Polydentate ligands crystal structures

A new tetranuclear cubane complex has been synthesized from an assembly of Cu ions and the polydentate ligand 19a (Figure 4). The crystal structure of the tetranuclear cubane, [Cu(19a )]4(N03)4.8H20 where the ligand 19a is the haemiacetal of the methanone 19a, is reported (Figure 14) (07EJI4574). 

Two mononuclear Wemer-type complexes based on Pd(III) have been characterized by X-ray crystallography. The X-ray crystal structure of mononuclear Pd (III) complex 1, in which the Pd(III) center is supported by two 1,4,7-trithiacyclo-nonane ligands, was reported in 1987 (Fig. 2) [37-39]. An analogous complex (2), supported by 1,4,7-triazacyclonOTiane ligands, was reported a year later [40]. Both complexes contain distorted octahedral Pd centers, as expected for low-spin (f Pd (III) [6]. Detailed examinatiOTi of the electrochemical and spectroscopic properties of Pd(III) complexes supported by macrocyclic polydentate ligands has indicated that the unpaired electron in 1 and 2 resides predominantly in the orbital [41 6]. 

Bai Y, Gao H, Dang D-B et al (2010) A series of metal-organic frameworks based on polydentate schiff-base ligands derived from benzil dihydrazone synthesis, crystal structures and luminescent properties. CrystEngComm 12 1422... 

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