Antitumor activity of copper(II) complexes with Schiff bases derived from N'-tosylbenzene-1,2-diamine.

The electrochemical oxidation of anodic metal copper in a solution of the ligands N-[(5-tert-butyl-2-hydroxyphenyl)methylidine]-N'-tosylbenzene-1,2-diamine [H2L1] and N-[(3,5-di-tert-butyl-2-hydroxyphenyl)methylidine]-N'-tosylbenzene-1,2-diamine, [H2L2] afforded homoleptic [CuL] compounds or solvate [CuLS] complexes. The addition to the electrochemical cell of coligands (L') such as 2,2'-bipyridine (2-bpy), 4,4'-bipyridine(4-bpy) or 1,10-phenanthroline (phen) allowed the synthesis, in one step, of heteroleptic [CuLL'] compounds, namely [CuL1(H2O)] (1), [CuL1(2,2'-bpy)]⋅CH3CN (2), [CuL1(phen)]·H2O (3), [Cu2L12(4,4'-bpy)] (4), [CuL2(CH3OH)] (5), [CuL2(2,2'-bpy)] (6), [CuL2(phen)] (7) and [Cu2L22(4,4'-bpy)] (8). The crystal structures of both ligands, H2L1, H2L2, and those of the complexes (2), (4), (5), (6) and (7) have been determined by X-ray diffraction techniques. Coordination polyhedron around metal atom is square planar for [CuL2(CH3OH)] (5) and [Cu2L12(4,4'-bpy)] (4) and square pyramid for the other complexes with additional chelating ligands. The cytotoxic activity of this new series of copper(II) complexes against the SH-SY5Y neuroblastoma cell line and U87-MG and U373-MG glioblastoma cell lines has been investigated. Most of the test compounds showed higher activity than cisplatin in the three cell lines. Among this series, compound [CuL1(phen)] (3) displayed the highest activity with IC50 equal to 1.77 µM on SH-SY5Y whereas compound [Cu2L12(4.4'-bpy)] (4) resulted the most potent compounds on U87 MG and U373 MG glioblastoma cell lines. Studies on the cytotoxic activity of these derivatives suggest that these compounds induce cell death by a mechanism other than apoptosis.

Electrochemical synthesis and structural characterization of silver(I) complexes of N-2-pyridyl sulfonamide ligands with different nuclearity: influence of the steric hindrance at the pyridine ring and the sulfonamide group on the structure of the complexes.

A new series of silver complexes, [AgL], of the anionic forms of potentially bidentate N-2-pyridyl sulfonamide ligands [N-(3-methyl-2-pyridyl)-p-toluenenesulfonamide (HTs3mepy), N-(3-methyl-2-pyridyl)mesitylenesulfonamide (HMs3mepy), N-(4-methyl-2-pyridyl)-p-toluenesulfonamide (HTs4mepy), and N-(6-methyl-2-pyridyl)mesitylenesulfonamide (HMs6mepy)] have been prepared by an electrochemical procedure. In addition, heteroleptic complexes of composition [AgLL'] (L' = 1,10-phenanthroline and 2,2'-bipyridine) were obtained when the coligand L' was added to the electrolytic phase. The complexes were characterized by microanalysis, IR and (1)H NMR spectroscopy, and LSI mass spectrometry. In the cases of the compounds [Ag(Ts3mepy)](n)() (1), [Ag(4)(Ms3mepy)(4)] (2a), [Ag(Ms3mepy)](n)() (2b), [Ag(4)(Ms6mepy)(4)] (3a), [Ag(2)(Ms6mepy)(2)](n)() (3b), [Ag(2)(Ms3mepy)(2)(phen)(2)] (5), [Ag(2)(Ms6mepy)(2)phen] (7), and [Ag(2)(Ts4mepy)(2)(bipy)(2)] (8), characterization was also carried out by single-crystal X-ray diffraction. Compounds 1 and 2b present a polymer structure formed by an {AgN(2)} digonal core. Compounds 2a and 3a are tetranuclear and also have a distorted {AgN(2)} digonal core. Compound 3b is based on binuclear distorted {AgN(2)} digonal units joined by an intermolecular sulfonyl oxygen atom to produce a stairlike polymer structure. The heteroleptic complexes 5 and 8 are dimeric with a distorted {AgN(4)} tetrahedral geometry, while compound 7 shows two different geometries around the metal, distorted {AgN(2)} digonal and {AgN(4)} tetrahedral. The supramolecular structures of all species are organized by pi,pi-stacking, C-H...pi, or C-H...O interactions.

Synthesis and Characterization of Zinc and Cadmium Compounds with Arenephosphinothiol Ligands. Crystal and Molecular Structures of [Cd(2){2-(Ph(2)PO)C(6)H(4)S}(4)], [Zn{2-(Ph(2)P)-6-(Me(3)Si)C(6)H(3)S}(2)], [Cd{2-(Ph(2)PO)-6-(Me(3)Si)C(6)H(3)S}(2)(CH(3)OH)], and [Zn{PhPO(C(6)H(4)S-2)(2)}(bipy)].

The electrochemical oxidation of a metallic anode (zinc or cadmium) in an acetonitrile solution of a series of arenephosphinothiol ligands, 2-(Ph(2)P)C(6)H(4)SH, 2-(Ph(2)P)-6-(Me(3)Si)C(6)H(3)SH, 2-(Ph(2)PO)-6-(Me(3)Si)C(6)H(3)SH, and PhP(C(6)H(4)SH-2)(2) [abbreviated RP-(SH)(x)(), x = 1 or 2], affords [M(RP-S)(2)] and [M(RP-S(2))], M = Zn, Cd. Adducts of several of these compounds with 1,10-phenanthroline and 2,2'-bipyridine have also been obtained by addition of these coligands to the electrolysis phase. The compounds obtained have been characterized by microanalysis, IR, UV-visible, FAB spectrometry and (1)H, (31)P NMR spectroscopic studies. The compounds, [Cd(2){2-(Ph(2)PO)C(6)H(4)S}(4)]CH(3)CN (1), [Zn{2-(Ph(2)P)-6-(Me(3)Si)C(6)H(3)S}(2)] (2), [Cd{2-(Ph(2)PO)-6-(Me(3)Si)C(6)H(3)S}(2)(CH(3)OH)] (3), and [Zn{PhPO(C(6)H(4)S-2)(2)}(bipy)] (4), have been also characterized by single-crystal X-ray diffraction. Compound 1 is binuclear with a {Cd(2)S(2)} core and distorted trigonal bipyramidal {CdO(2)S(3)} geometry about the Cd sites. Compounds 2, 3, and 4 are mononuclear with distorted tetrahedral {ZnP(2)S(2)}, distorted square pyramidal {CdO(3)S(2)}, and distorted trigonal bipyramidal {ZnON(2)S(2)} geometries, respectively. Crystal data: 1, C(42)H(37)N(3)O(2)P(2)S(2)Cd, triclinic, P&onemacr;, a = 13.5780(2) Å, b = 13.8505(2) Å, c = 13.9526(2) Å, alpha = 106.622(1) degrees, beta = 109.693(1) degrees, gamma = 107.137(1) degrees, V = 2133.30(5) Å(3), Z = 2, 9560 reflections, R = 0.0483; 2, C(46)H(50)N(2)P(2)S(2)Si(2)Zn, monoclinic, C2/c, a = 21.332(4) Å, b = 9.391(2) Å, c = 25.938(5) Å, beta = 113.84(3) degrees, V = 4753(2) Å(3), Z = 4, 2564 reflections, R = 0.0377; 3, C(43)H(48)CdO(3)P(2)S(2)Si(2), triclinic, P&onemacr;, a = 12.1237(4) Å, b = 14.0568(4) Å, c = 15.0938(2) Å, alpha = 70.836(2) degrees, beta = 83.410(2) degrees, gamma = 65.397(2) degrees, V = 2208.7(1) Å(3), Z = 2, 4936 reflections, R = 0.0738; 4, C(29)H(22)Cl(3)N(2)OP(2)S(2)Zn, triclinic, P&onemacr;, a = 8.9556(3) Å, b = 12.7911(4) Å, c = 14.0598(5) Å, alpha = 82.671(1) degrees, beta = 73.140(1) degrees, gamma = 74.113(1) degrees, V = 1480.44(9)(1) Å(3), Z = 2, 3820 reflections, R = 0.0511.

Synthesis and Structural Characterization of Neutral Silver(I) Complexes with Arenephosphinothiols. Crystal Structures of [Ag(4){2-(Ph(2)P)-6-(Me(3)Si)C(6)H(6)S}(4)] and [Ag(4){2-(Ph(2)PO)-6-(Me(3)Si)C(6)H(3)S}(4)].

Silver complexes of the anionic forms of 2-(diphenylphosphino)benzenethiol [2-(Ph(2)P)C(6)H(4)SH] (1), 2-(diphenylphosphino)-6-(trimethylsilyl)benzenethiol [2-(Ph(2)P)-6-(Me(3)Si)C(6)H(3)SH] (2), and 2-(diphenylphosphinyl)-6-(trimethylsilyl)benzenethiol [2-(Ph(2)PO)-6-(Me(3)Si)C(6)H(3)SH] (3) have been prepared by an electrochemical procedure and characterized by spectroscopic (IR, (1)H, (13)C, and (31)P NMR) methods, and ligand 3 and [Ag(4){2-(Ph(2)P)-6-(Me(3)Si)C(6)H(3)S}(4)] (5) and [Ag(4){2-(Ph(2)PO)-6-(Me(3)Si)C(6)H(3)S}(4)] (6) complexes were characterized by X-ray crystallographic techniques. Crystal data for 3: C(21)H(23)OPSSi, monoclinic, P2(1)/n, a = 11.3730(4) Å, b = 11.1562(4) Å, c = 17.1153(6) Å, beta = 103.961(1) degrees, V = 2107.4(1) Å(3), Z = 4, 2730 reflections with I(o) > 2sigma(I(o)), R = 0.0621. Crystal data for 5: C(84)H(88)Ag(4)P(4)S(4)Si(4), tetragonal, P4(2)2(1)2, a = 18.8454(7) Å, b = 18.8454(7) Å, c = 24.596(2) Å, V = 8735.1(7) Å(3), Z = 4, 4676 reflections with I(o) > 2sigma(I(o)), R = 0.0286. Crystal data for 6: C(90)H(97)Ag(4)N(3)O(4)P(4)S(4)Si(4), trigonal, P1, a = 13.4567(1) Å, b = 14.4148(2) Å, c = 14.8080(2) Å, alpha = 99.130(1) degrees, beta = 98.815(1) degrees, g = 114.211(1) degrees, V = 2509.38(5) Å(3), Z = 1, 6345 reflections with I(o) > 2sigma(I(o)), R = 0.0505. The [Ag(4){2-(Ph(2)P)-6-(Me(3)Si)C(6)H(3)S}(4)] (5) compound is tetranuclear with an array of four silver atoms bridged by four sulfur atoms. Each silver atom has a distorted trigonal [AgS(2)P] environment with each ligand acting as P,S bidentate S-bridging ligand. The [Ag(4)(2-(Ph(2)PO)-6-(Me(3)Si)C(6)H(3)S}(4)] (6) complex is also tetranuclear, but in this case two of the silver atoms are [AgO(2)S(2)] tetracoordinated and the other two Ag atoms are [AgS(2)] two coordinated.