Ruslan Ramazanov

• PhD
• PostDoc Position at University of Helsinki

Imidoylamidinate-based heteroleptic bis(2-phenylbenzothiazole)iridium(III) and -rhodium(III) complexes [(bt)2M(N∩N)] (bt = 2-phenylbenzothiazole, N∩N = N′-(benzo[d]thiazol-2-yl)acetimidamidyl (Ir1 and Rh1), N′-(6-fluorobenzo[d]thiazol-2-yl)acetimidamidyl (Ir2), N′-(benzo[d]oxazol-2-yl)acetimidamidyl (Ir3), N′-(1-methyl-1H-benzo[d]imidazol-2-yl)acet...

The manipulation of the photophysical properties of molecular emitters can be realized by composing the close environment of the metal center with the “heavier pnictogen atom” effect. Replacing a nitrogen atom with a heavier phosphorus atom in otherwise isostructural molecular systems results in a significant change of the photophysical parameters....

Applying femto-second time-resolved spectroscopy, we study intersystem crossing times τ(ISC) of two Cu(I) dimers, Cu2Cl2(dppb)2 1 (dppb = 1,2-bis-diphenylphosphino)benzene) and Cu2Cl2(N^P)2 2 (N^P = 2-(diphenylphosphino)-6-methylpyridine) used as powders. Τ(ISC) varies by more than one order of magnitude from 39 ps (1) to 3.7 ps (2). A similar tren...

A novel method for calculating rate constants for internal conversion (kIC) that simultaneously accounts for Duschinsky, anharmonic and Herzberg-Teller effects has been developed and implemented. This method has been applied to robust planar molecules like tetraoxa[8]circulene (4B), free-base porphyrin (H2P) and pyrometene (PM567) with small Duschi...

The luminescent quantum yield of silver-cluster emitters stabilized by short oligonucleotides (AgN-DNA) may be efficiently tuned by replacing nucleobases in their stabilization DNA matrices with analogues. In the present study, we proposed a valuable and straightforward theoretical methodology for assessing the photophysical behaviors emerging in A...

Here, we demonstrate through AFM imaging and CD spectroscopy that the binding of silver ions (Ag⁺) to poly(dGdC), a double-stranded (ds) DNA composed of two identical repeating strands, at a stoichiometry of one Ag⁺ per GC base pair induces a one-base shift of one strand relative to the other. This results in a ds nucleic acid-Ag⁺ conjugate consist...

In this work, we disclose a series of seven quadrupolar centrosymmetric 1,4-dihydropyrrolo[3,2-b]pyrroles (DHPPs) linked to the two peripheral, strongly electron-accepting heterocycles such as benzoxadiazole, benzothiadiazole and benzoselenadiazole. This represents the first study probing the influence of electron-deficient heterocycles, rather tha...

Organic luminescent materials attract growing interest as an elegant solution for sustainable and inexpensive light-emitting devices. Most of them are neutral-emitting molecules with an implicit restriction of 25% internal quantum efficiency due to a spin-forbidden nature of the T 1 → S 0 transition. Utilizing organic radicals allows one to overcom...

The electrochemical production of ammonia from nitrogen (so-called nitrogen reduction reaction - NRR) is one of the key tasks of modern electrochemistry. The use of photo-electrochemical approaches in NRR allows...

Here, we report the synthesis of a new family of extremely efficient TADF three-coordinated gold(I) emitters based on the chelating and bridging abilities of the 1,2,4,5-tetrakis(diphenylphosphino)benzene (tpbz) ligand and the...

Ammonia is one of the most widely produced chemicals worldwide, which is consumed in the fertilizer industry and is also considered an interesting alternative in energy storage. However, common ammonia production is energy-demanding and leads to high CO2 emissions. Thus, the development of alternative ammonia production methods based on available r...

The spatial arrangement of nanoobjects by using DNA is a promising nano-design technology. Polyadenine adhesive tails are increasingly used to anchor functional oligonucleotides on the surface of gold nanoparticles at low pH. Further hybridization of such functional oligonucleotides allows nanoparticles to be organized within the desired design. In...

Deep eutectic solvents (DESs) are one of the most rapidly evolving types of solvents, appearing in a broad range of applications, such as nanotechnology, electrochemistry, biomass transformation, pharmaceuticals, membrane technology, biocomposite development, modern 3D-printing, and many others. The range of their applicability continues to expand,...

Deep eutectic solvents (DESs) are one of the most rapidly evolving types of solvents, appearing in a broad range of applications such as nanotechnology, electrochemistry, biomass transformation, pharmaceuticals, membrane technology, biocomposite development, modern 3D-printing, and many others. The range of their applicability continues to expand,...

We put forward chemically modified asphaltenes, polycyclic aromatic byproducts of deep oil refining, for use as novel low-cost acceptor materials for bulk heterojunction (BHJ) solar cells. The electronic properties of asphaltenes with varying chemical structures are studied by density functional theory (DFT), while the morphology of DFT-selected ca...

The mechanism of fluorescence quenching of the human serum albumin by transferring the energy of the photoinduced electronic excitation from the single tryptophan residue in the structure to the nitrospiropyran donor introduced into its environment is studied by the hybrid computer simulation, including the classical molecular dynamics and the semi...

Nanostructures synthesized using DNA-conjugated gold nanoparticles have a wide range of applications in the field of biosensorics. The stability of the DNA duplex plays a critical role as it determines the final geometry of these nanostructures. The main way to control DNA stability is to maintain a high ionic strength of the buffer solution; at th...

DNA is a convenient and well-studied tool for nanostructures fabrication. Metal-mediated hybridization of DNA strands opens up new possibilities for nanobiotechnology. In this work, we studied the possibility of long DNA formation from short ones by gluing them through the formation of C-Ag ⁺ −C complexes. Such long formations were investigated usi...

We report a biased QM/MM molecular dynamics study of the dissociation process of cytosine-cytosine complexes mediated by Ag⁺ or H⁺ ions in monomeric and dimeric forms. We performed calculations under explicit solvent conditions and obtained the free energy profiles by thermodynamic integration technique to give deep insights on the dissociation pro...

The development of structured molecular systems based on a nucleic acid framework takes into account the ability of single-stranded DNA to form a stable double-stranded structure due to stacking interactions and hydrogen bonds of complementary pairs of nucleotides. To increase the stability of the DNA double helix and to expand the temperature rang...

In this experimental study fluorescent silver clusters on tRNA matrix were synthesized for the first time. Two types of the fluorescent complexes emitting in green (550 nm) and red (635 nm) regions of visible spectrum were obtained. Using FTIR spectroscopy, we identified possible binding sites for the clusters, which appeared to be within the helic...

In this experimental study fluorescent silver clusters on tRNA matrix were synthesized for the first time. Obtained complexes have two emission regions in visible part of spectrum. We have also studied our complexes using FTIR spectroscopy. The possible binding sites of the clusters have been suggested.

We report a biased QM/MM molecular dynamics study of the dissociation process of cytidine-cytidine complexes mediated by Ag+ or H+ ions. We performed calculations under real solvent conditions and obtained the free energy profiles (FEP) by thermodynamic integration technique to give deep insights on the dissociation process. For all geometries corr...

Binding of silver ion (Ag⁺) and two atomic neutral silver cluster (Ag2) with a set of amino acids has been studied using Density Functional Theory (DFT) and ab initio MP2 method. We show that binding energy with Ag2 is higher for deprotonated anionic amino acids. Cysteine, aspartic acid, and tyrosine with deprotonated side chain exhibit the highest...

Luminescent metal nanoclusters (NCs) stabilized by natural proteins are of special interest in bioimaging applications. However, the detailed structure of the protein-templated NCs and the nature of their emissive states remain poorly understood. A fair amount of nonluminescent metal ions and clusters complexed to the proteins hinders probing of th...

The atomic-level understanding of the nature of the electronically excited states in ligand-stabilized metal nanoclusters (NCs) is a prerequisite for the design of new NCs with desired properties. In this study, we investigate the emission dynamics of a Ag-DNA complex using fluorescence up-conversion technique. We show that most of the relaxation f...

The ordered structure of UV chromophores in DNA resembles photosynthetic light-harvesting complexes in which quantum coherence effects play a major role in highly efficient directional energy transfer. The possible role of coherent excitons in energy transport in DNA remains debated. Meanwhile, energy transport properties are greatly important for...

Spectroscopy is an important tool for detecting drug binding to amino acid sequences. One such important spectroscopic process is the fluorescence quenching due to charge transfer (CT) processes between a drug molecule and the chromophore center of Human Serum Albumin (HSA). We present a theoretical investigation of the CT occurring upon electronic...

Rapidly developing field of bionanotechnology requires detailed knowledge of the mechanisms of interaction between inorganic matter and biomolecules. Under the conditions different from aqueous solution, however, chemistry of these systems is elusive and may differ dramatically from the interactions in vitro and in vivo. Here we report for the firs...

Stimuli-responsive metal complexes are extensively studied due to their promising properties for various practical applications. In many cases, stimuli-induced response is provoked by phase transitions, which completely modify electronic properties of chromophoric center to give substantial modification of the phase emissive properties. However, co...

Ligand-stabilized luminescent metal clusters, in particular DNA-based Ag clusters, are now employed in a host of applications such as sensing and bioimaging. Despite their utility, the nature of their excited states as well as detailed structures of the luminescent metal-ligand complexes remain poorly understood. We apply a new joint experimental a...

Luminescent metal clusters are a subject of growing interest in recent years due to their bright emission from visible to near infrared range. Detailed structure of the fluorescent complexes of Ag and other metal clusters with ligands still remains a challenging task. In this joint experimental and theoretical study we synthesized Ag-DNA complexes...

Direct DNA absorption of UVB photons in a spectral range of 290-320 nm of terrestrial solar radiation is responsible for formation of cyclobutane pyrimidine dimers (CPDs) causing skin cancer. Formation of UVB-induced lesions is not random, and conformational features of their hot spots remain poorly understood. We calculated the electronic excitati...

Present work is dedicated to systematic study of equilibrium configurations of gold and silver clusters in size from 2 to 9 atoms. To the lowest energy configurations is performed calculation of electronic excitation spectra. All calculations are carried out within the framework of density functional theory (DFT) using the hybrid B3LYP functional a...

DNA binding to trans- and cis-isomers of azobenzene containing cationic surfactant in 5 mM NaCl solution was investigated by the methods of Dynamic Light Scattering (DLS), Low-Gradient Viscometry (LGV), Atomic Force Microscopy (AFM), Circular Dichroism (CD), Gel Electrophoresis (GE), Flow Birefringence (FB), UV-Vis Spectrophotometry. Light-responsi...

We study the formation and fluorescent properties of silver nanoclusters encapsulated in condensed DNA nanoparticles. Fluorescent globular DNA nanoparticles are formed using a dsDNA-cluster complex and polyallylamine as condensing agents. The fluorescence emission spectrum of single DNA nanoparticles is obtained using tip-enhanced fluorescence micr...

We calculate geometry and electronic excitation spectra of silver clusters containing 1-6 atoms bound to single DNA bases and also to dC3 cytosine oligomer using density functional theory method. We show that planar shaped silver clusters complexed with the bases exhibit nearly forbidden the lowest transitions and weak fluorescence ability. Their c...