Publikationen AG Molecular Modelling
Publikationen
1986-1990
1. F. Adler, I. Thondorf, M. Strube: "Die Chemie der 4-Heteromethylen-2-oxazolin-5-one", Wiss. Z. Univ. Halle 1986, 19-26.
2. I. Thondorf, M. Strube: "Phasentransfer-katalysierte hydrolytische Ringöffnung von 4-Aryliden-2-oxazolin-5-onen", Z. Chem. 1988, 28, 330-331.
3. I. Thondorf, M. Strube, M. Augustin: "Umsetzungen von 4-Aminomethylen-5-oxo-2-phenyl-4,5-dihydrooxazol mit Heterocumulenen", Synthesis 1990, 1169-1172.
4. I. Thondorf, O. Lichtenberger, S. Hoffmann: "Flüssigkristalline Polyribonucleotide - System Poly(U)", Z. Chem. 1990, 30, 171.
1991-1995
5. M. Wahab, W. Brandt, H. Schinke, I. Thondorf, A. Barth, "Halle Group Develops Molecular Graphics Package of IBM PCs", Chem. Des. Automat. News 1991, 6, 20-22.
6. W. Brandt, M. Wahab, H. Schinke, I. Thondorf, A. Barth, "HAMOG: Molecular graphics program for chemistry, biochemistry, molecular biology and enzyme research", J. Mol. Graphics, 1991, 9, 122-126.
7. W. Brandt, M. Wahab, I. Thondorf, H. Schinke, A. Barth, "HAMOG - Rechnergestützte Moleküluntersuchungen am Arbeitsplatz", CIC-Mitteilungsblatt, 1991, 13-23.
8. M. Wahab, I. Thondorf, W. Brandt, A. Barth, "Molekülgraphik auf Personalcomputern", Chemische Industrie, 1992, 33-36.
9. I. Thondorf, W. Brandt, H.-U. Demuth, "The Inhibition of Serine Proteases by N-Peptidyl O-aroyl hydroxylamines - Mechanistic Investigations by Means of Semiempirical Methods", J. Mol. Graphics, 1993, 11, 279-280.
10. I. Thondorf, G. Hillig, W. Brandt, J. Brenn, A. Barth, V. Böhmer, "Molecular Modelling Study of a Dissymmetric Calix[4]arene and Its Methyl Ethers", J. Chem. Soc., Perkin Trans. 2, 1994, 2259-2267.
11. C. Grüttner, V. Böhmer, W. Vogt, I. Thondorf, S. E. Biali, F. Grynszpan, "Calix[4]arenes with Alkylidene Bridges, Synthesis and Conformational Properties", Tetrahedron Lett. 1994, 35, 6267-6270.
12. W. Schroth, D. Ströhl, I. Thondorf, W. Brandt, M. Felicetti, T. Gelbrich, "On the Equilibrium between Hetareno-anellated 1,2-Dithiines and 12-Membered Cyclic Bis(butadiendiyl) Disulfides. NMR and Molecular Modelling Studies", Tetrahedron 1995, 51, 8853-8862.
13. R. Arnecke, V. Böhmer, S. Friebe, S. Gebauer, G. J. Krauss, I. Thondorf, W. Vogt, "Regio- and Diastereoselective Condensation of Resorcarenes with Primary Amines and Formaldehyde", Tetrahedron Lett. 1995, 36, 6221-6224.
14. I. Thondorf, J. Brenn, W. Brandt, V. Böhmer, "Ring Inversion Pathways of exo- and endo-Calix[4]arenes Studied by Means of the MM3 Force Field", Tetrahedron Lett. 1995, 36, 6665-6668.
15. B. König, M. Rödel, P. Bubenitschek, P. G. Jones, I. Thondorf, "Synthesis, Structure and Coordination Properties of Silicon-Bridged Macrocycles", J. Org. Chem. 1995, 60, 7406-7410.
16. W. Brandt, T. Lehmann, I. Thondorf, L. Born, M. Schutkowski, J.-U. Rahfeld, K. Neubert, A. Barth, "A model of the active site of dipeptidyl peptidase IV predicted by comparative molecular field analysis and molecular modelling simulations", Int. J. Pept. Protein Res. 1995, 46, 494-507.
17. W. Brandt, O. Ludwig, I. Thondorf, "Suggestion of a New Catalysis Mechanism in Serine Proteases Exhibited by Dipeptidyl Peptidase IV. Unusual Stabilization of the Oxyanion Tetrahedral Intermediate may cause trans-cisPro Isomerisation of the Substrates" (Posterabstract), J. Mol. Model. 1995, 1, 86-87.
18. J. Wöhnert, K. Frost, J. Brenn, S. E. Biali, I. Thondorf, "Conformational Analysis of Monospirodienone-Derivatives of Calix[4]arenes" (Posterabstract), J. Mol. Model. 1995, 1, 116-117.
1996-2000
19. V. Böhmer, R. Dörrenbächer, M. Frings, M. Heydenreich, D. de Paoli, W. Vogt, G. Ferguson, I. Thondorf, "Anellated Calixarenes Composed of Calix[4]arenes with Hydroxy Groups in Endo- and Exo-Position", J. Org. Chem. 1996, 61, 549-559.
20. B. König, W. Pitsch, I. Thondorf, "Synthesis, Structure and Reactivity of Enediyne Macrocycles", J. Org. Chem. 1996, 61, 4258-4261.
21. W. Brandt, O. Ludwig, I. Thondorf, A. Barth, "A new mechanism in serine protease catalysis exhibited by dipeptidyl peptidase IV (DP IV). Results of PM3 semiempirical thermodynamic studies supported by experimental results.", Eur. J. Biochem. 1996, 236, 109-114.
22. S. E. Biali, V. Böhmer, S. Cohen, G. Ferguson, C. Grüttner, F. Grynszpan, E. F. Paulus, I. Thondorf, W. Vogt, "Alkanediyl Bridged Calix[4]arenes: Synthesis, Conformational Analysis, and Rotational Barriers", J. Am. Chem. Soc. 1996, 118, 12938-12949.
23. I. Thondorf, W. Brandt, A. Stöckel, H.-U. Demuth, "Modeling of the Reaction Mechanism of the Decomposition of a New Class of Mechanism-Based Protease Inhibitors", Protein Pept. Lett. 1996, 3, 113-118.
24. O. Mogck, E. F. Paulus, V. Böhmer, I. Thondorf, W. Vogt, "Hydrogen-bonded dimers of tetraurea calix[4]arenes: unambiguous proof by single crystal X-ray analysis", J. Chem. Soc., Chem Commun. 1996, 2533-2534.
25. I. Thondorf, J. Brenn, "A simple method for the exploration of the conformational space and for the estimation of rotational barriers in calix[4]arene systems", J. Mol. Struct. (THEOCHEM), 1997, 398-399, 307-314.
26. J. M. van Gelder, J. Brenn, I. Thondorf, S. E. Biali, "Partial OH->Me Replacement in the Calixarene Scaffold: Preparation, Conformation, and Stereodynamics of Tetra-tert-butyl-25,27-dihydroxy-26,28-dimethylcalix[4]arene and its Dimethyl Ether Derivative", J. Org. Chem. 1997, 62, 3511-3519.
27. W. Schroth, E. Hintzsche, H. Jordan, T. Jende, R. Spitzner, I. Thondorf, "1,2-Dithiines and Precursors, XVII: Synthesis and Properties of Thieno Anellated 1,2-Dithiines, Structural Influence on Colour", Tetrahedron 1997, 53, 7509-7528.
28. I. Thondorf, J. Brenn, "Conformations of calix[5]arenes - a molecular mechanics study", J. Chem. Soc., Perkin Trans. 2 1997, 2293-2299.
29. K. Airola, V. Böhmer, E. F. Paulus, K. Rissanen, C. Schmidt, I. Thondorf, W. Vogt, "Selective Derivatization of Resorcarenes: 1. The Regioselective Formation of Tetra-Benzoxazine Derivatives", Tetrahedron 1997, 31, 10709-10724.
30. S. E. Biali, V. Böhmer, J. Brenn, S. Cohen, M. Frings, I. Thondorf, W. Vogt, J. Wöhnert, "Conformation, Inversion Barrier, and Solvent-Induced Conformational Shift in Exo- and Endo/Exo-Calix[4]arenes", J. Org. Chem. 1997, 62, 8350-8360.
31. B. König, T. Fricke, I. Dix, P. G. Jones, I. Thondorf, "Calixarene Carbamates", Liebigs Ann. Chem./Recueil 1997, 2315-2320.
32. J. Wöhnert, J. Brenn, M. Stoldt, O. Aleksiuk, F. Grynszpan, I. Thondorf, S. E. Biali, "Conformation and Stereodynamics of Monodioxamethylene Calix[4]arene Derivatives", J. Org. Chem. 1998, 63, 3866-3874.
33. U. Lüning, H. Ross, I. Thondorf, "Concave reagents. Part 27. Steric requirements of intraanular substituents in A,D-bridged calix[6]arenes", J. Chem. Soc., Perkin Trans. 2 1998, 1313-1317.
34. S. E. Biali, V. Böhmer, I. Columbus, G. Ferguson, C. Grüttner, F. Grynszpan, E. F. Paulus, I. Thondorf, "Conformational studies of calix[5]arenes containing a single alkanediyl bridge", J. Chem. Soc., Perkin Trans. 2 1998, 2261-2269.
35. I. Thondorf, J. Brenn, V. Böhmer, "Conformational Properties of Methylene-Bridged Resorcarenes", Tetrahedron 1998, 54, 12823-12828.
36. C. Schmidt, I. Thondorf, E. Kolehmainen, V. Böhmer, W. Vogt, K. Rissanen, "One-Step Synthesis of Resorcarene Dimers Composed of Two Tetra-Benzoxazine Units", Tetrahedron Lett. 1998, 39, 8833-8836.
37. I. Thondorf, "Conformational interconversions of partially dehydroxylated calix[4]arenes. A molecular mechanics study", J. Chem. Soc., Perkin Trans. 2 1999, 1791-1796.
38. I. Thondorf, "Molecular Modelling Untersuchungen zur Konformation und Stereodynamik von Calixarenen", Habilitationsschrift, Martin-Luther-Universität Halle-Wittenberg, 2000.
39. M. O. Vysotski, I. Thondorf, V. Böhmer, "Selbstorganisierte, über Wasserstoffbrücken gebundene dimere Kapseln mit hoher kinetischer Stabilität", Angew. Chem. 2000, 112, 1309-1312, Angew. Chem., Int. Ed. Engl. 2000, 39, 1264-1267.
40. P. Parzuchowski, V. Böhmer, S. E. Biali, I. Thondorf, "Conformational rigidity in mesitylene based calix[4]arenes adopting an 1,3-alternate conformation", Tetrahedron: Asymmetry, 2000, 11, 2393-2402.
2001-2005
41. I. Thondorf, "Conformations and Stereodynamics", in Calixarenes 2001, Z. Asfari, V. Böhmer, J. McB. Harrowfield, J. Vicens (Hrsg.), Kluwer Academic Publishers, Doordrecht, 2001, 280-295.
42. I. Thondorf, A. Shivanyuk, V. Böhmer, "Chemical Modification of Calix[4]arenes", in Calixarenes 2001, Z. Asfari, V. Böhmer, J. McB. Harrowfield, J. Vicens (Hrsg.), Kluwer Academic Publishers, Doordrecht, 2001, 26-53.
43. K. Akbaria, O. Aleksiuk, S. E. Biali, V. Böhmer, M. Frings, I. Thondorf, "Spirodienone Derivatives of a Spherand-Type Calixarene", J. Org. Chem., 2001, 66, 2891-2899.
44. K. Akbaria, S. E. Biali, V. Böhmer, J. Brenn, S. Cohen, M. Frings, F. Grynszpan, J. McB. Harrowfield, A. N. Sobolev, I. Thondorf, "Stereochemistry of a Spherand-Type Calixarene", J. Org. Chem., 2001, 66, 2900-2906.
45. M. O. Vysotsky, A. Pop, F. Broda, I. Thondorf, V. Böhmer, "Molecular Motions within Self-assembled Dimeric Capsules with Tetraethylammonium Cations as Guest", Chem. Eur. J., 2001, 7, 4403-4410.
46. M. O. Vysotsky, I. Thondorf, V. Böhmer, "Hydrogen bonded calixarene capsules kinetically stable in DMSO", Chem. Commun., 2001, 1890-1891.
47. I. Thondorf, F. Broda, K. Rissanen, M. O. Vysotski, V. Böhmer, "Dimeric Capsules of Tetraurea Calix[4]arenes. MD-Simulations and X-Ray Structures", J. Chem. Soc., Perkin Trans. 2, 2002, 1796-1800.
48. S. Simaan, K. Agbaria, I. Thondorf, S. E. Biali, "Conformation of Syn and Anti Phenylquinazoline Calix[4]arene Diethers", New. J. Chem., 2003, 27, 236-238.
49. M. Brandsch, I. Knütter, B. Hartrodt, S. Gebauer, S. Theis, M. Boll, I. Rubio-Aliaga, I. Born, I. Thondorf, H. Daniel, K. Neubert, "New insights into substrate specifity, inhibitors, pharmacophore structure and expression of the mammalian H+/peptide transporters", Nova Acta Leopoldina N.F. 37, 2003, 75-85.
50. S. Gebauer, I. Thondorf, I. Knütter, M. Brandsch, K. Neubert, "Determining the Pharmacophore Structure of Substrates of the Mammalian Peptide Transporter (PEPT1) by Molecular Modeling Investigations", Nova Acta Leopoldina N.F. 87, 2003, 349.
51. I. Thondorf, R. Andrecki, S. Bieler, C. Griehl, "New strategies for the asymmetric synthesis of peptides via conjugate addition of N-nucleophiles", in Peptides 2002, Proc. 27th Eur. Pept. Symp., 2003, 120-121.
52. I. Thondorf, S. Gebauer, A. Biegel, B. Hardrodt, I. Knütter, M. Brandsch, K. Neubert, "Determining the Pharmacophore Structure of Substrates of the Mammalian Peptide Transporter (PepT1) by Molecular Modeling Investigations", in Peptides 2002, Proc. 27th Eur. Pept. Symp., 2003, 296-297.
53. M. Vysotsky, M. Bolte, I. Thondorf, V. Böhmer, "New Molecular Topologies by Fourfold Metathesis Reaction within a Hydrogen-Bonded Calix[4]arene Dimer", Chem. Eur. J., 2003, 9, 3375-3382.
54. S. Gebauer, I. Knütter, B. Hartrodt, M. Bruch, M. Brandsch, K. Neubert, I. Thondorf, "Three-Dimensional Quantitative Structure- Activity Relationship Analyses of Peptide Substrates of the Mammalian H+/Peptide Cotransporter PEPT1", J. Med. Chem., 2003, 46, 5725-5734.
55. A. Shivanyuk, M. Saadioui, F. Broda, I. Thondorf, M. Vysotsky, K. Rissanen, E. Kolehmainen, V. Böhmer, "Sterically and Guest Controlled Self-Assembly of Calix[4]arene Derivatives", Chem. Eur. J., 2004, 10, 2138-2148.
56. V. Böhmer, D. Mesheryakov, M. Bolte, I. Thondorf, "5H,7H-12-Oxa-5,7-diaza-dibenzo[a,d]-cycloocten-6-one: a three-dimensional network assembled by hydrogen bonding, pi-pi and edge-to-face interactions", Acta Cryst. C, 2004, C60, o136-o139.
57. N. Seri, I. Thondorf, S. E. Biali, "Preparation and Conformation of Dioxocalix[4]arene Derivatives", J. Org. Chem., 2004, 69, 4774-4780.
58. Y. Rudzevich, M. O. Vysotsky, V. Böhmer, M. S. Brody, J. Rebek, Jr., F. Broda, I. Thondorf, "Preferred dimerization of tetra-tolyl- and metra-tosylurea derivatives of flexible and rigidified calix[4]arenes", Org. Biomol. Chem., 2004, 2, 3080-3084.
59. A. Barth, I. Thondorf, J. Stano, „Gedanken zum Funktionsmechanismus der Serinproteasen. Die Funktion der Tetrade: Asp...His...Ser...Xaa“, Acta Facult. Pharm. Univ. Comenianae, 2004, 51, 15-26.
60. C. Mrestani-Klaus, J. Faust, P. Fuchs, I. Thondorf, P. Kovacs, K. Neubert, „Enzymatic Activity of Dipeptidyl Peptidase IV (DP IV/CD26) in the Regulation of T Cell Activation: DP IV Inhibitors with the N-terminal MXP Sequence, Acta Facult. Pharm. Univ. Comenianae, 2004, 51, 164-172.
61. Y. Rudzevich, V. Rudzevich, D. Schollmeyer, I. Thondorf, V. Böhmer, "Hydrogen bonded dimers of triurea derivatives of triphenylmethanes", Org. Lett., 2005, 7, 613-616.
62. V. Böhmer, B. Costisella, J. Gloede, S. Ozegowski, M. Schneider, I. Thondorf, „Surprising conformational behaviour of a diphosphate derived from a spherand-type calixarene”, Eur. J. Org. Chem., 2005, 2788-2792.
63. A. Biegel, S. Gebauer, B. Hartrodt, M. Brandsch, K. Neubert, I. Thondorf, „Three-Dimensional Quantitative Structure-Activity Relationship (3D QSAR) Analyses of b-Lactam Antibiotics and Tripeptides as Substrates of the Mammalian H+/Peptide Cotransporter PEPT1”, J. Med. Chem. 2005, 48, 4410-4419.
64. I. Thondorf, F. Broda, M. Vysotsky, O. Mogck, V. Böhmer, „Do Pentaurea Calix[5]arenes Form Hydrogen Bonded Dimeric Capsules?”, Zh. Strukt. Khim. / J. Struct. Chem., 2005, 46, S40-S46/S39-S45.
65. A. Barth, I. Thondorf, S. Gebauer, W. Brandt, K. Neubert, J. Stano, M. Pšenák, P. Kovács, „Gedanken zum Funktionsmechanismus der Serinproteasen. Teil 2. Dipeptidyl Peptidase IV (DP IV/CD 26)“, Acta Facult. Pharm. Univ. Comenianae, 2005, 52, 7-21.
2006-2010
66. D. Meshcheryakov, V. Böhmer, M. Bolte, V. Hubscher-Bruder, F. Arnaud-Neu, H. Herschbach, A. Van Dorsselaer, I. Thondorf, W. Mögelin, „Zwei Chloridionen als Templat bei der Bildung eines cyclischen Harnstoff-Moleküls”, Angew. Chem., 2006, 118, 1679-1682; Angew. Chem. Int. Ed., 2006, 45, 1648-1652.
67. A. Biegel, I. Knütter, B. Hartrodt, S. Gebauer, S. Theis, P. Luckner, G. Kottra, M. Rastetter, K. Zebisch, I. Thondorf, H. Daniel, K. Neubert, M. Brandsch, „The renal type H+/peptide symporter PEPT2: structure-affinity relationships”, Amino Acids, 2006, 31, 137-156.
68. F. Broda, M. Vysotsky, V. Böhmer, I. Thondorf, „Orientational preferences of aromatic guests in dimeric capsules of tetraurea calix[4]arenes – MD and NMR studies”, Org. Biomol. Chem., 2006, 4, 2424-2432.
69. O. Kasyan, I. Thondorf, M. Bolte, V. Kalchenko, V. Böhmer, „Unusual conformations of 1,3-Dialkoxythiacalix[4]arenes in the solid state”, Acta Cryst. C, 2006, C62, o289-o294.
70. A. Biegel, S. Gebauer, M. Brandsch, K. Neubert, I. Thondorf, „Structural Requirements for Substrates of the H+/Peptide Cotransporter PEPT2 determined by Three-Dimensional Quantitative Structure-Activity Relationship Analyses”, J. Med. Chem., 2006, 49, 4286-4296.
71. A. Barth, I. Thondorf, S. Gebauer, K. Neubert, P. Kovacs, J. Stano, „Gedanken zum Funktionsmechanismus der Serinproteasen; Teil 3. Dipeptidyl Peptidase IV – a) Das tetrahedrale Intermediat im Acylierungsprozess, b) Die Boronsäuren, Acta Facult. Pharm. Univ. Comenianae, 2006, 53, 5-14.
72. A. Barth, I. Thondorf, K. Neubert, S. Hoffmann, P. Kovacs, J. Stano, „Gedanken zum Mechanismus der Serinproteasen; Teil IV. Dipeptidyl Peptidase IV – Transition State Inhibitoren – Das asymmetrische tetrahedrale Intermediat TI1,Acta Facult. Pharm. Univ. Comenianae, 2006, 53, 16-20.
73. O. Molokanova, M. O. Vysotsky, Y. Cao, I. Thondorf, V. Böhmer, „Vierfache [2]Rotaxane von Calix[4]arenen durch Ringschluß", Angew. Chem., 2006, 118, 8220-8224, "Fourfold [2]Rotaxanes of Calix[4]arenes by Ring Closure", Angew. Chem. Int. Ed., 2006, 45, 8051-8055.
74. Y. Rudzevich, V. Rudzevich, D. Schollmeyer, I. Thondorf V. Böhmer, „Hydrogen bonding in dimers of tritolyl and tritosylurea derivatives of triphenylmethanes", Org. Biomol. Chem., 2006, 4, 3938-3944.
75. A. Biegel, S. Gebauer, B. Hartrodt, I. Knütter, K. Neubert, M. Brandsch, I. Thondorf, „Recognition of 2-aminothiazole-4-acetic acid derivatives by the peptide transporters PEPT1 and PEPT2", Eur. J. Pharm. Sci. 2007, 32, 69-76.
76. I. Thondorf, Y, Rudzevich, V. Rudzevich, V. Böhmer, „Reasons for the exclusive formation of heterodimeric capsules between tetra-tolyl and tetra-tosylurea calix[4]arenes", Org. Biomol. Chem., 2007, 5, 2775-2782.
77. A. Barth, I. Thondorf, „Gedanken zum Mechanismus der Serinproteasen. Teil V: Dipeptidyl Peptidase IV, biochemisch-physiologische Aspekte – eine Übersicht –", Acta Facult. Pharm. Univ. Comenianae, 2007, 54, 7-12.
78. M. Bolte, I. Thondorf, V. Böhmer, V. Rudzevich, Y. Rudzevich, „Heterodimeric capsules formed by tetratosyl and tetratolyl urea calix[4]arenes", CrystEngCommun, 2008, 10, 270-272.
79. D. Meshcheryakov, F. Arnaud-Neu, V. Böhmer, M. Bolte, V. Hubscher-Bruder, E. Jobin, I. Thondorf, S. Werner, „Cyclic triureas - synthesis, crystal structures and properties”, Org. Biomol. Chem., 2008, 6, 1004-1014.
80. D. Meshcheryakov, F. Arnaud-Neu, V. Böhmer, M. Bolte, V. Hubscher-Buder, I. Thondorf, S. Werner, "Cyclic tetraureas with variable flexibility - synthesis, crystal structures and properties, Org. Biomol. Chem. 2008, 6, 3244-3255.
81. A. Barth, I. Thondorf, "Gedanken zum Mechanismus der Serinproteasen. Teil VI. DP IV Inhibitoren. Wirkstoffe gegen Diabetes Typ II mit neuartigem Wirkmechanismus", Acta Facult. Pharm. Univ. Comenianae, 2008, 55, 5-10.
2011-
82. A. Bräutigam, D. Schaumlöffel, H. Preud'Homme, I. Thondorf, D. Wesenberg, "Physiological characterization of cadmium-exposed Chlamydomonas reinhardtii", Plant, Cell Environ., 2011, 34, 2071-2082.
83. I. Thondorf, V. Vogt, S. Schäfer, S. Gebauer, K. Zebisch, L. Laug, M. Brandsch, "Three-dimensional quantitative structure-activity relationship analyses of substrates of the human proton-coupled amino acid transporter 1 (hPAT1)", Bioorg. Med. Chem., 2011, 19, 6409-6418.
84. A. Wierig, W. Seichter, I. Thondorf, E. Weber, "Crystalline inclusion compounds of a new diol host featuring a combination of anthracene and 9-fluorenol units", Supramol. Chem., 2012, 24, 713-725.
85. V. Voigt, L. Laug, K. Zebisch, I. Thondorf, M. Brandsch, "Transport of the areca nut alkaloid arecaidine by the human proton-coupled amino acid transporter 1 (hPAT1), J. Pharm. Pharmacol. 2013, 65, 582-590.
86. J. Pettelkau, I. Thondorf, S. Theisgen, H. Lilie, T. Schröder, C. Arlt, C. H. Ihling, A. Sinz, "Structural Analysis of Guanylyl Cyclase-Activating Protein-2 (GCAP-2) Homodimer by Stable Isotope-Labeling, Chemical Cross-Linking, and Mass Spectrometry, J. Am. Soc. Mass Spectrom. 2013, DOI: 10.1007/s13361-013-0734-6.