A 330-pL chromatographic bed was fabricated on a glass substrate as part of an electroosmotically pumped microfluidic system. Two weirs within a sample channel formed a cavity in which octadecylsilane (ODS) coated silica beads (1.5-4 microns diameter) were trapped. ODS beads were mobilized into and out of the cavity using electroosmotic flow through a bead-introduction channel which accessed the cavity. This procedure allowed the beads in the cavity to be repeatedly exchanged. A 1 nM solution of a nonpolar analyte (BODIPY 493/503) in buffer was loaded onto the beads for different lengths of time using an electroosmotic flow of 1.2 nL/s. The material retained on the ODS phase was then eluted by electroosmotic flow of acetonitrile with a concentration enhancement of up to 500 times. Capillary electrochromatography was conducted using a similar device. BODIPY and fluorescein were loaded onto a 200-micron-long chromatographic bed and then separated in an isocratic CEC run with an acetonitrile/buffer mobile phase. Complete separation was achieved in less than 20 s with a 2-micron plate height.

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Density Functional Theory (DFT) calculations produce optimized geometries of the complexes [Re(CO)3(bpy)Cl] (1), [Re(CO)3(bpy)(py)](CF3SO3) (2), [Re(CO)3(bpy)(CNx)](CF3SO3) (3), and [Re(CO)(bpy)(CNx)3](CF3SO3) (4), where bpy = 2,2'-bipyridine, py = pyridine, and CNx = 2,6-dimethylphenylisocyanide in their ground and lowest-lying triplet states. The ground-state optimized geometry for the cation of [Re(CO)3(bpy)(CNx)](CF3SO3) (3) results in a Re-C (CNx) bond length of 2.10 Å, a Re-C (CO) bond length trans to CNx of 2.01 Å, and a Re-C (CO) bond length cis to CNx of 1.96 Å which compares favorably to the single-crystal analysis of a Re-C (CNx) bond length of 2.074(4) Å, a Re-C (CO) bond length trans to CNx of 1.971(4) Å, and Re-C (CO) bond length cis to CNx of 1.932(4) Å. The majority of the singlet excited-state energies calculated using Time-dependent Density Functional Theory (TDDFT) and Conductor-like Polarizable Continuum Model (CPCM) are metal-ligand-to-ligand charge transfer (MLLCT) states and are in good agreement with the UV-vis spectral energies for the complexes in ethanol. The complexes exhibit emission both at room temperature and at 77 K except 4 which is only emissive at 77 K. The 77 K emission lifetimes range from 3.9 μs for 1 to 8.8 μs for 3. The emissive lowest-lying triplet state is a (3)MLLCT state for complexes 1-3 but a triplet ligand-to-metal charge transfer ((3)LMCT) state for complex 4. The electronic, electrochemical, thermodynamic, HOMO-LUMO, and emitting-state energy gaps as well as the emission lifetimes increase in the order 1 < 2 < 3. A (3)d-d excited- state, which is located above the (3)LMCT state, accounts for the loss of room-temperature emission for complex 4.

The isocyanide ligand forms complexes with ruthenium(II) bis-bipyridine of the type [Ru(bpy)(2)(CNx)Cl](CF(3)SO(3)) (1), [Ru(bpy)(2)(CNx)(py)](PF(6))(2) (2), and [Ru(bpy)(2)(CNx)(2)](PF(6))(2) (3) (bpy = 2,2'-bipyridine, py = pyridine, and CNx = 2,6-dimethylphenylisocyanide). The redox potentials shift positively as the number of CNx ligands increases. The metal-to-ligand charge-transfer (MLCT) bands of the complexes are located at higher energy than 450 nm and blue shift in proportion to the number of CNx ligands. The complexes are not emissive at room temperature but exhibit intense structured emission bands at 77 K with emission lifetimes as high as 25 micros. Geometry optimization of the complexes in the singlet ground and lowest-lying triplet states performed using density functional theory (DFT) provides information about the orbital heritage and correlates with X-ray and electrochemical results. The lowest-lying triplet-state energies correlate well with the 77 K emission energies for the three complexes. Singlet excited states calculated in ethanol using time-dependent density functional theory (TDDFT) and the conductor-like polarizable continuum model (CPCM) provide information that correlates favorably with the experimental absorption spectra in ethanol.