camundongo Swiss para todos os complexos avaliados, com exceção do complexo [Au(xant)(dmstc)]. Através do estudo de interação destes complexos com DNA-ct e albumina humana (HSA), é possível descartar o DNA como principal alvo biológico responsável pelas atividades observadas e sugerir uma adequada distribuição in vivo por meio da HSA. / This work describes the synthesis of gold(III) complexes with the ligand (diethylaminocarbonyl)benzimidoyl-morpholinyl thiosemicarbazone and the co-ligand L varying between Cl-, CN-, SCN-, C3H5OS2- and C9H13N. The complexes characterization involved various techniques such as melting point, conductivity, infrared, UV-Vis, 1H and 13C NMR spectroscopies, ESI(+)-MS mass spectrometry and elemental analysis (C, H, N). The study consists on the evaluation of the influence of the ligand L front anti-tumor and anti-Trypanosoma cruzi activities, as well as in assessing their influence on interactions with possible biological targets (DNA and albumin). The biological experiments showed potential antitumor activity for the complexes against HepG2, HeLa, DU-145 and MDA-MB-231 cells, especially the results obtained for the complexes of the type [AuCl(dmstc)] (IC50 = 8,05 ?molL-1) and [Au(xant)(dmstc)] (IC50 = 28,5 ?molL-1) against the MDA-MB-231 cell, the complex [AuCl(dmstc)] (IC50 = 8,37 ?molL-1) against the DU-145 cell, and the complex [AuSCN(dmstc)] which showed promising results for all tumor cells lines evaluated. In vitro assays against LacZ Tulahuen Trypanosoma cruzi presented promising results, showing high activity against the parasite with negligible general cytotoxicity against the Swiss mouse spleen cells in all evaluating complexes, except for complex [Au(xant)(dmstc)]. Through the studies of interaction of the complexes with DNA-ct and human albumin (HSA) can discard the DNA as the primary biological target responsible for the observed activities and suggest a proper distribution in vivo through the HSA.

Este trabalho apresenta a síntese de complexos de ouro(III) com ligante (dietilaminotiocarbonil)benzimidoíla-morfolinil-tiossemicarbazona e co-ligante L variando entre Cl-, CN-, SCN-, C3H5OS2- e C9H13N. Para a caracterização destes complexos foram envolvidas diversas técnicas, como espectroscopia na região do infravermelho e do UV-Vis, ponto de fusão, condutividade, espectroscopia de ressonância magnética nuclear 1H e 13C, espectrometria de massas ESI(+)-MS e análise elementar (C,H,N). O estudo consiste na avaliação da influência do ligante L frente a atividade antitumoral e anti-Trypanossoma cruzi, assim como na avaliação de sua influência em interações com possíveis alvos biológicos (DNA e albumina). Nos experimentos biológicos foi verificada a potencial atividade antitumoral destes complexos em células HepG2, HeLa, DU-145 e MDA-MB-231, dando destaque aos resultados obtidos para os complexos do tipo [AuCl(dmstc)] (IC50 = 8,05 ?molL-1) e [Au(xant)(dmstc)] (IC50 = 28,5 ?molL-1) frente à célula MDA-MB-231, ao complexo [AuCl(dmstc)] (IC50 = 8,37 ?molL-1) frente à célula DU-145 e ao complexo [AuSCN(dmstc)] o qual apresentou resultados promissores para todas as linhagens celulares tumorais avaliadas. Os ensaios in vitro contra cepas Tulahuen LacZ de Trypanossoma cruzi apresentaram resultados promissores, demonstrando uma elevada atividade contra o parasita e citotoxicidade geral negligenciável frente à células de baço de camundongo Swiss para todos os complexos avaliados, com exceção do complexo [Au(xant)(dmstc)]. Através do estudo de interação destes complexos com DNA-ct e albumina humana (HSA), é possível descartar o DNA como principal alvo biológico responsável pelas atividades observadas e sugerir uma adequada distribuição in vivo por meio da HSA. / This work describes the synthesis of gold(III) complexes with the ligand (diethylaminocarbonyl)benzimidoyl-morpholinyl thiosemicarbazone and the co-ligand L varying between Cl-, CN-, SCN-, C3H5OS2- and C9H13N. The complexes characterization involved various techniques such as melting point, conductivity, infrared, UV-Vis, 1H and 13C NMR spectroscopies, ESI(+)-MS mass spectrometry and elemental analysis (C, H, N). The study consists on the evaluation of the influence of the ligand L front anti-tumor and anti-Trypanosoma cruzi activities, as well as in assessing their influence on interactions with possible biological targets (DNA and albumin). The biological experiments showed potential antitumor activity for the complexes against HepG2, HeLa, DU-145 and MDA-MB-231 cells, especially the results obtained for the complexes of the type [AuCl(dmstc)] (IC50 = 8,05 ?molL-1) and [Au(xant)(dmstc)] (IC50 = 28,5 ?molL-1) against the MDA-MB-231 cell, the complex [AuCl(dmstc)] (IC50 = 8,37 ?molL-1) against the DU-145 cell, and the complex [AuSCN(dmstc)] which showed promising results for all tumor cells lines evaluated. In vitro assays against LacZ Tulahuen Trypanosoma cruzi presented promising results, showing high activity against the parasite with negligible general cytotoxicity against the Swiss mouse spleen cells in all evaluating complexes, except for complex [Au(xant)(dmstc)]. Through the studies of interaction of the complexes with DNA-ct and human albumin (HSA) can discard the DNA as the primary biological target responsible for the observed activities and suggest a proper distribution in vivo through the HSA.

ABSTRACT AXIAL LIGAND SUBSTITUTION REACTION KINETICS OF PYRIMIDINE-2-THIONATO BRIDGED BINUCLEAR PLATINUM(III) COMPLEXES G&ouml / y, Aytun&ccedil / M. S. Department of Chemistry Supervisor: Prof. Dr. H&uuml / seyin iS&ccedil / i Co-supervisor: Assoc. Prof.Dr. Seniz &Ouml / zalp Yaman September 2007, 89 pages The kinetics of the ligand substitution reactions, which is represented by the equation, [Pt2(C4H3N2S)4X2] + 2Y- Pt2(C4H3N2S)4Y2 + 2X- where X- = Cl-, Br-, I- and Y- = Cl-, Br-, I- are studied in acetonitrile in the presence of excess Y- ion concentrations, under constant ionic strength. All reactions are reversible. The rate of the above reaction is dependent on binuclear complex and entering ligand concentrations. Thus general rate equation can be written as Rate = k [Y-]a[Pt2(C4H3N2S)4X2]b The reaction rates are first order with respect to the substrate complex (b=1). The experimentally determined values of the order of the reaction with repect to entering ligand, &ldquo / a&rdquo / , are 0.96&plusmn / 0.057 (X=I-, Y=Cl-), -0.49&plusmn / 0.037 (X=Cl-, Y=I-), 0.28&plusmn / 0.023 (X=I-, Y=Br-), 0.48&plusmn / 0.044 (X=Br-, Y=I-), 0.53&plusmn / 0.042 (X=Br-, Y=Cl-), and -0.21&plusmn / 0.014 (X=Cl-, Y=Br-). The rate constants are 12.1&plusmn / 2.05 M-1s-1 (X=I-, Y=Cl-), (5.7&plusmn / 1.6)x10-3 M1/2s-1 (X=Cl-, Y=I-), 0.3&plusmn / 0.27 M-0.3s-1 (X=I-, Y=Br-), 0.53&plusmn / 0.11 M-1/2s-1 (X=Br-, Y=I-), 1.74&plusmn / 0.16 M-1/2s-1 (X=Br-, Y=Cl-), and 1.71&plusmn / 0.37x10-2 M0.2s-1 (X=Cl-, Y=Br-). To obtain information about the energetics of the reactions, the temperature dependence of the rate constants is determined and the activation parameters &amp / #916 / H* and &amp / #916 / S* are calculated. The values &amp / #916 / S* are negative and, in the range of -81 and -236 J K-1 mol-1. These results support an associative-interchange, Ia, mechanism. All data obtained in this work are used to propose a mechanism which will be consistent with the experimentally determined rate law.

Conducting metallopolymers have been investigated for a variety of applications due to their ability to take advantage of both the mechanical processability of the polymer material, as well as the optical and electronic properties of the metal. Our project goal is to design, synthesize and characterize novel iridium(III)-containing conducting metallopolymers for use as the active layer in polymer light-emitting diodes. We have utilized thiophene functionalized ligands that can be readily electropolymerized into conducting polymer thin films and can be easily incorporated into a device structure. Iridium(III) was chosen as the metal center due to its promising photophysical properties, as similar complexes have demonstrated high luminescent quantum yields and short phosphorescent lifetimes. The coordination environment around the metal can be altered synthetically to tune the emission wavelength across the visible spectrum. The synthetic control over the polymer backbone, as well as the iridium(III) ligand environment, allowed us to independently vary each component, which has provided a variety of materials. The materials are characterized through 1H and 13C NMR, mass spectrometry, elemental analysis, electrochemistry, X-Ray diffraction and X-Ray Photoelectron Spectroscopy. The photophysical properties of the materials are studied through UVvii Visible absorption spectroscopy, UV-Vis-NIR spectroelectrochemistry and steadystate/ time-resolved emission spectroscopy. / text

Lanthanide (III) complexes are used extensively in solar conversion devices, such as Luminescent Solar Concentrators (LSCs) and Luminescent Down-Shifting (LDS) for their peculiar characteristics of narrow band emission, avoidance of re-absorption losses due to large Stokes shift and possibility of high photoluminescence quantum yield (PLQY). The study has looked into the synthesis of Ln (III) complexes of the general formula: [Ln(hfac)3DPEPO], where DPEPO = bis(2-(diphenylphosphino)phenyl)ether oxide, and hfac = hexafluoroacetylacetonate. The work presented in this thesis focuses on the synthesis, and subsequent photophysical characterisation of these Ln(III) complexes, plus characterisation and spectroscopic study of [Tb(pobz)3(hacim)2], (where Hpobz = phenoxybenzoic acid, and Hacim = acetylacetone imine), yielding results that open new design of functional Ln(III) systems. Spectroscopic study of Chromium dioxalate and analogous compounds has revealed that with the appropriate design, Cr(III)Ln(III) energy transfer can be achieved, while study of polyaromatic hydrocarbons (PAH) such as coronene, enable to explore a ligand with better absorption in the whole UV region. These results open attractive perspectives for light-conversion systems, such as LSC devices.