List of Abbreviations s2

List of Abbreviations bpy 2,2’-bipyridine dppz dipyrido[3,2-a:2’,3’-c]phenazine phen-allox phenanthroline-alloxazine phen-dap phenanthroline-diaminopyrimidine phen-dione 1,10-phenanthroline-5,6-dione phen-dma phenanthroline-dimethylalloxazine phen-pterin phenanthroline-pterin L phen-allox, phen-dap, phen-dma, and/or phen- pterin

1 II II Abstract: A selection of [(bpy)2Ru (L)](PF6)2, [M (L)3]Cl2 (M = II II II Ru or Fe ), and [Cu (L)2](NO3)2 compounds were synthesized. Their characterizations by 1H NMR, infrared, UV/vis, and electrochemical spectroscopy are reported. Extinction coefficients were estimated from UV/vis data, and E and E1/2 values were calculated for electrochemical data. For the purpose of determining II II the role of hydrogen bonding in [M (L)3] and [Cu (L)2] crystals crystallization is desired. Methods are discussed and results seem promising, but x-ray diffraction studies have yet to be completed. II The [(bpy)2Ru (L)] complexes are being investigated as possible DNA intercalators. Additionally, charge transfer reactivity between RuII and ligands and other redox activity of ligands suggest that the complexes synthesized here in could participate in electron transportation reactions.

2 Introduction Molecules capable of intercalating DNA are greatly sought after for numerous biomedical and biochemical applications. Duanomycin and Adriamycin are two drugs currently on the market that utilize DNA intercalation for the treatment of cancers. Extended planar aromatic ring structures are able to intercalate DNA by inserting themselves between base pairs.

II [(bpy)2Ru (dppz)] has been extensively studied for its intercalation capability. To investigate the effect that substitution of dppz has on intercalation four

II [(bpy)2Ru (L)] compounds whose ligand structures are a composite of dppz and various pyrimidines were designed and synthesized. The general structure of

II [(bpy)2Ru (L)], dppz, and the ligand structures are shown in Figure 1. It is yet

II uncertain as to which, if any, of the new [(bpy)2Ru (L)]

N N N'

N General ligand L.

[Ru (bpy) (L)] 2

N N N N N N

N N N N N O N N N O

Dppz Phen-dma Phen-allox

O NH 2

N N N N

N N N NH N N N NH 2 2

Phen-pterin Phen-dap

FIGURE 1. A general representation of the ligands inv0lved in syntheses to be discussed is given along with the actual structures of the ligands. Dppz is shown to illustrate the II inspiration for the ligands’ design and the [(bpy)2Ru (L)] drawing demonstrates the form of these possible intercalators.

3 complexes can intercalate DNA. The substitutions made to dppz to give the new ligands may prevent intercalation by creating too much steric bulk to slide

II between base pairs. Other possible interactions between the [(bpy)2Ru (L)] complexes and a DNA double helix, including hydrogen bonding with a base, groove binding, and electrostatic surface binding with the anionic phosphate backbone of DNA, Figure 2, may be preferred. Intercalation of a DNA strand

QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture.

FIGURE 2. From left to right: an image of a ligand chelated to a metal, M, and intercalating DNA, an example of a molecule groove binding with DNA, and a II suggestion of how [(bpy)2Ru (phen-allox)] could hydrogen bong to guanine in DNA (only a small portion of a DNA strand is shown to clearly demonstrate hydrogen bonds). causes the double helix to lengthen, unwind, and stiffen. There are a number of experimental methods for detecting whether these changes in DNA occur upon

II [(bpy)2Ru (L)] addition. Fluorescence titrations, melting temperature curves, gel electrophoresis, and viscocity titrations are being carried out to examine the

II interactions between [(bpy)2Ru (L)] and DNA. Justification of the synthetic

II pathways for the [(bpy)2Ru (L)] complexes and their characterization data are included in the Results and Discussion section.

II II Like their model [(bpy)2Ru (dppz)], [(bpy)2Ru (L)] undergo metal-to- ligand charge transfer (MLCT) upon photo excitation. The MLCT of

II II [(bpy)2Ru (dppz)] is believed to involve the excitation of a 4d electron on Ru to a low lying * molecular orbital localized on the bpy-like portion of dppz1. Furthermore, pteridines like those incorporated into the ligands (especially phen- pterin) are known to undergo proton transfer/reduction reactions greatly localized on the pyrazine ring2. It is of interest as to whether the MLCT reactions

4 II of [(bpy)2Ru (L)] complexes can correspond with coupled proton/electron transfer reactions of ligands to create electron transfer pathways. Absorption bands in UV/vis measurements may be assigned to MLCT excitations for a

II complex by comparison with [Ru (bpy)3] data and trends for excitation

II III wavelengths. Trends in E1/2 values for Ru Ru oxidation suggest relative stabilizing effects of the various substituents on ligands. Describing light absorbance and redox mechanisms for the ligands requires a much more involved study of the complexes, including molecular orbital modeling and determination of relative energies of available spin states. Thus, the entire set of UV/vis and electrochemical data will not be resolved in this paper.

II The synthesis and characterization studies of [(bpy)2Ru (L)] complexes branched into a separate synthetic study where the ligands are chelated with RuII,

II II II II II II II Fe , and Cu to make [M (L)3] (M = Ru or Fe ) and [Cu (L)2] complexes.

III II MLCT peak assignments in UV/vis spectra and M /M E1/2 values for

II electrochemical spectra were made by comparison with [Ru (bpy)3] and

II [Fe (bpy)3] spectra. There is the possibility that replacing bpy ligands with larger planar ring structures could negatively effect the molecules’ potential electron

II II transfer activity. However, these [M (L)3] and [M (L)2] complexes are of interest for another reason. Through x-ray diffraction analysis of the crystalline complexes it can be determined whether they are polymeric crystals held together by hydrogen bonds between ligands. Shown in Figure 3 are several ways in which these ligands can hydrogen bond to each other and a computer simulation of a possible extended hydrogen-bonded array of molecules.

5 (a) i. ii. H

H O N N N

N N N N H O N

N H N N O N N H N N N O N N H O N H N N N N

H N N N O

iii. N N N N H iv. H

N O N N N N N H H N N H H N H H N N N H N N N N N N O H N N N N H

N N N N H

v. H H

vi. N N N N O N N N

N N N N N N H N N

N O H N O N N H H N N H N H N N

H N N N N

FIGURE 3. (a) Hydrogen bonding interactions between various ligands: i) phen-pterin bonding to phen-pterin; ii) phen-allox bonding to phen-allox; iii) phen-dap bonding to phen- dap; iv) phen-dap bonding to phen-allox; v) phen-pterin bonding to phen-dap; vi) phen-pterin bonding to phen- allox. (b) A simulated extended structure of hydrogen-bound [Ru II(phen- pterin)3] molecules.

6 II II An actual crystal structure for a [M (L)3] or [M (L)2] compound, or a mixture of the compounds has not yet been obtained though crystal growing methods have been explored and are reported. The crystal design proposed in Figure 3 may not be reasonable to expect because it is built with an enantiomerically pure set of molecules and the large gaps that would result in the structure are unlikely to exist without a sizable support to fill them, so the molecules may resort to pi- stacking interactions for crystallization. If the complexes do form hydrogen bound crystal lattices, they may have zeolite-like material sciences applications.

Experimental Section

Materials. Cis-dichloro-bis(bpy)ruthenium (II)Ч2 H2O was obtained from Alfa Aesar. All other reagents were purchased from Aldrich. Ultra high purity acetonitrile/dimethylformamide was purchased from Burdick & Jackson for use in electrochemical measurements. Synthesis of phen-dione followed the procedure according to Yamada et al.3 and synthesis of phen-dma and

II 4 [(bpy)2Ru (phen-dma)] followed procedures 0f Black et al. Methods. 1H NMR spectra were run on a Bruker 300 MHz Fourier

Transform NMR in d6-DMSO (Aldrich). KBr (Aldrich) pellets were made for IR spectra run on a Perkin-Elmer Infrared Spectrophotometer 283. All UV/Vis absorption spectra were taken in a quartz crystal cuvett with a Aligent Technologies UV/Vis Diode Array Spectrophotometer. ESI-MS analyses were done at the university of Arizona. A Bioanalytical Systems, Inc. CV-50W Voltammetric Analyzer was used to make electrochemical measurements. Measurements were taken in a single compartment (5-10 mL samples) cell with a platinum working electrode, a platinum auxiliary electrode, and a silver chloride saturated silver reference electrode. Due to solubility difficulties, a complete set

II II of data for could not be collected for [Ru (phen-pterin)3] and [Ru (phen-dap)3].

-1 1 Phen-dione. IR (KBr): vC=O 1718, 1687 cm . H-NMR (DMSO), ppm (TMS): 7.67 (m, 2H), 8.39 (d, 2H), 8.99 (d, 2H).

7 Phen-allox. 1,10-phenanthroline-5,6-dione (0.8330 g, 4.001 mmol) was added to 5,6-diamino-2,4-dihydroxypyrimidine sulfate (0.6544 g, 4.605 mmol) in 95 mL methanol and heated under reflux for 2 h. The reaction solution was cooled then vacuum filtered using a Buchner funnel. The crude product was recrystallized from 0.5 M HCl (75 mL). Yield 0.8402 g light yellow powder

-1 1 (66.40%). IR (KBr): vC=O 1718, 1703 cm . H-NMR (DMSO), ppm (TMS): 8.15 (m, 2H), 9.3 (d, 2H), 9.46 (d, 2H), 11.96 (s, 1H), 12.42 (s, 1H).

Phen-dma. 1H-NMR (DMSO), ppm (TMS): 3.68 (s, 3H), 3.91 (s, 3H), 7.85 (m, 2H), 9.34 (d, 2H), 9.3 (d, 2H).

Phen-pterin. This ligand was prepared by dissolving 1,10-phenanthroline-5,6- dione (0.831 g, 3.9901 mmol) and 6-hydroxy-2,4,5-triaminopyrimidine sulfate (0.823 g, 3.440 mmol) in ethanol (25 mL), adding sodium acetate (1.502 g) in water (50 mL) and refluxed for 2 h. The reaction solution was cooled then vacuum filtered. The crude product was recrystallized from 2 M HCl (100 mL).

-1 Yield 0.7599 g yellow-orange sliver crystals (70.08%). IR (KBr): vC=O 1596 cm . 1H-NMR (DMSO), ppm (TMS): 8.12 (m, 2H), 9.02 (d, 2H), 9.11 (d, 2H), 10.47 (s, 1H).

Phen-dap. This ligand was prepared similarly to phen-pterin. The crude product was purified by suspension in hot water with addition of NaOH drop wise to promote dissolution. Slow cooling produced a marigold colored product. Yield 0.7826 g marigold colored powder (59.18%). 1H-NMR (DMSO), ppm (TMS): 7.03 (s, 2H), 7.89 (m, 2H), 8.07 (s, 1H), 8.54 (s, 1H), 9.15 (d, 2H), 9.55 (d, 2H).

II 1 [(bpy)2Ru (phen-dma)](PF6)2. H-NMR (DMSO), ppm (TMS): 3.48 (s, 3H), 4.05 (s, 3H), 7.37 (m, 2H), 7.60 (t, 2H), 7.72 (d, 2H), 7.83 (d, 2H), 8.03 (m, 2H), 8.13 (t, 2H), 8.26 (d, 2H), 8.87 (t, 4H), 9.44 (d, 1H), 9.60 (d, 1H).

8 II [(bpy)2Ru (phen-allox)](PF6)2. Ru(bpy)2Cl2 (0.0998 g , 0.1921 mmol) and phenanthroline-alloxazine (0.0429 g, 0.1356 mmol) were combined in ethylene glycol (60 mL) and refluxed for 2 h. The solution was cooled and 60 ml water were added then filtered to remove insoluble impurities. To the orange filtrate was added NH4PF6 until precipitation was complete. Filtration produced a bright orange-red solid. Yield 0.0841 g red-orange powder (70.89%). 1H-NMR (DMSO), ppm (TMS): 7.37 (m, 2H), 7.59 (t, 2H), 7.71 (d, 2H), 7.82 (d, 2H), 8.01 (m, 2H), 8.13 (t, 2H), 8.25 (d, 2H), 8.86 (t, 4H), 9.31 (d, 1H), 9.41 (d, 1H), 12.06 (s, 1H), 12.55 (s, 1H).

II [(bpy)2Ru (phen-dap)](PF6)2. Prepared similarly to Ru(bpy) 2(phen-allox).

0.1002 g (0.1929 mmol) Ru(bpy)2Cl2 and 0.049 g (0.1428 mmol) phen-diamino. Yield 0.0631 g brown powder (50.61%). 1H-NMR (DMSO), ppm (TMS): 7.42 (t, 2H), 7.65 (t, 2H), 8.00 (t, 2H), 8.18 (d, 2H), 8.27 (m, 2H), 8.34 (t, 2H), 8.51 (m, 3H), 8.85 (t, 4H), 9.39 (d, 1H), 9.81 (d, 1H).

II [(bpy)2Ru (phen-pterin)](PF6)2. Prepared according to above preparation for Ru(bpy) 2(phen-allox) with 0.110 g (0.2118 mmol) Ru(bpy)2Cl2 and 0.0448 g (0.1428 mmol) phen-pterin. Yield 0.0092 g olive-brown powder (7.41%). 1H- NMR (DMSO), ppm (TMS): 7.58 (t, 4H), 7.73 (m, 6H), 7.95 (d, 2H), 8.20 (t, 4H), 8.54 (d, 2H), 8.85 (d, 4H), 10.32 (s, 2H).

II III [Ru (phen-allox)3]Cl2. Phen-allox (0.3560 g, 1.125 mmol) and Ru Cl3 (0.0620 g, 0.2989 mmol) were added to ethylene glycol (20 mL), refluxed at 215C for 2 h., and cooled to room temperature. Precipitate was filtered and discarded. Acetone (150 mL) was added drop wise to the filtrate. Precipitate was filtered and washed with 10 mL cold water, 10 mL cold ethanol, 30 mL chloroform, and excess diethyl ether. Yield 0.2461 g orange-red powder (73.45%). 1H-NMR (DMSO), ppm (TMS): 7.93 (m, 2H), 8.31 (d, 2H), 9.33 (d, 2H), 12.02 (s, 1H), 12.55 (broad s, 1H).

9 II [Ru (phen-dap)3]Cl2. Prepared similarly to [Ru(phen-allox)3]Cl2 with phen-

III diamino (0.3610 g, 1.148 mmol) and Ru Cl2 (0.0633 g, 0.3052 mmol). Yield 0.2780 g orange-brown powder (81.70%).

II III [Ru (phen-pterin)3]Cl2. Phen-pterin (0.3564 g, 1.130 mmol) and Ru Cl2 (0.0608 g, 0.2931 mmol) were added to ethylene glycol (20 mL), refluxed at 215C for 2 hr., and cooled to room temperature. Solution was reheated in a r.b. flask for several hours at 220C and then cooled to room temperature. Precipitate was filtered and washed with 10 mL cold water, 10 mL cold ethanol, 30 mL chloroform, and excess diethyl ether. Yield small amount of dark brown powder. 1H-NMR (DMSO), ppm (TMS): 8.14 (dd, 6H), 9.12 (d, 6H), 9.19 (d, 6H).

II [Fe (phen-allox)3]Cl2. Phen-allox (0.1530 g, 0.4837 mmol) was dissolved in

II DMF (50 mL) with sonication. Fe Cl2 (0.0326 g, 0.1640 mmol) was added to the solution with stirring and the color changed from orange to red to deep purple. The solution was filtered and the drop wise addition of ether to the filtrate precipitated purple solid. Yield 0.1213 g dark purple powder (67.78%). 1H-NMR (DMSO), ppm (TMS): 7.95 (m), 9.30 (m, 6H), 9.43 (m, 6H).

II [Fe (phen-pterin)3]Cl2. Prepared by the above method for Fe(phen-allox)3

II with phen-pterin (0.1763 g, 0.5591 mmol) and Fe Cl2 (0.0420 g, 0.2112 mmol). Yield 0.1588 g rosy red powder (80.47%). 1H-NMR (DMSO), ppm (TMS): 7.47 (d, 6H), 7.63 (m, 6H), 8.73 (d, 6H), 10.45 (s, 3H).

II [Fe (phen-dap)3]Cl2. Prepared by the above method for Fe(phen-allox)3 with

II phen-diamino (0.1563 g, 0.4972 mmol) and Fe Cl2 (0.0331 g, 0.1665 mmol). Yield 0.1185 g cherry red powder (66.83%).

II [Cu (phen-pterin)2](NO3)2. Prepared by the above method for Fe(phen-

II allox)3 with phen-pterin (0.1513 g, 0.4798 mmol) and Cu (NO3)22H2O (0.0777 g, 0.3475 mmol). Yield: 0.0651 g bright green powder (33.16%).

10 Results and Discussion Syntheses. Phen-dione was synthesized for the purpose of making the ligands. Previous synthetic pathways for phen-dione included a several step catalysis reaction of 1,10-phenanthroline with Pd. A much shorter synthesis was eventually adopted where in concentrated acid is added to 1,10-phenathroline and NaBr. Further improvements were made to this reaction by Yamada et al. that simplified the process of extracting product such that yield was increased from 60% to 90% and the purity was enhanced, Scheme 1. Best results were

1) con. H SO , con. HNO , 2 4 3

NaBr; 90 C for 2 h

2) neutralize w/H O, NaHCO 2 3

SCHEME 1. Synthesis of phen-dione from 1,10-phenanthroline. obtained the reaction was performed over a single day. The ligands were synthesized by a condensation reaction of the phen-dione and a 5,6- diaminopyridine, Scheme 2.

O H N 2

N O , NaCOOCH N N 3

H N N NH 2 2 NH

H O/EthOH (2:1) solvent, 2

N O reflux 2 hr N N N NH 2

H N 2 NH 2 N

, NaCOOCH N N 3 H N 2 N NH 2 N

H O/EthOH (2:1) solvent, 2

reflux 2 hr N N N NH 2

H N 2 N O

H N N O 2 N N

MeOH solvent,

reflux 2 hr N N N O

H N 2 O NH

N N N O H N 2 H NH

MeOH solvent,

reflux 2 hr N N N O

SCHEME 2. Ligand syntheses from the top down: phen- pterin, phen-dap, phen-dma, and phen-allox.

II The [(bpy)2Ru (L)] complexes needed to be synthesized in high purity for the low concentration DNA intercalation studies. The previous method of synthesis produced compounds that were pure by standards of an old fluorescence spectrometer that has been replaced since the last student worked on this project in 1995. The similar solubilities of each ligand and its

II [(bpy)2Ru (L)] complex made purification of the product unachievable by most methods other an inefficient crystallization. Rather, the approach was to

II synthesize [(bpy)2Ru (L)] with an excess of Ru(bpy)2Cl2, Scheme 3. Hence, cost efficiency

1) ethylene glycol, solvent N N N

220 C, 2 h +2

II Ru + 1.4 eqiv Ru (bpy) Cl 2 2

2) H O, excess NH PF N 2 4 6 N N'

II SCHEME 3. Synthesis of [(bpy)2Ru (L)](PF6)2. was sacrificed for the sake of time because only a small amount of product needed to be synthesized for the DNA intercalation studies. The use of a stoichiometric excess worked to minimize the amount of unreacted ligand to undetectable by the standards of the fluorimeter. The difficulty in chelating the ligands to RuII may be due to the strength of the Ru-Cl bonds that must be broken in Ru(bpy)2Cl2 before ligand chelation can occur. This reaction takes place in a viscous solvent capable of refluxing at about 214C, providing enough heat to

II break the Ru-Cl bonds. The resulting [(bpy)2Ru (L)] products appear to be stable at these temperatures for the two hours. The driving force of the reaction that partly explains such stability is illustrated in Figure 4 with ligand field theory.

II II II [(bpy) Ru L] [Ru L ] Ru 2 3

' delta o

delta o

FIGURE 4. Ligand field theory description of how chelation of phen-ligands stabilize the 4d electrons of low spin octahedral RuII more than Cl-1 by causing a greater split in the energy field ’ (shown as deltao

13 II Syntheses of [Ru (L)3] complexes were carried out by much the same method, Scheme 4, but without a stoichiometric excess of the ruthenium starting

ethylene glycol, solvent N

N N 220 C, 2 h +2 III Ru + 3 equiv Ru Cl 3

II SCHEME 4. Synthesis of [Ru (L)3] complexes.

II material. The chemistry of the reactions is different since the [Ru (L)3] syntheses involve the reduction of RuIII to RuII, as well as breaking Ru-Cl bonds to chelate ligands. It is uncertain how the bond breaking and making is orchestrated in relation to the reduction of the RuIII. Again, the overall stability gained in the product of this reaction can be described by a ligand field theory analysis of the

II Ru 4d electrons in Figure 5. Both [Ru (L)3](PF6)2 and

II II Ru [Ru L ] III III 3 Ru Ru Cl 3

' delta o

delta o

5 6 4d 4d

t 2g t 2g

FIGURE 5. Ligand field theory description of why RuII chelated to phen-ligands is more stable than RuIII bound to Cl-1. The unpaired electron of RuIII is more II II easily excited than any of the lower energy paired electrons of Ru in [Ru (L)3].

14 II [Ru (L)3]Cl2 salts were synthesized. The additional planar ring structures of

II II -1 [Ru (L)3] decreased solubility as compared to [(bpy)2Ru (L)] such that PF6 counterions were unnecessary for product precipitation.

II II The [Cu (phen-pterin)2](NO3)2 and [Fe (L)3]Cl2 syntheses were much simpler and faster than aforementioned syntheses in that chelation occurred immediately upon addition of the CuII or FeII starting material to a ligand solution. The phen nitrogens chelate to CuII in a square planar arrangement. Though there are six coordination sites on square planar CuII, Jaun-Teller distortion of the axial bond lengths allow for chelation of only two phen-pterin

-1 ligands, Figure x, so NO3 or H2O probably occupy the axial coordination cites on the CuII complex. FeII reacts quickly with the phenanthroline nitrogens because they stabilize the arrangement of FeII 3d electrons, similarly to the way in which they were shown to stabilize RuII in Figure 4, and prevent oxidation to FeIII under

II atmospheric conditions. Despite this prediction, the [Fe (L)3] complexes change color in DMF solution to yellow given a day or two to let stand. This behavior was

II first noticed for [Fe (phen-pterin)3] in DMF under regular atmospheric room temperature conditions. It was speculated that the enamine proton of phen- pterin is deprotonated in solution, since this anion is associated a strong yellow

II color. Then [Fe (phen-allox)3] solvated in DMF was found to change color in DMF, making the previous explanation less likely.

1 II NMR and Mass spec. The H NMR spectra of [Ru (phen-allox)3] and

II [Ru (phen-pterin)3] each had one clean set of peaks. Difficulty dissolving

II [Ru (phen-dap)3] prevented the spectrum from being obtained. A single set of

II peaks suggests that the arrangement of three ligands on Ru is facial with a C3 axis of symmetry, Figure 3. The mass spec analyses also imply homoleptic

II structures. A meridial arrangement of [Ru (L)3] would have two identical ligands and a third with a separate set of 1H NMR peaks. The sharpness of the peaks

II III II obtained for [Ru (L)3] compounds indicates that the reduction of Ru to Ru did take place, as RuIII with 5 4d electrons is paramagnetic, Figure 5, and would interfere with the magnetic field of an NMR spectrometer.

15 II 1 The [Fe (L)3] compounds also had H NMR spectra with single sets of

II sharp peaks. To test the whether the color change of [Fe (L)3] solutions was indicative of oxidization to a Fe+3, which would seem to immediately follow the dissociation of these ligands from FeII, an NMR sample was set aside in a dessicator for several days. When the solution finally appeared to change colors from a pinkish red to a pinkish orange a spectrum for the sample was retaken. A double set of peaks appeared, but the peaks remained sharp suggesting that FeII had not been oxidized to FeIII. It remains a mystery as to what exactly is causing

II II the change in color such that [Ru (phen-pterin)3] and [Ru (phen-allox)3] do not experience this in DMF.

UV/vis. A chart of absorbance wavelengths and the corresponding estimated extinction coefficients can be found on pages C13-C14 of the Appendix. Data for the MLCT absorbances of RuII compounds are marked there in. The absorbance

II spectrum for [Cu (phen-pterin)2] serves as a diagnostic tool for symmetry about CuII since the absorbance wavelength for a CuII d-electron excitation is known to be indicative of the complex’s geometry. Absorbance around 700 nm implies a square planar configuration of the ligands about CuII.

Electrochemistry. The electrochemical data, along with the E and the E1/2 values, is presented in Appendix D. This will be considered a preliminary collection of data because certain sets of data are imperfect, which is apparent by the looks of their graphs. A few Ru+3/Ru+2 values are highlighted in Table 1.

16 Compound Ea Ec delta E E1/2

[Ru(bpy)3] 1.29 49 1.38 39 0.08 9 1.33 94

[Ru(bpy)2(dma)](PF6)2 1.52 13 1.56 77 0.04 64 1.54 45

[Ru(bpy)2(pallox)](PF6)2 0.82 35 1.35 5 0.53 15 1.08 925

[Ru(bpy)2(pptn)](PF6)2 1.38 88 1.51 39 0.12 51 1.45 135

[Ru(bpy)2(pdiam)](PF6)2 1.33 73 1.48 54 0.14 81 1.41 135

[Ru(pallox)3]Cl2 0.82 84 1.10 56 0.27 72 0.96 7 TABLE 1. The Ru+3\Ru+2 redox potentials for DMF solutions. E values in Volts.

II II Notice how [(bpy)2Ru (phen-dma)] and and [(bpy)2Ru (phen-phen-allox)]

III II appear to be structurally similar, but have such different Ru /Ru E and  E1/2 values. Hence substitution at the end of a ligand does effect the ability of RuII to be oxidited. This implies that the MLTC, which is thought to change the formal oxidation state of Ru from +2 to +3, could be tuned by deliberate ligand substitutions. As speculation, one might say that the methyl substitution in phen-dma does not allow for a loss of proton and anionization that might be possible for phen-allox. It should be noted in this section that after e-chem experiments had been

II run with [Ru (phen-allox)3], the compound was found cling to the Pt wire electrode. This did not happen for experiments with any of the other compounds tested. Perhaps this behavior has the potential for materials applications.

Crystallization. Compounds were crystallized by first dissolving them in a polar solvent, acetonitrile of DMF depending upon the compound’s solubility, followed by the slow diffusion of a non-polar solvent, ether, into the solution. The most successful set-up is shown in Figure 6. This slowly allows ether vapor

17 FIGURE 6. Lab set-up for solvent diffusion recrystallization. into a vial, in which the compound’s solution is contained, to control the rate at which ether layers on top of and seeps through the solution.

Conclusion The explanation of electrochemical and UV/vis data needs to be given to determine just how promising these complexes are electron transports. A close

II look at this data may also shed light on the color change that the [Fe (L)3] complexes undergo in DMF. It would be beneficial to establish protocalls for enantiomerically pure syntheses of all complexes5. DNA intercalation and lattice structure are two examples of enantiomer-sensitive topics that are currently relevant to this project. The study of metal center effects on the ligands can be

III 6 expanded by the synthesis of [Co (L)3] complexes .

Acknowledgments I’d like to thank my research advisor Dr. Sharon Burgmayer for her guidance of my developing chemistry understanding and for the freedom to explore the melding of my newfound knowledge with intuitive thought. I highly

18 value the attention that all of my professors have spent their time giving to me and I thank them all. I’d also like to thank my peers for their advice, company, and assistance throughout our undergraduate careers. A special thanks to Mary Kim, ’06, for her help with syntheses and to Alanna Albano, ’05, for her correspondence concerning analytical experiments. This research was made possible by the generous funding of Bryn Mawr College, for which I am literally greatly indebted (with no regrets!).

19 Appendices

A. NMR and IR spectra B. Mass spec C. UV/vis spectra D. Electrochemical data

20 Appendix A: NMR and IR spectra

Table of Contents

Phen-dione NMR A1 Phen-dione IR A2 Phen-dma NMR A3 Phen-allox NMR A4 Phen-allox IR A5 Phen-pterin NMR A6 Phen-pterin IR A7 Phen-dap NMR A8

II [(bpy)2Ru (phen-dma)](PF6)2 NMR A9-10

II [(bpy)2Ru (phen-allox)](PF6)2 NMR A11-12

II [(bpy)2Ru (phen-pterin)](PF6)2 NMR A13

II [(bpy)2Ru (phen-dap)](PF6)2 NMR A14-15

II [Ru (phen-allox)3]Cl2 NMR A16

II [Ru (phen-pterin)3]Cl2 NMR A17

II [Fe (phen-allox)3]Cl2 NMR A18

II [Fe (phen-pterin)3]Cl2 NMR A19

21 Appendix B: Mass spec

Table of Contents

II [(bpy)2Ru (phen-dma)](PF6)2 B1

II [(bpy)2Ru (phen-allox)](PF6)2 B2

II [(bpy)2Ru (phen-pterin)](PF6)2 B3

II [(bpy)2Ru (phen-dap)](PF6)2 B4

II [Ru (phen-allox)3]Cl2 B5

II [Ru (phen-diamino)3]Cl2 B6

II [Fe (phen-allox)3]Cl2 B7

II [Fe (phen-pterin)3]Cl2 B8

II [Cu (phen-pterin)2](NO3)2 B9

22 Appendix C: UV/vis Spectra

Table of Contents

II [Ru (bpy)3]Cl2 C1

II [(bpy)2Ru (phen-dma)](PF6)2 C2

II [(bpy)2Ru (phen-allox)](PF6)2 C3

II [(bpy)2Ru (phen-pterin)](PF6)2 C4

II [(bpy)2Ru (phen-dap)](PF6)2 C5

II [Ru (phen-allox)3]Cl2 NMR C6

II [Ru (phen-pterin)3]Cl2 NMR C7

II [Fe (phen-allox)3]Cl2 NMR C8

II [Fe (phen-pterin)3]Cl2 NMR C9

II [Fe (phen-dap)3]Cl2 NMR C10

II [Cu (phen-pterin)2](NO3)2 C11-12 Table of data and ext. coeff. for comp.s C13

23 Appendix D: Electrochemical data

Table of Contents

II [Ru (bpy)3]Cl2 D1

II [(bpy)2Ru (phen-dma)](PF6)2 D2-3

II [(bpy)2Ru (phen-allox)](PF6)2 D4

II [(bpy)2Ru (phen-pterin)](PF6)2 D5-6

II [(bpy)2Ru (phen-dap)](PF6)2 D7

II [Ru (phen-allox)3]Cl2 NMR D8-9

II [Fe (phen-allox)3]Cl2 NMR D10-11

II [Fe (phen-pterin)3]Cl2 NMR D12-13

II [Fe (phen-dap)3]Cl2 NMR D14-15 Phen-dma D16 Phen-allox D17 Phen-pterin D18 Phen-dap D19

Table of data, E, and E1/2 for comp.s D20

24 25 1 Fees, Jorg, W. Kaim, M. Moscherosch, W. Matheis, J. Klima, M. Krejcik, and S. Zalis. Inorg. Chem. 1993 (32), 166. 2 Burgmayer, Sharon J. N., D. L. Pearsall, S. M. Blaney, E. M. Moore, C. Sauk-Schubert. J Biol Inor Chem. 2004 (9), 59. 3 Yamada, Masak, Y. Tanaka, Y. Yoshimoto, S. Kuroda, and I. Shimao. Bull. Chem. Soc. Jpn. 1992 (65), 1006. 4 Black, Kirk J., H. Huang, L. Starks, M. Olson, and M. McGuire. Inorg. Chem. 1993 (32), 5591. 5 Hiort, Catharina, P. Lincoln, and B. Norden. J. Am. Chem. Soc. 1993 (115), 3448. 6 Szafran, Zvi, R. M. Pike, and M. M. Sing. Microscale Inorganic Chemistry: A Comprehensive Laboratory Experience. John Wiley & Sons, Inc: New York, 1991.