Two-Photon Absorbing Phosphorescent Metalloporphyrins: Effects of π-Extension and Peripheral Substitution.
Two-Photon Absorbing Phosphorescent Metalloporphyrins: Effects of π-Extension and Peripheral Substitution.
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DOI：
10.1021/jacs.6b09157
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发表时间：
2016-12-07
影响因子：
15
通讯作者：
Vinogradov SA
中科院分区：
文献类型：
--
作者：
Esipova TV;Rivera-Jacquez HJ;Weber B;Masunov AE;Vinogradov SA
The ability to form triplet excited states upon two-photon excitation is important for several applications of metalloporphyrins, including two-photon phosphorescence lifetime microscopy (2PLM) and two-photon photodynamic therapy. Here we analyzed one-photon (1P) and degenerate two-photon (2P) absorption properties of several phosphorescent Pt (II) porphyrins, focusing on the effects of aromatic π-extension and peripheral substitution on triplet emissivity and two-photon absorption (2PA). Our 2PA measurements for the first time made use of direct time-resolved detection of phosphorescence, having the ability to efficiently reject laser background through microsecond time gating. π-Extension of the porphyrin macrocycle by way of syn-fusion with two external aromatic fragments, such as in syn-dibenzo- (DBP) and syn-dinaphthoporphyrins (DNP), lowers the symmetry of the porphyrin skeleton. As a result, DBP’s and DNP’s exhibit stronger 2PA into the one-photon-allowed B- (Soret) and Q-states than fully-symmetric (D4h) non-extended porphyrins. However, much more 2P-active states lie above the B-state and cannot be accessed due to the interfering linear absorption. Alkoxycarbonyl groups (CO2R) in the benzo-rings dramatically enhance 2PA near the B-state level. Time-dependent density functional theory (TDDFT) calculations in combinations with the Sum-Over-States (SOS) formalism revealed that the enhancement is due to the stabilization of higher-lying 2P-active states, which are dominated by the excitations involving orbitals extending onto the carbonyl groups. Furthermore, calculations predicted even stronger stabilization of the 2P-allowed gerade-states in symmetric Pt octaalkoxycarbonyltetrabenzoporphyrins. Experiments confirmed that the 2PA cross-section of PtTBP(CO2Bu)8 near 810 nm reaches above 500 GM in spite of its completely centrosymmetric structure. Combined with exceptionally bright phosphorescence (ϕphos=0.45), strong 2PA makes Pt(II) complexes of π-extended porphyrins a valuable class of chromophores for 2P applications. Another important advantage of these porphyrinoids is their compact size and easily scalable synthesis.
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影响因子：
35
作者：
Collins, Hazel A.;Khurana, Mamta;Anderson, Harry L.
通讯作者：
Anderson, Harry L.
DOI：
10.1007/bf01114537
发表时间：
1990-04-01
期刊：
THEORETICA CHIMICA ACTA
影响因子：
--
作者：
ANDRAE, D;HAUSSERMANN, U;PREUSS, H
通讯作者：
PREUSS, H
影响因子：
3.2
作者：
Balaz, Milan;Collins, Hazel A.;Anderson, Harry L.
通讯作者：
Anderson, Harry L.
影响因子：
15
作者：
Drobizhev, M;Stepanenko, Y;Anderson, HL
通讯作者：
Anderson, HL
影响因子：
15
作者：
Drobizhev, Mikhail;Stepanenko, Yuriy;Anderson, Harry L.
通讯作者：
Anderson, Harry L.