Gangamallaiah Velpula

Gangamallaiah Velpula
KU Leuven | ku leuven · Department of Chemistry

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21
Publications
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443
Citations

Publications

Publications (21)
Article
Full-text available
Self-assembled molecular networks (SAMNs) on surfaces evoke a lot of interest, both from a fundamental as well as application point of view. When formed at the liquid-solid interface, precise control over different polymorphs can be achieved by simply adjusting the concentration of molecular building blocks in solution. Significant influence of sol...
Article
Full-text available
The self-assembly of an asymmetric perylene diimide (PDI) with a dove-tailed side chain is investigated after thermal annealing at various temperatures in solid-state. After annealing at low temperatures PDI dimers are formed through hydrogen bonding between the imide and carbonyl groups, together with π–stacking interactions leading to a helical p...
Article
Graphene-based two-dimensional (2D) materials are promising candidates for a number of different energy applications. A particularly interesting one is in next generation supercapacitors, where graphene is being explored as an electrode material in combination with room temperature ionic liquids (ILs) as electrolytes. Because the amount of energy t...
Article
Full-text available
Halogen bonding has emerged as a promising tool in two-dimensional (2D) crystal engineering. Since halogen bonds are similar to hydrogen bonds in a number of aspects, the existing knowledge of hydrogen bonded systems can be applied to halogenated systems. Here we evaluate the applicability of a retrosynthetic approach based on topological similarit...
Article
Full-text available
The self‐assembly of molecular inorganic/organic hybrid building blocks into ordered hierarchical nanomaterials with a tunable morphology is an enormous challenge. Here, we describe the synthesis and characterization of a novel liquid crystalline hydrogen‐bonding hepta(dimethylsiloxane) azobenzene carboxylic acid dimer. This inorganic/organic hybri...
Article
Strong electric fields are known to influence the properties of molecules as well as materials. Here we show that by changing the orientation of an externally applied electric field, one can locally control the mixing behavior of two molecules physisorbed on a solid surface. Whether the starting two-component network evolves into an ordered two-dim...
Article
Full-text available
We report on the design and fabrication of a four-component supramolecular network using the 'core-shell' approach. Each 'core' component templates the formation of an outer 'shell' leading to formation of three concentric 'shells' around the central guest. The 'shells' are formed only in presence of guests thus demonstrating remarkable selectivity...
Article
Structurally well-defined graphene nanoribbons (GNRs) have attracted great interest as next-generation semiconductor materials. The functionalization of GNRs with polymeric side chains, which can widely broaden GNR-related studies on physiochemical properties and potential applications, has remained unexplored. In this work, we demonstrate the bott...
Article
A multistep synthesis of hexa-peri-hexabenzocoronene (HBC) with four additional K-regions was developed through a precursor based on two benzotetraphene units bridged with p-phenylene, featuring pre-installed zigzag moieties. Characterization by laser desorption/ionization time-of-flight mass spectrometry, Raman and IR spectroscopy, and scanning tu...
Article
Full-text available
Dynamically switchable supramolecular systems offer exciting possibilities in building smart surfaces, the structure and thus the function of which can be controlled by using external stimuli. Here we demonstrate an elegant approach where the guest binding ability of a supramolecular surface can be controlled by inducing structural transitions in i...
Article
To understand how the organized structure of the ionic liquids influences the location and mobility of nondipolar solutes, rotational diffusion of 2,5-dimethyl-1,4-dioxo-3,6-diphenylpyrrolo[3,4-c]pyrrole (DMDPP) and 1,4-dioxo-3,6-diphenylpyrrolo[3,4-c]pyrrole (DPP) has been examined in 1-alkyl-3-methylimidazolium (alkyl = ethyl, butyl, hexyl and oc...
Article
Rotational diffusion of a nonpolar solute 9-phenylanthracene (9-PA) and a cationic solute rhodamine 110 (R110) has been examined in a series of 1-alkyl-3-methylimidazolium (alkyl = octyl, decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl) bis(trifluoromethylsulfonyl)imides to understand the influence of alkyl chain length on solute rotation. In...
Article
To understand the influence of organized structure of the ionic liquids on the rotational diffusion of a hydrogen bond donating ionic solute, reorientation times (tau_r) of rhodamine 110 (R110) have been measured in 1-alkyl-3-methylimidazolium ([Rmim+]) based ionic liquids with anions tetrafluoroborate (BF4-) and hexafluorophosphate (PF6-). The vis...
Article
Temperature-dependent fluorescence anisotropies of a nonpolar solute 9-phenylanthracene (9-PA) have been measured in 1-alkyl-3-methylimidazolium-based ionic liquids with anions such as bis(trifluoromethylsulfonyl)imide ([Tf2N-]), tris(pentafluoroethyl) trifluorophosphate ([FAP-]), tetrafluoroborate ([BF4-]) and hexafluorophosphate ([PF6-]) to find...
Article
In an attempt to find out whether the length of the alkyl chain on the imidazolium cation has a bearing on solute rotation, temperature-dependent fluorescence anisotropies of three structurally similar solutes have been measured in a series of 1-alkyl-3-methylimidazolium (alkyl = methyl, ethyl, propyl, butyl, and hexyl) bis(trifluoromethylsulfonyl)...
Article
Full-text available
Photoisomerization dynamics of 3,3'-diethyloxadicarbocyanine iodide (DODCI) has been examined in a series of 1-alkyl-3-methylimidazolium (alkyl = methyl, ethyl, propyl, butyl, and hexyl) bis(trifluoromethylsulfonyl)imides by measuring its fluorescence lifetimes and quantum yields. This study has essentially been undertaken to find out whether the p...
Article
Full-text available
Photoisomerization of two carbocyanine derivatives has been examined in bis(2-ethylhexyl) sodium sulfosuccinate (AOT) reverse micelles to understand the factors that govern this process in the interfacial region of organized assemblies. To this effect, fluorescence lifetimes and quantum yields of 3,3(')-diethyloxadicarbocyanine iodide and merocyani...