ISSN:
1573-1111
Keywords:
Macrocyclic chemistry of Pd2+
;
deprotonation of secondary amino group
;
supramolecular chemistry
;
anion coordination chemistry
;
anion inclusion
;
crystal structures
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The interaction of PdCl 4 2− with the macrocyclic ligands of the series [3k]aneN k has been studied both in solution and in the solid state. [18]aneN6 and [21]aneN7 form both mono- and binuclear Pd2+ complexes, whose stability constants have been determined in 0.5 mol dm−3 NaCl at 298.15 K. [21]aneN7 also forms, in solution, a trinuclear species in which an amino group deprotonates to bridge two Pd2+ ions, as observed in the solid state. The crystal structure of the complexes [Pd2([18]aneN6)Cl2][ClO4]2 and [Pd3([21]aneN7)Cl3][ClO4]2 · H2O have been solved by single crystal X-ray analysis. C12H30N6Cl4O8Pd2: monoclinic, space group C2/m,a = 10.876(2),b = 18.117(2),c = 7.043(2) Å,β = 113.78(2)°,V = 1270(12) Å3,Z = 2,D calc = 1.92 g cm-3,μ = 16.94 cm−1.R = 0.063,R w = 0.059. C14H36N7CI5O9Pd3: orthorhombic, space groupPcab,a = 13.125(7),b = 13.213(3),c = 33.570(5) Å,V = 5822(3) Å3,Z = 8,D calc = 2.15 g cm−3,μ = 21.20 cm−1.R = 0.074,R w = 0.061. In very acidic solutions the polyammonium cations (H k [3k]aneN k ) k+ interact with PdCl 4 2− forming second sphere coordinated species. These reactions have been followed by a microcalorimetric technique in 2 mol dm−3 HCl solutions. The slowness of the reactions of (H10[30]aneN10)10+ with PdCl 4 2− has been interpreted in terms of inclusion of the anion into the receptor's cavity as shown by the crystal structure of [(PdCl4)(H10[30]aneN10)][PdCl4]2Cl4: triclinic, space group PT,a = 7.760(3),b = 11.448(4),c = 13.399(11) Å, α = 96.31(8)°,β = 104.50(6)°,γ = 92.30(3)°,Z = 1.R = 0.046 andR w = 0.039.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01053869
Permalink
