Synthesis and characterisation of manganese(II) compounds with tetradentate ligands based on the bispidine backbone

Structural Variation in Transition-Metal Bispidine Compounds

“…Forty datasets of experimentally determined structures of transition‐metal compounds with tetradentate bispidine ligands with an N 2 py 2 donor set (Scheme ) and one (tetragonal pyramidal), two (pseudo‐octahedral), or three additional donors (pentagonal bipyramidal) are known so far. These include complexes with chromium( III ), manganese( II ),60 iron( II ),53 cobalt( II ),52 copper( I ),48, 49 copper( II )6, 48–51 and zinc( II ). ORTEP61 plots of the structures not published elsewhere are given in Figure 1.…”

The Synthesis and Structural Characterisation of a Series of Hydrophobic Piperidones and Bispidones

“…In all three structures the pyridyl rings are rotated such that the nitrogen atoms are pointing away from the bicyclic ring nitrogen atoms, whilst in metal complexes the pyridyl rings rotate by 180°, and thus a pocket is created whereby the ligand can coordinate to the metal atom through all four nitrogen atoms. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] The pyridine rings in 2, 3 and 4 thus exhibit opposite chirality, in contrast to the situation observed for the piperidone 1. This arrangement is not as energetically favourable in terms of sterics, but the energy gained by the formation of the stable bicyclic nonanone skeleton overcomes this.…”

“…[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] They have shown that the rigid nature of the backbone allows preorganisation of the coordination sphere around the metal centre, resulting in the formation tion reaction with N,N-disubstituted diamines, H 2 N(CH 2 ) 2 -NR 2 (R = Me, Et, iPr). Solid-state structures have been obtained for three of these bispidones, all of which display a double-chair conformation.…”

Bispidine Coordination Chemistry

“…Other Metal Ions. The bispidine coordination chemistry of a number of other transition metal ions has been studied in some detail (166,167,189,190,198). Of specific interest and discussed here are the redox chemistry of vanadium, in combination with some structural and spectroscopic studies (198), and the cobalt(II)-bispidine hydrogen peroxide chemistry (167).…”

“…There is a variety of possible sites for ligand modification. Of particular interest is the C9 position, which has been selectively and stereospecifically reduced to an alcohol (190), and the two hydrolyzed C1,C5 ester groups (167).…”