Dicopper(II) complexes of several new binucleating ligands

Dicopper(II) complexes of three new series of binucleating ligands has been synthesized and studied to understand how the different types of ligands affect the properties of the binuclear copper(II) site.; The binuclear copper(II) complex ({dollar}rm Cusb2(pzda{dollar}-{dollar}rm Mesb2 en)(Hsb2 O)sb2(mu{dollar}-{dollar}rm Nsb3)rbrack{lcub}cdot{rcub} Hsb2 O{dollar} (where pzda-Me{dollar}sb2{dollar}en = N,N-3,5-(bis(dimethylamino)ethyl) pyrazole dicarboxamide) has been synthesized and its properties have been compared to the previously known complex, ({dollar}rm Cusb2(pzda{dollar}-{dollar}rm Mesb2 en)(OH)(Hsb2 O)sb2rbrack{lcub}cdot{rcub}6.5 Hsb2 O.{dollar} A crystal structure determination of ({dollar}rm Cusb2(pzda{dollar}-{dollar}rm Mesb2 en)(Hsb2 O)sb2(mu{dollar}-{dollar}rm Nsb3)rbrack{lcub}cdot{rcub}Hsb2 O{dollar} reveals that the exogenous azide bridges the two Cu(II) ions in a 1,3 fashion. The Cu(II) - Cu(II) distance is 4.309 A and each copper(II) ion has a square pyramidal geometry. Complete assignments of the electronic spectra for both of the binuclear copper(II) complexes has been made.; Another new series of binucleating ligands based on the bridging pyrazolate ion has been synthesized and studied. The four new ligands and their abbreviations are: (1) N,N-bis(2{dollar}spprime{dollar}-pyridylmethyl)-3-aminomethylpyrazole, HD55; (2) N,N-bis(2{dollar}spprime{dollar}-pyridylethyl)-3-aminomethylpyrazole, HD66; (3) N,N,N{dollar}spprime{dollar},N{dollar}spprime{dollar}-tetrakis(2{dollar}spprime {dollar}-pyridyl-methyl)-3,5-bis-(aminomethyl)pyrazole, HB55; (4) N,N,N{dollar}spprime{dollar},N{dollar}spprime{dollar}-tetrakis(2{dollar}spprime {dollar}-pyridyl-ethyl)-3,5-bis-(aminomethyl)pyrazole, HB66. Evidence has been obtained to show that the different chelate rings and bridging groups produce significant differences in the coordination geometry and the spectral characteristics of the binuclear copper(II) complexes.; Binuclear copper(II) complexes of three new binucleating ligands containing two PY2 units (PY2 = bis(2-(2{dollar}spprime {dollar}-pyridyl)ethyl)amine) connected by a carbon chain; cis-1,4-(PY2)-2-butene (C4PY2), trans-1,4-(PY2)-2-butene (T4PY2), and 1,3-(PY2)-(2-benzyl)propane (P3PY2) have been synthesized and studied. The binuclear copper(II) complexes which were isolated as chloride salts in the solid state were found to exhibit an equilibrium between an "open" form and a "closed" dihydroxy-bridged form in DMSO:H{dollar}sb2{dollar}O solution. The structure of an "open" form complex, ({dollar}rm Cusb2(C4PY2)(Hsb2 O)sb4rbrack (ClOsb4)sb2,{dollar} has been determined by x-ray crystallography. The Cu(II) - Cu(II) distance is 7.9 A and the two copper ions were found to exhibit different coordination geometries; a nearly trigonal bipyramidal geometry for one copper(II) ion and a distorted square pyramidal geometry for the other copper(II) ion.; Electronic spectroscopy and EPR have been used to follow the pH study of the removal of an exogenous hydroxide bridge from two phenolate based binuclear copper(II) complexes, ({dollar}rm Cusb2(bpmp)(OH)rbrack (ClOsb4)sb2{dollar}(bpmp = 2,6-bis(bis-(2{dollar}spprime{dollar}-pyridylmethyl)aminomethyl-4-methylphenol) and ({dollar}rm Cusb2(bpmpOMe)(OH)rbrack (ClOsb4)sb2{dollar}(bpmpOMe = 2,6-bis(bis(2{dollar}spprime{dollar}-pyridylmethyl)aminomethyl-4-methoxyphenol) Evidence is shown for the loss of the exogenous hydroxide bridge upon lowering the pH of the solution.