Proceedings of the Thirteenth International Conference on Time-Resolved Vibrational Spectroscopy

The thirteenth meeting in a long-standing series of “Time-Resolved Vibrational Spectroscopy” (TRVS) conferences was held May 19th to 25th at the Kardinal Döpfner Haus in Freising, Germany, organized by the two Munich Universities - Ludwig-Maximilians-Universität and Technische Universität München. This international conference continues the illustrious tradition of the original in 1982, which took place in Lake Placid, NY. The series of meetings was initiated by leading, world-renowned experts in the field of ultrafast laser spectroscopy, and is still guided by its founder, Prof. George Atkinson (University of Arizona and Science and Technology Advisor to the Secretary of State). In its current format, the conference contributes to traditional areas of time resolved vibrational spectroscopies including infrared, Raman and related laser methods. It combines them with the most recent developments to gain new information for research and novel technical applications. The scientific program addressed basic science, applied research and advancing novel commercial applications. The thirteenth conference on Time Resolved Vibrational Spectroscopy promoted science in the areas of physics, chemistry and biology with a strong focus on biochemistry and material science. Vibrational spectra are molecule- and bond-specific. Thus, time-resolved vibrational studies provide detailed structural and kinetic information about primary dynamical processes on the picometer length scale. From this perspective, the goal of achieving a complete understanding of complex chemical and physical processes on the molecular level is well pursued by the recent progress in experimental and theoretical vibrational studies. These proceedings collect research papers presented at the TRVS XIII in Freising, German

Advances in Thermoresponsive Polymers

Thermoresponsive polymers, materials able to undergo sharp and often reversible phase separations in response to temperature stimuli, are introducing new paradigms in different fields, including medicine, advanced separations and oil and gas. In "Advances in Thermoresponsive Polymers", a clear picture of the frontiers reached in the understanding of the mechanistic behavior associated with temperature-induced phase separation, the influence of the polymer structure in regulating the macroscopic behavior of these materials and the latest applications for which thermoresponsive polymers show great potential is provided

Non-covalent interactions in organotin(IV) derivatives of 5,7-ditertbutyl- and 5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine as recognition motifs in crystalline self- assembly and their in vitro antistaphylococcal activity

Non-covalent interactions are known to play a key role in biological compounds due to their stabilization of the tertiary and quaternary structure of proteins [1]. Ligands similar to purine rings, such as triazolo pyrimidine ones, are very versatile in their interactions with metals and can act as model systems for natural bio-inorganic compounds [2]. A considerable series (twelve novel compounds are reported) of 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp) and 5,7-diphenyl- 1,2,4-triazolo[1,5-a]pyrimidine (dptp) were synthesized and investigated by FT-IR and 119Sn M\uf6ssbauer in the solid state and by 1H and 13C NMR spectroscopy, in solution [3]. The X-ray crystal and molecular structures of Et2SnCl2(dbtp)2 and Ph2SnCl2(EtOH)2(dptp)2 were described, in this latter pyrimidine molecules are not directly bound to the metal center but strictly H-bonded, through N(3), to the -OH group of the ethanol moieties. The network of hydrogen bonding and aromatic interactions involving pyrimidine and phenyl rings in both complexes drives their self-assembly. Noncovalent interactions involving aromatic rings are key processes in both chemical and biological recognition, contributing to overall complex stability and forming recognition motifs. It is noteworthy that in Ph2SnCl2(EtOH)2(dptp)2 \u3c0\u2013\u3c0 stacking interactions between pairs of antiparallel triazolopyrimidine rings mimick basepair interactions physiologically occurring in DNA (Fig.1). M\uf6ssbauer spectra suggest for Et2SnCl2(dbtp)2 a distorted octahedral structure, with C-Sn-C bond angles lower than 180\ub0. The estimated angle for Et2SnCl2(dbtp)2 is virtually identical to that determined by X-ray diffraction. Ph2SnCl2(EtOH)2(dptp)2 is characterized by an essentially linear C-Sn-C fragment according to the X-ray all-trans structure. The compounds were screened for their in vitro antibacterial activity on a group of reference staphylococcal strains susceptible or resistant to methicillin and against two reference Gramnegative pathogens [4] . We tested the biological activity of all the specimen against a group of staphylococcal reference strains (S. aureus ATCC 25923, S. aureus ATCC 29213, methicillin resistant S. aureus 43866 and S. epidermidis RP62A) along with Gram-negative pathogens (P. aeruginosa ATCC9027 and E. coli ATCC25922). Ph2SnCl2(EtOH)2(dptp)2 showed good antibacterial activity with a MIC value of 5 \u3bcg mL-1 against S. aureus ATCC29213 and also resulted active against methicillin resistant S. epidermidis RP62A

Polyzwitterionic copolymers via polymerization induced self-assembly

In this master's thesis, polyzwitterionic copolymers were synthesized and analyzed with various methods. In the literature part, the theory behind the reactions and results is covered in order to explain the phenomena. In the literature part of the thesis, articles were used to describe the theory as extensively as possible. The theory elaborates on the most important topics considering the research part. The main topics are reversible addition-fragmentation polymerization (RAFT), polymerization-induced self-assembly (PISA), and polyzwitterions. In the reversible addition-fragmentation polymerization chapter the kinetics and possible monomers and RAFT agents are gone through also considering the pros and cons. Different disadvantages are dealt with as well when talking about RAFT polymerization. In the PISA chapter different possible morphologies and different types of PISA polymerizations are covered, concentrating still on RAFT polymerization. In this chapter also core blocks of PISA were discussed covering the core forming block used in the research, diacetone acrylamide. lastly, polyzwitterions were discussed explaining the theory, possible applications, polyelectrolyte complexes, and thermoresponsivity of polyzwitterions. Also, in this part polysulfobetaines were covered since it is the zwitterionic block in the copolymer synthesis. In the experimental part, PSBMA-PDAAM diblock copolymers were synthesized and studied with different methods. Different lengths of block copolymer were synthesized and they were studied with the most common characterization methods. Thermoresponsivity, morphology, and also the effect of the solids content of different block lengths were studied. Measurements turned out to be a success since many different morphologies were witnessed and the thermoresponsive behavior of this copolymer showed interesting results

Amorphous Metal-Free Organic Phosphors for Sensor Applications

Phosphorescent organic light-emitting diodes are promising for many applications such as display and solid-state lighting because they can reach 100% theoretical internal quantum efficiency. In order to realize bright purely organic phosphors, efficiently promoting intersystem crossing from singlet to triplet and suppressing vibrational dissipation of triplets must be achieved. In this dissertation, I systematically investigated the two critical processes and devised some strategies to achieve bright room temperature purely organic phosphorescence in amorphous films and optical ozone sensors based on phosphorescence phenomena. Embedding organic phosphors into amorphous glassy polymer was investigated as the first strategy to efficiently suppress the triplet vibration by restricting molecular motion of the embedded organic phosphors. This system showed temperature dependent phosphorescence attributed to changing vibrational characteristics of the matrix polymer. An optical temperature sensor integrated in a microfluidic device was devised and demonstrated. Incorporating strong hydrogen bonding between a newly devised purely organic phosphor and hydrogen bonding capable matrix polymer was the second strategy, resulting in much brighter phosphorescence. Modulation of hydrogen bonding by water showed unique reversible phosphorescence-to-fluorescence switching behavior, which was utilized to develop a ratiometric water sensor. Based on the finding that the phosphorescence intensity of the purely organic phosphors is sensitive to environmental ozone concentration, I revealed that the origin of the ozone sensitivity is oxidation of the aldehyde moiety of the organic phosphors and devised highly sensitive and convenient optical ozone sensors by utilizing the observed inverse linear correlation between the phosphorescence emission intensity and the ozone concentration. Since manipulating conjugation length of organic phosphors is a powerful tool to tune the emission color, establishing an understanding on the conjugation length effects on the phosphorescent emission intensity is important. The effects of the conjugation length of the purely organic phosphors on their phosphorescence intensity were systematically studied using a combined experimental and computational approach. The obtained knowledge regarding the role of intermolecular interactions for vibration suppression was adapted to achieve high thermal conductivity in amorphous polymers by designing hydrogen bonding donating and accepting polymer pairs, providing uniformly distributed strong interpolymer linkage, and leading to high thermal conductivity of 1.5 Wm-1K-1.PHDMacromolecular Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/111449/1/dongwook_1.pd