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N,N′-Bis(2-ammonioethyl)oxamide diaquabis(oxalato-κ2O,O′)cuprate(II) dihydrate

“…The cation and anion each lie on a symmetry centre. The interatomic bond distances and angles are comparable to those reported in the literature (Su et al, 1999;Novosad et al, 2000).…”

“…Both diaquabis(oxalato-2 O,O 0 )cuprate(II) group, [Cu(ox) 2 -(H 2 O) 2 ] 2À , and N,N 0 -bis(2-ammonioethyl)oxamide, H 2 aeoxd, have played a key role as bridging ligands in the synthesis of polynuclear complexes (Andruh et al, 1996;Novosad et al, 2000;Chen et al, 1998;Yan et al, 1998). The crystal structures of other salts of [Cu(ox) 2 (H 2 O) 2 ] 2À (Andruh et al, 1996;Novosad et al, 2000) and H 4 aeoxd 2+ (Su et al, 1999) have already been determined.…”

trans-Bis(2-aminoanilinium-κN2)bis(oxalato-κ2O,O′)copper(II)

“…This has been demonstrated with chelating amines and kinetically inert ions such as Cr III (Lethbridge et al, 1970;Rochon & Massarweh, 1999;Russell et al, 2001) and Co III (Yasui et al, 1987;Lappin et al, 1993), resulting in a cis-[M(ox) 2 X 2 ] species. For Cu II , the favoured square-planar coordination geometry with weak axial interactions means that, although it is seldom seen in structural studies (Insausti et al, 1994) (Bloomquist et al, 1981;Gajapathy et al, 1983;Novosad et al, 2000;Lohn, 1969).…”

Linkage isomeric oxamate chelates:rac-bis(ethane-1,2-diamine)oxamatocobalt(III) bis(trifluoromethanesulfonate) dihydrate and Λ(+)578-bis(ethane-1,2-diamine)[oxamato(2−)]cobalt(III) trifluoromethanesulfonate

“…However, anionic forms of derivatives such as oxamide (H 2 NCOCONH 2 ), dithiooxamide (H 2 NCS-CSNH 2 ), oxamic acid (H 2 NCOCO 2 H) and their derivatives are also employed in bridging capacities due to the structural and electronic variation offered by such species (Verdaguer et al, 1985;Kahn, 2000;Cangussu et al, 2008). The unsymmetrical nature of oxamic acid, whether singly or doubly deprotonated, gives rise to different coordination modes for the oxamate entity in both bridging and nonbridging roles (Novosad et al, 2000;Rodrígez-Martín et al, 2001). For bidentate oxamate in mononuclear systems, both the O,O 0 -and N,O-coordination modes are possible.…”

“…For bidentate oxamate in mononuclear systems, both the O,O 0 -and N,O-coordination modes are possible. However, essentially all reported crystal structures of mononuclear oxamate complexes have the ligand O,O 0 -bound at a labile metal centre (Braibanti et al, 1971;Pellinghelli et al, 1972;Skoulika et al, 1988a,b;Veltsistas et al, 1995Veltsistas et al, , 1999Papa-dimitriou et al, 1998;Novosad et al, 2000;Rodrígez-Martín et al, 2001;Wang et al, 2003). The sole example of a robust metal centre is the cobalt(III) complex p-[Co(O 2 CCONH 2 -O,O 0 )-(tren)]Cl 2 Á2H 2 O [tren is tris(2-aminoethyl)amine; Chun et al, 1999].…”