Bleeding through… compositional processes in the integration of Middle Eastern and Western art music

This thesis consists of a portfolio of 10 compositions accompanied by a written commentary with audio and video recordings of my works. These compositions span a wide variety of instrumentations from large orchestral works to solo instrumental works, of both Western and Eastern traditions, as well as vocal and live art installation pieces. Throughout the commentary I explore the continuum of how Eastern traditional idioms and Western art music play a role in the creation of my musical language. This includes an overview of the history of bi-cultural integration and an exploration of the motivations for integrating musics, both in my own work and that of other composers. I explore particular parameters within my works, focusing on the spectrums between composition and improvisation, the concepts of translation and transcription and collaborative practice with Western classical and musicians of Eastern traditional music. Additionally, I examine how my application of Eastern musical parameters and techniques are filtered through four of my other interests and influences: namely, my development of a gestural and timbral language which stems from an engagement with my approach to pitch and harmony

Crystal Engineering with 2‑Aminopurine and 2,6-Diaminopurine Derivatives: Dimers, Metallaquartets, and Halide-Bridged Clusters

Design, synthesis, and single crystal structure elucidation of modified purine ligands 2-(2-amino-9<i>H</i>-purin-9-yl) acetic acid (<b>L1</b>) and 2-(2,6-diamino-9<i>H</i>-purin-9-yl) acetic acid (<b>L2</b>) and their interaction with certain d¹⁰ transition metal ions is described. Copper complex <b>1 </b>(C₂₈H₃₄Cu₂N₂₂O₁₉) afforded a two-dimensional polymeric structure composed of metallaquartets, while corresponding silver complex <b>2 </b>(C₁₄H₂₀AgN₁₀O₈) was formed as a discrete dimer. Complexes <b>3 </b>(C₁₄H₂₄CdN₁₀O₁₀) and <b>5 </b>(C₁₄H₂₂CdN₁₂O₈), cadmium complexes of <b>L1</b> and <b>L2</b>, respectively, afforded different coordinating modes, where <b>3</b> resulted in a two-dimensional (2D) polymeric structure consisting of metallaquartets and <b>5</b> as a discrete dimeric structure, with an octahedral coordination geometry. Complex <b>4 (</b>C₁₄H₁₃Cl₁₃Hg₆N₁₀O₈) afforded a unique hexanuclear, 2D polymeric structure, supported by mercury-chloride bridges, presenting as interconnected dimeric, trimeric, and hexameric mercury halide (μ_2double, μ_3triple, and μ_6six) clusters. The potential of halide ions as bridges is interesting. We have also studied the fluorescence properties of ligand <b>L1</b> and <b>L2</b> along with complexes <b>1</b>–<b>5</b>

Crystallographic Signatures of <i>N</i>⁶-Methoxyadenine Imino Tautomer–Silver Complexes

Detailed crystallographic analysis of four silver complexes of <i>N</i>9-benzyl-<i>N</i>⁶-methoxyadenine, <b>1</b>, on the basis of three different counteranions and silver ion stoichiometry, is discussed in this article. <b>1</b> is a rare tautomer of adenine, which exhibits promutagenic behavior as it partly mimics hydrogen bond donor and acceptor properties of guanine and mispairs with cytosine. Complexes <b>2</b> and <b>4</b> exhibit discrete Ag₂L₂ dimer, while complex <b>3</b> shows two AgL₂ units in addition to a Ag₂L₂ dimer, all in a head-to tail fashion. Complex <b>5</b>, on the other hand, shows four AgL₂ units coordinated in a head-to-head fashion affording a three-dimensional lattice stabilized by CH···F interactions. Various noncovalent interactions such as hydrogen bonding, CH-π interactions, argentophilic interactions, and Ag-π interactions stabilize these complexes

Role of Core–Shell Formation in Exciton Confinement Relaxation in Dithiocarbamate-Capped CdSe QDs

The possibility of exciton delocalization in alkyldithiocarbamate (ATC)-capped CdSe has been investigated for several alkyl groups and compared with phenyldithiocarbamates (PTCs). We find a bathochromic shift for ATC similar to the one obtained for PTC. Our computational studies show reduction in HOMO–LUMO gaps in both PTC and ATC, albeit with a lower shift. However, TDDFT studies revealed that ATC-capped CdSe is more of a localized HOMO state as compared with partly delocalized HOMO in PTC-capped CdSe, hinting at a difference in electronic interaction between the two binding groups. We hypothesized the formation of sulfide layer over the CdSe QDs as the possible reason for the observed bathochromic shift, as verified by absorption spectra of S^2– ligand exchange samples. The formation of CdS shell leads to substantial electron delocalization because CdSe CB is in close resonance with CdS, which is exactly the opposite of what was previously concluded in the literature

Crystallographic Signatures of <i>N</i>⁶-Methoxyadenine Imino Tautomer–Silver Complexes

Detailed crystallographic analysis of four silver complexes of <i>N</i>9-benzyl-<i>N</i>⁶-methoxyadenine, <b>1</b>, on the basis of three different counteranions and silver ion stoichiometry, is discussed in this article. <b>1</b> is a rare tautomer of adenine, which exhibits promutagenic behavior as it partly mimics hydrogen bond donor and acceptor properties of guanine and mispairs with cytosine. Complexes <b>2</b> and <b>4</b> exhibit discrete Ag₂L₂ dimer, while complex <b>3</b> shows two AgL₂ units in addition to a Ag₂L₂ dimer, all in a head-to tail fashion. Complex <b>5</b>, on the other hand, shows four AgL₂ units coordinated in a head-to-head fashion affording a three-dimensional lattice stabilized by CH···F interactions. Various noncovalent interactions such as hydrogen bonding, CH-π interactions, argentophilic interactions, and Ag-π interactions stabilize these complexes

Tuning Interfacial Charge Separation by Molecular Twist: A New Insight into Coumarin-Sensitized TiO₂ Films

The 7-aminocoumarin class of dyes exhibits significant molecular twisting in their electronic excited state, which has important consequences on the reaction mechanism involving the intramolecular charge-transfer (ICT) state. In this work, the relationship between the molecular structure of coumarin dye and charge separation on TiO₂ surface has been explored using 7-(di­alkyl­amino)­coumarin-3-carboxylic acid dyes C343 and D1421. The alkylamino group in the form of tethered constraint geometry of the julolidyl ring of coumarin C343 and rotation free geometry of 7-<i>N,N</i>′-di­ethyl­amino moiety of coumarin D1421 compel planar and twisted ICT (TICT) excited states in polar solvents, respectively. The femtosecond transient absorption studies show that both the charge-transfer states participate in directional electron injection from coumarin dye into the conduction band of the TiO₂ semiconductor substrate. The TICT state formation in the excited state minimizes the donor and acceptor orbital overlap and causes slow back electron-transfer reaction. Current–voltage and incident photon-to-current efficiency measurements verify the beneficial electronic decoupling of the TICT state producing superior photovoltaic response of dye-sensitized solar cells based on coumarin D1421. This work presents tuning of interfacial charge separation by molecular twist at the electron-donating site in D-π-A dye/TiO₂ systems

Crystal Engineering with 2‑Aminopurine Containing a Carboxylic Acid Pendant

This article reports synthesis, design, and luminescent properties of a series of structurally interesting coordination frameworks prepared from a modified purine ligand, 3-(2-amino-9<i>H</i>-purin-9-yl) propanoic acid (<b>L</b>). Corresponding transition metal complexes reported in this study were unambiguously characterized by X-ray crystallography to reveal an array of diverse crystallographic signatures reflecting crystal design around varying coordination geometries of a central metal ion. While silver complex <b>1</b> [C₁₆H₁₈Ag₂N₁₀O₅] affords formation of coordination framework with embedded dimeric, tetrameric, and pentameric metallacycles, corresponding copper complexation results in a discrete dimer <b>2</b> [C₃₂H₄₆Cl₂Cu₂N₂₀O₁₄]. Changing the counteranion from strongly coordinating chloride ion to weakly coordinating perchlorate anion resulted in the formation of a 1D coordination polymer <b>3</b> [C₁₈H₂₆Cl₂CuN₁₀O₁₄]. Cobalt complexes <b>4</b> [C₁₆H₃₂CoN₁₀O₁₂] and <b>5</b> [C₁₆H₃₀CoN₁₂O₁₆] yielded 2D grid-type assembly and a discrete dimer, respectively. Change in pH offered an interesting effect on the structural outcome of cadmium complexes: acidic and neutral conditions lead to the formation of 1D coordination polymer <b>6</b> [C₈H₁₂CdCl₂N₆O₆] and <b>7</b> [C₁₆H₂₄Cd₂N₁₂O₁₄], while basic conditions yielded an unusual porous metal organic framework <b>8</b> [C₉H₁₅CdN₅O_5.5]

Ion Channel-like Crystallographic Signatures in Modified Guanine–Potassium/Sodium Interactions

This communication describes crystallographic details of structures reminiscent of ion channels, formed from regioisomeric N7 and N9 guanine-carboxylate conjugates with potassium/sodium ions and their subsequent STM observations on Au(111) surface. Ion channel-like crystal structures were obtained with the observation of a notable shift in metal ion coordination from carbonyl to carboxylate oxygen. These results are expected to provide insight into competing sites for modified guanine–metal coordination, an entry into guanine-based ion channels and a route toward guanine-functionalized surfaces

Charge Separation by Indirect Bandgap Transitions in CdS/ZnSe Type-II Core/Shell Quantum Dots

Femtosecond time-resolved absorption and picosecond time-resolved emission studies have been carried out to study the indirect type exciton of CdS/ZnSe core/shell quantum dots (QDs). The CdS/ZnSe core/shell QD samples are synthesized with increasing thickness of ZnSe shell on CdS core QDs. In these CdS/ZnSe core/shell samples, a new energy band lower than the energy gap of both the CdS core and ZnSe shell has been observed and attributed to indirect bandgap transitions from the valence band of the ZnSe shell to the conduction band of the CdS core. The transient PL studies have revealed that the indirect type exciton, e­(CdS)/h­(ZnSe) due to photoexcitation of this low-energy band, endures less carrier trapping than selective excitation of the CdS core and charge transfer in the staggered photoexcited state. Femtosecond transient absorption studies have revealed that carrier trapping is as fast as 100 fs and interfacial charge recombination slows down with increasing ZnSe shell thickness on the CdS QD in CdS/ZnSe core/shell QDs

Size Quantization Effects on Interfacial Electron Transfer Dynamics in Ru(II)–Polypyridyl Complex Sensitized ZnO QDs

Quantum-size confinement in semiconductor material offers size based tunability of interband gap energy as well as intraband sublevels. In this work, size quantization of wide bandgap ZnO quantum dots has been explored in the study of interfacial charge separation reaction using a catechol functionalized Ru­(II)–polypyridyl complex as a photosensitizer molecule. Femtosecond time-resolved transient absorption studies have revealed multiple electron injection events based on discrete conduction band states of ZnO QDs. The electron injection rates have been rationalized for quantum confinement effects owing to different sizes of ZnO QDs. Furthermore, the size dependency of the intrinsic lifetime of electrons injected into discrete energy levels of ZnO QDs has been revealed in charge recombination reaction with the Ru­(III)–polypyridyl complex cation. The charge recombination dynamics reveals a competing trend of carrier confinement and carrier leak upon reducing particle size. This study shows the optimization of finite size effects in achieving better interfacial charge separation at the dye/semiconductor interface