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Farrow GA, Quick M, Kovalenko SA, Wu G, Sadler A, Chekulaev D, Chauvet AAP, Weinstein JA, Ernsting NP. On the intersystem crossing rate in a Platinum(II) donor-bridge-acceptor triad. Phys Chem Chem Phys 2021; 23:21652-21663. [PMID: 34580688 DOI: 10.1039/d1cp03471e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The rates of ultrafast intersystem crossing in acceptor-bridge-donor molecules centered on Pt(II) acetylides are investigated. Specifically, a Pt(II) trans-acetylide triad NAP--Pt--Ph-CH2-PTZ [1], with acceptor 4-ethynyl-N-octyl-1,8-naphthalimide (NAP) and donor phenothiazine (PTZ), is examined in detail. We have previously shown that optical excitation in [1] leads to a manifold of singlet charge-transfer states, S*, which evolve via a triplet charge-transfer manifold into a triplet state 3NAP centered on the acceptor ligand and partly to a charge-separated state 3CSS (NAP--Pt-PTZ+). A complex cascade of electron transfer processes was observed, but intersystem crossing (ISC) rates were not explicitly resolved due to lack of spin selectivity of most ultrafast spectroscopies. Here we revisit the question of ISC with a combination and complementary analysis of (i) transient absorption, (ii) ultrafast broadband fluorescence upconversion, FLUP, which is only sensitive to emissive states, and (iii) femtosecond stimulated Raman spectroscopy, FSR. Raman resonance conditions allow us to observe S* and 3NAP exclusively by FSR, through vibrations which are pertinent only to these two states. This combination of methods enabled us to extract the intersystem crossing rates that were not previously accessible. Multiple timescales (1.6 ps to ∼20 ps) are associated with the rise of triplet species, which can now be assigned conclusively to multiple ISC pathways from a manifold of hot charge-transfer singlet states. The analysis is consistent with previous transient infrared spectroscopy data. A similar rate of ISC, up to 20 ps, is observed in the trans-acetylide NAP--Pt--Ph [2] which maintains two acetylide groups across the platinum center but lacks a donor unit, whilst removal of one acetylide group in mono-acetylide NAP--Pt-Cl [3] leads to >10-fold deceleration of the intersystem crossing process. Our work provides insight on the intersystem crossing dynamics of the organo-metallic complexes, and identifies a general method based on complementary ultrafast spectroscopies to disentangle complex spin, electronic and vibrational processes following photoexcitation.
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Affiliation(s)
- G A Farrow
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
| | - M Quick
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
| | - S A Kovalenko
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
| | - G Wu
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
| | - A Sadler
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
| | - D Chekulaev
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
| | - A A P Chauvet
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
| | - J A Weinstein
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
| | - N P Ernsting
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
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2
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Atkins AJ, González L. Trajectory Surface-Hopping Dynamics Including Intersystem Crossing in [Ru(bpy) 3] 2. J Phys Chem Lett 2017; 8:3840-3845. [PMID: 28766339 DOI: 10.1021/acs.jpclett.7b01479] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Surface-hopping dynamics coupled to linear response TDDFT and explicit nonadiabatic and spin-orbit couplings have been used to model the ultrafast intersystem crossing (ISC) dynamics in [Ru(bpy)3]2+. Simulations using an ensemble of trajectories starting from the singlet metal-to-ligand charge transfer (1MLCT) band show that the manifold of 3MLCT triplet states is first populated from high-lying singlet states within 26 ± 3 fs. ISC competes with an intricate internal conversion relaxation process within the singlet manifold to the lowest singlet state. Normal-mode analysis and principal component analysis, combined with further dynamical simulations where the nuclei are frozen, unequivocally demonstrate that it is not only the high density of states and the large spin-orbit couplings of the system that promote ISC. Instead, geometrical relaxation involving the nitrogen atoms is required to allow for state mixing and efficient triplet population transfer.
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Affiliation(s)
- Andrew J Atkins
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna , Währinger Straße 17, A-1090 Vienna, Austria
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna , Währinger Straße 17, A-1090 Vienna, Austria
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3
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Magde D, Magde MD, Glazer EC. So-called “dual emission” for 3MLCT luminescence in ruthenium complex ions: What is really happening? Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2015.01.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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4
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Wächtler M, Maiuri M, Brida D, Popp J, Rau S, Cerullo G, Dietzek B. Utilizing Ancillary Ligands to Optimize the Photophysical Properties of 4H-Imidazole Ruthenium Dyes. Chemphyschem 2013; 14:2973-83. [DOI: 10.1002/cphc.201300383] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Indexed: 11/09/2022]
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5
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Horvath R, Lombard J, Leprêtre JC, Collomb MN, Deronzier A, Chauvin J, Gordon KC. Excited-state spectroscopic investigations of multinuclear complexes based on [Ru(bpy)3]2+ moieties connected to 2,2′-bipyridine and 2,2′;6′,2′′-terpyridine ligands. Dalton Trans 2013; 42:16527-37. [DOI: 10.1039/c3dt52153b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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6
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Li K, Cheng G, Ma C, Guan X, Kwok WM, Chen Y, Lu W, Che CM. Light-emitting platinum(ii) complexes supported by tetradentate dianionic bis(N-heterocyclic carbene) ligands: towards robust blue electrophosphors. Chem Sci 2013. [DOI: 10.1039/c3sc21822h] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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7
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Wächtler M, Guthmuller J, González L, Dietzek B. Analysis and characterization of coordination compounds by resonance Raman spectroscopy. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2012.02.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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8
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Sahoo SK, Umapathy S, Parker AW. Time-resolved resonance Raman spectroscopy: exploring reactive intermediates. APPLIED SPECTROSCOPY 2011; 65:1087-115. [PMID: 21986070 DOI: 10.1366/11-06406] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The study of reaction mechanisms involves systematic investigations of the correlation between structure, reactivity, and time. The challenge is to be able to observe the chemical changes undergone by reactants as they change into products via one or several intermediates such as electronic excited states (singlet and triplet), radicals, radical ions, carbocations, carbanions, carbenes, nitrenes, nitrinium ions, etc. The vast array of intermediates and timescales means there is no single "do-it-all" technique. The simultaneous advances in contemporary time-resolved Raman spectroscopic techniques and computational methods have done much towards visualizing molecular fingerprint snapshots of the reactive intermediates in the microsecond to femtosecond time domain. Raman spectroscopy and its sensitive counterpart resonance Raman spectroscopy have been well proven as means for determining molecular structure, chemical bonding, reactivity, and dynamics of short-lived intermediates in solution phase and are advantageous in comparison to commonly used time-resolved absorption and emission spectroscopy. Today time-resolved Raman spectroscopy is a mature technique; its development owes much to the advent of pulsed tunable lasers, highly efficient spectrometers, and high speed, highly sensitive multichannel detectors able to collect a complete spectrum. This review article will provide a brief chronological development of the experimental setup and demonstrate how experimentalists have conquered numerous challenges to obtain background-free (removing fluorescence), intense, and highly spectrally resolved Raman spectra in the nanosecond to microsecond (ns-μs) and picosecond (ps) time domains and, perhaps surprisingly, laid the foundations for new techniques such as spatially offset Raman spectroscopy.
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Affiliation(s)
- Sangram Keshari Sahoo
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore-560012, India
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9
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Lu W, Kwok WM, Ma C, Chan CTL, Zhu MX, Che CM. Organic triplet excited states of gold(I) complexes with oligo(o- or m-phenyleneethynylene) ligands: conjunction of steady-state and time-resolved spectroscopic studies on exciton delocalization and emission pathways. J Am Chem Soc 2011; 133:14120-35. [PMID: 21846130 DOI: 10.1021/ja205831v] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A series of mononuclear and binuclear gold(I) complexes containing oligo(o- or m-phenyleneethynylene) (PE) ligands, namely [PhC≡C(C(6)H(4)-1,2-C≡C)(n-1)Au(PCy(3))] (n = 2-4, 4a-c), [μ-{C≡C-(1,2-C(6)H(4)C≡C)(n)}{Au(PCy(3))}(2)] (n = 1-6, 8, 5a-g), [PhC≡C(C(6)H(4)-1,3-C≡C)(n-1)Au(PCy(3))] (n = 2-4, 6a-c), and [μ-{C≡C-(1,3-C(6)H(4)C≡C)(n)}{Au(PCy(3))}(2)] (n = 1, 2, 7a,b), were synthesized and structurally characterized. Extensive spectroscopic measurements have been performed by applying combined methods of femtosecond transient absorption (fs-TA), fs time-resolved fluorescence (fs-TRF), and nanosecond time-resolved emission (ns-TRE) coupled with steady-state absorption and emission spectroscopy at both ambient and low (77 K) temperatures to directly probe the temporal evolution of the excited states and to determine the dynamics and spectral signatures for the involved singlet (S(1)) and triplet (T(1)) excited states. The results reveal that S(1) and T(1) both feature ligand-centered electronic transitions with ππ* character associated with the phenyl and acetylene moieties. The (3)ππ* emission of the PE ligands is switched on by the attachment of [Au(PCy(3))](+) fragment(s) due to the heavy-atom effect. T(1)((3)ππ*) was found to form with nearly unity efficiency through intersystem crossing (ISC) from S(1)((1)ππ*). The ISC time constants were determined to be ∼50, 35, and 40 ps for 4b and 6a,b, respectively. Dual emission composed of fluorescence from S(1) and phosphorescence from T(1) were observed for most of the complexes except 5a and 7a, where only phosphorescence was found. The fluorescence at ambient temperature is accounted for by both the short-lived prompt fluorescence (PF) and long-lived delayed fluorescence (DF, lifetime on microsecond time scale). Explicit evidence was presented for a triplet-triplet annihilation mechanism for the generation of DF. Ligand length and substitution-dependent dynamics of T(1) are the key factors governing the dual emission character of the complexes. By extrapolation from the plot of emission energy against the PE chain length of the [Au(PCy(3))](+) complexes with oligo(o-PE) or oligo(m-PE) ligands, the triplet emission energies were estimated to be ∼530 and ∼470 nm for poly(o-PE) and poly(m-PE), respectively. Additionally, we assign the unusual red shifts of 983 cm(-1) from [PhC≡CAu(PCy(3))] (1) to [μ-{1,3-(C≡C)(2)C(6)H(4)}{Au(PCy(3))}(2)] (7a) and 462 cm(-1) from 7a to [μ(3)-{1,3,5-(C≡C)(3)C(6)H(3)}{Au(PCy(3))}(3)] (8) in the phosphorescence energies to excitonic coupling interactions between the C≡CAu(PCy(3)) arms in the triplet excited states. These complexes, together with those previously reported [Au(PCy(3))](+) complexes containing oligo(p-PE) ligands ( J. Am. Chem. Soc. 2002 , 124 , 14696 - 14706 ), form a collection of oligo(phenyleneethynylene) complexes exhibiting organic triplet emission in solution under ambient conditions. The remarkable feature of these complexes in exhibiting TTA prompted DF in conjunction with high formation efficiency of T(1)((3)ππ*) affords an opportunity for emission spectra to cover a wide range of wavelengths. This may have implication in the development of PE-based molecular materials for future optical applications.
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Affiliation(s)
- Wei Lu
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials, Department of Chemistry, The University of Hong Kong, People's Republic of China
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10
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McCusker CE, McCusker JK. Synthesis and Spectroscopic Characterization of CN-Substituted Bipyridyl Complexes of Ru(II). Inorg Chem 2011; 50:1656-69. [DOI: 10.1021/ic102085b] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Catherine E. McCusker
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - James K. McCusker
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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11
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Sen R, Koner S, Bhattacharjee A, Kusz J, Miyashita Y, Okamoto KI. Entrapment of [Ru(bpy)3]2+ in the anionic metal–organic framework: Novel photoluminescence behavior exhibiting dual emission at room temperature. Dalton Trans 2011; 40:6952-60. [DOI: 10.1039/c0dt01647k] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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Xiao L, Xu Y, Yan M, Galipeau D, Peng X, Yan X. Excitation-Dependent Fluorescence of Triphenylamine-Substituted Tridentate Pyridyl Ruthenium Complexes. J Phys Chem A 2010; 114:9090-7. [DOI: 10.1021/jp1040234] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lixin Xiao
- Center of Applied Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, South Dakota 57007, USA, State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012, People’s Republic of China, and State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871, People’s Republic of China
| | - Yongqian Xu
- Center of Applied Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, South Dakota 57007, USA, State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012, People’s Republic of China, and State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871, People’s Republic of China
| | - Ming Yan
- Center of Applied Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, South Dakota 57007, USA, State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012, People’s Republic of China, and State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871, People’s Republic of China
| | - David Galipeau
- Center of Applied Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, South Dakota 57007, USA, State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012, People’s Republic of China, and State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871, People’s Republic of China
| | - Xiaojun Peng
- Center of Applied Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, South Dakota 57007, USA, State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012, People’s Republic of China, and State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871, People’s Republic of China
| | - Xingzhong Yan
- Center of Applied Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, South Dakota 57007, USA, State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012, People’s Republic of China, and State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871, People’s Republic of China
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13
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Keyes TE, Forster RJ, Blackledge C. Time resolved spectroscopy of inorganic complexes. SPECTROSCOPIC PROPERTIES OF INORGANIC AND ORGANOMETALLIC COMPOUNDS 2010. [DOI: 10.1039/9781849730853-00211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Time resolved spectroscopy has revolutionised our understanding of photochemical and photophysical reactions of inorganic complexes. In this review, we briefly describe the most common time resolved optical spectroscopic methods applied to inorganic complexes and outline some examples and highlights from the recent literature. The review is not intended to be exhaustive, but highlights key recent papers from coordination chemistry, supramolecular chemistry, carbonyl chemistry and bioinorganic chemistry, as well as, recent insights from ultrafast spectroscopy into the photophysics of important prototypes such as [Ru(bpy)3]2+ and [Cu(dmp)2]+. A brief perspective is then presented which discusses areas where time resolved spectroscopy of inorganic complexes could play a particularly important role in the next few years.
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Affiliation(s)
- Tia E. Keyes
- National Biophotonics and Imaging Platform School of Chemical Sciences, Dublin City University Glasnevin, Dublin 7 Ireland
| | - Robert J. Forster
- National Biophotonics and Imaging Platform School of Chemical Sciences, Dublin City University Glasnevin, Dublin 7 Ireland
| | - Charles Blackledge
- National Biophotonics and Imaging Platform School of Chemical Sciences, Dublin City University Glasnevin, Dublin 7 Ireland
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14
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Rochford J, Botchway S, McGarvey JJ, Rooney AD, Pryce MT. Photophysical and Electrochemical Properties of meso-Substituted Thien-2-yl Zn(II) Porphyrins. J Phys Chem A 2008; 112:11611-8. [DOI: 10.1021/jp805809p] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jonathan Rochford
- School of Chemical Sciences, SRC for Solar Energy Conversion, Dublin City University, Dublin 9, Ireland, Central Laser Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, School of Chemistry, The Queen’s University of Belfast, Belfast BT9 5AG, Northern Ireland, United Kingdom, and Department of Chemistry, National University of Ireland Maynooth, Co. Kildare, Ireland
| | - Stanley Botchway
- School of Chemical Sciences, SRC for Solar Energy Conversion, Dublin City University, Dublin 9, Ireland, Central Laser Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, School of Chemistry, The Queen’s University of Belfast, Belfast BT9 5AG, Northern Ireland, United Kingdom, and Department of Chemistry, National University of Ireland Maynooth, Co. Kildare, Ireland
| | - John J. McGarvey
- School of Chemical Sciences, SRC for Solar Energy Conversion, Dublin City University, Dublin 9, Ireland, Central Laser Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, School of Chemistry, The Queen’s University of Belfast, Belfast BT9 5AG, Northern Ireland, United Kingdom, and Department of Chemistry, National University of Ireland Maynooth, Co. Kildare, Ireland
| | - A. Denise Rooney
- School of Chemical Sciences, SRC for Solar Energy Conversion, Dublin City University, Dublin 9, Ireland, Central Laser Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, School of Chemistry, The Queen’s University of Belfast, Belfast BT9 5AG, Northern Ireland, United Kingdom, and Department of Chemistry, National University of Ireland Maynooth, Co. Kildare, Ireland
| | - Mary T. Pryce
- School of Chemical Sciences, SRC for Solar Energy Conversion, Dublin City University, Dublin 9, Ireland, Central Laser Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom, School of Chemistry, The Queen’s University of Belfast, Belfast BT9 5AG, Northern Ireland, United Kingdom, and Department of Chemistry, National University of Ireland Maynooth, Co. Kildare, Ireland
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15
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Henry W, Coates CG, Brady C, Ronayne KL, Matousek P, Towrie M, Botchway SW, Parker AW, Vos JG, Browne WR, McGarvey JJ. The Early Picosecond Photophysics of Ru(II) Polypyridyl Complexes: A Tale of Two Timescales. J Phys Chem A 2008; 112:4537-44. [DOI: 10.1021/jp711873s] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- William Henry
- National Centre for Sensors Research, Dublin City University, Dublin 9, Ireland, School of Chemistry & Chemical Engineering, Queen’s University Belfast, Belfast BT9 5AG, Northern Ireland, U.K., Central Laser Facility, Science & Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, U.K., and Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Colin G. Coates
- National Centre for Sensors Research, Dublin City University, Dublin 9, Ireland, School of Chemistry & Chemical Engineering, Queen’s University Belfast, Belfast BT9 5AG, Northern Ireland, U.K., Central Laser Facility, Science & Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, U.K., and Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Clare Brady
- National Centre for Sensors Research, Dublin City University, Dublin 9, Ireland, School of Chemistry & Chemical Engineering, Queen’s University Belfast, Belfast BT9 5AG, Northern Ireland, U.K., Central Laser Facility, Science & Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, U.K., and Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Kate L. Ronayne
- National Centre for Sensors Research, Dublin City University, Dublin 9, Ireland, School of Chemistry & Chemical Engineering, Queen’s University Belfast, Belfast BT9 5AG, Northern Ireland, U.K., Central Laser Facility, Science & Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, U.K., and Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Pavel Matousek
- National Centre for Sensors Research, Dublin City University, Dublin 9, Ireland, School of Chemistry & Chemical Engineering, Queen’s University Belfast, Belfast BT9 5AG, Northern Ireland, U.K., Central Laser Facility, Science & Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, U.K., and Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Michael Towrie
- National Centre for Sensors Research, Dublin City University, Dublin 9, Ireland, School of Chemistry & Chemical Engineering, Queen’s University Belfast, Belfast BT9 5AG, Northern Ireland, U.K., Central Laser Facility, Science & Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, U.K., and Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Stanley W. Botchway
- National Centre for Sensors Research, Dublin City University, Dublin 9, Ireland, School of Chemistry & Chemical Engineering, Queen’s University Belfast, Belfast BT9 5AG, Northern Ireland, U.K., Central Laser Facility, Science & Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, U.K., and Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Anthony W. Parker
- National Centre for Sensors Research, Dublin City University, Dublin 9, Ireland, School of Chemistry & Chemical Engineering, Queen’s University Belfast, Belfast BT9 5AG, Northern Ireland, U.K., Central Laser Facility, Science & Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, U.K., and Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Johannes G. Vos
- National Centre for Sensors Research, Dublin City University, Dublin 9, Ireland, School of Chemistry & Chemical Engineering, Queen’s University Belfast, Belfast BT9 5AG, Northern Ireland, U.K., Central Laser Facility, Science & Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, U.K., and Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Wesley R. Browne
- National Centre for Sensors Research, Dublin City University, Dublin 9, Ireland, School of Chemistry & Chemical Engineering, Queen’s University Belfast, Belfast BT9 5AG, Northern Ireland, U.K., Central Laser Facility, Science & Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, U.K., and Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - John J. McGarvey
- National Centre for Sensors Research, Dublin City University, Dublin 9, Ireland, School of Chemistry & Chemical Engineering, Queen’s University Belfast, Belfast BT9 5AG, Northern Ireland, U.K., Central Laser Facility, Science & Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, U.K., and Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
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16
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Browne WR, Passaniti P, Gandolfi MT, Ballardini R, Henry W, Guckian A, O’Boyle N, McGarvey JJ, Vos JG. Probing inter-ligand excited state interaction in homo and heteroleptic ruthenium(II) polypyridyl complexes using selective deuteriation. Inorganica Chim Acta 2007. [DOI: 10.1016/j.ica.2006.08.049] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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17
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Harriman A, Izzet G, Goeb S, De Nicola A, Ziessel R. Photophysical Properties of Ruthenium(II) Tris(2,2‘-bipyridine) Complexes Bearing Conjugated Thiophene Appendages. Inorg Chem 2006; 45:9729-41. [PMID: 17112269 DOI: 10.1021/ic060921w] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A small series of ruthenium(II) tris(2,2'-bipyridine) complexes has been synthesized in which ethynylated thiophene residues are attached to one of the 2,2'-bipyridine ligands. The photophysical properties depend on the conjugation length of the thiophene-based ligand, and in each case, dual emission is observed. The two emitting states reside in thermal equilibrium at ambient temperature and can be resolved by emission spectral curve-fitting routines. This allows the properties of the two states to be evaluated in both fluid butyronitrile solution and a transparent KBr disk. It is concluded that both emitting states are of metal-to-ligand charge-transfer (MLCT) character, and despite the presence of conjugated thiophene residues, there is no indication for a low-lying pi,pi*-triplet state that promotes nonradiative decay of the excited-state manifold. A key feature of these systems is that the conjugation length imposed by the thiophene-based ligand helps to control the rate constants for both radiative and nonradiative decay from the two MLCT triplet states.
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Affiliation(s)
- Anthony Harriman
- Molecular Photonics Laboratory, School of Natural Sciences, Bedson Building, University of Newcastle, Newcastle upon Tyne, NE1 7RU, United Kingdom.
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18
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Benniston AC, Harriman A, Li P, Patel PV, Rostron JP, Sams CA. An Apparent Angle Dependence for the Nonradiative Deactivation of Excited Triplet States of Sterically Constrained, Binuclear Ruthenium(II) Bis(2,2‘:6‘,2‘ ‘-terpyridine) Complexes. J Phys Chem A 2006; 110:9880-6. [PMID: 16898690 DOI: 10.1021/jp061059g] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The photophysical properties are reported for a series of binuclear ruthenium(II) bis(2,2':6',2"-terpyridine) complexes built around a geometrically constrained, biphenyl-based bridge. The luminescence quantum yield and lifetime increase progressively with decreasing temperature, but the derived rate constant for nonradiative decay of the lowest-energy triplet state depends on the length of a tethering strap attached at the 2,2'-positions of the biphenyl unit. Since the length of the strap determines the dihedral angle for the central C-C bond, the rate of nonradiative decay shows a pronounced dependence on angle. The minimum rate of nonradiative decay occurs when the dihedral angle is 90 degrees, but there is a maximum in the rate when the dihedral angle is about 45 degrees. This effect does not appear to be related to the extent of electron delocalization at the triplet level but can be explained in terms of variable coupling with a low-frequency vibrational mode associated with the strapped biphenyl unit.
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Affiliation(s)
- Andrew C Benniston
- Molecular Photonics Laboratory, School of Natural Sciences, Bedson Building, University of Newcastle, Newcastle upon Tyne, NE1 7RU, U.K
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19
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Dietzek B, Kiefer W, Blumhoff J, Böttcher L, Rau S, Walther D, Uhlemann U, Schmitt M, Popp J. Ultrafast Excited-State Excitation Dynamics in a Quasi-Two-Dimensional Light-Harvesting Antenna Based on Ruthenium(II) and Palladium(II) Chromophores. Chemistry 2006; 12:5105-15. [PMID: 16628758 DOI: 10.1002/chem.200501093] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A detailed study on the excited-state-excitation migration taking place within the tetranuclear complex [{(tbbpy)(2)Ru(tmbi)}(2){Pd(allyl)}(2)](PF(6))(2) (tbbpy = 4,4'-di-tert-butyl-2,2'-bipyridine and tmbi = 5,6,5',6'-tetramethyl-2,2'-bibenzimidazolate) is presented. The charge transfer is initiated by the photoexcitation into the lowest metal-to-ligand charge-transfer (MLCT) band of one of the peripheral ruthenium(II) chromophores and terminates on the central structurally complex Pd(2) (II)(allyl)(2) subunit. Thus, the system under investigation can be thought of as a functional model for the photosynthesis reaction center in plants. The kinetic steps involved in the overall process are inferred from femtosecond time-resolved transient-grating kinetics recorded at spectral positions within the regions of ground-state bleach and transient absorption. The kinetics features a complex non-exponential time behavior and can be fitted to a bi-exponential rise (tau(1)> or =200 fs, tau(2) approximately 1.5 ps) and a mono- or bi-exponential decay, depending on the experimental situation. The data leads to the formulation of a model for the intramolecular excitation-hopping ascribing intersystem crossing and subsequent cooling as the two fastest observed processes. Following these initial steps, charge transfer from the ruthenium to the central complex Pd(2)(allyl)(2) moiety is observed with a characteristic time constant of 50 ps. A 220-ps component that is observed in the ground-state recovery only is attributed to excitation equilibration between the two identical Pd(allyl) chromophores.
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Affiliation(s)
- Benjamin Dietzek
- Institut für Physikalische Chemie, Bayerische Julius-Maximilians Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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20
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Cannizzo A, van Mourik F, Gawelda W, Zgrablic G, Bressler C, Chergui M. Broadband Femtosecond Fluorescence Spectroscopy of [Ru(bpy)3]2+. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200600125] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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21
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Cannizzo A, van Mourik F, Gawelda W, Zgrablic G, Bressler C, Chergui M. Broadband Femtosecond Fluorescence Spectroscopy of [Ru(bpy)3]2+. Angew Chem Int Ed Engl 2006; 45:3174-6. [PMID: 16586519 DOI: 10.1002/anie.200600125] [Citation(s) in RCA: 204] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Andrea Cannizzo
- Laboratoire de Spectroscopie Ultrarapide, ISIC, FSB-BSP, Ecole Polytechnique Fédérale de Lausanne, EPFL SB ISIC LSU, Ch-1015 Lausanne-Dorigny, Switzerland
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22
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Yoon S, Kukura P, Stuart CM, Mathies RA. Direct observation of the ultrafast intersystem crossing in tris(2,2′-bipyridine)ruthenium(II) using femtosecond stimulated Raman spectroscopy. Mol Phys 2006. [DOI: 10.1080/00268970500525846] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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23
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Rivarola CR, Bertolotti SG, Previtali CM. Photoreduction of Ru(bpy)32+ by Amines in Aqueous Solution. Kinetics Characterization of a Long-Lived Nonemitting Excited State†. Photochem Photobiol 2006; 82:213-8. [PMID: 16097860 DOI: 10.1562/2005-05-31-ra-558] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The photochemistry of Ru(bpy)(3)+2 in the presence of amines was investigated in water by laser flash photolysis. N,N'-Dimethylaniline and p-phenylenediamine quench the luminescent metal to ligand charge transfer (MLCT) excited state of the complex by an electron transfer reaction that produces the semireduced form Ru(bpy)3+ in relatively high yields. On the other hand, triethylamine (TEA) and aniline do not quench the MLCT. Nevertheless, when laser flash irradiation at 532 nm is carried out in the presence of these amines, the formation of Ru(bpy)3+ is clearly detected by its transient absorption at 510 nm. These results are interpreted by an electron transfer reaction with the participation of a nonemitting excited state of the complex, formed independently of the MLCT from the Franck-Condon or the relaxed singlet excited state. The rate constants for the quenching of this state by TEA and aniline and the quantum yields for Ru(bpy)(3)+ were determined. The new state is formed in a very fast process and has a lifetime of ca 4 micros in water.
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Affiliation(s)
- Claudia R Rivarola
- Departamento de Química, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina
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24
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Glazer EC, Magde D, Tor Y. Dual emission from a family of conjugated dinuclear Ru(II) complexes. J Am Chem Soc 2005; 127:4190-2. [PMID: 15783199 DOI: 10.1021/ja0440304] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dual emission is observed from a family of simple acetylene-linked dinuclear RuII complexes, where two MLCT excited states coexist at room temperature and in fluid solution. This unique behavior is attributed to a specific substitution pattern on the bridging ligand and provides the opportunity to investigate the structural and electronic features that result in decoupling of standard nonradiative decay pathways.
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Affiliation(s)
- Edith C Glazer
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, USA
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25
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McFarland SA, Lee FS, Cheng KAWY, Cozens FL, Schepp NP. Picosecond Dynamics of Nonthermalized Excited States in Tris(2,2-bipyridine)ruthenium(II) Derivatives Elucidated by High Energy Excitation. J Am Chem Soc 2005; 127:7065-70. [PMID: 15884949 DOI: 10.1021/ja0461872] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The picosecond excited-state dynamics of several derivatives have been investigated using high photon energy excitation combined with picosecond luminescence detection. Instrument response-limited fluorescence (tau(1) approximately equal to 3-5 ps) at 500 nm was observed for all of the complexes, while longer-lived emission (tau(2) > 50 ps), similar in energy, was observed for only some of the complexes. Interestingly, the presence of tau(2) required substitution at the 4,4-positions of the bipyridine ligands and D(3) symmetry for the complex; only the 4,4-substituted homoleptic complexes exhibited tau(2). On the basis of previous assignments of the ultrafast dynamics measured for Ru(bpy)(2+)3 and Ru(dmb)(2+)3, tau(2) has been tentatively ascribed to relaxation from higher electronic or vibrational levels in the triplet manifold having slightly more triplet character than the state responsible for tau(1). However, given that the kinetics for these transition metal complexes are highly dependent on both pump and probe wavelengths and that there is considerable interest in utilizing such complexes for electron transfer in the nonergodic limit, further characterization of the state giving rise to tau(2) is warranted.
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Affiliation(s)
- Sherri A McFarland
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4J3, Canada.
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26
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Ma C, Kwok WM, Chan WS, Zuo P, Wai Kan JT, Toy PH, Phillips DL. Ultrafast Time-Resolved Study of Photophysical Processes Involved in the Photodeprotection ofp-Hydroxyphenacyl Caged Phototrigger Compounds. J Am Chem Soc 2005; 127:1463-72. [PMID: 15686379 DOI: 10.1021/ja0458524] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A combined femtosecond Kerr gated time-resolved fluorescence (fs-KTRF) and picosecond Kerr gated time-resolved resonance Raman (ps-KTR(3)) study is reported for two p-hydroxyphenacyl (pHP) caged phototriggers, HPDP and HPA, in neat acetonitrile and water/acetonitrile (1:1 by volume) solvents. Fs-KTRF spectroscopy was employed to characterize the spectral properties and dynamics of the singlet excited states, and the ps-KTR(3) was used to monitor the formation and subsequent reaction of triplet state. These results provide important evidence for elucidation of the initial steps for the pHP deprotection mechanism. An improved fs-KTRF setup was developed to extend its detectable spectral range down to the 270 nm UV region while still covering the visible region up to 600 nm. This combined with the advantage of KTRF in directly monitoring the temporal evolution of the overall fluorescence profile enables the first time-resolved observation of dual fluorescence for pHP phototriggers upon 267 nm excitation. The two emitting components were assigned to originate from the (1)pipi (S(3)) and (1)npi (S(1)) states, respectively. This was based on the lifetime, the spectral location, and how these varied with the type of solvent. By correlating the dynamics of the singlet decay with the triplet formation, a direct (1)npi --> (3)pipi ISC mechanism was found for these compounds with the ISC rate estimated to be approximately 5 x 10(11) s(-)(1) in both solvent systems. These photophysical processes were found to be little affected by the kind of leaving group indicating the common local pHP chromophore is largely responsible for the fluorescence and relevant deactivation processes. The triplet lifetime was found to be approximately 420 and 2130 ps for HPDP and HPA, respectively, in the mixed solvent compared to 150 and 137 ns, respectively, in neat MeCN. The solvent and leaving group dependent quenching of the triplet is believed to be associated with the pHP deprotection photochemistry and indicates that the triplet is the reactive precursor for pHP photorelease reactions for the compounds examined in this study.
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Affiliation(s)
- Chensheng Ma
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., P. R. China
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27
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Puntoriero F, Serroni S, Galletta M, Juris A, Licciardello A, Chiorboli C, Campagna S, Scandola F. A New Heptanuclear Dendritic Ruthenium(II) Complex Featuring Photoinduced Energy Transfer Across High-Energy Subunits. Chemphyschem 2005; 6:129-38. [PMID: 15688656 DOI: 10.1002/cphc.200400240] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The new heptanuclear ruthenium(II) dendron, [Cl(2)Ru{(micro-2,3dpp)Ru[(micro-2,3-dpp)Ru(bpy)2]2}2](PF6)12 (1; 2,3-dpp=2,3-bis(2'-pyridyl)pyrazine; bpy = 2,2'-bipyridine), was prepared by means of the "complexes as ligands/complexes as metals" synthetic strategy, and its absorption spectrum, redox behavior, and luminescence properties were investigated. Compound 1 is a multicomponent species, which contains three different types of chromophores (namely, the {Cl(2)Ru(micro-2,3-dpp)2} core, the {Ru(micro-2,3dpp)3}2+ intermediate, and the {(bpy)2Ru(micro-2,3-dpp)}2+ peripheral subunits) and several redox-active sites. The new species exhibits very intense absorption bands in the UV region (epsilon value in the 10(5)-10(6) M(-1) cm(-1) range) as a result of spin-allowed ligand-centered (LC) transitions, and intense bands in the visible region (epsilon value in the 10(4)-10(5) M(-1) cm(-1) range) as a result of the various spin-allowed metal-to-ligand charge-transfer (MLCT) transitions. The redox investigation (accomplished by cyclic and differential pulse voltammetry) indicates that 1 undergoes a series of reversible metal-centered oxidation and ligand-centered reduction processes within the potential window investigated (+1.90 / -1.40 V vs. the standard calomel electrode, SCE). The assignment of each absorption bond and redox process to specific subunits of 1 was achieved by comparison with the properties of smaller multinuclear species of the same family, namely [Cl(2)Ru{(micro-2,3-dpp)Ru(bpy)2}2]4+ (2), [(bpy)2Ru(u-2,3-dpp)Ru(bpy)2]4+ (4), and [Ru{(micro-2,3-dpp)Ru(bpy)2}3]4+ (5). The title compound exhibits luminescence both at room temperature in acetonitrile fluid solution and at 77 K in butyronitrile rigid matrix. The emission is attributed to the triplet MLCT (3MLCT) state involving the core {Cl(2)Ru(micro-2,3-dpp)2} subunit. Interestingly, the 3MLCT levels involving the peripheral {(bpy)2Ru(micro-2,3-dpp)}2+ subunits are deactivated by energy transfer to the emitting level, in spite of the presence of interposed high-energy (Ru(micro-2,3-dpp)3}2+ components, which, in other dendrimers, acted as "isolating" subunits toward energy-transfer processes. Ultrafast experiments on 1 and on the parent species 2 and 5 allowed us to rationalize this behavior and highlight that a sequential two-step electron-transfer process can be held responsible for the efficient overall energy transfer, which offers a way to overcome a limitation in antenna metal dendrimers.
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Affiliation(s)
- Fausto Puntoriero
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, V Sperone 31, 98166 Messina, Italy.
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28
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Liu Y, Song SH, Chen Y, Zhao YL, Yang YW. The construction of a supramolecular polymeric rotaxane from bipyridine-ruthenium and cyclodextrin. Chem Commun (Camb) 2005:1702-4. [PMID: 15791304 DOI: 10.1039/b415930f] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A luminescent supramolecular link is constructed by a very simple method using bipyridine-ruthenium and cyclodextrin, which displays not only a quasi-linear structure, but also a satisfactory fluorescence emission in both solution and the solid state.
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Affiliation(s)
- Yu Liu
- Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, PR China.
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29
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Draper SM, Gregg DJ, Schofield ER, Browne WR, Duati M, Vos JG, Passaniti P. Complexed nitrogen heterosuperbenzene: the coordinating properties of a remarkable ligand. J Am Chem Soc 2004; 126:8694-701. [PMID: 15250721 DOI: 10.1021/ja0491634] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tetra-peri-(tert-butyl-benzo)-di-peri-(pyrimidino)-coronene 1, the parent compound of the nitrogen heterosuperbenzene family N-HSB, is employed as a novel monotopic ligand in the formation of [Pd(eta3-C3H5)(1)]PF6 2 and [Ru(bpy)2(1)](PF6)2 (where bpy = 2,2'-bipyridine 3a and d8-2,2'-bipyridine 3b). These N-coordinated complexes are fully characterized by 1H NMR and IR spectroscopy and ESI-MS. Metal coordination has a profound effect on both the absorption and the emission properties of 1. Pd(II) coordination causes a red-shift in the low-energy absorptions, a decrease in the intensity of the n-pi absorptions, and a quenching of the emission. Ru(II) coordination causes absorption throughout the visible region and creates two new complexes that join an elite group of compounds known as "black" absorbers. 3a and 3b possess two discernible 1MLCT bands. The one of exceptionally low energy (lambda(max) = 615 nm) has an associated (3)MLCT emission (lambda(max) = 880 nm) due to the unprecedented electron delocalization and acceptor properties of the rigid aromatic N-HSB 1. Both Ru(II) complexes are near-IR emitters with unusually protracted emission lifetimes of 320 ns at 77 K. They are photochemically inert, and their electrochemical properties are consistent with the presence of a low-lying pi orbital on 1. The first two reversible reductions (E(1/2) (CH3CN), -0.54 V, -1.01 V vs SCE) are due to the stepwise reduction of 1 and are anodically shifted as compared to [Ru(bpy)3]2+. Temperature- and concentration-dependent NMR studies on 2 and 3a suggest extensive aggregation is occurring in solution.
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Affiliation(s)
- Sylvia M Draper
- Department of Chemistry, University of Dublin, Trinity College, D2, Ireland.
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30
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Shaw GB, Styers-Barnett DJ, Gannon EZ, Granger JC, Papanikolas JM. Interligand Electron Transfer Dynamics in [Os(bpy)3]2+: Exploring the Excited State Potential Surfaces with Femtosecond Spectroscopy. J Phys Chem A 2004. [DOI: 10.1021/jp0363850] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- George B. Shaw
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290
| | - David J. Styers-Barnett
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290
| | - Erika Z. Gannon
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290
| | - Jeremy C. Granger
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290
| | - John M. Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290
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31
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Andersson J, Puntoriero F, Serroni S, Yartsev A, Pascher T, Polı́vka T, Campagna S, Sundström V. Ultrafast singlet energy transfer competes with intersystem crossing in a multi-center transition metal polypyridine complex. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.01.081] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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