Mercury Complexes of a Benzimidazole Selone: Synthesis, Structures &

Characterization

Christian Joseph with help from Lizeth Hernandez

University of North Carolina at Charlotte Department of ChemistryDR Group

Introduction• Ligand System

• Why Hg Complexes?– Good way to probe the reactivity of a ligand– Toxic Heavy metal– Thermally robust and stable

• Why Selenium?– N-heterocyclic selones are less common than their sulfur analogs– Softer Lewis base– Biologically significant

N

N

Se

N

N

S

N

N

S

Intermediate and Ligand Synthesis

N

HN K2CO3

iPrBr

EtOH , refluxN

N

Br-

Huynh, V. H. et al. Organometallics 2006, 25, 245-249 & 3267-3274.

K2CO3Se

MeOHN

N

Br-

• Prolonged exposure to air causes ligand to decompose

Hg(II) Complex Synthesis

• All reactions were performed under a N2 atmosphere• Complexes are more air stable than free ligand• Pale yellow or white solids

HgX2

X = Cl, Br, I

(iPr2bimSe)2HgX249-63%

iPr2bimSe(iPr2bimSe)HgX2

72-98%

2 iPr2bimSe

EtOH or Et2O

MeCN

Structures of 1:1 Complexes

X=Cl X=IHg-Se /ÅHg-X / Å

Se-Hg-X / °X1-Hg-X2 / °

2.512.38-2.7797.4-145.491.6-109.9

2.612.71-3.17

101.8-112.888.2-130.9

tau parameter

τ4

0.74Seesaw/ Trigonal

pyramidal

0.82Trigonal pyramidal

Structures of 1:2 Complexes

X=Cl X=Br X=IHg-Se /ÅHg-X / Å

Se-Hg-X / °X1-Hg-X2 / °

2.632.52

102.9-104.3

116.51

2.652.63

102.6-106.2

117.44

2.702.77

104.6-110.9

118.62tau parameter

τ4

0.83Trigonal

pyramidal

0.85Trigonal

pyramidal

0.93Tetrahedral/

Trigonal Pyramidal

Ongoing and Future Work

N

N

SeN

N SeCu

Se

N

N

X

MeCN2

CuX or CuBr•SMe2X = Cl, I

N

N

Se

N

N

Se

Toluene

+S Au XX = Cl, Br, I

Au X- tht

• Copper Chemistry:

• Gold Chemistry:

Conclusions• Five out of the six Hg(II) complexes have successfully

been synthesized and fully characterized – (iPr2bimSe)2HgCl2 is pending EA

• Hg(II) complexes are more air stable than free ligand

• (iPr2bimSe)AuCl has been synthesized and characterization is ongoing

• (iPr2bimSe)CuX (X = Cl, Br, I) EA’s are pending– 1H NMR shows that a MeCN molecule may be coordinated

to the metal

Acknowledgements• Prof. Daniel Rabinovich- UNC Charlotte• Lizeth Hernandez (Chemistry Masters Candidate)-

– UNC Charlotte• DR Research Group- UNC Charlotte• My mom