Prashanth K Poddutoori

Prashanth K Poddutoori
University of Minnesota Duluth | UMD · Department of Chemistry and Biochemistry

Ph.D.

About

55
Publications
4,132
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739
Citations
Additional affiliations
June 2013 - May 2020
University of Prince Edward Island
Position
  • Professor (Assistant)
June 2005 - June 2011
Brock University
Position
  • Research Associate

Publications

Publications (55)
Article
Full-text available
The axial bonding ability of aluminum(III) porphyrin (AlPor) has been exploited to synthesize the vertically linked dyad ‘aluminum(III) porphyrin–gold(III) porphyrin’ (AlPor-Ph–AuPor+) and the two corresponding self-assembled triads ‘tetrathiafulvalene–aluminum(III) porphyrin–gold(III) porphyrin’ (TTF-py→AlPor-Ph–AuPor+ and TTF-Ph-py→AlPor-Ph–AuPor...
Article
Full-text available
a The distance dependence of sequential electron transfer has been studied in six, vertical, linear supramo-lecular triads, (TTF-Ph n-py → AlPor-Ph m-C 60 , n = 0, 1 and m = 1, 2, 3), constructed using tetrathiafulva-lene (TTF), aluminum(III) porphyrin (AlPor) and fullerene (C 60) entities. The C 60 and TTF units are bound to the Al center on oppos...
Article
Full-text available
The well-known oxophilicity of aluminum(III) ion and the well-defined redox and photochemical properties of aluminum(III) porphyrins have been exploited to synthesize the functionally active, 'axial-bonding’-type free base–aluminum(III) porphyrin dimer (H2–Al) and free base–[aluminum(III) porphyrin]2 trimer (H2–Al2), as well as the corresponding co...
Article
Full-text available
A novel phosphorus(V) porphyrin bearing two ptp[4'-(4-phenyloxy)-2,2'ratio6',2''-terpyridine] groups was prepared and modulation of the intramolecular PET (lambda(ex)= 566 nm) and PET --> EET (lambda(ex)= 300 nm) processes was studied from ptp to phosphorus(V) porphyrin by Zn2+ or Cd2+ ions.
Article
Phosphorus(V) porphyrins hold an important place in porphyrin chemistry. The hexacoordinated phosphorus center in these porphyrins has a formal oxidation state of +5 and is, thus, extremely electron deficient. As a result, the midpoint potential for oxidation of the phosphorus(V) porphyrin is shifted to a much higher value (1.66 V for PTPP+) compar...
Article
Photoinduced electron transfer properties are reported for a triad composed of a central aluminum porphyrin (AlPorF3) with a secondary electron donor, bis-triphenylaminoborondipyrromethene (TPA2-BDP) attached covalently to AlPorF3, and an electron acceptor, pyridine-appended naphthalenediimide (NDI), attached by coordination of the pyridine group t...
Article
Full-text available
Spin polarized transient EPR spectra are reported for an aluminium porphyrin (AlPorF3) triad in which the electron donor bis-triphenylaminoborondipyrromethene (BDP-TPA2) is attached covalently to one face of the porphyrin and an imidazole-appended C60 is attached by coordination of the imidazole group to the Al center on the opposite face. Excitati...
Article
The +5 oxidation state of antimony induces push-pull style intramolecular charge transfer in an elegantly designed axial dimethoxyantimony(V) porphyrin series: SbP(OMe)2.PF6, SbMP(OMe)2.PF6, SbDMP(OMe)2.PF6, SbTMP(OMe)2.PF6 with phenyl (P), 4-methoxyphenyl (MP), 3, 5-dimethoxyphenyl (DMP), and 3,4,5-trimethoxyphenyl (TMP) units, respectively, in it...
Article
A cofacial ‘aluminum(III) porphyrin – phosphorus(V) porphyrin’ (AlPor-Ph-PPor.PF6) heterodimer has been synthesized to investigate the factors that govern the energy and electron transfer processes in a direction perpendicular to the porphyrin plane. The AlPor and PPor+ are bound in the cofacial arrangement through a benzoate spacer. The electron-r...
Article
In supramolecular reaction center models, the lifetime of the charge-separated state depends on many factors. However, little attention has been paid to the redox potential of the species that lie between the donor and acceptor in the final charge-separated state. Recently, we reported a series of self-assembled aluminum porphyrin-based triads that...
Article
The synthesis and initial spectroscopic characterization of a phosphorus(V) octaethylporphyrin-nitroxide adduct is reported. The nitroxide (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) is axially and covalently bound to the phosphorus porphyrin (PPor+) to give the studied PPor+-TEMPO conjugate. The complex allows the influence of the type of bond...
Article
A series of fluorinated free-base porphyrins (H2TPPFn, n = 0, 8, 12, 20, 24) and the corresponding aluminum(III) porphyrin (AlTPPFn-Ph, n = 0, 8, 12, 20, 24) derivatives have been synthesized and their spectroscopic, redox and optical properties were investigated. The absorption studies show that the spectral shapes of investigated porphyrins are s...
Article
Photosensitizers with high energy, long lasting charge-transfer states are important components in systems designed for solar energy conversion by multistep electron transfer. Here, we show that in a push-pull type, -oxo-bridged porphyrin heterodimer composed of octaethylporphyrinatoaluminum(III) and octaethylporphyrinatophosphorus(V), the strong...
Article
Despite being the most abundant metal on the Earth, aluminum(III) metal ion centered porphyrin (AlPor, where Por = Porphyrin) derivatives have received much less attention compared to the transition metal porphyrin derivatives. The exceptional dual bonding features, (i) the axial hydroxide readily reacts with carboxylic acid or alcohol and (ii) the...
Article
Aluminum(III) porphyrins (AlPor) are well suited for the construction of axially linked multicomponent donor-acceptor systems. The axial hydroxide reacts with carboxylic acids or alcohols to form covalent ester or ether linkage, respectively. Moreover, they bind Lewis bases such as imidazole or pyridine to form a coordination bond with the Al cente...
Article
Generation of high potential, long-lived charge separated states in donor-acceptor systems are invaluable for converting light energy into either electricity or fuels. The majority of the donor-acceptor conjugates designed for this purpose are derived mainly from short-lived singlet sensitizers. 1,2 In such conjugates, charge separation from the si...
Article
In supramolecular reaction center models, the lifetime of the charge-separated state depends on many factors. However, little attention has been paid to the redox potential of the species that lie between the donor and acceptor in the final charge separated state. Here, we report on a series of self-assembled aluminum porphyrin-based triads that pr...
Article
The formation of a high-energy, long-lived radical ion-pair by electron transfer exclusively from the triplet excited state, is demonstrated in a newly synthesized platinum porphyrin-fullerene dyad, in which the porphyrin...
Article
Full-text available
The generation and transfer of electron spin polarization and coherence plays an important role in quantum information technologies and spintronics. In this context, the excited state spin dynamics of molecular systems in which a stable free radical is attached to a chromophore are of particular interest. In such complexes, the coupling between the...
Article
A series of vertically assembled photoanodes, consisting of 5,10,15,20-tetrakis(3,4,5-trifluorophenyl)aluminum(III) porphyrin (AlPorF3), pyridine appended electron donor (PTZ-Py, PTZ = phenothiazine; TTF-Py, TTF = tetrathiafulvalene), and semiconductor TiO2, have been fabricated by exploiting the unique axial properties of AlPorF3. The new photoano...
Article
A high potential supramolecular triad (TPE-AlPor←Im-C60) composed of aluminum(III) porphyrin (AlPor), fullerene (C60), and tetraphenylethylene (TPE) has been constructed. The fullerene and tetraphenylethylene units are bound axially to opposite faces of the porphyrin plane via coordination and covalent bonds, respectively. The ground and excited-st...
Article
Transient electron paramagnetic resonance (TREPR) spectroscopy is used to investigate the pathway and dynamics of electron transfer in a palladium porphyrin-fullerene donor-acceptor conjugate. The heavy Pd atom in the porphyrin greatly enhances the rate of intersystem crossing and as a result, electron transfer from the porphyrin to fullerene occur...
Article
Three, broad band capturing, vertically aligned supramolecular triads, R2-BDP-AlPorF3Im-C60 [R = H, styryl (C2H2-Ph), C2H2-TPA (TPA = triphenylamine);  = coordinate bond], are constructed using BODIPY derivative (BDP, BDP-Ph2 or BDP-TPA2), 5,10,15,20-tetrakis(3,4,5-trifluorophenyl)aluminum(III) porphyrin (AlPorF3) and fullerene (C60) entities. Th...
Article
Reversible solution π‐dimerization is observed in the stable neutral phenoxyl radical 2,6‐bis‐(8‐quinolylamino)‐4‐(tert‐butyl)phenoxyl baqp and is spectroscopically characterized. This behavior, not previously observed for π‐extended phenoxyl radicals, is relevant to the formation of multicenter bonding in the π‐dimer at low temperature akin to pre...
Article
Extending the lifetime of the charge separated states generated during photoinduced electron transfer in a covalently linked high-potential zinc porphyrin-fullerene dyad, (F15P)Zn-C60, was accomplished by metal-ligand axial coordination of pyridine functionalized tetrathiafulvalene (TTF) via a dual electron transfer/hole migration mechanism. The me...
Article
Two self-assembled photoanodes have been constructed by exploiting the unique optical and structural properties of aluminum(III) porphyrin (AlPor) in conjunction with TiO2 nanoparticles as an electron acceptor and bis(p-anisole)aminopyridine (BAA-Py) as an electron donor. AlPor is bound to the TiO2 surface by either: (i) a benzohydroxamic acid brid...
Article
Full-text available
We describe the synthesis of a new tetratopic phenoxyl radical ligand based on the previously reported ditopic “baqp” radical. The tetratopic ligand is prepared in five steps from 4-tert-butylphenol. Coordination of the ligand with Cu(OAc)2 produced a tetranuclear complex with an S = ½ ground state featuring a coordinated hexa-anion radical with ve...
Article
The synthesis and study of redox-active ligand complexes has received much recent attention. We have recently explored the coordination chemistry of arylazo redox-active ligand 1-(2-pyridylazo)-2-phenanthrol (papl) and herein expand the series of complexes to the Group 8 transition metal ion, iron. We report the preparation and structure of a dival...
Article
The stabilization of light-induced charge separation in two axially bound triads based on aluminum(III) porphyrin (AlPor) are investigated using the electron spin polarization patterns of the final radical pair state. In the triads, TTF-(Ph)n-py-AlPor-AQ, (n=0, 1) anthraquinone (AQ) is attached covalently to the Al(III) center, while the donor tetr...
Article
Stepwise reduction of the diiminopyridine (dimpyr) complex, dimpyrZnCl2, by KC8 leads to molecular zinc compounds dimpyrZnCl (2) and dimpyrZnCl(DMAP) (3, DMAP = 4-dimethylaminopyridine), which were characterized by X-ray diffraction and EPR spectroscopy. Compound 2 shows an unusual nearly square planar geometry of the zinc atom equally ligated by t...
Article
Full-text available
The electron transfer pathways in two axially bound triads based on aluminum(III) porphyrin (AlPor) are investigated using the electron spin polarization patterns of the final radical pair state. In the triads, TTF-(Ph)n-py-AlPor-Ph-H2Por (n = 0, 1), free-base porphyrin (H2Por) is attached covalently to the Al(III) center, while the donor tetrathia...
Article
Herein we describe the synthesis, structure and electronic properties of an unusual redox-active ditopic ligand with a stable open-shell configuration. This stable phenoxyl radical features intense and very low energy electronic transitions in the near infrared (NIR) part of the spectrum and is structurally set up to strongly spin couple coordinate...
Article
This study demonstrates molecular engineering of a series of donor-acceptor systems to allow control of the lifetime and initial spin multiplicity of the charge-separated state. By tuning the rate of intersystem crossing (ISC) and the donor-acceptor distance, electron transfer can be made to occur exclusively from the triplet excited state of the e...
Chapter
Time-resolved electron paramagnetic resonance (TREPR) methods often play an important role in characterizing artificial photosynthetic systems. The radical pairs and triplet states generated in such systems are spin polarized because of the initial correlation of the electron spins and the spin selectivity of the electronic relaxation and electron...
Article
We report the structural properties and electronic structure of a neutral homoleptic copper(II) complex bearing the anion of 1-(2-pyridylazo)-2-phenanthrol (papl). In the solid state the complex is disordered and this presents itself as a nearly equal mixture of five and six coordinate copper ions with the ligand bound in two different configuratio...
Article
Axially assembled aluminum(III) porphyrin based dyads and triads have been constructed to investigate the factors that govern the energy and electron transfer processes in a perpendicular direction to the porphyrin plane. In the aluminum(III) porphyrin-free-base porphyrin (AlPor-Ph-H2Por) dyad, the AlPor occupies the basal plane, while the free-bas...
Article
We introduce phosphorus(V) porphyrins (PPors) as sensitizers of high-potential photoanodes with potentials in the 1.62–1.65 V (vs. NHE) range when codeposited with Ir(III)Cp* on SnO2. The ability of PPors to advance the oxidation state of the Ir(III)Cp* to Ir(IV)Cp*, as required for catalytic water oxidation, is demonstrated by combining electron p...
Article
Full-text available
Photosystem II (PSII) of photosynthesis has the unique ability to photochemically oxidize water. Recently an engineered bacterioferritin photochemical 'reaction centre' (BFR-RC) using a zinc chlorin pigment (ZnCe6) in place of its native heme has been shown to photo-oxidize bound manganese ions through a tyrosine residue, thus mimicking two of the...
Article
Full-text available
Two self-assembled supramolecular donor-acceptor triads consisting of Al(III) porphyrin (AlPor) with axially bound naphthalenediimide (NDI) as an acceptor and tetrathiafulvalene (TTF) as a secondary donor are reported. In the triads, the NDI and TTF units are attached to Al(III) on opposite faces of the porphyrin, through covalent and coordination...
Article
Full-text available
The light-induced spin polarization generated by sequential electron transfer in an axially bound triad based on Al(III) porphyrin (AlPor) is discussed. In the triad, TTF􏰁Ph􏰁py!AlPor􏰁Ph􏰁NDI, the electron acceptor naphthalene diimide (NDI) is attached covalently to the Al(III) center, while the donor tetra- thiafulvalene (TTF) coordinates to Al(III)...
Article
Full-text available
The spin selectivity of electron transfer in a series of metalloporphyrin pyridyl-linked naphthalenediimides (MTPP-Pyr(CH2)n NDI, where M = Zn, n = 2, 4, 7, and M = Al(OCOPh), n = 7) is studied by time-resolved electron paramagnetic resonance (TREPR) spectroscopy in the nematic liquid crystal 4-cyano-4′-pentylbiphenyl (5CB). Following pulsed laser...
Article
A phosphorus(V) porphyrin bearing an axially linked bis(ethylenedithio)tetrathiafulvalene, dyad 1, and its radical cation phosphorus(V) porphyrin-O-CH2-(bis(ethylenedithio)tetrathiafulvalene)+•, dyad 2, have been synthesized and studied as an electron hole donor-acceptor system. The absorption spectrum of dyad 1 does not show evidence for electroni...
Article
New supramolecular triads (PTZpy→AlPor-C(60), TPTZpy→AlPor-C(60)), containing aluminum(III) porphyrin (AlPor), fullerene (C(60)), and phenothiazine (phenothiazine = PTZ, 2-methylthiophenothaizine = TPTZ) have been constructed. In these triads the fullerene and phenothiazine units are bound axially to opposite faces of the porphyrin plane via covale...
Article
Light-induced electron transfer is investigated in a ferrocene-aluminum(III) porphyrin-fullerene supramolecular triad (FcAlPorC(60)) and the constituent dyads (AlPorC(60) and FcAlPorPh). The fullerene unit (C(60)) is bound axially to the aluminum(III) porphyrin (AlPor) via a benzoate spacer, and ferrocene (Fc) is attached via an amide linkage to on...
Article
The spin-spin interactions in a complex consisting of a metalloporphyrin with a verdazyl radical attached at one of the beta positions of the porphyrin ring are investigated. The X-ray crystal structure of the copper porphyrin complex shows that the plane of the verdazyl moiety is oriented such that it is nearly perpendicular to the plane of the po...
Article
We describe the synthesis of a new 3,3'-diethynyl-2,2'-bithienyl bridging bis-QsalH ligand (5), and the preparation of four bimetallic iron(3+) complexes containing 5 with Cl(-) (6), SCN(-) (7), PF(6)(-) (8), and ClO(4)(-) (9) counteranions. We show with variable temperature magnetic susceptibility, Mossbauer, and electron paramagnetic resonance (E...
Article
The photophysical properties of axial-bonding types (terpyridoxy)aluminum(III) porphyrin (Al(PTP)), bis(terpyridoxy)tin(IV) porphyrin (Sn(PTP) 2), and bis(terpyridoxy)phosphorus(V) porphyrin ([P(PTP) 2] (+)) are reported. Compared with their hydroxy analogues, the fluorescence quantum yields and singlet-state lifetimes were found to be lower for Sn...
Article
Full-text available
A bis(terpyridine)ruthenium(II) complex ([Ru] 2+) was covalently connected via a floppy -OCH 2 CH 2 O-spacer to the free-base porphyrin (H) or zinc(II) porphyrin (Zn) or both, to obtain dyads ([HRu] 2+ , [ZnRu] 2+) and triads ([HRuH] 2+ , [ZnRuH] 2+ , [ZnRuZn] 2+). These compounds have been fully characterized by MALDI, UV-vis, 1 H NMR (1D and 1 H-...
Article
Full-text available
Laser flash-induced spin-polarized transient electron paramagnetic resonance (TREPR) spectra for bis(terpyridoxy)phosphorus(V) porphyrin in a nematic liquid crystal isotropic and in frozen solution are presented. At room temperature, two sequential spin-polarized TREPR spectra are observed. The first is consistent with the triplet state of a radica...
Article
A series of nucleobase appended tri-cationic porphyrins (AT4, TT4, GT4 and CT4) have been synthesized and their binding and cleaving ability of DNA were investigated in this present study. UV-vis, fluorescence, circular dichroism and thermal melting studies were carried out to investigate binding of the porphyrin with calf thymus DNA (CTDNA). The a...
Article
Full-text available
Free-base (H 2 L 2), copper(II) (CuL 2) and zinc(II) (ZnL 2) derivatives of a porphyrin–anthraqui-none conjugate with an azomethine group separating the two photoactive subunits have been synthesized and characterized by mass (FAB), IR, UV–visible, 1 H NMR and ESR spectroscopic techniques and also by cyclic and differential pulse voltammetric metho...
Article
Free-base, copper(II) and zinc(II) derivatives of a porphyrin-pyrene conjugate having an azomethine group separating the two photoactive subunits have been synthesized and fully characterized by mass (FAB), IR, UV/visible, 1H NMR and ESR spectroscopies and also by the cyclic- and differential pulse voltammetric methods. An analysis of the data reve...
Article
Full-text available
Photochemistry of Arrays, Switches and Energy Transfer Systems based on Metalloid Porphyrin Building Blocks

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