We report a SERS-based method for the simultaneous and independent determination of two environmental metallic pollutants, Cu(II) Co(II). This was achieved by exploiting coordination-sensitive Raman bands terpyridine (TPY) derivative detecting transition metal ions. Changes in vibrational SERS spectra dithiocarbamate anchored (TPY-DTC) were correlated as function each ion concentration, with limits detection comparable to those several conventional analytical methods. Simultaneous ultratrace...

The ionic dissociation of H–X acids (X=F, Cl, Br, I) in water was examined by conducting a theoretical study on the properties clusters formed with up to five molecules: X–H(H2O)n (n=1–5). Calculations were done using DFT/B3LYP and MP2 methods conjunction TZVP basis set allowed identification several minima potential surfaces for clusters. Based results, method predicts lower tendency ionization than does method; however, both provide similar results. characteristics terms various parameters...

In this paper, a new partitioning of the complex interaction energy is proposed. This based on decomposition one-electron and exchange-correlation densities into unperturbed deformation densities. Thus, proposed fragmentation can be applied at SCF level post-SCF levels as long corresponding density matrices have been evaluated previously. It provides typical description summation electrostatic, exchange-repulsion, polarization terms. However, method allows splitting up exchange-repulsion...

The photochemistry of a model merocyanine-spiropyran system was analyzed theoretically at the MS-CASPT2//SA-CASSCF(14,12) level. Several excited singlet states were studied in both closed spiropyran and open merocyanine forms, paths to different S(1)/S(0) conical intersections found analyzed. After absorption UV light from form, there are two possible ultrafast routes efficient conversion ground state; one involves rupture C(spiro)-O bond leading form other lengthening C(spiro)-N with no...

We introduce here a simple approach in which cyclodextrin, functionalized with thiols the narrower rim, is assembled onto silver surface of SERS platform composed polystyrene beads coated nanoparticles. Trapping properties fabricated sensor are demonstrated through retention different enantiomers (R,R or/and S,S) hydrobenzoin (HBZ), molecule that has not been reported before because it no affinity for coinage metal surfaces. Further, selective recognition each enantiomer and...

The first example of evolution an iridanaphthalene into indanone through intermediate indenyl is reported, serving as a good starting material to obtain indanones. Two new iridanaphthalenes are obtained by intramolecular C–H activation phenyl ring carbene ligand in [IrCp*{═C(OMe)CH═CPh2}(L)]PF6 (L = PPh2Me, PMe3) complexes. It demonstrated that these complexes can undergo thermal reaction give and 3-phenylindanone.

The nature of the bonding a series gas-phase all-metal clusters containing Al4 unit attached to an alkaline, alkaline earth, or transition metal is investigated at DFT level using Mulliken, quantum theory atoms in molecules (QTAIM), and Hirshfeld iterative (Hirshfeld-I) atomic partitionings. characterization ionic, covalent, metallic bonds done by means charge polarization multicenter electron delocalization. This Article uses for first time Hirshfeld-I indices as well based energy...

Iridanaphthalene complexes are synthesized from the corresponding methoxy(alkenyl)carbeneiridium compounds. The electronic character of substituents on 6-position metallanaphthalene ring is crucial point view stability iridanaphthalene, [Ir[upper bond 1 start]Cp*{=C(OMe)CH=C(o-C[upper end]6H4)(Ph)}(PMe3)]PF6, vs. its transformation to indanone derivatives. Stability studies iridanaphthalene compounds revealed that strong electron donor (-OMe) stabilize while weak (-Me) and withdrawing (-NO2)...

Trans-cinnamaldehyde is a specialised metabolite that naturally occurs in plants of the Lauraceae family. This study focused on phytotoxic effects this compound morphology and metabolism Arabidopsis thaliana seedlings.To evaluate phytotoxicity trans-cinnamaldehyde, dose-response curve was first performed for root growth process order to calculate reference inhibitory concentrations IC50 IC80 (trans-cinnamaldehyde inducing 50% 80% inhibition, respectively). Subsequently, structure...

Molecular tweezers are simple molecular receptors that can be characterized by the presence of two flat pincers separated a more or less rigid tether. They have ability to form complexes with substrate molecule gripping between tips in similar manner mechanical tweezers. Klärner et al. synthesized one structurally simplest tweezers, which is reported bind electrodeficient aromatic and aliphatic substrates as well organic cations. Complexes these electron-rich aromatic, aliphatic, anionic not...

An analytical function representing the energy of interaction in acetone dimer was constructed on basis ab initio (MP2/6-31+G*) calculations for 327 configurations. The inclusion electron correlation essential satisfactory reproduction experimental data, as avoidance set superposition error by means counterpoise method. potential fitted to data using a weighting scheme favoring good fit low-energy regions. minimum function, −4.83 kcal/mol, corresponds C2h symmetry which monomers are...

A comprehensive B3LYP/6-31G** study of various thermal cheletropic decarbonylations was conducted. The complete pathway for each reaction determined, and changes in magnetic susceptibility its anisotropy were monitored with a view to estimating the aromatization associated process. This information, together energy structural results, allowed us clarify cases that are not clearly pseudopericyclic or pericyclic from previous work. Also, our results reveal reactions involve no disconnection...

An ab initio study was performed in clusters up to four H(2)S molecules and benzene using calculations at MP26-31+G(*) MP2/aug-cc-pVDZ levels. Differences between both sets of show the importance large basis describe intermolecular interactions this system. The obtained binding energies reflect that has not same behavior as water, pointing a higher solubility molecule than water. Bz-cluster energy fitted an asymptotic representation with maximum value -8.00 kcal/mol converges cluster 12...

[reactions: see text] Electrocyclization reactions of (3Z)-1,3,5-hexatrienone and nitrogen derivatives were studied by performing density functional theory (DFT) calculations together with the 6-31+G* basis set. Reactants, products, transition states for each reaction localized IRC connecting reactants products was also obtained. Magnetic properties evaluated along path to elucidate characteristics studied. As obtained from calculations, electrocyclization is a pericyclic process, as...

Abstract An intramolecular NEMO potential is presented for the N‐formylglycinamide molecule together with an intermolecular N‐formylglycinamide‐water system. The can be used as a building block backbone of polypeptides and proteins. Two minima have been obtained. One, denoted C5, stabilized by hydrogen bonded five member ring, other, C7, corresponds to seven membered ring. interaction between one water system also studied compared Hartree‐Fock SCF calculations results obtained some more...

A comprehensive B3LYP/6-31+G* study on the electrocyclization of 1,2,4,6-heptatetraene analogues was conducted. Starting from cyclization (2Z)-2,4,5-hexatrienal, a pericyclic disrotatory process favored by assistance electron lone pair, we incorporated small modifications in its molecular structure to obtain truly pseudopericyclic process. To this purpose electronegative atoms (fluorine and nitrogen) were added give more electrophilic character carbon atom which is attacked pair oxygen atom....

Abstract Ab initio complete optimizations at MP2/6‐31++G** level have been performed in the T‐shaped geometry of benzene–benzene and benzene–naphthalene complexes. To check effect basis set superposition error (BSSE), done BSSE corrected uncorrected potential energy surfaces. The calculation Hessian has also evaluated to its influence frequency values. Quantum theory atoms molecules (QTAIM) calculations on both dimers. Intermolecular energies differ around a 25% when optimization is with or...

A combined quantum chemical statistical mechanical method has been used to study the solvation of urea in water, with emphasis on structure urea. The model system consists three parts: a Hartree-Fock core, 99 water molecules described polarizable force-field, and dielectric continuum. free-energy profile along transition from planar nonplanar is calculated. This mode aqueous solution found be floppy. That is, not well-defined because requires an energy order thermal at room temperature. We...

The iridium methoxycarbene [IrCp*Cl{═C(OMe)CH═CPh2}(PPh2Me)]PF6 (3) can undergo a clean attack by nucleophiles at least two different pathways: (1) an unusual nucleophilic of primary, secondary, and tertiary amines the sp3 carbon–oxygen bond, which gives acyl complex amine alkylation (2) ammonia carbenic carbon, forms primary aminocarbene.

An intermolecular potential for a formaldehyde dimer that includes many body effects was constructed from the monomer properties and perturbation theory calculations. The interaction energy calculated as sum of various terms with physical significance. A global minimum Cs symmetry similar to arrived at experimental calculations predicted dimer; its energy, −3.82 kcal/mol, is comparable provided by ab initio MP2/6-31G++(2d,2p) (−3.54 kcal/mol). Stationary points trimer were preliminarily...