Chemistry News and Events
Upcoming Seminars
7 - 11 August 2017
Dynamic control of function by light-driven molecular switches and motors

Monday 7 August 2017 - 4:00pm Chemistry Lecture Theatre 2 (Special Seminar)

S.J. (Sander) Wezenberg, Assistant Professor, Faculty of Science and Engineering, University of Groningen, Netherlands

Host:
Professor Phil Gale

Abstract:
Stimuli-responsive molecular systems that mimic the highly complex and dynamic functions found in nature (e.g. allostericity, signalling, motion and transport) are receiving major interest and will form the basis of future nanomachines.[1] In this context, molecular switches and motors that are activated by light are emerging as powerful tools to control the properties of materials as well as biological functions.[2] Light offers the advantage that it can be applied with high spatiotemporal control without producing waste.

In this presentation synthetic systems, in which control of motion at the molecular level is coupled to specific functions, will be discussed. Particular focus is on the use of light-driven molecular rotary motors as multi-state switches for the modulation of receptor-ligand interactions and self-assembly processes. Finally, strategies to regulate the speed of rotation and to red-shift the excitation wavelength of these molecular motors are illustrated.

[1] M. Peplow, “The tiniest Lego: a tale of nanoscale motors, rotors, switches and pumps” Nature 2015, 525, 18−21.

[2] A. S. Lubbe, T. van Leeuwen, S. J. Wezenberg, B. L. Feringa, “Designing dynamic functional molecular systems” Tetrahedron 2017, 73, 4837−4848.




Multi-Photon Absorption in Metal Alkynyl Complexes

Wednesday 9 August 2017 - 11:00am Chemistry Lecture Theatre 4 (School Seminar)

Professor Mark Humphrey, Research School of Chemistry, Australian National University

Host:
Professor Lou Rendina

Abstract:
We have been studying the nonlinear optical (NLO) properties of metal alkynyl complexes, in studies ranging from small complexes1 to dendrimers.2 While our early focus was on molecular quadratic and cubic NLO coefficients, materials with multi-photon absorption (MPA) properties have become of increasing interest for applications such as microfabrication, bioimaging, photodynamic therapy, and frequency upconversion lasing. We have recently been exploring the MPA behaviour of rod-like, star, and dendritic OPVs and oligo(phenyleneethynylene)s (OPEs) bearing bis(diphosphine)ruthenium moieties (e.g. examples at right); the results of these studies will be presented.3 

1. (a) I. R. Whittall, M. G. Humphrey, M. Samoc and B. Luther-Davies, Angew. Chem. Int. Ed., 1997, 36, 370-371. (b) C.E. Powell, M.P. Cifuentes, J.P.L. Morrall, R. Stranger, M.G. Humphrey, M. Samoc, B. Luther-Davies and G.A. Heath, J. Am. Chem. Soc., 2003, 125, 602-610. (c) M. Samoc, N. Gauthier, M.P. Cifuentes, F. Paul, C. Lapinte and M.G. Humphrey, Angew. Chem. Int. Ed., 2006, 45, 7376-7379. (d) G.T. Dalton, M.P. Cifuentes, S. Petrie, R. Stranger, M.G. Humphrey and M. Samoc, J. Am. Chem. Soc., 2007, 129, 11882-11883. (e) K.A. Green, M.P. Cifuentes, T.C. Corkery, M. Samoc and M.G. Humphrey, Angew. Chem. Int. Ed., 2009, 48, 7867-7870. (f) B. Babgi, L. Rigamonti, M.P. Cifuentes, T.C. Corkery, M.D. Randles, T. Schwich, S. Petrie, R. Stranger, A. Teshome, I. Asselberghs, K. Clays, M. Samoc, and M.G. Humphrey, J. Am. Chem. Soc., 2009, 131, 10293-10307.

2. (a) A.M. McDonagh, M.G. Humphrey, M. Samoc, B. Luther-Davies, S. Houbrechts, T. Wada, H. Sasabe and A. Persoons, J. Am. Chem. Soc., 1999, 121, 1405-1406. (b) C.E. Powell, J.P. Morrall, S.A. Ward, M.P. Cifuentes, E.G.A. Notaras, M. Samoc and M.G. Humphrey, J. Am. Chem. Soc., 2004, 126, 12234-12235. (c) M.P. Cifuentes, C.E. Powell, J.P. Morrall, A.M. McDonagh, N.T. Lucas, M.G. Humphrey, M. Samoc, S. Houbrechts, I. Asselberghs, K. Clays, A. Persoons and T. Isoshima, J. Am. Chem. Soc., 2006, 128, 10819-10832. (d) M. Samoc, J.P. Morrall, G.T. Dalton, M.P. Cifuentes and M.G. Humphrey, Angew. Chem. Int. Ed., 2007, 46, 731-733. (e) R.L. Roberts, T. Schwich, T.C. Corkery, M.P. Cifuentes, K.A. Green, J.D. Farmer, P.J. Low, T.B. Marder, M. Samoc and M.G. Humphrey, Adv. Mater., 2009, 21, 2318-2322. (f) T. Schwich, M.P. Cifuentes, P.A. Gugger, M. Samoc and M.G. Humphrey, Adv. Mater., 2011, 23, 1433-1435.

3. (a) P.V. Simpson, L.A. Watson, A. Barlow, G. Wang, M.P. Cifuentes and M.G. Humphrey, Angew. Chem. Int. Ed., 2016, 55, 2387-2391. (b) B. Gao, L. Mazur, M. Morshedi, A. Barlow, H. Wang, C. Quintana, C. Zhang, M. Samoc, M.P. Cifuentes and M.G. Humphrey, Chem. Commun., 2016, 52, 8301-8304. (c) T. Schwich, A. Barlow, M. P. Cifuentes, J. Szeremeta, M. Samoc, M. G. Humphrey, Chem. Eur. J. 2017, 23, 8395-8399.






Biomimetic Synthesis of Natural Products

Friday 11 August 2017 - 11:00am Chemistry Lecture Theatre 4 (School Seminar)

Dr Jonathan George, School of Chemistry, The University of Adelaide

Host:
Mr Timothy Katte

Abstract:
In the first half of my talk, I will describe the development of biomimetic cascade reactions based on the natural products hyperjaponol C1 and verrubenzospirolactone.2

In the second half of my talk, I will present a more detailed discussion of chlorinated (and unchlorinated) naphthoquinone meroterpenoid antibiotics that have been isolated from marine and soil strains of Streptomyces bacteria, including merochlorins, napyradiomycins, naphterpins and marinones. They possess unusual aromatic oxidation patterns that are known to be biosynthesized from 1,3,6,8-tetrahydroxynaphthalene (THN). We propose that chlorination of THN derivatives by vanadium-dependent chloroperoxidase (VCPO) enzymes is key to these biosynthetic pathways. This hypothesis has inspired biomimetic syntheses of merochlorin A,3 the napyradiomycins,4 and 7-demethylnaphterpin.


References:

1. H. C. Lam, J. T. J. Spence, J. H. George, Angew. Chem. Int. Ed. 2016, 55, 10368.

2. H. C. Lam, H. P. Pepper, J. H. George, Angew. Chem. Int. Ed. 2017, 56, 8532.

3. H. P. Pepper, J. H. George, Angew. Chem. Int. Ed. 2013, 52, 12170.

4. Z. D. Miles, S. Diethelm, H. P. Pepper, D. M. Huang, J. H. George, B. S. Moore, Nature Chem. 2017, DOI: 10.1038/NCHEM.2829




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