Tanja Lahtinen

University of Jyväskylä | JYU · Department of Chemistry

Three novel monomethine cyanine dyes were synthesized carrying electron donating groups to obtain even brighter nucleic acids probes. Photophysical properties of these dyes were evaluated with DNA and selected dyes...

In recent years, the studies of RNA and its use for the development of RNA based vaccines have increased drastically. Although cyanine dyes are commonly used probes for studying nucleic acids, in a wide range of applications, there is still a growing need for better and brighter dyes. To meet this demand, we have systematically studied the structur...

We present a novel strategy for tailoring the fluorescent azadioxatriangulenium (KU) dye-based pH sensor to the target pH range by regulating the pK a value of the gold nanoclusters. Based on the correlation between the pK a and surface curvature of ligand-protected nanoparticles, the pK a value of the gold nanoclusters was controlled by size. In p...

Interactions between an atomically precise gold nanocluster Au102(p-MBA)44 (p-MBA = para mercaptobenzoic acid) and a fluorescent organic dye molecule (KU, azadioxatriangulenium) are studied. In solution, the constituents form spontaneously a weakly bound complex leading to quenching of fluorescence of the KU dye via energy transfer. The KU can be s...

Five nucleic acid binding cyanine dyes were synthesized and their photophysical properties were evaluated. Changing a single heteroatom in the chromophore causes major differences both in brightness and photostability between...

Fluorescent probes for sensing nucleic acids have found widespread use in the field of cell and molecular biology. However, probes combined with potential for post-synthetic conjugation, e.g. for intra-endosomal measurements of RNA, are unavailable. Herein we developed cyanine dyes that can be conjugated to viral capsid or other targets. First, we...

As proof-of-principle of chemically selective, spatially resolved imaging of individual bonds, we carry out electron energy-loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM) on atomically precise, thiolate-coated, gold nanoclusters linked with 5,5′-bis(mercaptomethyl)-2,2′-bipyridine dithiol ligands. The images allow th...

Water-soluble gold nanoclusters with well-defined molecular structure and stability possess particular biophysical properties making them an excellent candidate for biological application as well as for fundamental spectroscopic studies. The currently existing synthetic protocols for atomically monodisperse thiolate-protected gold nanoparticles (Au...

Controlled synthesis of nanostructure oligomers requires detailed understanding of their wet chemistry and the forces driving the polymerization process. In this paper, we report the main factors affecting the reaction yields of a dithiol-induced synthesis of covalently bound nanocluster dimers and oligomers and present a detailed analysis of possi...

We present the self‐assembled structures of atomically precise, ligand‐protected noble metal nanoclusters leading to encapsulation of plasmonic gold nanorods (GNRs). Unlike highly sophisticated DNA nanotechnology, our approach demonstrates a strategically simple hydrogen bonding‐directed self‐assembly of nanoclusters leading to octahedral nanocryst...

We present the self‐assembled structures of atomically precise, ligand‐protected noble metal nanoclusters leading to encapsulation of plasmonic gold nanorods (GNRs). Unlike highly sophisticated DNA nanotechnology, our approach demonstrates a strategically simple hydrogen bonding‐directed self‐assembly of nanoclusters leading to octahedral nanocryst...

Hepatitis E Virus-like particles self-assemble in to noninfectious nanocapsids that are resistant to proteolytic/acidic mucosal delivery conditions. Previously, the nanocapsid was engineered to specifically bind and enter breast cancer cells, where successful tumor targeting was demonstrated in animal models. In the present study, the nanocapsid su...

Monolayer-protected (MP) Au clusters present attractive quantum systems with a range of potential applications e.g. in catalysis. Knowledge of the atomic structure is needed to obtain a full understanding of their intriguing physical and chemical properties. Here we employed aberration-corrected scanning transmission electron microscopy (ac-STEM),...

We report supracolloidal self-assembly of atomically precise and strictly monodisperse gold nanoclusters involving p-mercaptobenzoic acid ligands (Au102-pMBA44) under aqueous conditions into hexagonally packed monolayer-thick two-dimensional facetted colloidal crystals (thickness 2.7 nm) and their bending to closed shells leading to spherical capsi...

We report supracolloidal self-assembly of atomically precise and strictly monodisperse gold nanoclusters involving p-mercaptobenzoic acid ligands (Au102-pMBA44) under aqueous conditions into hexagonally packed monolayer-thick two-dimensional facetted colloidal crystals (thickness 2.7 nm) and their bending to closed shells leading to spherical capsi...

We present the synthesis, separation, and characterization of covalently-bound multimers of para-mercaptobenzoic acid (p-MBA) protected gold nanoclusters. The multimers were synthesized by performing a ligand-exchange reaction of a pre-characterized Au102(p-MBA)44 nanocluster with biphenyl-4,4'-dithiol (BPDT). The reaction products were separated u...

The pK(a) of the p-mercaptobenzoic acid (pMBA) ligands in the Au-102(pMBA)(44) nanocluster was measured by using acid base and IR titration. The observed macroscopic pK(a) = 6.18 +/- 0.05 is significantly more basic than that of free pMBA (pK(a) = 4.16), and the protonation behavior is anticooperative according to the Hill coefficient n = 0.64 +/-...

Worldwide reports over the last few decades have shown that the amount of natural organic matter (NOM) in surface water is continuously increasing, which has an adverse effect on drinking water purification. For many practical and hygienic reasons, the presence of NOM in drinking water is undesirable. Various technologies have been proposed for NOM...

Visualization and tracking of viruses without compromising their functionality is crucial in order to understand virus targeting to cells and tissues, and to understand the subsequent subcellular steps leading to virus uncoating and replication. Enteroviruses are important human pathogens causing a vast number of acute infections, and are also sugg...

Photodynamics of a highly monodisperse sample of a water-soluble gold nanocluster tentatively identified as Au130(pMBA)50 (pMBA = p-mercaptobenzoic acid) was studied by mid-IR transient absorption spectroscopy with visible excitation. The observed long-lived excited states (>1 ns) indicate a molecular behavior of the cluster. By combining the trans...

The title compound, C29H42N4O5·0.5H2O, comprises four structural units. A flexible prop-yloxy unit in a gauche conformation, with a -C(H2)-C(H2)-C(H2)-O- torsion angle of -64.32 (18)°, connects an isoxazole ring and an approximately planar phenyl-oxa-diazole ring system [with a maxixmum devation of 0.061 (2) Å], which are oriented almost parallel t...

Photophysical properties of a water-soluble cluster Au102(pMBA)44 (pMBA = para-mercaptobenzoic acid) are studied by ultrafast time resolved mid-IR spectroscopy and DFT calculations in order to distinguish between molecular and metallic behavior. In the mid-IR transient absorption studies visible or near infrared light is used to electronically exci...

3-Ethyl ester- (1) and 3-carboxylic acid-isoxazole (2) derivatives of an antiviral drug analogue WIN 61893 were synthesized and characterized by X-ray crystallography and NMR spectroscopy. Crystallization experiments afforded two polymorphic structures for the ethyl ester derivative and two solvate structures for the carboxylic acid derivative base...

Energy relaxation dynamics of a gold nanocluster with atomically precise composition, Au-144(SC2H4Ph)(60), is studied by transient mid-IR spectroscopy. The experiment is designed to simultaneously probe electronic and vibrational dynamics by using excitation at 652 nm to prepare an electronic state localized on the gold core (as shown by high level...

The hydrodynamic diameter of Aum(pMBA)n [(m, n) = (102, 44) and (144, 60)] clusters in aqueous media was determined via DOSY NMR spectroscopy. The apparent size of the same (n, m) cluster depends on the counter ion of the deprotonated pMBA(-) ligand as explained by the competing ion-pair strength and hydrogen bonding interactions studied in DFT cal...

The title compound, C18H21BF2N2, is a lipophilic dye based on a BODIPY fluoro-phore backbone, which was developed for microscopic imaging of lipid droplets; the mol-ecule has a planar BODIPY core [dihedral angle between the pyrrole rings = 2.3 (3)°] and two tetra-methyl-ene substituents at the 2,3- and 5,6-positions in a half-chair conformation. On...

Significance Development of precise protocols for accurate site-specific conjugation of monodisperse inorganic nanoparticles to large biomolecules and bionanoparticles is one of the challenges in contemporary bionanoscience and nanomedicine, providing new tools for bioimaging and tracking in biological systems. Here we report a success in labeling...

We have determined vibrational signatures and optical gap of the Au144(PET)60 (PET: phenylethylthiol, SC2H4Ph) nanocluster solvated in deuterated dichloromethane (DCM-D2, CD2Cl2) and in a single crystal. For crystals, solid-state 13C NMR and X-ray diffraction were also measured. A revised value of 2200 cm–1 (0.27 eV) was obtained for the optical ga...

Diffusion ordered NMR spectroscopy (DOSY) was used as an analytical tool to estimate the size of thiol-stabilized gold nanoclusters in solution - namely phenylethanethiol (PET) stabilized Au25(PET)18, Au38(PET)24 and Au144(PET)60. This was achieved by determining the diffusion coefficient and hydrodynamic radius from solution samples that were conf...

The carbon nanotube (CNT) is known to be very sensitive to changes in its surrounding environment. Our study is on the effects of mild, liquid-phase alkali-doping on electronic transport in individual CNTs. We find clear and consistent reversal from p- to n-type behavior, with all seven investigated CNT field-effect transistors (FETs) retaining a s...

Natural organic matter (NOM) is found in all surface, ground and soil waters. During recent decades, reports worldwide show a continuing increase in the color and NOM of the surface water, which has an adverse affect on drinking water purification. For several practical and hygienic reasons, the presence of NOM is undesirable in drinking water. Var...

In the title compound, C14H8F5NO, the dihedral angle between the planes of the pentafluorophenyl and phenyl rings is 18.34 (5)degrees. An intermolecular N-H center dot center dot center dot O hydrogen bond between the amide groups connects these molecules to form an infinite chain through the crystal structure. One weak intermolecular C-H center do...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The title compound, C(23)H(20)O(2), is a precursor of a pyrene-based supra-molecular element for non-covalent attachment to a carbon nanotube. The asymmetric unit contains three independent mol-ecules. The carb-oxy-lic acid group in each of these mol-ecules serves as an inter-molecular hydrogen-bond donor and acceptor, generating the commonly obser...

The title compound, C23H20O2, is a precursor of a pyrene-based supramolecular element for non-covalent attachment to a carbon nanotube. The asymmetric unit contains three independent molecules. The carboxylic acid group in each of these molecules serves as an intermolecular hydrogen-bond donor and acceptor, generating the commonly observed double O...

In the title compound {systematic name: N-[3-(5-aza-2,8,9-trioxa-1-silabicyclo[3.3.3]undecan-1-yl)propyl]pentafluorobenzamide}, C16H19F5N2O4Si, unexpected weak anion...π-type C=O...C(aromatic) interactions form a dimer [O...C distances of 3.096 (3) and 3.036 (3) Å]. These dimers are further connected by a normal N—H...O hydrogen bond [2.955 (2) Å],...

The title compound, C10H8INO2, is an N-substituted phthalimide derivative in which the crystallographic intermolecular contact pattern consists of I� � �I, C—H� � �I, C—H� � �O and aromatic �–� interactions.

The title compound, C10H8INO2, is an N-substituted phthalimide derivative in which the crystallographic intermolecular contact pattern consists of I⋯I, C-H⋯I, C-H⋯O and aromatic π-π interactions. © 2007 International Union of Crystallography All rights reserved.

Ion-selective electrodes (ISEs) were constructed by using spherical hydrocarbons (cyclophanes) as π-coordinating ionophores in solvent polymeric membranes. Four structurally similar cyclophanes, i.e., [2.2.2] p,p,p-cyclophane, [2.2.2]m,p,p-cyclophane, [2.2.1]p,p,p-cyclophane and [2.2.1]m,p,p-cyclophane were studied as ionophores for Ag+. The ion-se...

Small hydrocarbon cyclophanes, such as [2.2.0]m,m,m-cyclophane (20) and [2.2.0]p,m,m-cyclophane (21), are strained analogues of the well-known π-prismand [2.2.2]p,p,p-cyclophane (1). The synthetic route to these molecules is based on well-established cyclophane methodology which offers a general access to a whole family of hydrocarbon cyclophanes....

Ion-selective electrodes (ISEs) were constructed by using spherical hydrocarbons (cyclophanes) as π-coordinating ionophores in solvent polymeric membranes. Four structurally similar cyclophanes, i. e., [2.2.2]p,p,p-cyclophane, [2.2.2]m,p,p-cyclophane, [2.2.1]p,p,p-cyclophane and [2.2.1]m,p,p-cyclophane were studied as ionophores for Ag+. The ion-se...

All-solid-state ion-selective electrodes (ISEs) based on two ionophores with similar structure, i.e., [2.2.2] p,p,p-cyclophane and [2.2.2]m,p,p-cyclophane, were prepared and investigated. The ion-selective membranes were composed of the corresponding ionophore (1%), potassium tetrakis(4-chlorophenyl)borate (0.5%), 2-nitrophenyl octyl ether (65-66%)...

The synthesis of the smaller analogues of the well-known [2.2.2]p,p,p-cyclophane (1) π-prismand were performed ia a well-established pyrolysis route from the corresponding disulfones. In spite of their smaller size and increased rigidity, these cyclophanes showed remarkably similar complexation behaviour with Ag+ ions compared to [2.2.2]p,p,p-cyclo...

All-solid-state ion-selective electrodes (ISEs) based on two ionophores with similar structure, i.e., [2.2.2] p,p,p-cyclophane and [2.2.2]m,p,p-cyclophane, were prepared and investigated. The ion-selective membranes were composed of the corresponding ionophore (1 %), potassium tetrakis(4-chlorophenyl)borate (0.5 %), 2-nitrophenyl octyl ether (65–66...

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

We report the synthesis of a series of new hydrocarbon macrocycles. Following the dithia-phane route, four large rings 3-6 of the cyclophane type containing different numbers of ring atoms were prepared confirming the general applicability of this route compared to alternative macrocyclizations. Cycle 3 is the hydrocarbon analogue to the tetra-lact...

New small concave hydrocarbon cyclophanes were prepared via the well-known HD-2SO2-method. The cyclophanes obtained are isomers of the very well-known [2.2.2]p,p,p-cyclophane, C24H24, a π-prismand efficiently complexing Ag+-ion. X-ray crystal structure determinations showed the bis-sulfide 7 (1,10-dithia[3.3.2]m,p,p-cyclophane) to be helically chir...