@article{SengeRyppaFazekasetal.2011,
  author    = {Senge, Mathias O. and Ryppa, Claudia and Fazekas, Marijana and Zawadzka, Monika and Dahms, Katja},
  title     = {5,10-A2B2-Type meso-Substituted PorphyrinsuA Unique Class of Porphyrins with a Realigned Dipole Moment},
  series = {Chemistry - a European journal},
  volume    = {17},
  journal   = {Chemistry - a European journal},
  number    = {48},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0947-6539},
  doi       = {10.1002/chem.201101934},
  pages     = {13562 -- 13573},
  year      = {2011},
  abstract  = {Current applications in porphyrin chemistry require the use of unsymmetrically substituted porphyrins. Many current industrial interests in optics and biomedicine require systems with either pushpull (electron-donating and -withdrawing groups) or amphiphilic systems (hydrophobic and hydrophilic groups). In this context we present the class of 5,10-A2B2-type porphyrins for which two different substituents are positioned in diagonally opposite meso positions. Thus, the intramolecular dipole moment in these tetrapyrroles is positioned along a beta-beta vector passing through two pyrrole rings. This is opposite to the situation of the frequently used 5,15-A2BC porphyrins for which the dipole moment is oriented along a mesomeso axis. We have elaborated syntheses of the 5,10-A2B2 porphyrins by using transition-metal-catalyzed transformations of 5,10-A2 porphyrins or direct substitutions reactions thereof; this gives the target molecules in 2277\% overall yields. The compounds exhibit interesting structural, spectroscopic, and optical features and can serve as building blocks for new porphyrin arrays and applications.},
  language  = {en}
}
@article{SengeFlanaganRyanetal.2016,
  author    = {Senge, Mathias O. and Flanagan, Keith J. and Ryan, Aoife A. and Ryppa, Claudia and Donath, Mandy and Twamley, Brendan},
  title     = {Conformational and structural studies of meso monosubstituted metalloporphyrins-Edge-on molecular interactions of porphyrins in crystals},
  series = {Tetrahedron},
  volume    = {72},
  journal   = {Tetrahedron},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0040-4020},
  doi       = {10.1016/j.tet.2015.11.008},
  pages     = {105 -- 115},
  year      = {2016},
  abstract  = {A series of meso monosubstituted metalloporphyrins were synthesized to assess the structural chemistry of porphyrins with only one substituent. The structures of four nickel(II) and zinc(II) complexes with either alkyl or aryl residues indicate primarily planar macrocycles. This gives rise to a different type of pi-interactions in the crystal and the formation of dimeric, trimeric or tetrameric porphyrin units that function as building blocks for the overall crystal structure. Notably, some structures exhibit a unique edge-on packing of porphyrins, while the molecules of (5-n-butylporphyrinato)nickel(II) forms an unusual bilayer type structure where rows of two porphyrin macrocycles are separated by the alkyl residues arranged in a head-to-head fashion. This adds to the canon of intermolecular porphyrin packing arrangements and is of relevance for the preparation of ordered nanoscopic porphyrin devices. (C) 2015 Elsevier Ltd. All rights reserved.},
  language  = {en}
}
@article{WackerDahmsSengeetal.2007,
  author    = {Wacker, Philipp and Dahms, Katja and Senge, Mathias O. and Kleinpeter, Erich},
  title     = {Conformational Landscape of meso-(1,3-Dithian-2-yl)porphyrins},
  doi       = {10.1021/Jo0708700},
  year      = {2007},
  abstract  = {An investigation of the conformational landscape of 1,3-dithian-2-yl bearing porphyrins and the rotational behavior of the dithianyl substituents in meso position was carried out by variable-temperature (VT) NMR spectroscopy. Additionally, theoretical results for alternative conformations and energy barriers were obtained by molecular modeling. The study revealed different NH trans tautomers with regard to the orientation of the dithianyl ligands for the free base porphyrins 1-3. Relatively ruffled porphyrin core conformations were established for the transition states of the dithianyl rotation, resulting in a lower rotational energy barrier for the nickel(II) complex 4 compared to that of the free base systems. The data obtained and the first depiction of a rotational transition state for the rotation of bulky meso-alkyl substituents illustrate the close structural interplay between meso-alkyl substituents and the macrocycle conformation in porphyrins.},
  language  = {en}
}
@article{RathAnandSankaretal.2003,
  author    = {Rath, Harapriya and Anand, V. G. and Sankar, J. and Venkatraman, S. and Chandrashekar, T. K. and Joshi, Bhawani S. and Khetrapal, C. L. and Schilde, Uwe and Senge, Mathias O.},
  title     = {Core-Modified Hexaphyrins; Characterization of Two- and Four-Ring Inverted 26 {\^o} Aromatic Macrocycles},
  year      = {2003},
  language  = {en}
}
@article{RyppaSenge2004,
  author    = {Ryppa, C. and Senge, Mathias O.},
  title     = {Dodecasubstituted porphyrins : an easily accessible type of dendritic porphyrins with tunable properties},
  issn      = {0385-5414},
  year      = {2004},
  abstract  = {Dodecasubstituted dendritic porphyrins with nonplanar macrocycles were synthesized by a convergent approach via Lindsey condensation reactions in good yields},
  language  = {en}
}
@article{BarkigiaRennerSengeetal.2004,
  author    = {Barkigia, Kathleen M. and Renner, Mark W. and Senge, Mathias O. and Fajer, Jack},
  title     = {Interplay of axial ligation, hydrogen bonding, self-assembly, and conformational landscapes in high-spin Ni(II) porphyrins},
  issn      = {1520-6106},
  year      = {2004},
  abstract  = {The molecular structures of four bis-ligated high-spin Ni(II) complexes of the sterically crowded, nonplanar 2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetranitroporphytin (NiOETNP) are reported. The ligands are imidazole (Im), imidazole plus 2-methylimidazole (2-MeIm) in the crystal lattice, 1-methylimidazole (1-MeIm), and 2,1,3- benzoselenadiazole (BSeD). Extensive intermolecular hydrogen bonding is observed in the three imidazole-ligated structures consisting of NH...O and CH...O bonding from the imidazoles to neighboring nitro groups and of NH...N interactions to a nearby 2-MeIm. The different modes of hydrogen bonding, typical of those frequently observed in proteins, mediate the self-assembly of discrete porphyrin dimers as well as more extensive two- and three-dimensional arrays. Only the bis-BSeD complex remains monomeric. The presence or absence of the different types of hydrogen bonds controls the orientations of the axial ligands and also modulates the conformations of the porphyrin skeletons. This interplay of axial ligation, hydrogen bonding, and self-assembly further illustrates the multi conformational landscapes that porphyrins can access as a function of their microenvironment. Such nonplanar deformations have been shown to significantly affect the optical, redox, magnetic, radical, and excited state properties of porphyrin derivatives. That hydrogen bonding can influence ligand interactions with neighboring functional groups as well as macrocycle conformations with their concomitant consequences on physical and chemical properties may thus be particularly relevant to the bioenergetic roles of porphyrin in vivo. These results also raise the question whether point mutations near porphyrins in vivo are structurally, and consequently functionally, innocent},
  language  = {en}
}
@article{WieheShakerBrandtetal.2005,
  author    = {Wiehe, A. and Shaker, Y. M. and Brandt, J. C. and Mebs, S. and Senge, Mathias O.},
  title     = {Lead structures for applications in photodynamic therapy : Part 1: Synthesis and variation of m-THPC (Temoporfin) related amphiphilic A(2)BC-type porphyrins},
  issn      = {0040-4020},
  year      = {2005},
  abstract  = {Photodynamic therapy (PDT) is a developing modality for the treatment of certain tumorous and other diseases. Considerable progress has been made in recent years in the search for new photosensitizers, in particular elucidating the role of localization of the photosensitizer. Known successful photosensitizers of the tetrapyrrole type are amphiphilic molecules, preferably localizing in cellular membrane structures. Thus, the quest for new photosensitizers requires the synthesis of unsymmetrically Substituted (amphiphilic) tetrapyrroles. In this article. we describe strategies for the de novo synthesis of amphiphilic tetrapyrroles using a 3-hydroxyphenyl substituted tetrapyrrolic system (Temoporfin) as the lead structure. From an applied science-oriented approach, such a set of amphiphilic porphyrins is best synthesized by combining well-developed condensation methods with subsequent functionalization via organolithium compound or transition metal catalyzed coupling protocols. Starting from simple A(2)- or AB-porphyrins, the synthesis of A(2)B-, A(3)-, A(3)B-, and A(2)BC-porphyrins with a mixed hydrophilic/hydrophobic substitution pattern is described. Because of the versatility of this approach to unsymmetrically Substituted porphyrins it is also applicable to other areas where porphyryns with a tailor-made substitution patterns are needed. for example. catalysts or molecular electronic devices based on tetrapyrroles. (c) 2005 Elsevier Ltd. All rights reserved},
  language  = {en}
}
@article{VenkatramanKumarSankaretal.2004,
  author    = {Venkatraman, S. and Kumar, R. and Sankar, J. and Chandrashekar, T. K. and Sendhil, K. and Vijayan, C. and Kelling, Alexandra and Senge, Mathias O.},
  title     = {Oxasmaragdyrin-ferrocene and oxacorrole-ferrocene conjugates : Synthesis, structure, and nonlinear optical properties},
  issn      = {0947-6539},
  year      = {2004},
  abstract  = {Ferrocenyl macrocyclic conjugates involving 22pi oxasmaragdyrins and 18pi oxacorroles have been synthesized and characterized. The direct covalent linkage of the ferrocenyl moiety to the meso position of the macrocycle is achieved by simple oxidative coupling of appropriate precursors with trifluoroacetic acid as catalyst. The electronic coupling between the ferrocenyl moiety and the macrocyclic pi system is apparent from: a) the red shifts (293-718 cm(-1)) of the Soret and Q-bands in the electronic absorption spectra of ferrocenyl conjugates; b) the shift of oxidation potentials (50 130 mV) of both the ferrocene and the corrole rings to the positive potentials; and c) considerable shortening of the C-C bond which connects the ferrocene and the meso-carbon atom of the macrocycle. The single-crystal X-ray structure of oxasmaragdyrin-ferrocene conjugate 9 reveals the planarity of the 22pi skeleton with very small deviations of the meso-carbon atoms. The meso-ferrocenyl substituent has a small dihedral angle of 38degrees, making way for mixing of the molecular orbitals of the ferrocene and the macrocycle. However, the other two meso substituents are almost perpendicular to the mean plane, defined by the three meso carbon atoms. Classical C-(HO)-O-... and nonclassical C- H(...)pi interactions lead to a two-dimensional supramolecular network. Ferrocene-smaragdyrin conjugate 9 bonds to a chloride ion in the protonated form and a rhodium(i) ion in the free base form. Nonlinear optical measurements reveal a larger nonlinear refractive index (-5.83 x 10(-8) cm(2) W-1) and figure of merit (2.28 x 10(-8) cm(3)W(-1)) for the rhodium smaragdyrin-ferrocene conjugate 19 than for the others, suggesting its possible application in optical devices},
  language  = {en}
}
@article{SengeDahmsHoldtetal.2015,
  author    = {Senge, Mathias O. and Dahms, Katja and Holdt, Hans-J{\"u}rgen and Kelling, Alexandra},
  title     = {Porphyrin substituent regiochemistry, conformation and packing - the case of 5,10-diphenylporphyrin},
  series = {Zeitschrift f{\"u}r Naturforschung : B, Chemical sciences},
  volume    = {70},
  journal   = {Zeitschrift f{\"u}r Naturforschung : B, Chemical sciences},
  number    = {2},
  publisher = {De Gruyter},
  address   = {T{\"u}bingen},
  issn      = {0932-0776},
  doi       = {10.1515/znb-2014-0217},
  pages     = {119 -- 123},
  year      = {2015},
  abstract  = {5,10-Disubstituted porphyrins are more recent additions to the family of meso-substituted porphyrins. A crystallographic comparison of 5,10-diphenylporphyrin with the regioisomeric 5,15-disubstituted system reveals striking differences in their conformation. In the free base porphyrins the former uses mainly out-of-plane distortion to alleviate steric strain while in-plane core elongation predominates in the latter. In contrast, the structure of the Cu(II) complex is planar and forms strong p-p aggregates with very small lateral shifts. Macroscopically, the packing is similar to that of porphyrin sponges of the 5,10,15,20-tetraphenylporphyrin type.},
  language  = {en}
}
@article{SengeBischoff2004,
  author    = {Senge, Mathias O. and Bischoff, Ines},
  title     = {SNAr reactions of beta-substituted porphyrins and the synthesis of meso substituted tetrabenzoporphyrins},
  issn      = {0040-4039},
  year      = {2004},
  abstract  = {Reaction of 2,3.7,8,12,13,17,18-octaethylporphyrin with LiR reagents containing functional groups readily yields meso substituted derivatives suitable for further transformations with residues such as -p-C6H5Br, -p-C6H5-C=CH - p-C6H5-NH2 or -(CH2)(3)-CH=CH2. Similar reactions of tetrabenzoporphyrin with alkyllithium reagents afforded the first entry into meso mono- and dialkylsubstituted tetrabenzoporphyrins while reaction of bicyclo[2.2.2]oct-type masked isoindole precursors with LiR followed by in situ retro-Diels-Alder reaction also afforded the 5-phenyl and 5,10- diphenyltetrabenzoporphyrins in high purity. (C) 2004 Elsevier Ltd. All rights reserved},
  language  = {en}
}
@article{OuTagliatestaSengeetal.2003,
  author    = {Ou, Z. P. and Tagliatesta, P. and Senge, Mathias O. and Shao, J. G. and Kadish, K. M.},
  title     = {Synthesis and electrochemical investigation of covalently linked porphyrin dimers containing a beta-brominated subunit : Crystal structure of H-2[tripp-tpp(Br-8)]H-2},
  issn      = {1088-4246},
  year      = {2003},
  abstract  = {Ten meso-tetraphenylporphyrin-type heterodimers containing a partly or completely beta-brominated subunit were synthesized and characterized by UV-visible spectroscopy, cyclic voltammetry and spectroelectrochemistry, showing the presence of low electronic interactions between the two subunits. The investigated compounds are represented as M[(tripp- tpp(Br-4)]M and M[tripp-tpp(Br-8)]M (M = 2H, Zn, Ni, Co and Cu) where tripp-tpp(Br-4) is the tetraanion of 1-[5- (10,15,20-triphenylporphyrinyl)]-4-[10-(2,3,12,13-tetrabromoporphyr inyl)]-benzene and tripptpp(Br-8) is the tetraanion of 1-[5-(10,15,20-triphenylporphyrinyl)]-4-[10-(2,3,7,8,12,13,17,18-octabro moporphyrinyl)] -benzene. One of the synthesized dimers, H-2[tripp-tpp(Br-8)]H-2, was characterized by a single-crystal X-ray investigation. Copyright (C) 2003 Society of Porphyrins \& Phthalocyanines},
  language  = {en}
}
@article{SengeShakerPinteaetal.2010,
  author    = {Senge, Mathias O. and Shaker, Yasser M. and Pintea, Monica and Ryppa, Claudia and Hatscher, Sabine S. and Ryan, Aoife and Sergeeva, Yulia},
  title     = {Synthesis of meso-substituted ABCD-Type porphyrins by functionalization reactions},
  issn      = {1434-193X},
  doi       = {10.1002/ejoc.200901113},
  year      = {2010},
  abstract  = {Considerable progress has been made in recent years in the search for synthetic methods leading to functionalized porphyrins, especially for modification of either the beta- or meso positions. For the latter, total synthesis based on condensation methods or partial synthesis through functionalization of preformed porphyrin have emerged as possible methods. The increasing number of possible technical and medicinal applications for unsymmetrically meso-substituted porphyrins requires straightforward methods for the preparation of the so-called ABCD-porphyrins, i.e., porphyrins with up to four different meso substituents. Here, we describe new strategies for the synthesis of ABCD-type porphyrins based on porphyrin reactions with organolithium reagents and the use of Pd-catalyzed coupling reactions. With the whole repertoire of contemporary functionalization methods, a comprehensive analysis and comparison of the various strategies for A-, AB-, A(2)B-, ABC-, A(2)BC- and ABCD-type porphyrins is given. In addition, we report on the synthesis of new functionalized derivatives for some of these porphyrin classes. In practical terms and taking an applied-science- oriented approach, the synthesis of unsymmetrically meso-substituted porphyrins is best accomplished by a combination of well-developed condensation methods with subsequent functionalization. by organolithium compounds or transition-metal- catalyzed coupling protocols. The methods described are suitable for the preparation of porphyrins for many divergent applications ranging over amphiphilic porphyrins for photodynamic therapy, push-pull systems for optical applications and chiral systems useful in catalysis to donor-acceptor systems suitable for electron-transfer studies.},
  language  = {en}
}
@article{RyppaSengeHatscheretal.2005,
  author    = {Ryppa, C. and Senge, Mathias O. and Hatscher, S. S. and Kleinpeter, Erich and Wacker, Philipp and Schilde, Uwe and Wiehe, A.},
  title     = {Synthesis of mono- and disubstituted porphyrins : A- and 5,10-A(2)-type systems},
  issn      = {0947-6539},
  year      = {2005},
  abstract  = {General syntheses have been developed for meso-substituted porphyrins with one or two substituents in the 5,10- positions and no beta substituents. 5-Substituted porphyrins with only one meso substituent are easily prepared by an acid-catalyzed condensation of dipyrromethane, pyrrole-2-carbaldehyde. and an appropriate aldehyde using a "[2+1+1]" approach. Similarly, 5,10-disubstituted porphyrins are accessible by simple condensation of unsubstituted tripyrrane with pyrrole and various aldehydes using a "[3+1]" approach. The yields for these reactions are low to moderate and additional formation of either di- or mono-substituted porphyrins due to scrambling of the intermediates is observed. However, the reactions can be performed quite easily and the desired target compounds are easily removed due to large differences in solubility. A complementary and more selective synthesis involves the use of organolithium reagents for SNAr reactions. Reaction of in situ generated porphyrin (porphine) with 1.1-8 equivalents of RLi gave the monosubstituted porphyrins, while reaction with 3-6 equivalents of RLi gave the 5,10-disubstituted porphyrins in yields ranging from 43 to 90\%. These hitherto almost inaccessible compounds complete the series of different homologues of A-, 5,15-A(2)-, 5,10-A(2)-, A(3)-, and A(4)-type porphyrin's and allow an investigation of the gradual influence of type, number, and regiochemical arrangement of substituents on the properties of meso-substituted porphyrins. They also present important starting materials for the synthesis of ABCD porphyrins and are potential synthons for supramolecular materials requiring specific substituent orientations},
  language  = {en}
}
@article{SengeRichter2004,
  author    = {Senge, Mathias O. and Richter, J.},
  title     = {Synthetic, transformations of porphyrins : Advances 2002-2004},
  issn      = {1088-4246},
  year      = {2004},
  abstract  = {Contemporary methods for the modification of porphyrins are presented. In association with the Third International Conference on Porphyrins and Phthalocyanines (ICPP-3) a survey of current method developments and reactivity studies is made. The review focuses on synthetic transformations of porphyrins currently in use for various applications and on functional group transformations. A brief survey of important developments covers selectively the literature from late 2001 to early 2004. Copyright (c) 2004 Society of Porphyrins C Phthalocyanines},
  language  = {en}
}
@article{SengeHatscherWieheetal.2004,
  author    = {Senge, Mathias O. and Hatscher, S. S. and Wiehe, A. and Dahms, Katja and Kelling, Alexandra},
  title     = {The dithianyl group as a synthon in porphyrin chemistry : condensation reactions and preparation of formylporphyrins under basic conditions},
  issn      = {0002-7863},
  year      = {2004},
  language  = {en}
}
@article{SengeRosslervonGersdorffetal.2004,
  author    = {Senge, Mathias O. and Rossler, B. and von Gersdorff, J. and Schafer, A. and Kurreck, H.},
  title     = {The meso-beta-linkage as structural motif in porphyrin-based donor-acceptor compounds},
  issn      = {0040-4039},
  year      = {2004},
  abstract  = {Synthetic strategies for using the beta-linkage as a structural motif in electron transfer mimics have been tested. Exploratory syntheses of directly meso-beta-linked bis- and trisporphyrins and the first representative X-ray structure of a meso-beta-linked bisporphyrins are reported. The structure reveals a unique form of intramolecular- pi-pi stabilization between one porphyrin and a meso-aryl substituent in a second porphyrin unit that accounts for the stability of different atropisomers in trimers. Using beta-formyl porphyrins, dipyrromethanes, and suitable quinone precursor aldehydes, mixed condensations gave convenient access to porphyrin-porphyrin-quinone (P-P-Q) donor acceptor systems consisting of a meso-beta-linked bisporphyrin. a spacer, and a quinone acceptor. (C) 2004 Elsevier Ltd. All rights reserved},
  language  = {en}
}