In this study, a series of novel luminescent cyclometalated Ir(III) complexes has been synthesized and evaluated for use in unimolecular oxygen-sensing materials. The complexes Ir(C6)(2)(vacac), 1, Ir(ppy)(2)(vacac), 2, fac-Ir(ppy)(2)(vppy), 3, and mer-Ir(ppy)(2)(vppy), 4, where C6 = Coumarin 6, vacac = allylacetoacetate, ppy = 2-phenylpyridine, and vppy = 2-(4-vinylphenyl)pyridine, all have pendent vinyl or allyl groups for polymer attachment via the hydrosilation reaction. These luminophore complexes were characterized by NMR, absorption, and emission spectroscopy, luminescence lifetime and quantum yield measurements, elemental analysis, and cyclic voltammetry. Complex 1 was structurally characterized using X-ray crystallography, and a series of 1-D ((1)H, (13)C) and 2-D ((1)H-(1)H, (1)H-(13)C) NMR experiments were used to resolve the solution structure of 4. Complexes 1 and 3 displayed the longest luminescence lifetimes and largest quantum efficiencies in solution (tau = 6.0 micros, phi = 0.22 for 1; tau = 0.4 micros, phi = 0.2 for 3) and, as result, are the most promising candidates for future luminescence-quenching-based oxygen-sensing studies.

The novel product profile obtained by incubating chiral fluorinated substrate analogues with castor stearoyl-ACP Delta(9) desaturase has been rationalized through a series of labeling studies. It was found that the introduction of the Z-double bond between C-9 and C-10 of the parent substrate occurs with pro-R enantioselectivity--a result that accounts for the observed stereochemistry of oxidation products derived from (9R)- and (9S)-9-fluorostearoyl-ACP. Oxidation of (9R)-9-fluorostearoyl-ACP occurs via at least two rapidly interchanging substrate conformations in the active site as detected by reaction pathway branching induced by deuteration at C-10 and C-11. Hydroxylation and desaturation of this substrate share the same site of initial oxidative attack.