@article{chen_sun_fan_taniguchi_mcdowell_yang_diers_bocian_holten_lindsey_2012, title={Synthesis and Physicochemical Properties of Metallobacteriochlorins}, volume={51}, ISSN={["1520-510X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84865712494&partnerID=MN8TOARS}, DOI={10.1021/ic301262k}, abstractNote={Access to metallobacteriochlorins is essential for investigation of a wide variety of fundamental photochemical processes, yet relatively few synthetic metallobacteriochlorins have been prepared. Members of a set of synthetic bacteriochlorins bearing 0-4 carbonyl groups (1, 2, or 4 carboethoxy substituents, or an annulated imide moiety) were examined under two conditions: (i) standard conditions for zincation of porphyrins [Zn(OAc)(2)·2H(2)O in N,N-dimethylformamide (DMF) at 60-80 °C], and (ii) treatment in tetrahydrofuran (THF) with a strong base [e.g., NaH or lithium diisopropylamide (LDA)] followed by a metal reagent MX(n). Zincation of bacteriochlorins that bear 2-4 carbonyl groups proceeded under the former method whereas those with 0-2 carbonyl groups proceeded with NaH or LDA/THF followed by Zn(OTf)(2). The scope of metalation (via NaH or LDA in THF) is as follows: (a) for bacteriochlorins that bear two electron-releasing aryl groups, M = Cu, Zn, Pd, and InCl (but not Mg, Al, Ni, Sn, or Au); (b) for bacteriochlorins that bear two carboethoxy groups, M = Ni, Cu, Zn, Pd, Cd, InCl, and Sn (but not Mg, Al, or Au); and (c) a bacteriochlorin with four carboethoxy groups was metalated with Mg (other metals were not examined). Altogether, 15 metallobacteriochlorins were isolated and characterized. Single-crystal X-ray analysis of 8,8,18,18-tetramethylbacteriochlorin reveals the core geometry provided by the four nitrogen atoms is rectangular; the difference in length of the two sides is ∼0.08 Å. Electronic characteristics of (metal-free) bacteriochlorins were probed through electrochemical measurements along with density functional theory calculation of the energies of the frontier molecular orbitals. The photophysical properties (fluorescence yields, triplet yields, singlet and triplet excited-state lifetimes) of the zinc bacteriochlorins are generally similar to those of the metal-free analogues, and to those of the native chromophores bacteriochlorophyll a and bacteriopheophytin a. The availability of diverse metallobacteriochlorins should prove useful in a variety of fundamental photochemical studies and applications.}, number={17}, journal={INORGANIC CHEMISTRY}, publisher={American Chemical Society (ACS)}, author={Chen, Chih-Yuan and Sun, Erjun and Fan, Dazhong and Taniguchi, Masahiko and McDowell, Brian E. and Yang, Eunkyung and Diers, James R. and Bocian, David F. and Holten, Dewey and Lindsey, Jonathan S.}, year={2012}, month={Sep}, pages={9443–9464} }
 @misc{ptaszek_mcdowell_taniguchi_kim_lindsey_2007, title={Sparsely substituted chlorins as core constructs in chlorophyll analogue chemistry. Part 1: Synthesis}, volume={63}, ISSN={["0040-4020"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33947635677&partnerID=MN8TOARS}, DOI={10.1016/j.tet.2007.02.038}, abstractNote={Five routes to stable chlorins bearing 0 or 1 meso substituents have been investigated, among which reaction of a 9-bromo-1-formyldipyrromethane and 2,3,4,5-tetrahydro-1,3,3-trimethyldipyrrin proved most effective. Application of this route afforded metallochlorins [Cu(II), Zn(II), and Pd(II)] including the chlorin lacking any β-pyrrole and meso substituents.}, number={18}, journal={TETRAHEDRON}, publisher={Elsevier BV}, author={Ptaszek, Marcin and McDowell, Brian E. and Taniguchi, Masahiko and Kim, Han-Je and Lindsey, Jonathan S.}, year={2007}, month={Apr}, pages={3826–3839} }
 @article{taniguchi_ptaszek_mcdowell_lindsey_2007, title={Sparsely substituted chlorins as core constructs in chlorophyll analogue chemistry. Part 2: Derivatization}, volume={63}, ISSN={["0040-4020"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33947700461&partnerID=MN8TOARS}, DOI={10.1016/j.tet.2007.02.076}, abstractNote={Stable chlorins bearing few or no substituents have been subjected to a variety of reactions including demetalation, magnesium insertion, oxochlorin formation, and bromination followed by Suzuki coupling. The kinetics of deuteration also have been determined for two oxochlorins and a series of chlorins bearing 0, 1, 2, or 3 meso-aryl substituents.}, number={18}, journal={TETRAHEDRON}, publisher={Elsevier BV}, author={Taniguchi, Masahiko and Ptaszek, Marcin and McDowell, Brian E. and Lindsey, Jonathan S.}, year={2007}, month={Apr}, pages={3840–3849} }
 @article{taniguchi_ptaszek_mcdowell_boyle_lindsey_2007, title={Sparsely substituted chlorins as core constructs in chlorophyll analogue chemistry. Part 3: Spectral and structural properties}, volume={63}, ISSN={["0040-4020"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33947694765&partnerID=MN8TOARS}, DOI={10.1016/j.tet.2007.02.040}, abstractNote={The availability of stable chlorins bearing few or no substituents has enabled a variety of fundamental studies. The studies described herein report absorption spectra of diverse chlorins, comparative NMR features of chlorins bearing 0-3 meso-aryl substituents, and X-ray structures of the fully unsubstituted chlorin and the oxochlorin.}, number={18}, journal={TETRAHEDRON}, publisher={Elsevier BV}, author={Taniguchi, Masahiko and Ptaszek, Marcin and McDowell, Brian E. and Boyle, Paul D. and Lindsey, Jonathan S.}, year={2007}, month={Apr}, pages={3850–3863} }
 @article{ptaszek_mcdowell_lindsey_2006, title={Synthesis of 1-formyldipyrromethanes}, volume={71}, ISSN={["0022-3263"]}, DOI={10.1021/jo060119b}, abstractNote={1-Formyldipyrromethanes are versatile precursors to porphyrins and chlorins. Two methods of synthesis of 1-formyldipyrromethanes have been investigated: (1) Vilsmeier formylation followed by selective removal of the unwanted 1,9-diformyldipyrromethane by dialkyltin complexation and (2) reaction with mesitylmagnesium bromide (MesMgBr) followed by formylation with phenyl formate. The two approaches are complementary (acidic versus basic conditions; statistical versus selective formylation). The latter was found to be more efficient for the preparation of 1-formyldipyrromethanes.}, number={11}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Ptaszek, Marcin and McDowell, Brian E. and Lindsey, Jonathan S.}, year={2006}, month={May}, pages={4328–4331} }
 @article{laha_muthiah_taniguchi_mcdowell_ptaszek_lindsey_2006, title={Synthetic chlorins bearing auxochromes at the 3- and 13-positions}, volume={71}, ISSN={["0022-3263"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33646926396&partnerID=MN8TOARS}, DOI={10.1021/jo060208o}, abstractNote={Synthetic chlorins bearing diverse auxochromes at the 3- and 13-positions of the macrocycle are valuable targets given their resemblance to chlorophylls a and b, which bear 3-vinyl and 13-keto groups. A de novo route has been exploited to construct nine zinc chlorins bearing substituents at the 3- and 13-positions and two benchmark zinc chlorins lacking such substituents. The chlorins are sterically uncongested and bear (1) a geminal dimethyl group in the reduced pyrroline ring, (2) a H, an acetyl, a triisopropylsilylethynyl (TIPS-ethynyl), or a vinyl at the 3-position, (3) a H, an acetyl, or TIPS-ethynyl at the 13-position, and (4) a H or a mesityl at the 10-position. The synthesis of the 13-substituted chlorins relied on p-TsOH x H2O-catalyzed condensation of an 8,9-dibromo-1-formyldipyrromethane (eastern half) and 2,3,4,5-tetrahydro-1,3,3-trimethyldipyrrin (western half), followed by metal-mediated oxidative cyclization, affording the 13-bromochlorin. Similar use of a bromo- or TIPS-ethynyl-substituted western half provided access to 3-substituted chlorins. A 3-bromo, 13-bromo, or 3,13-dibromochlorin was further transformed by Pd-coupling to introduce the vinyl group (via tributylvinyltin), TIPS-ethynyl group (via TIPS-acetylene), or acetyl group (via tributyl(1-ethoxyvinyl)tin, followed by acidic hydrolysis). In the 10-mesityl-substituted zinc chlorins, the series of substituents, 3-vinyl, 13-TIPS-ethynyl, 3-TIPS-ethynyl, 13-acetyl, 3,13-bis(TIPS-ethynyl), 3-TIPS-ethynyl-13-acetyl, or 3,13-diacetyl, progressively causes (1) a redshift in the absorption maximum of the B band (405-436 nm) and the Q(y) band (606-662 nm), (2) a relative increase in the intensity of the Q(y) band (I(B)/I(Q) = 4.2-1.5), and (3) an increase in the fluorescence quantum yield phi(f) (0.059-0.29). The zinc chlorins bearing a 3-TIPS-ethynyl-13-acetyl or a 3,13-diacetyl group exhibit a number of spectral properties resembling those of chlorophyll a or its zinc analogue. Taken together, this study provides access to finely tuned chlorins for spectroscopic studies and diverse applications.}, number={11}, journal={JOURNAL OF ORGANIC CHEMISTRY}, publisher={American Chemical Society (ACS)}, author={Laha, Joydev K. and Muthiah, Chinnasamy and Taniguchi, Masahiko and McDowell, Brian E. and Ptaszek, Marcin and Lindsey, Jonathan S.}, year={2006}, month={May}, pages={4092–4102} }
 @article{taniguchi_balakumar_fan_mcdowell_lindsey_2005, title={Imine-substituted dipyrromethanes in the synthesis of porphyrins bearing one or two meso substituents}, volume={9}, ISSN={["1099-1409"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33244492173&partnerID=MN8TOARS}, DOI={10.1142/S1088424605000678}, abstractNote={ 5,15-substituted porphyrins are valuable compounds in bioorganic and materials chemistry. A new synthesis has been developed that employs 1,9-diformylation of a dipyrromethane, conversion of the diformyldipyrromethane to the bis(imino) derivative, and reaction of the bis(imino)dipyrromethane + a dipyrromethane to give the zinc-porphyrin bearing trans-AB-substituents. 1,9-diformylation was achieved via Vilsmeier reaction. Imination was achieved by treatment of the 1,9-diformyldipyrromethane with excess amine under neat conditions at room temperature. The porphyrin-forming reaction was carried out over 2 h in refluxing ethanol containing zinc acetate exposed to air. Oxidation of the intermediate porphyrinogen occurs aerobically. A complex composed of two bis(imino)dipyrromethanes and two zinc atoms was observed to form reversibly during the course of the reaction. A set of zinc-porphyrins with trans-AB-, A 2-, or A-substituents has been prepared in yields of ~30% (without detectable scrambling) with straightforward purification. The reaction is applicable to A/B substituent combinations of aryl/aryl, aryl/alkyl, and aryl/H. }, number={8}, journal={JOURNAL OF PORPHYRINS AND PHTHALOCYANINES}, publisher={World Scientific Pub Co Pte Lt}, author={Taniguchi, M and Balakumar, A and Fan, DZ and McDowell, BE and Lindsey, JS}, year={2005}, pages={554–574} }