Non-Paddlewheel

A small assortment of Fe2 complexes have diverse geometries that do not fit into the above families. 

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The RUj non-paddlewheel complexes can be classified by their geometry - tetragon2il versus trigonal - and further classified by their supporting ligands. Nearly all the unsupported Ruj complexes are tetragonal. 

Porphyrin The non-paddlewheel Ru complexes consist primarily of binuclear Ru porphyrin dimers. Though the synthesis of RUjlOEP) (where OEP = octaethylporphyrin dianion) was first formulated in 1975, evidence for the dimer was scant and primarily based on mass spectrometry [116]. The solid-state structure was reported 2ilmost a decade later in 1984 [117]. 

An elegant and efficient approach for the synthesis of structural models of carboxylate-rich non-heme dinuclear iron proteins involves the use of bulky ligands of the terphenyl carboxylate family [47, 48]. The resulting dinuclear iron(II) complexes can adopt two conformations, called the windmill and the paddlewheel motif (Scheme 2.9). 

Figure 9 The crystal structure of [Cu4(ad)4(oxalate)2] H20 (CCDC deposition XACZEH) shows (a) four adenine ligands forming a Cuj paddlewheel with terminally bound water molecules. Further coordination to ions, also bound to oxalate anions, results in (b) an extended network with cylindrical channels, (c) In the crystal structure of bio-MOF-11 (CCDC deposition YUVSUE), each adenine unit acts as both a bidentate linker and a monodentate capping ligand to form a Coj paddlewheel SBU with two acetate ligands, generating (d) a highly porous extended network. All non-coordinated solvents and protons removed for clarity...

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