Host−Guest Interactions of Inorganic Phosphates with the Copper(II) Complexes of the Hexaaza Macrocyclic Ligand 3,6,9,17,20,23-Hexaazatricyclo[23.3.1.1^11,15]triaconta-1(29),11(30),12,14,25,27-hexaene

Abstract

The host-guest interactions between ortho-, pyro-, and tripolyphosphate anions and the mono and dinuclear copper(II) complexes of the hexaaza macrocyclic ligand BMXD (3,6,9,17,20,23-hexaazatricyclo[23.3.1.1(11,15)]triaconta-1(29),11(30),12,14,25,27-hexaene) were investigated by potentiometric equilibrium methods. Ternary complexes are formed in aqueous solution as a result of coordinate bonding, hydrogen bond formation, and Coulombic attraction between the host and guest. Formation constants for all the species found are reported. The dinuclear copper(II) complexes of BMXD show strong selectivity for pyrophosphate ions in the presence of orthophosphate ions over the whole p[H] range; the pyrophosphate/tripolyphosphate selectivity is p[H] dependent. The dinuclear copper(II) complex of BMXD, (Cu(2)-BMXD)(SO(4))(2), crystallizes in the orthorhombic space group Pccn, with a = 15.73(2) Å, b = 20.27(1) Å, c = 9.045(5) Å, and Z = 4. The sulfate counterions are found to bridge the copper(II) ions in adjacent molecules leading to an extended polymeric structure.

Artificial Receptors for the Recognition of Phosphorylated Molecules

“…559 In addition, direct competition experiments led to the conclusion that the dinuclear complex 509:Cu 2 interacts more favorably with pyrophosphate than it does with monophosphate near neutral pH. A slight selectivity for triphosphate over pyrophosphate by this complex was also found under these conditions.…”

Pyrophosphate Detection in Water by Fluorescence Competition Assays: Inducing Selectivity through the Choice of the Indicator

“…We have now chosen as a receptor the dicopper( II ) complex of the bisdiene macrocycle 3,6,9,16,19,22‐hexaazatricyclo[22.2.2.2(11.14)]triaconta‐1(26),11(12),13,24,27, 29‐hexaene ( L ). We expected that, in view of the coordinative unsaturation of the two metal centers and the correct Cu II ⋅⋅⋅Cu II distance, the dinuclear complex of L , [Cu${{{\rm II}\hfill \atop 2\hfill}}$ ( L )] 4+ ( R ), could be a reasonably good candidate for behaving as a fluorescent CE for PPi 11…”

3,6,9,16,19,22-Hexaazatricyclo[22.2.2.211,14]triaconta-11,13,24,26(1),27,29-hexaene pentahydrate

“…Recently, it was reported that the binuclear complexes of the title compound, (I), and its analogues can accelerate the hydrolysis of bis(p-nitrophenyl)phosphate and adenosine triphosphate (Ragunathan & Schneider, 1996;Lu et al, 1998). On the other hand, these compounds and their metal complexes are good receptors for inorganic phosphates and ribonucleic acid (Nation et al, 1996;Li et al, 1997). Therefore, the structure of the title compound may prove useful both for understanding the mechanisms of hydrolysis and for the design of new compounds.…”