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Department of Chemistry

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1 Department of Chemistry
Synthesis and Characterization of bis(2-hydroxyethyl)dithiocarbamate complexes of Zinc, Mercury, Uranium, Lead, Chromium, and Calcium Gregory Trzcinski Department of Chemistry McDaniel College February 27, 2009

2 Overview Introduction Why this ligand? Why these metals?
Facts on metals What type of analyses? “The Big Nine” Syntheses Ligand Proposed Mechanism Metal complexes Self Assembly Results/Discussion Conclusion Future Work Questions?

3 Why this ligand? Increased interest
Analytical agents Medicinal drugs Known treatment for heavy metal and organometallic cation poisoning Known metal binding capacities Potassium bis(2-hydroxyethyl)dithiocarbamate

4 Why these metals? Interested in the metals
Recognized toxicity in sufficient amounts Availability In the environment In reagents More complete study of Zinc and Mercury started by Pages et al.

5 Calcium Essential Most abundant metal in the body
Body needs a constant level Muscle contractions Daily recommended amount ~1000mg Excess can lead to health concerns Decreased absorption of other metals  

6 Chromium Essential in trace amounts Adequate intake ~35μg
Found in two forms 3+, biologically active, and 6+, toxic Few adverse effects

7 Zinc Essential Variety of cellular functions Adequate intake ~11mg
Excess can lead to health concerns Decrease of HDL Toxicity has led to deficiencies in other essential metals

8 Mercury Non-essential, toxic
Vaporizes at ambient temperature and pressure Vaporized form can remain in the air for up to a year Deposited all over the world

9 Uranium Non-essential Used in power plants
Depleted uranium most common Byproduct Military use 90μg is present in body Increased use can be hazardous

10 Lead Non-essential Very toxic Typically found in paint
More readily absorbed by children Myriad of health concerns

11 “The Big Nine” Melting Point (in Celsius) Yield (in grams)
Percent Yield 1H Nuclear Magnetic Resonance spectroscopy (NMR) 13C NMR Infrared Spectroscopy (IR) Ultraviolet-Visible Spectrophotometry (UV-Vis) Mass Spectrometry (Mass Spec): Electrospray + or - Elemental Analysis

12 What to look for and accomplish?
The presence of the metal in the resultant complexes Theorize a structure for each complex

13 Ligand Synthesis KOH 2. 1. CS2 DEA 3. K[bhedtc]

14 Proposed Mechanism

15 Complex Syntheses K[bhedtc] in H2O CaCl2 in EtOH HgCl2 in MeOH
ZnCl2 in H2O M[bhedtc]2 M = Ca, Hg, Zn

16 Complex Syntheses K[bhedtc] in H2O UO2(OAc)2· 2H2O in H2O
Pb(OAc)2 · 3H2O in H2O K2Cr2O7 in H2O K[UO2(bhedtc)3] Pb[bhedtc]2 Cr[bhedtc]3

17 Self Assembly DEA 2. 1. MCl2 CS2 in MeOH 3. M[bhedtc]2 M = Hg or Zn

18 Solubility Chart

19 Data Chart

20 K[bhedtc] 1H NMR in DMSO 4.100 3.638 4.777

21 Zn[bhedtc]2 1H NMR in DMSO
Up: 0.163 Down: 0.084 Down: 0.149

22 Hg[bhedtc]2 1H NMR in DMSO
Up: 0.220 Down: 0.108 Down: 0.234

23 Pb[bhedtc]2 1H NMR in DMSO
Down: 0.095 Up: 0.208 Down: 0.134

24 K[bhedtc] 13C NMR in DMSO

25 13C NMR results

26 K[bhedtc] IR

27 Ca[bhedtc]2 over K[bhedtc]

28 Cr[bhedtc]3 over K[bhedtc]

29 Zn[bhedtc]2 over K[bhedtc]

30 Hg[bhedtc]2 over K[bhedtc]

31 K[UO2(bhedtc)3] over K[bhedtc]

32 Pb[bhedtc]2 over K[bhedtc]

33 UV-Vis

34 Mass Spec Complexes Mass/Charge ratio (m/z) Molecular Weight (amu)
Ca[bhedtc]2 401.2 400.2 Cr[bhedtc]3 ~ Zn[bhedtc]2 425.0 424.0 Hg[bhedtc]2 563.0 562.0 K[UO2(bhedtc)3] 810.4 849.5 Pb[bhedtc]2 591.0 568.0 *Central Analytical Laboratory at University of Colorado at Boulder

35 Elemental Analysis *Columbia Analytical Services, Tucson, Arizona

36 Conclusion Study of Zinc and Mercury is complete
Calcium, Chromium, and Uranium have a promising beginning New complex formed Pb[bhedtc]2

37 Future Work Self-Assembly Additional trials Rotary evaporator
Atomic Absorption Spectroscopy Attempt more metals

38 Acknowledgements Big Thanks: McDaniel College Chemistry Department
Dr. Craig for the opportunity Dr. Smith for advising the seminar process Fran Wetzel for supplying reagents Teresa Tilyou for her knowledge and assistance Thao Tran and Kevin Bowman

39 References Pages, A.; Casas, J.S.; Sanchez, A.; Sordo, J.; Bravo, J.; Gayoso, M. Dithiocarbamates in Heavy Metal Poisoning: Complexes of N,N-di(2-hydroxyethyl)dithiocarbamate with Zn(II), Cd(II), Hg(II), CH3Hg(II), and C6H5Hg(II). J. Inorg. Biochem. 1985, 25, Fenton, D.E. More metalloenzymes. Biocoordination Chemistry; Oxford University Press Inc.: New York, 1995; pp Johnston, M. Genetic evidence that zinc is an essential co-factor in the DNA binding domain of GAL4 protein. Nature. 1987, 328, Facts About Dietary Supplements: Zinc. (accessed April 17, 2008), National Institute of Health, Office of Dietary Supplements. Zinc in Drinking-water: Background document for development of WHO Guidelines for Drinking-water Quality; Technical Report for World Health Organization: Geneva, CH, 2003. Mercury in Health Care; Policy Paper for World Health Organization: Geneva, CH, August 2005. Exposure to Mercury: A Major Public Health Concern; Policy Paper for World Health Organization: Geneva, CH, 2007.

40 References Depleted uranium. (accessed April 17, 2008), World Health Organization. Lead in Paint, Dust, and Soil. (accessed August 15, 2008), Environmental Protection Agency. Dietary Supplement Fact Sheet: Chromium. (accessed February 19, 2009), National Institute of Health, Office of Dietary Supplements. Dietary Supplement Fact Sheet: Calcium. (accessed August 7, 2008), National Institute of Health, Office of Dietary Supplements. Zhong, Y.; Zhang, W.; Fan J.; Tan, M.; Lai, C.S.; Tiekink, E.R.T. Bis[μ-N,N bis(2- hydroxyethyl)dithiocarbamato]-1:2κ3S,S’:S’;2:1κ3S,S’:S’-bis{[N,N-bis(2-hydroxyethyl)dithiocarbamate-κ2S,S’]cadmium(II)}. Acta Crystallogr., Sect. E: Struct. Rep. 2004, E60, m1633-m1635. Zingaro, R.A. The Reaction of Uranyl Ion with Xanthates and Diethyldithiocarbamate. J. Am. Chem. Soc. 1956, 78, Skoog, D.; Holler, F.; Crouch, S. Principles of Instrumental Analysis, 6th ed.; Thomson Brooks/Cole: Belmont, CA; pp 526, ,

41 Questions?

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