I evaluated the potential of isomers of the low molecular weight phosphomonoester naphthyl phosphate as general diagnostic substrates for differentiating between two families of protein phosphatases: the protein-tyrosine phosphatases [PTPs] and the dual-specificity protein phosphatases [DSPs]. Three PTPs, PTP-1B, Tc-PTPa, and PTP-H1, and three DSPs, Cdc-14, VHR, and IphP, were challenged in vitro with alpha-naphthyl phosphate and beta-naphthyl phosphate. Both the DSPs and PTPs readily hydrolyzed beta-naphthyl phosphate. As expected, the DSPs also hydrolyzed alpha-naphthyl phosphate at rates comparable to beta-naphthyl phosphate and two of the PTPs, PTP-1B and Tc-PTPa, hydrolyzed alpha-naphthyl phosphate at a rate one-tenth that of beta-naphthyl phosphate. However, PTP-H1 hydrolyzed both alpha- and beta- naphthyl phosphate at nearly equal rates. Intriguingly, when challenged with radiolabeled phosphoproteins, PTP-H1 was markedly less stringent, by a factor of 40- to 200- fold, than PTP-1B or Tc-PTPa in its selectivity for [32P]phosphotyrosyl- over [32P]phosphoseryl- proteins in vitro. The DSPs and PTPs listed above also were challenged in vitro with free phosphoserine. Each displayed little or no activity towards free phosphoserine. However, the addition of a hydrophobic "handle" to form N-(cyclohexane carboxyl)-O-phospho-L-serine produced a derivative that was hydrolyzed by IphP at rates comparable to that of the avid substrates p-nitrophenyl phosphate and beta-naphthyl phosphate. VHR also hydrolyzed N-(cyclohexane carboxyl)-O-phospho-L-serine, though at a lower rate than IphP. Cdc14 displayed little activity towards N-(cyclohexane carboxyl)-O-phospho-L-serine. The active site of VHR was mapped and amino acid residues potentially involved in binding N-(cyclohexane carboxyl)-O-phospho-L-serine were identified. The amino acid sequence of VHR was aligned with the amino acid sequences of IphP and Cdc14 to identify the nature of the corresponding residues in IphP and Cdcd14. Low molecular weight phosphomonoesters have proven to be effective in vitro indicators of protein phosphatase activity. They also have shown potential as diagnostic substrates for specific subclasses of protein phosphatases. However, neither alpha- and beta- naphthyl phosphate nor N-(cyclohexane carboxyl)-O-phospho-L-serine proved to be universal discriminatory substrates for the functional subgroups within the family of protein-tyrosine phosphatases. Indeed, the probability of identifying such a substrate would appear to be relatively low. / Master of Science

(¤@) Pyrolysis of 1,2-bis(3-methoxy-2-naphthyl)ethene (35) gave polycyclic aromatic hydrocarbons (PAH) 42¡B43¡B44 and 45. In addition, photolysis of 35 gave photocyclic products 50. (¤G) Photolysis of £\-azidotoluene (35) and 2-azido1-(2-furanyl)ethanone(45) gave dimer products benzylbenzene (51)¡B2-(furan-2-carbon-yl)-amino-1-(2-furyl)ethan-one (60) and 2-(2-formylfuranyl)-4-(2-furan-yl)-imidazole (48).

Chapter 1.<br />1-Ethynyl-2-phenyltetramethyldisilanes HCºCSiMe2SiMe2C6H4-p-X [X = NMe2(1.1), Me (1.2), H (1.3), Br (1.4), CF3 (1.5)] are accessible from ClSiMe2SiMe2Cl, BrMgC6H4X and HCºCMgBr in a two step Grignard reaction. The crystal structure of 1.1 as determined by single crystal X-ray crystallography exhibits a nearly planar PhNMe2 moiety and an unusual gauche array of the phenyl and the acetylene group with respect to rotation around the Si-Si-bond. Full geometry optimization (B3LYP/6- 31+G**) of the gas phase structures of 1.1 and 1.3 affords minima for the gauche and the trans rotational isomers, both being very close in energy with a rotational barrier of only 3 – 5 kJ/mol. Experimental and calculated (time-dependent DFT B3LYP/TZVP) UV absorption data of 1.1 – 1.5 show pronounced electronic interactions of the HCºC- and the C6H4X p-systems with the central Si-Si bond.<br /><br />Chapter 2.<br />A family of [( 5-Cp*)Ru( 6-arene)]+ (Cp* = C5Me5) sandwich complexes of 1- and 1,4-substituted phenyl and naphthyl systems are described along with the regioselectivities of the reactions under various conditions. Finally, the (h 5-Cp*) Ru+ arenophile was found to act as a gate to the flow of electrons between para-substituted termini. When it is complexed onto the phenyl or A naphthyl ring, the gate is closed. On the contrary, when it is complexed onto the B naphthyl ring, the gate is open.<br /><br />Chapter 3.<br />Regioselective complexation reactions of the organoiron acetylide derivatives (h 2- dppe)(h 5-Cp*)Fe-C C-Ar (Ar = phenyl, 1-naphthyl; dppe = 1,2- bis(diphenylphosphino)ethane) with [(h 5-Cp*Ru(CH3CN)3][PF6] to afford heterobimetallic complexes formulated as [(h 2-dppe)(h 5-Cp*)Fe-C C-{(h 6-Ar)Ru(h 5- Cp*)}][PF6], were achieved. In the case of the FeII-RuII 1-naphthyl derivative, the (h 5-Cp*)Ru+ arenophile was complexed both onto the substituted ring and free rings of the acetylide 1-naphthyl linker. The first redox-driven h 6-h 6 inter-ring haptotropic migration of the (h 5-Cp*)Ru+ moeity was shown to occur. Crystal structures of all of the seven new iron acetylenes were resolved, including both haptotropomers of the naphthyl compound.<br /><br />Chapter 4.<br />The diorganoiron [{(h2-dpppe)(h5-Cp*)Fe-CC-}2(1,4-naphthyl)] (4.12) was synthesized in good yield in two steps via the vinylidene, and oxidation led to the mixed valence (MV) and iron(III)-iron(III) species in good to excellent yields. This exhaustive empirical study on the family of complexes 4.12[PF6]n (n = 0,1,2) includes a crystal structure for the case in which n = 2. This work clearly establishes good electronic and magnetic communication between the iron centers across the bis(ethynyl)naphthalene bridge. All empirical measurements of these naphthyl compounds reveal that their properties fall between those of known phenyl and anthracenyl derivatives. In some cases, the naphthyl derivative behaves as an average of the phenyl and anthracenyl complexes. For example, the comproportionation constant of the naphthyl species falls at the midpoint between those for the phenyl and anthracenyl compounds. The same is true for the UV absorption maxima in all three oxidation states (Fe[II]- Fe[II], MV, and Fe[III]- Fe[III]). The large electronic (2043 cm-1) and magnetic (-526 cm-1) coupling constants were determined via NIR spectroscopy and SQUID magnetometry, respectively. As for the heterotrinuclear species, the iron(II) acetylene, 4.14B[PF6] [{Cp*(dppe)Fe-C C}2-(h 6 – [1,4-napthyl])RuCp*](PF6), [Cp* = h 5 - C5Me5; Fe = FeII] was prepared in high yields with an adapted, regioselective synthesis via the trinuclear vinylidene. Complete characterization, including a crystal structure, of this sandwich complex reveals that the arenophile perturbs the organoiron ligand more in the bis(iron) than in the previously reported mono(iron) case.

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