Lead(II) and Bismuth(III) Complexes with Macrocyclic Ligands

Abstract

The preparation and X‐ray characterization of a Pb2+ and a Bi3+ complex formed with macrocyclic ligands are reported. In the dimeric complex [{Pb(CH3COO)LBPh4}2], where L is 1,4,7‐triazacyclononane, the metal atoms are chelated by L and bridged by an acetate group; moreover, each of the metal atoms is at contact distance from a tetraphenylborate phenyl group, which completes the coordination. The unsymmetrically derivatized macrocycle 1‐carboxymethyl‐4,7‐bis(1‐methylimidazol‐2‐ylmethyl)‐1,4,7‐triazacyclononane HL1, in its deprotonated (L1, anionic) form gives the complex of formula BiClL1BPh4 with Bi3+, which contains [BiClL1]22+ dimeric cations with eight‐coodinated Bi3+ and bridging acetate groups within the dimer.

DOTA complexes with divalent zinc, cadmium and mercury: X-ray and solid-state NMR studies and solution isomerism

“…Among Zn(II) complexes, the dynamics was followed only for Zn(II)-DOTAM in DMF and was proven to be very fast. 16 Several Cd(II) complexes of cyclen derivatives bearing alcohol 15,30 or pyrazol-1-ylmethyl 27,31 pendant arms have a similar coalescence temperature as the complex studied here. The Hg(II) complexes of DOTA, 29 DOTAM, 16 cyclen bearing alcohol 30 or pyrazol-1-yl-methyl 31 pendant arms were also subjected to the 13 C VT-NMR study.…”

“…16 Several Cd(II) complexes of cyclen derivatives bearing alcohol 15,30 or pyrazol-1-ylmethyl 27,31 pendant arms have a similar coalescence temperature as the complex studied here. The Hg(II) complexes of DOTA, 29 DOTAM, 16 cyclen bearing alcohol 30 or pyrazol-1-yl-methyl 31 pendant arms were also subjected to the 13 C VT-NMR study. A full analysis of our 13 C VT-NMR spectra provided energy barriers for the isomerisation process.…”

“…27 The same effect was also observed for the Cd(II) complex of the related bis(methylpyrazol)-bis(carboxymethyl) substituted cyclen. 31 The fluxionality of the coordination sphere has also been demonstrated by 13 C NMR for Zn(II) and Cd(II) complexes of symmetric tetrakis(hydroxypropyl) cyclen. 15 Surprisingly, only a handful of complexes of the parent ligand, DOTA, with divalent metal ions have been structurally characterized.…”

“…13,26 The N-Q N -Q O -O torsion angles in the published structures range from 11.6°to 25.6°, clearly demonstrating the preference of Cd(II) complexes of cyclenbased ligands bearing four coordinating pendant arms for the TSA geometry. 13,15,16,[24][25][26][27]43,44 These structures can be classified according to the distances of the pendant donor atoms to the Cd(II) ion in a [6 + 2] fashion 15,16,25,41 (6 examples) and [7 + 1] fashion 15,24,26,31,41,42 (6 examples) and close to the regular octacoordination 13,26 (three examples).…”

Crystal structure of catena-poly[mono(μ-aqua)di(μ-acetato)cobalt(II)] monohydrate, [Co(CH3COO)2(H2O)] · H2O

“…From the structural point of view, acetate is an important organic ligand, which exhibits various coordination modes observed in by [Co^-O^-CHsCOOMCsHjNMsCHCb [4], Pb(CH 3 COO)L(BPh 4 ) (L = 1,4,7-trizacyclononane) [5], [Ag2(4-hmt)^-CH3COO)]CH 3 COO · 4.5H 2 0 (hmt = hexamethylethylenetetraamine), [6], [Re(CO)3^-CH 3 COO)THF)] 4 [7], [РРЬ 4 ]2[Яи20(ц-СНзС00) 2 С1б] [8].…”