Functional Porphyrinoids from a Biomimetically Decorated Bipyrrole

Bröring, Martin; Brégier, Frédérique; Krüger, Robin; Kleeberg, Christian

doi:10.1002/ejic.200800946

Cited by 25 publications

(17 citation statements)

References 96 publications

(17 reference statements)

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“…Figure reveals a small but distinct bond-length alternation in and around the bipyrrole unit of the three MnCl structures. An analogous bond-length alternation is also found for other structurally characterized halogenomanganese corroles (MIKWOU, TORMET, YAWQES, YAWQAO, GIFJEL, and XIDRUY) but is essentially nonexistent in the X-ray structure of Mn[T p OMePC]Ph (as well as CISGUH and CISHAO). We have recently shown that such a bond-length alternation is indicative of a corrole a 2u -type radical (allowing ourselves to use D 4 h symbols for orbital symmetries that are standard for porphyrins). − DFT calculations also reproduce this difference in the skeletal bond-length alternation between Mn[TPC]Cl and Mn[TPC]Ph (Figure ).…”

Section: Resultssupporting

confidence: 69%

“…Thus, Table 3 shows that halogenomanganese corroles (including the previously reported structures MIKWOU, 41 TORMET, 44 YAWQES, 14 YAWQAO, 14 GIFJEL, 45 and XI-DRUY 42 ) exhibit significantly larger out-of-plane Mn−N 4 displacements than Mn-aryl corroles (including CISGUH 35 and CISHAO 35 ). The higher displacements for the MnCl complexes facilitate antiferromagnetic coupling between the d z 2 electron of the high-spin Mn III center and the "a 2u -type" corrole radical.…”

Section: ■ Introductionmentioning

confidence: 75%

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Electronic Structure of Manganese Corroles Revisited: X-ray Structures, Optical and X-ray Absorption Spectroscopies, and Electrochemistry as Probes of Ligand Noninnocence

et al. 2018

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Presented herein is a detailed multitechnique investigation of ligand noninnocence in S = / manganese corrole derivatives at the formal Mn oxidation state. The Soret maxima of Mn[T pXPC]Cl (T pXPC = meso-tris( p-X-phenyl)corrole, where X = CF, H, Me, and OMe) were found to red-shift over a range of 37 nm with increasing electron-donating character of X. For Mn[T pXPC]Ph, in contrast, the complex Soret envelopes were found to be largely independent of X. These observations suggested a noninnocent corrole-like ligand for the MnCl complexes and an innocent corrole ligand for the MnPh complexes. Single-crystal X-ray structures of three Mn[T pXPC]Cl complexes revealed skeletal bond-length alternations indicative of a noninnocent corrole, while no such alternation was observed for Mn[T pOMePC]Ph. B3LYP density functional theory (DFT) calculations on Mn[TPC]Cl yielded strong spatial separation of the α and β spin densities, consistent with an antiferromagnetically coupled Mn-corrole description. By comparison, relatively little spatial separation of the α and β spin densities was found for Mn[TPC]Ph, consistent with an essentially Mn-corrole description. X-ray absorption of near-edge spectroscopy (XANES) revealed a moderate blue shift of 0.6 eV for the Mn K-pre-edge of Mn[T pCFPC]Ph and a striking enhancement of the pre-edge intensity, relative to Mn[T pCFPC]Cl, consistent with a more oxidized, i.e., Mn, center in Mn[T pCFPC]Ph. Time-dependent DFT calculations indicated that the enhanced intensity of the Mn K-pre-edge of Mn[T pCFPC]Ph results from the extra 3d hole, which mixes strongly with the Mn 4p orbital. Combined with similar results on Fe[TPC]Cl and Fe[TPC]Ph, the present study underscores the considerable potential of metal K-edge XANES in probing ligand noninnocence in first-row transition-metal corroles. Cyclic voltammetry measurements revealed highly negative first reduction potentials for the Mn[T pXPC]Ph series (∼-0.95 V) as well as large electrochemical HOMO-LUMO gaps of ∼1.7 V. The first reductions, however, are irreversible, suggesting cleavage of the Mn-Ph bond.

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Section: Resultssupporting

confidence: 69%

Section: ■ Introductionmentioning

confidence: 75%

Electronic Structure of Manganese Corroles Revisited: X-ray Structures, Optical and X-ray Absorption Spectroscopies, and Electrochemistry as Probes of Ligand Noninnocence

et al. 2018

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“…[4,5] Nevertheless, all efforts to obtain a suitable single crystal of complex 1 were unsuccessful, which hindered a detailed structural view of this complex. Thus, comparison was carried out on similar complexes with known solid-state structures.…”

Section: Introductionmentioning

confidence: 99%

Conformational dynamics of bis(BF₂)‐2,2′‐bidipyrrins revealed by through‐space ¹³C¹⁹F and ¹⁹F¹⁹F couplings

Xie

Yuan

Krüger

et al. 2009

Magnetic Reson in Chemistry

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The conformation of [bis-(N,N'-difluoroboryl)]-3,3'-diethyl-4,4',8,8',9,9',10,10'-octamethyl-2,2'-bidipyrrin (1) in solution was studied by analyzing the 13C-19F and 19F-19F through-space spin-spin couplings. The 1H and 13C NMR spectra were assigned on the basis of nuclear Overhauser effect spectroscopy (NOESY), heteronuclear single-quantum correlation (HSQC), and heteronuclear multiple-bond correlation (HMBC) experiments. The 19F spectrum of 1 was compared with that of 2-ethyl-1,3,5,6,7-pentamethyl-4,4-difluoro-4-bor-3a,4a-diaza-s-indacen (2). The 19F-19F through-space spin--spin coupling in 1 was thus assigned and the coupling constant was obtained by simulating the coupling patterns. The obtained conformation of 1 was compared with those of the known complexes [bis-(N,N'-difluoroboryl)]-3,3',8,8',9,9'-hexaethyl-4,4',10,10'-tetramethyl-6,6'-(4-methylphenyl)-2,2'-bidipyrrin (3)and [bis-(N,N'-difluoroboryl)]-9,9'-diethyl-4,4',8,8',10,10'-hexamethyl-3,3'-bis(methoxycarbonylethyl)-2,2'-bidipyrrin (4). The conformational dynamics of 1, 3, and 4 was surveyed by observing the temperature dependence of the through-space coupling constants between 253 and 333 K. The 13C-19F and 19F-19F through-space spin-spin couplings thus confirm similar conformations of different BisBODIPYs in solution in contrast to earlier findings in the solid state.

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“…And 19 F NMR gives no signal of any resonance, further proving the absence of BF 2 group. Although BODIPY dyes normally exhibit high chemical-and photo-stability, decomposition also happens in certain chemical conditions, especially under attack of radicals in this case [33,34]. Ligand L2 could also be synthesized through bromination of L1 by bromine with excellent yield (82%), following previously reported procedure [35].…”

mentioning

confidence: 98%

Synthesis and characterization of novel fluorescent BOPIM dyes with large Stokes shift

Mao

Xiao

et al. 2011

Journal of Fluorine Chemistry

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Functional Porphyrinoids from a Biomimetically Decorated Bipyrrole

Cited by 25 publications

References 96 publications

Electronic Structure of Manganese Corroles Revisited: X-ray Structures, Optical and X-ray Absorption Spectroscopies, and Electrochemistry as Probes of Ligand Noninnocence

Electronic Structure of Manganese Corroles Revisited: X-ray Structures, Optical and X-ray Absorption Spectroscopies, and Electrochemistry as Probes of Ligand Noninnocence

Conformational dynamics of bis(BF₂)‐2,2′‐bidipyrrins revealed by through‐space ¹³C¹⁹F and ¹⁹F¹⁹F couplings

Synthesis and characterization of novel fluorescent BOPIM dyes with large Stokes shift

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Functional Porphyrinoids from a Biomimetically Decorated Bipyrrole

Cited by 25 publications

References 96 publications

Electronic Structure of Manganese Corroles Revisited: X-ray Structures, Optical and X-ray Absorption Spectroscopies, and Electrochemistry as Probes of Ligand Noninnocence

Electronic Structure of Manganese Corroles Revisited: X-ray Structures, Optical and X-ray Absorption Spectroscopies, and Electrochemistry as Probes of Ligand Noninnocence

Conformational dynamics of bis(BF2)‐2,2′‐bidipyrrins revealed by through‐space 13C19F and 19F19F couplings

Synthesis and characterization of novel fluorescent BOPIM dyes with large Stokes shift

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Conformational dynamics of bis(BF₂)‐2,2′‐bidipyrrins revealed by through‐space ¹³C¹⁹F and ¹⁹F¹⁹F couplings