First examples of 3d-uranium compounds derived from single-compartment Schiff base ligands: Syntheses, crystal structures and d–d band correlation

Mononuclear and heterometallic dinuclear, trinuclear and dimer-of-dinuclear complexes derived from single- and double-compartment Schiff base ligands having a less utilized diamine

“…A few compounds containing both a bivalent 3d metal ion of either Cu II and Ni II and the 5f metal ion U VI O 2 have been previously reported for double-compartment Schiff base ligands (3-methoxy/ [1,[74][75][76][77][78][79][80]. Most of those compounds which are derived from H 2 L double are cocrystals in which the uranium(VI) center is not coordinated with the phenoxo or methoxy/ethoxy/3-hydroxy oxygen atoms or Schiff base ligand [1,[76][77][78], while all of those compounds which are derived from H 2 L single are discrete dinuclear systems in which the uranium(VI) center is coordinated with the two phenoxo oxygen atoms [74,75], i.e., those are diphenoxo-bridged, as are the three compounds 1-3 in the present investigation.…”

“…Most of those compounds which are derived from H 2 L double are cocrystals in which the uranium(VI) center is not coordinated with the phenoxo or methoxy/ethoxy/3-hydroxy oxygen atoms or Schiff base ligand [1,[76][77][78], while all of those compounds which are derived from H 2 L single are discrete dinuclear systems in which the uranium(VI) center is coordinated with the two phenoxo oxygen atoms [74,75], i.e., those are diphenoxo-bridged, as are the three compounds 1-3 in the present investigation. On the other hand, only one of the compounds derived from H 2 L double (the concerned ligand is 3-ethoxysalicylaldehyde-1,3-diaminopropane, H 2 L 8 ; Table 3) is a discrete dinuclear systems in which the uranium(VI) center is also coordinated with the two phenoxo oxygen atoms (i.e., also diphenoxo-bridged), but not coordinated with the ethoxy oxygen atoms.…”

“…On the other hand, only one of the compounds derived from H 2 L double (the concerned ligand is 3-ethoxysalicylaldehyde-1,3-diaminopropane, H 2 L 8 ; Table 3) is a discrete dinuclear systems in which the uranium(VI) center is also coordinated with the two phenoxo oxygen atoms (i.e., also diphenoxo-bridged), but not coordinated with the ethoxy oxygen atoms. For all of those few diphenoxo-bridged discrete dinuclear 3d-uranyl(VI) compounds, the 3d metal ion is copper(II) and the general composition ( (3) are among only a few examples of dinuclear 3d-uranyl(VI) compounds and 3 is the only example of a discrete dinuclear nickel(II)-uranyl(VI) compound derived from the above mentioned single/double-compartment Schiff base ligands [1,[74][75][76][77][78][79][80].…”

“…A correlation was reported [90] and has been explored recently [74,76,77] regarding the position of the d-d transition (k max ) as a function of the displacement (d Cu ) of the copper(II) ion from the corresponding basal plane. According to this correlation, the d-d band of copper(II) should be blue shifted as d Cu becomes smaller and it will be red shifted as d Cu becomes larger.…”

Syntheses, structures and catecholase activity of two cobalt(III) complexes derived from N,N′-ethylenebis(3-ethoxysalicylaldiimine): A special host–guest system from a special ligand

“…Many mono/di/oligonuclear metal complexes have been reported from the following types of acyclic Schiff base ligands: (i) Single-compartment ligands (H 2 L Single ), obtained on [2+1] condensation of salicylaldehyde/2-hydroxyacetophenone/2-hydroxypropiophenone and a diamine [1][2][3][4][5][6][7][8][9][10][11]; Double-compartment ligands H 2 L OMe [1,[12][13][14][15][16][17][18] and H 2 L OEt [1,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] ligands, obtained on [2+1] condensation of 3-methoxysalicylaldehyde and 3-ethoxysalicylaldehyde, respectively, and a diamine. It has been established that H 2 L OEt ligands are something special because its O(phenoxo) 2 O(ethoxy) 2 compartment is strongly potential to act as a hydrogen bond acceptor with hydrogen bond donors such as water [1,[19][20][21][22][23][24][25]…”