Pt(II)- and Pt(IV)-Bridged Cofacial Diporphyrins via Carbon−Transition Metal σ-Bonds

Yamaguchi, Shigeru; Katoh, Taisuke; Shinokubo, Hiroshi; Osuka, Atsuhiro

doi:10.1021/ja8066385

Cited by 66 publications

(26 citation statements)

References 20 publications

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“…Unlike for the dimeric systems 5-7, for 8 the chirality is primarily defined by the orientation of the porphyrinoid rings, so the coupling enhances the CD signals. The values of the molar amplitudes De are comparable to those observed for some platinum(IV)-linked cofacial bis(porphyrinatonickA C H T U N G T R E N N U N G el(II)) complexes, [49] but five times lower than those of analogous platinum(II) complexes. The signal intensities are also similar to some of those reported by us for platinum-ortho-metalated bisA C H T U N G T R E N N U N G (NCP) systems, [30] but are about three times lower than in the case of zinc complexes of this ligand with a coordinated chiral anion.…”

Section: -Aza-21-carbaporphyrinato-a C H T U N G T R E N N U N G Nicksupporting

confidence: 75%

Enantiomer Resolution of Intrinsically Chiral C21‐Alkylated N‐Confused Porphyrin Complexes

Chmielewski

Szterenberg

Siczek

2010

Chemistry A European J

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The resolution of stereoisomers of C21-alkylated nickel(II) complexes of N-confused porphyrin (NCP) was performed by means of chiral-phase HPLC with an effectiveness of above 90 % molar ratio for each isomer. The reverse signs of the Cotton effects in the circular dichroism (CD) spectra of the separated fractions are indicative of the pair of enantiomers. The application of low-temperature 2D NMR methods to the separated diastereomers of the system comprising a chiral 2-(S)-methylbutyl substituent, in connection with the CD spectra and relative HPLC migration rates, allowed the assignment of the absolute configuration of the chiral C21-substituted complexes of NCP. The assignment was confirmed by time-dependent DFT (TDDFT) calculations of CD spectra for the C21-methylated nickel(II) complex. The system remains chiral after removal of the metal ion from the macrocyclic crevice, despite the fact that this demetalation is connected with a change of the C21 hybridization from pyramidal to trigonal. The retention of chirality was established by means of CD spectra and confirmed by TDDFT calculations for a C21-methylated NCP free base. Stereoisomers were also separated for three covalently linked bis(NCP) systems with bridges involving one or two C21 carbon atoms. The occurrence of a pair of enantiomers was established for nonsymmetrical dimers comprising only one stereogenic center. In the case of the 21,21'-(o-xylene)-linked dimer, three stereoisomers, that is, a pair of enantiomers and an optically inactive meso-form, were separated and analyzed by CD and (1) H NMR spectroscopy. The stereoisomers of a diastereoselectively formed nonsymmetrical chloroplatinum(II)-linked dimer, consisting of heterochiral C21-alkylated NCP nickel(II) subunits, after separation displayed a strong optical activity, which can be ascribed to the rigid helical structure of the complex.

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Section: -Aza-21-carbaporphyrinato-a C H T U N G T R E N N U N G Nicksupporting

confidence: 75%

Enantiomer Resolution of Intrinsically Chiral C21‐Alkylated N‐Confused Porphyrin Complexes

Chmielewski

Szterenberg

Siczek

2010

Chemistry A European J

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“…[52] Meso triarylporphyrins in which the fourth meso position was unsubstituteda nd one of the two neighboring b-pyrrolic positions was functionalized with ap yridyl group were used as buildingb locks for the synthesis of ac ofacial dimer 34 with a C meso -Pt II -C meso linkagei nacis geometry (Scheme19). [53] The two porphyrins strongly interact through the cis Pt II ,a ss hown by electrochemical studies. As plitting value of 230 mV between the first two one-electron oxidation waves waso bserved.…”

Section: Factors Governing Electronic Interactions Betweenporphyrinsimentioning

confidence: 99%

Peripherally Metalated Porphyrins with Applications in Catalysis, Molecular Electronics and Biomedicine

Longevial

Clément

Wytko

et al. 2018

Chemistry A European J

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Porphyrins are conjugated, stable chromophores with a central core that binds a variety of metal ions and an easily functionalized peripheral framework. By combining the catalytic, electronic or cytotoxic properties of selected transition metal complexes with the binding and electronic properties of porphyrins, enhanced characteristics of the ensemble are generated. This review article focuses on porphyrins bearing one or more peripheral transition metal complexes and discusses their potential applications in catalysis or biomedicine. Modulation of the electronic properties and intramolecular communication through coordination bond linkages in bis-porphyrin scaffolds is also presented.

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“…Representative examples synthesized through this method include ¢,¢-bis(acrylyl)-substituted porphyrins that can serve as an effective sensitizer in solar cells, 118,119 multi-porphyrin oligomers, 120,121 planar doubly 1,3-butadiyne-bridged diporphyrins, 122 heterocycle-bridged porphyrin rings, 123125 2-borylated corroles, 126 biscorrolebased stable singlet biradicals, 127,128 face-to-face dioxoisobacteriochlorin dimers, 129 porphyrin pincer complexes that exhibited catalytic activity in Heck reactions, 130 Ptpincer complexes that undergo tweezers-like molecular motions responding to the oxidation state of the incorporated Pt metal, 131 and © 2 coordinating Ru(II) complexes. 132 Recent remarkable examples are ¢,¢-doubly linked porphyrin belts with significant molecular curvatures 133 and ring forming porphyrin barrels, 134 both of which can capture C 60 efficiently.…”

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confidence: 99%

Subporphyrins: A Legitimate Ring-Contracted Porphyrin with Versatile Electronic and Optical Properties

Osuka

Tsurumaki

Tanaka

2011

Bulletin of the Chemical Society of Japan

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118

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After a brief survey of our efforts in the development of novel porphyrinoids that include mesomeso-linked porphyrin arrays, meso-aryl expanded porphyrins, and transition-metal-catalyzed functionalizations of porphyrins, a particular focus in this account is placed on the chemistry of subporphyrins that has been explored in our group. Subporphyrin is a legitimate ring-contracted porphyrin consisting of three pyrrolic subunits domed in a C 3 symmetric bowl shape. While subporphyrins are simple and small macrocycles and possess a key position in porphyrin chemistry, they had been elusive until our first synthesis of tribenzosubporphines in 2006. Shortly after, synthetic protocols of mesoaryl-substituted subporphyrins were developed to produce various subporphyrins with versatile electronic properties that can be widely tuned by meso-aryl substituents. Raney nickel reduction was used to prepare meso-alkyl-substituted subporphyrins from meso-thienyl-substituted subporphyrins. Subchlorins and subbacteriochlorins were prepared respectively by the reduction of subporphyrins with p-tosylhydrazide and Raney nickel. While subporphyrins and subchlorins share conjugated 14³-electronic circuits, subbacteriochlorins have a rare [13]diazaannulene circuit maintained through the lone-pair electrons of the nitrogen atom. The aromaticity decreases in the order of subporphyrin > subchlorin > subbacteriochlorin, as indicated from 1 H-and 11 B NMR spectra and nuclear independent chemical shift (NICS) calculations. Despite these progresses, the chemistry of subporphyrins is still in the infant stage with many untouched aspects and further improvements in synthetic yields are highly desirable for the developments of the chemistry of subporphyrins as well as their applications in diverse fields. A Brief Survey of Our Efforts in the Exploration of Novel PorphyrinoidsIn the last three decades, we have been involved in the exploration of novel porphyrinoids with intriguing structures, electronic and optical properties, and functions. We entered porphyrin chemistry with the aim to synthesize covalently linked organic constructs that can mimic the whole excitation energy transfer and electron transfer events of the photosynthetic reaction centers within a single molecular entity. 13 In the course of these studies, we fortunately encountered new reactions and structures, which drove us to change our research style from a well-designed, goal-orientated path to a flexible discovery-searching strategy to explore novel porphyrinoids. By following the flexible research style, we have explored mesomeso-linked Zn(II) porphyrin arrays, meso-aryl expanded porphyrins, transition-metal-catalyzed porphyrin modifications, and subporphyrins. After a brief survey of the former three topics, a particular focus is placed on the chemistry of subporphyrins that are legitimate ring-contracted porphyrins. As described below, subporphyrins are a new class of functional molecules, particularly in view of their highly tunable electronic and optical properties.

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Pt(II)- and Pt(IV)-Bridged Cofacial Diporphyrins via Carbon−Transition Metal σ-Bonds

Cited by 66 publications

References 20 publications

Enantiomer Resolution of Intrinsically Chiral C21‐Alkylated N‐Confused Porphyrin Complexes

Enantiomer Resolution of Intrinsically Chiral C21‐Alkylated N‐Confused Porphyrin Complexes

Peripherally Metalated Porphyrins with Applications in Catalysis, Molecular Electronics and Biomedicine

Subporphyrins: A Legitimate Ring-Contracted Porphyrin with Versatile Electronic and Optical Properties

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