Synthesis and Structural Characterization of Trinuclear Cu^II−Pyrazolato Complexes Containing μ₃-OH, μ₃-O, and μ₃-Cl Ligands. Magnetic Susceptibility Study of [PPN]₂[(μ₃-O)Cu₃(μ-pz)₃Cl₃]

Abstract

The nine-membered [-Cu(II)-N-N-](3) ring of trimeric copper-pyrazolato complexes provides a sturdy framework on which water is twice deprotonated in consecutive steps, forming mu(3)-OH and mu(3)-O species. In the presence of excess chlorides the mu(3)-O(H) ligand is replaced by two mu(3)-Cl ions. The interconversion of mu(3)-OH and mu(3)-O and the exchange of mu(3)-O(H) and mu(3)-Cl are reversible, and the three species involved have been structurally characterized: [PPN][Cu(3)(mu(3)-OH)(mu-pz)(3)Cl(3)(thf)].CH(2)Cl(2) (1a), monoclinic P2(1)/n, a = 10.055(2) A, b = 35.428(5) A, c = 15.153(2) A, beta = 93.802(3) degrees, V = 5386(1) A(3), Z = 4; [Bu(4)N][Cu(3)(mu(3)-OH)(mu-pz)(3)Cl(3)] (1b), triclinic P-1, a = 9.135(2) A, b = 13.631(2) A, c = 14.510(2) A, alpha = 67.393(2) degrees, beta = 87.979(2) degrees, gamma = 80.268(3) degrees, V = 1643.2(4) A(3), Z = 2; [PPN](2)[Cu(3)(mu(3)-O)(mu-pz)(3)Cl(3)] (2), monoclinic P2/c, a = 12.807(2) A, b = 13.093(2) A, c = 23.139(4) A, beta = 105.391(3) degrees, V = 3741(1) A(3), Z = 2; [PPN](2)[Cu(3)(mu(3)-Cl)(2)(mu-pz)(3)Cl(3)].0.75H(2)O.0.5CH(2)Cl(2) (3a), triclinic P-1, a = 14.042(2) A, b = 23.978(4) A, c = 25.195(4) A, alpha = 76.796(3) degrees, beta = 79.506(3) degrees, gamma = 77.629(3) degrees, V = 7988(2) A(3), Z = 4; [Bu(4)N](2)[Cu(3)(mu(3)-Cl)(2)(mu-pz)(3)Cl(3)] (3b), monoclinic C2/c, a = 17.220(2) A, b = 15.606(2) A, c = 20.133(2) A, beta = 103.057(2) degrees, V = 5270(1) A(3), Z = 4; [Et(3)NH][Cu(3)(mu(3)-OH)(mu-pz)(3)Cl(3)(pzH)] (4), triclinic P-1, a = 11.498(2) A, b = 11.499(2) A, c = 12.186(2) A, alpha = 66.475(3) degrees, beta = 64.279(3) degrees, gamma = 80.183(3) degrees, V = 1331.0(5) A(3), Z = 2. Magnetic susceptibility measurements show that the three copper centers of 2 are strongly antiferromagnetically coupled with J(Cu-Cu) = -500 cm(-1).

Synthesis, crystal structure and bioactivity of a novel linear trinuclear nickel(II) complex

“…Trinuclear compounds can be classified as linear or nonlinear according to the arrangements of the metal centers and a number of linear trinuclear compounds have been structurally characterized to date [9,10]. But most of them have two, three or four simple or intricate bridging ligands between the metal centers which usually contain simple anions such as chloride, hydroxide, acetate, methoxide or azide, only a minority of them have the trinuclear core bridged by just one single organic ligand [11][12][13][14][15]. Thus, the rational design and preparation of such trinuclear complexes still remains a difficult challenge and attracts continuing interest.…”

Anion Encapsulation by Neutral Supramolecular Assemblies of Cyclic CuII Complexes: A Series of Five Polymerization Isomers, [{cis‐CuII(μ‐OH)(μ‐pz)}n], n=6, 8, 9, 12, and 14

“…[20] A similar procedure employing (Bu 4 N) 2 [Cu 3 (m 3 -Cl) 2 (m-pz) 3 Cl 3 ] yielded 3. Subsequently, 2 was prepared in a rational procedure from the reaction of Cu(OH) 2 and pzH, in the presence of Bu 4 NCl (Supporting Information).…”

{[Cu(phen)]3Cl4}2[GeMo12O40]: Synthesis, crystal structure and magnetic property of a new trinuclear copper complex based on germanomolybdate

“…The above-mentioned data indicate that the geometric configurations of the three Cu atoms in 1 are severely distorted. To our knowledge, 1a represents the first asymmetric trinuclear copper cluster in which three Cu atoms display three different geometric configurations, though similar but symmetric trinuclear copper complex containing Cl atoms as bridges has been described in 2002 by Boča and coworkers [20]. As shown in Fig.…”

“…On the other hand, polynuclear copper complexes have generated a lot of interest because of their interesting magnetic properties and their relevance to the active centers of a number of metalloproteins [7][8][9][10]. To date, in spite of a large number of trinuclear copper (II) complexes have been reported in the linear geometry [11][12][13][14][15][16][17] and triangular arrays of copper ions [18][19][20][21][22][23] [29]. The successful synthesis of 1 was based on a bi-Cu II -substituted sandwich-type germanomolybdate precursor.…”