Diimine complexes of ruthenium(ii), rhenium(i) and iron(ii): from synthesis to DFT studies

The chloro and pyridinate derivatives of rhenium(I) tricarbonyl complexes containing the diimine ligands 2,2’-bipyrazine (bpz) and 5,5’-dimethyl-2,2’-bipyrazine (Me2bpz) are discussed. When compared to similar rhenium(I) tricarbonyl complexes of 2,2’-bipyridine (bpy) and 2,2’-bipyrimidine (bpm), the Me2bpz complexes are comparable to bpm derivatives and their properties are intermediate between those of bpy and bpz complexes. Also discussed is the synthesis and properties of two new analogues of ruthenium(II) tris-bipyridine, a monomer and dimer. The complexes contain the ligand 6,6’-(1,2-ethanediyl)bis-2,2’-bipyridine (O-bpy) which contains two bipyridine units bridged in the 6,6’ positions by an ethylene group. Crystal structures of the two complexes formulated as [Ru(bpy)(O-bpy)](PF6)2 and [(Ru(bpy)2)2(O-bpy)](PF6)4 reveal structures of lower symmetry than D3 which affects the electronic properties of the complexes as revealed by Density Functional Theory (DFT) and Time Dependent Density Functional Theory (TDDFT) calculations. Iron(II) tris-bipyrazine undergoes dissociation in solution with loss of the three bipyrazine ligands. The rate of the reaction in acetonitrile depends on the concentration of anions present in the solution. The rate is fastest in the presence of Cl- and slowest in the presence of Br-. In a second discussion DFT calculations are used to explore four iron(II) diimine complexes. DFT calculations show the higher energy HOMO (highest occupied molecular orbital) orbitals of the four complexes are metal centered and the lower energy LUMO (lowest unoccupied molecular orbitals) are ligand centered.

Grantor dc:publisher

Wichita State University

Year dc:date.issued

2007

Author dc:creator

• Kirgan, Robert A.

Advisor dc:contributor.advisor

• Rillema, D. Paul

• Diimine ligands
• Rhenium(I) complexes
• Density Functional Theory

Statement dc:rights

• © Copyright 2007 by Robert Anthony Kirgan. All rights reserved

Language dc:language.iso

en_US

Dc Identifier Other

d07035

OAI record oai:identifier

https://soar.wichita.edu/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Anull%3A10057%2F3981