Coordination Polymers of Silver Arienne King Chem 765: Advanced Polymer Chemistry October 30, 2000

Overview What are coordination polymers? Why is silver useful? Structure of silver polymers Applications Summary and conclusions

What are coordination polymers? “Infinite” chains or networks Contain metals and organic ligands Held together with coordinate covalent bonds Mukanata, et. al. Inorg.Chem. 1994, 33: 1284

Why silver? Coordination chemistry well-understood Soft Lewis acid Strong bonds to soft Lewis bases Stable complexes Structural diversity

Structures of silver polymers One-dimensional Chains Helices Two-dimensional Sheets Three-dimensional Networks

One-dimensional polymers Linear N-Ag-N angle: 177º Counterion: BF 4 - Carlucci, et al, J. Am. Chem. Soc. 1995, 117: 4562

One-dimensional polymers Helix Optically pure Wu, et al, J. Chem. Soc., Dalton Trans. 1997: 1795

Here at Mac… Double-stranded silver polymer Centre of helix forms a cavity Four silvers per helix turn Bell, et al, SETAC 19 th Annual Meeting Abstract. Charlotte, NC, Nov p.22

Two-dimensional polymers Ag and hexamethylenetetraamine (1:1) Three Ag bond to each ligand Carlucci, et al. Chem. Commun, 1997: 631

Two-dimensional polymers A view of the sheets Carlucci, et al, Chem. Commun.1997: 631

Two-dimensional polymers Silver coordinated to I and N (ICH 2 CN) Chains held together through ClO 4 - coordination to Ag Gives rise to sheets Ino, et al. Inorg. Chem. 2000, 39: 4273

Two-dimensional polymers Graphite-like arrays Hexagonal arrangement of silvers Sulfur acts as bridge between silvers Gives rise to semiconductor activity 2.04x10 -5 Scm -1 at 298K Su, et al, Angew Chem. Int. Ed. Engl. 2000, 39: 2911

Three-dimensional polymers Ag-N bonds In situ synthesis of ligand Blake, et al., Chem. Commun. 1997: 1675

Generation of ligand in situ Cyclization of 1,2 trans-(4-pyridyl)ethene

Polymeric species

Three-dimensional polymers T-shaped Vacant site for counterion Host-guest chemistry Yaghi and Li. J. Am. Chem. Soc. 1996, 118: 295

Overarching trends Cationic frameworks Counterions No interaction Included as “guests” Make give rise to more complex architectures Many coordination environments for Ag Linear preferred

Why bother? Semiconductors Nanostructures Non-linear optics Drugs Catalysis

Summary Silver forms polymeric coordination complexes Wide range of structures Many potential uses…. Someday