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Baran Lab GM S. McKerrall Singlet Oxygen in Organic Synthesis 03/19/11 Reviews: Acc. Chem. Res. 2008, 1001 Prototypical Singlet Oxygen Reactions Tetrahedron, 2006, 5308 Ene: Tetrahedron, 2005, 6665 Characteristics of Singlet Oxygen Pure Appl. Chem., 1975, 481 R1 R1 H R2 1 H R2 R1 R2 Chem. Rev., 1981, 91 O2 - 94.3 kJ/mol above Triplet State O O - Singlet Triplet transition is spin forbidden HOO - Lifetime of 74 minutes in gas phase [2+2] - Solution lifetime is highly solvent dependent R O 3 1 O O -CCl4 : 59 ms O2 R4 O R R R -Benzene : 30 s 3 1 3 R1 R -H O : 3.5 s 4 R2 R4 2 R2 R1 R2 [4+2] Generation and Reaction Conditions Concerted -Easily generated using light and a suitable photosensitizer 1O O -Typically sensitized with Methylene Blue, 2 Tetraphenylporphryin, or Rose Bengal O O O Ph Ph N Heteroatom Oxidation N 1 Chem. Rev., 2008, 1052 O2 Me N S NMe Ph3P PPh3 OO 2 2 NH HN Methylene Blue Cl Relative Rates of Reaction Cl N Cl Ph Ph O Tetraphenylporphryin Cl 25 1 I O I 0.16 H N HO O OH O O I I N Rose Bengal 11 233 40 - Can also be generated by decomposition of hydrogen peroxide or organic peroxides - Typical reaction conditions involve irradiation at low temperature because of the instability of many organic peroxides 43 3.1 1985 Frimer, A. A., Singlet O2, 1 Baran Lab GM S. McKerrall Singlet Oxygen in Organic Synthesis 03/19/11 RHN O '[2+2] Cycloadditions' '[2+4] Cycloadditions' cont. O O O O CDCl3 O MeO OMe 1 RHN O O Olefin + O2 NMe MeO OMe "High Yield" 94% Air, hv RHN O O O O O 67% RHN O Ph Ph OMe RHN O O O Solid O O O 100% 80% O 100% O RHN O -Most significant limitation is a lack of protons because NC the competing 'ene' reaction is significantly faster. O O '[2+4] Cycloadditions' 1 O2 O 1 O O O2 O O HN N O OOH O H N N N O 73% 2 O R > 95% O OO H N HN TPP, O2, hv HN NH O O Diene + 1O O 2 N DCM; DMS N N O O H2N N Mechanism? HN H O R R ~100% 74% JACS, 2004, 16777 O MeO O MeO OTES O O O HO OTES OMe O OMe 98% O O2, hv MeO O O O O Hunigs Base 90% OTES O O RB, DCM O H OMe -78 C 88% Handbook of Synthetic Photochemistry, 353 Tet. Let., 2008, 10831 2 Baran Lab GM S. McKerrall Singlet Oxygen in Organic Synthesis 03/19/11 Regioselectivity of the Ene Reaction Ene Reactions O "Cis Effect" O2 O H HOO 1 k1 k2 k3 O HOO MeO 1 2 O2 MeO MeO MeO HOO Mechanistic Details: 100% 72% OMe OMe Exciplex Formation: OMe - Rate of reaction is > 103 less than diffusion control 1 O2 OMe O OOH 1 - Reactions are characterized by low (or negative) O2 O activation enthalpies and high activation entropy 100% H Periperoxide: Tet. Let. 100% - Inter vs Intramolecular Isotope Effects , 1977, 2517 Tet. Let., 1978, 3227 Ph Ph Ph Ph H3C CH3 D3C CD3 Steric and Electronic Effects H C CH D C CD H H OOH 3 3 3 3 H3C CH3 D3C CD3 1 O2 CCl4 k /k = 1.08 H D kH/kD = 1.11 H H 92:8 dr D C CH 3 3 H3C CH3 Tet. Let., 1992, 443 H C CD 3 3 D3C CD3 k /k = 1.40 H D kH/kD = 1 OMe Cl F Cl F Ene Reaction is Suprafacial MeO Cl Cl F F H Me H DOO H Trans/Cis 79:21 80:20 48:52 46:54 D 1O Me 2 Ph JACS Ph + Ph , 1978, 6510 D H3C H HOO H In-situ ene/epoxidation OH 1 O2 Tetrahedron, 2000, 9151 O 16% Ti(OiPr)4 91% JACS, 1989, 203 98:2 cis:trans 3 Baran Lab GM S. McKerrall Singlet Oxygen in Organic Synthesis 03/19/11 Synthetic applications of [4+2] and of resulting endoperoxides O O Me Me 1 Me 1) O2, MB, hv Me O2 O O OMe O OMe O Naturwissenschafen, 1944, 157 2) RuCl (PPh ) quant. Me H 2 3 2 Me H Me Me O O -terpene ascaridole Org. Lett., 2005, 2901 Me Me Elysiapyrone A CH OBz CH2OBz 2 CH2OBz CH2OBz O O OAc O O O 1 O2 (MeO)3P O O O O O 80% O 88% 1 KOAc OAc O2 O O rt Senepoxide O 65% O O JACS, 1978, 352 94% OH Named CH OBz CH2OBz CH2OBz 2 O CH2OBz Reaction? 1 O Org. Lett. 2009, 1591 O OH O2 OAc O OH O 15% O 56% O O O OAc O O O Crotepoxide H Tet. Lett., 1977, 3361 H O O (+)-Phomactin 1O O 2 O O O O O O OH O O O O Fusicogigantone HO 1 Fusicogigantepoxide PIFA O2 30% 20% O O Fusicocca-2(6),3-diene DCM Tet. Lett., 1994, 8205 CH3CN O OtBu 54% 95% Br Br O O Steps Br PPh3=CHCO2tBu O H2, Pd/C Ar C7H15 LiBr, 15d O 90% Ar C7H15 O 55% 8 Step synthesis OH OH O Mechanism? of Ryanodine BCE O OH H ring system N Br Ph O Org. Biomol. Chem., 2006, 323 C7H15 Tet., 2003, 8855 O Grenadamide O HO Br 4 Baran Lab GM S. McKerrall Singlet Oxygen in Organic Synthesis 03/19/11 Synthetic applications of [4+2] and of resulting endoperoxides (cont). H OH OMe OMe OMe OMe O OMe H H O O 1 O O 1 O Al/Hg 1. O2 2 O OH H H 58% 2. H2SO4 H over H 67% HO 2 steps OMe CO2Me Chem. Eur. J., 1999, 646 O O O O 1O 2 O Al2O3 36% R OMe OMe OMe OMe OMe OMe Solanone Soloanofuran H2SO4 O Helv. Chem. Act., 1972, 265 O O OMe Reactions of Singlet Oxygen with Arenes OMe OH2 O2, TPP, hv O acetone O OMe OMe OMe OMe O OMe -40 C, 5d 1 56% HOO 1. O2 Mechanism? J. Org. Chem., 1998, 8544 2. H2SO4 57% OH OH O OH MeO C OMe 1:1 2 R2 1 R2 O2, NaBH4 + then Air OBn O OBn OMe O OMe R1 R1 OH OH O O OH O BnO HO CO2Bn CO2Me CO2Me O H O Me O Me OH Ar J. Org. Chem., 1998, 4403 HN N OH O H HO (-)-Balanol OH Vineomycinone B2 Methyl Ester JACS, 1991, 6320 5 Baran Lab GM S. McKerrall Singlet Oxygen in Organic Synthesis 03/19/11 Reactions of Singlet Oxygen with Furans 1 + O O2 O O H O O 1 O H O2 -HCO2Et 42% CHO OH O O O O O O O EtOH O O O JACS, 1962, 4611 Furfural OHC Chem. Abstr., 1956, 5035 1O O 1 2 O TBAF O2 O CO H O 2 OEt Ibid. 1977, 3361 MeOH EtOH OTBDPS MeO 72% O O 96% OTBDPS O O 1 H C O2 3 OMe O MeO O OOH O MeOH O O O CH3 O O Tet., 1967, 2583 1 (+)-Decarestrictine L Tet. Lett., 2006, 1333 O O2 + OMe aq. H OH O O O TMS MeOH O O O HO O O Ann. Chem., 1953, 156 O 1) 1O H Ann. Chem., 1966, 42 2 OMOM O OMOM 1 2) NaBH4 O O2 O O O CeCl SiMe3 O O 3 MeOH O O H Me3SiO O H Me3Si Tet. Lett. 1981, 3505 1) PPTS O 2) IBX 36% brsm O O O O O O HO H H O H H OH OMOM H O , Rose Bengal H H 2 OH H hv, iPr EtN, DCM 2 H H 78% JACS, 1997, 12425 O O R R Org. Lett., 2000, 3177 Pallavicinolide Dysidiolide Angew. Chem. Int. Ed., 2009, 2351 6 Baran Lab GM S. McKerrall Singlet Oxygen in Organic Synthesis 03/19/11 Using Furan Endoperoxides in Cascade Reactions Using Furan Endoperoxides in Cascade Reactions (cont.) R3 R2 Me3Si R1 O OH O O2, Rose Bengal O O R MeOH, 5 C O O 3 OH Ar R2 then DMS i) O , RB, hv O O R1 2 O Name Reaction? Ar MeOH, 2 min 2-97% ii) SiO2 O Ar Ar 80% R2 OH OH cis:trans 2:1 R2 SiMe3 R3 DMS O Core of Prunolides O R3 R1 E:Z = 3:1 MeO OOH Ar = p-anisyl Org. Lett. 2005, 2357 R1 O O OH Biomimetic Synthesis of Peroxide Containing Natural Products HO 1)NaBH4 O , RB, hv 2 2) H2, Pd/C OH OH OH Et O O O MeOH, 5C; 80% TPP, O2 DTBN R2 R2 OH DMS; TsOH O O R1 R2 hv R1 65% R1 2 Steps, Enantiopure 53% Et Et 2-Hydroxy-exo- 62% OOH 1:1.2 OOH Org. Lett., 2011, 1166 brevicomin R1 O O R MeO C16H33 HO 2 CO Me CO Me R2 1 O O 2 2 O2, MeOH; C16H33 H MeO H R R O O O 1 3 DMS; TsOH Me (+)-Plakorin (+)-Chondrillin R 3 71-90% O J. Org. Chem., 1999, 1789 H OH Org. Lett., 2009, 313 1 O2 1) AcCl, Py O 79% 2) dil. HCl O O OH 1 37% O2, MeOH 7 OOH 9:1 A:B O O Clavukerin A Clavukerin C DMS, CHCl ; O O 3 O 8 Steps (39%) O TsOH O OH 49% Me + O O O 7:3 dr at C-7 Clavulerin A Clavulerin B Chem.
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  • Enhancing the Performance of Dye Sensitized Solar Cells Using Silver Nanoparticles Modified Photoanode

    Enhancing the Performance of Dye Sensitized Solar Cells Using Silver Nanoparticles Modified Photoanode

    molecules Article Enhancing the Performance of Dye Sensitized Solar Cells Using Silver Nanoparticles Modified Photoanode Faizah Saadmim 1, Taseen Forhad 1, Ahmed Sikder 1, William Ghann 1 , Meser M. Ali 2, Viji Sitther 3 , A. J. Saleh Ahammad 4 , Md. Abdus Subhan 5 and Jamal Uddin 1,* 1 Center for Nanotechnology, Department of Natural Sciences, Coppin State University, 2500 W. North Ave, Baltimore, MD 21216, USA; [email protected] (F.S.); [email protected] (T.F.); [email protected] (A.S.); [email protected] (W.G.) 2 Department of Neurosurgery, Cellular and Molecular Imaging Laboratory, Henry Ford Hospital, Detroit, MI 48202, USA; [email protected] 3 School of Computer, Morgan State University, Mathematical and Natural Sciences, Morgan State University, Baltimore, MD 21251, USA; [email protected] 4 Department of Chemistry, Jagannath University, Dhaka 1100, Bangladesh; [email protected] 5 Department of Chemistry, School of Physical Sciences, Shah Jalal University of Science and Technology, Sylhet 3114, Bangladesh; [email protected] * Correspondence: [email protected] Academic Editor: Mário Calvete Received: 22 July 2020; Accepted: 1 September 2020; Published: 3 September 2020 Abstract: In this study, silver nanoparticles were synthesized, characterized, and applied to a dye-sensitized solar cell (DSSC) to enhance the efficiency of solar cells. The synthesized silver nanoparticles were characterized with UV–Vis spectroscopy, dynamic light scattering, transmission electron microscopy, and field emission scanning electron microscopy. The silver nanoparticles infused titanium dioxide film was also characterized by Fourier transform infrared and Raman spectroscopy. The performance of DSSC fabricated with silver nanoparticle-modified photoanode was compared with that of a control group.