We demonstrate in this study the application of square-wave voltammetry (SWV), an electrochemical technique that has been commonly employed in electroanalysis but much less utilized in electrocrystallization, in the shape-invariant size-tuning of the electrodeposited cuprous oxide (Cu2O) crystalline cubic particles from ∼30 nm to 3 μm in aqueous solution under ambient conditions without using any organic surfactant and surface capping agent. We show systematically how each and every adjustable parameter in SWV technique affects the size-tuning of Cu2O nanocubes under shape invariance. A systematic comparison was made between SWV and several other EC techniques, including linear-sweep voltammetry (LSV), stair-case voltammetry (SCV), chronoamperometry (CA or simple i vs t), square-wave chronoamperometry (SWCA), and differential pulse voltammetry (DPV), for the shape-invariant electrodeposition of crystalline Cu2O nanocubes. The as-fabricated Cu2O nanocubes were employed as the size- and shape-controlled galvanic templates to fabricate Cu2O@Ag core–shell structures which display excellent performance in “single-particle” surface-enhanced Raman spectroscopy (sp-SERS).

We report a facile method for the fabrication of 2-dimensional networks of Au nanoparticle−nanocavity dual structures supported on dielectric nanosieves. The optical extinctions of the as-fabricated network films were found to be dominated by optical transmission, a signature characteristic to nanocavities. The surfaces of the as-fabricated Au films were found to be hydrophobic toward water with a measured contact angle of 125.4° but quite wettable with ethanol with a contact angle of 9.5° at room temperature and are readily convertible to totally hydrophobic or hydrophilic when chemically modified with self-assembled monolayer of molecules with desired functional groups. High quality surface-enhanced Raman spectra (SERS) from a monolayer of self-assembled 4-mercaptobenzoic acid (4-MBA), an electrostatic double layer of 4-mercaptobenzoic acid and rhodamine-6G (4-MBA-R6G), and nonspecifically adsorbed R6G were obtained, respectively, demonstrating that the dual structured network films are active, stable, and uniform as substrates in SERS. Employing the SERS spectra from a monolayer of self-assembled 4-MBA, the enhancement factors of 106 and 105 were achieved with excitations at 632.8 and 785 nm, respectively. Discrete dipole approximation (DDA) calculations were conducted to examine the electric field intensity distributions on linearly and circularly aggregated nanoparticles, two typical local aggregation patterns of nanoparticles in the as-fabricated network films. The DDA calculations reveal an important relationship between three factors: the generation of the hottest E-field spot on a linear chain aggregate, the position of the extinction peak of the aggregate, and the excitation wavelength used. It was found that the hottest spot on a linear aggregate is generated only when the excitation wavelength is in resonance with the extinction peak of the aggregate. An “effective aggregation number” scale is proposed to measure the effectiveness of the aggregation of nanoparticles in 1- and 2-dimensions at a given excitation. A “hot-spot” delocalization picture is proposed for the nanocavities formed by circular aggregation of nanoparticles to account for the observed isotropic SERS on the as-fabricated films.

The highly bulky bis-pocket corrole 5,10,15-tris(2,4,6-triphenylphenyl)corrole (H3TTPPC) has been synthesized. Resonance Raman spectroscopy revealed a triply bonded Mn≡O moiety in its manganese(V)−oxo complex. Direct oxygen atom transfer from (TTPPC)Mn≡O to styrene was confirmed by an 18O-labeling experiment. The (TTPPC)MnIII complex also exhibits significant shape selectivity in the catalytic epoxidation of nonconjugated dienes.

Two asymmetric tridentate copper(II) complexes, [Cu(dppt)Cl2] · 0.25H2O (1) (dppt=3-(1,10-phenanthrolin-2-yl)-5,6-diphenyl-as-triazine) and [Cu(pta)Cl2] (2) (pta=3-(1,10-phenanthrolin-2-yl)-as-triazino[5,6-f]acenaphthylene), have been prepared and characterized by elemental analysis, IR and Fast atomic bombardment mass spectra. Complex 1 has also been structurally characterized. The complexes exist as distorted square pyramid with five co-ordination sites occupied by the tridentate ligand and the two chlorine anions. DNA interaction studies suggest that the ligand planarity of the complex has a significant effect on DNA binding affinity increasing in the order [Cu(dppt)Cl2] < [Cu(pta)Cl2]. In the presence of ascorbate or glutathione, the two complexes are found to cause significant cleavage of double-strand pBR 322 DNA and [Cu(pta)Cl2] exhibited the higher cleaving efficiency.

The surface-enhanced Raman scattering (SERS) of C60 adsorbed on aqueous gold colloid was reported for the first time. We used the pyridine molecule as a intermediate to connect and fix the C60 molecule to the surface of the golden crystal nanoparticle. The enhancement factor is 104. Not only was the number of vibrational modes greatly increased, but also were the significant Raman bands splitted as well as frequencies up and down shifted, respectively, arising from symmetry lowering and selection rule relaxing of C60 induced by the gold surface. The splittings of the Raman modes is consistent with the calculation based on group theory.

Three novel asymmetrical tridentate ligands, 3-(1,10-phenanthrolin-2-yl)-5,6-diphenyl-as-triazine (dppt), 3-(1,10-phenanthrolin-2-yl)-as-triazino[5,6-f]acenaphthylene (pta) and 3-(1,10-phenanthrolin-2-yl)-as-triazino[5,6-f]phenanthrene (ptp) have been prepared. Their homoleptic ruthenium complexes [Ru(L)2]2+ (L = dppt, pta or ptp) and heteroleptic ruthenium complexes [Ru(tpy)(L)]2+ have been synthesized and characterized by 1H NMR, ES-MS, electronic absorption spectroscopy and cyclic voltammetry. The heteroleptic ruthenium complexes were also characterized by X-ray crystallography. The electrochemical and spectroscopic studies of the complexes display the changes in properties in comparison with [Ru(tpy)3]2+ owing to the structural differences.

Mono-, di- and tetra-nuclear ruthenium(II) complexes containing 2,2′-p-phenylenebis(imidazo[4,5-f]phenanthroline) (H2bpib) have been synthesized and characterized. Electrochemical and UV/Vis data show that the first redox process in these complexes is bipyridine based and the metal–metal interaction in di- and tetra-nuclear complexes is very weak. Resonance Raman spectra provide direct evidence for a low-energy bipyridine to H2bpib charge-transfer transition. Furthermore, the non-linear optical properties of the ruthenium(II) complexes were investigated by Z-scan techniques with 12 ns laser pulses at 540 nm, and all of them exhibit both NLO absorption and self-defocusing effect. The corresponding effective NLO susceptibilities |χ3| of the complexes are 5.76 × 10−12–21.06 × 10−12 esu.