Mononuclear (Pd, Pt), heterodinuclear (PdAg, PtAg), and tetranuclear (Pd2Ag2, Pt2Ag2) 1,1-ethylenedithiolato complexes

lp;&-5q;1 The reactions of [Tl2[S2C=C[C(O)Me]2]]n with [MCl2L2] (1:1) or with [MCl2(NCPh)2] and PPh3 (1:1:2) give complexes [M[eta2-S2C=C[C(O)Me]2]L2] [M = Pt, L2 = 1,5-cyclooctadiene (cod) (1); L2 = bpy, M = Pd (2a), Pt (2b), L = PPh3, M = Pd (3a), Pt (3b)] whereas with MCl2 and QCl (2:1:2) anionic derivatives Q2[M[eta2-S2C=C[C(O)Me]2]2] [M = Pd, Q = NMe4 (4a), Ph3P=N=PPh3 (PPN) (4a'), M = Pt, Q = NMe4 (4b)] are produced. Complexes 1 and 3 react with AgClO4 (1:1) to give tetranuclear complexes [[ML2]2Ag2[mu2,eta2-(S,S')-[S2C=C[C(O)Me]2]2]](ClO4)2 [L = PPh3, M = Pd (5a), Pt (5b), L2 = cod, M = Pt (5b')], while the reactions of 3 with AgClO4 and PPh3 (1:1:2) give dinuclear [[M(PPh3)2][Ag(PPh3)2][mu2,eta2-(S,S')-S2C=C[C(O)Me]2]]]ClO4 [M = Pd (6a), Pt (6b)]. The crystal structures of 3a, 3b, 4a, and two crystal forms of 5b have been determined. The two crystal forms of 5b display two [Pt(PPh3)2][mu2,eta2-(S,S')-[S2C=C[C(O)Me]2]2] moieties bridging two Ag(I) centers.     

Synthesis and reactivity of a bis(disulfide)-bridged RuMo3S4 double-cubane cluster: a new family of nona- or decanuclear mixed-metal sulfide clusters with two RuMo3S4 units

A bis(disulfide)-bridged RuMo3S4 double-cubane cluster [{(Cp*Mo)3(mu3-S)4Ru}(mu2-eta2:eta1-S2)]2[PF6]2 (2, Cp* = eta5-C5Me5) is readily available from cluster [(Cp*Mo)3(mu3-S)4RuH2(PPh3)][PF6] (1) and S8. The reactions of cluster 2 with [M(PPh3)4] (M = Pd, Pt) give rise to the formation of a new family of nona- or decanuclear mixed-metal sulfide clusters, [{(Cp*Mo)3(mu3-S)4Ru}2(mu3-S)2{Pd(S)(PPh3)}][PF6]2 (3), [{(Cp*Mo)3(mu3-S)4Ru}2(mu3-S)2{(Pd(PPh3))2(mu2-S)}][PF6]2 (4), and [{(Cp*Mo)3(mu3-S)4Ru}2(mu3-S)2{Pt(PPh3)2}][PF6]2 (5), with two RuMo3S4 cubane units, the structures of which have been determined by X-ray diffraction studies.     

Palladium(II) and platinum(II) organometallic complexes with 4,7-dihydro-5-methyl-7-oxo[1,2,4]triazolo[1,5-a]pyrimidine. Antitumor activity of the platinum compounds

Palladium and platinum complexes with HmtpO (where HmtpO=4,7-dihydro-5-methyl-7-oxo[1,2,4]triazolo[1,5-a]pyrimidine, an analogue of the natural occurring nucleobase hypoxanthine) of the types [M(dmba)(PPh3)(HmtpO)]ClO4[dmba=N,C-chelating 2-(dimethylaminomethyl)phenyl; M=Pd or Pt], [Pd(N-N)(C6F5)(HmtpO)]ClO4[N-N=2,2'-bipyridine (bpy), 4,4'-dimethyl-2,2'-bipyridine (Me2bpy), or N, N, N', N'-tetramethylethylenediamine (tmeda)] and cis-[M(C6F5)2(HmtpO)2] (M=Pd or Pt) (head-to-head atropisomer in the solid state) have been obtained. Pd(II) and Pt(II) complexes with the anion of HmtpO of the types [Pd(tmeda)(C6F5)(mtpO)], [Pd(dmba)(micro-mtpO)] 2, and [NBu4]2[M(C6F5)2(micro-mtpO)]2(M=Pd or Pt) have been prepared starting from the corresponding hydroxometal complexes. Complexes containing simultaneously both the neutral HmtpO ligand and the anionic mtpO of the type [NBu4][M(C6F5)2(HmtpO)(mtpO)] (M=Pd or Pt) have been also obtained. In these mtpO-HmtpO metal complexes, for the first time, prototropic exchange is observed between the two heterocyclic ligands. The crystal structures of [Pd(dmba)(PPh 3)(HmtpO)]+, cis-[Pt(C6F5)2(HmtpO)2].acetone, [Pd(C6F5)(tmeda)(mtpO)].2H2O, [Pd(dmba)(micro-mtpO)]2, [NBu4]2[Pd(C6F5)2(micro-mtpO)]2.CH2Cl2.toluene, [NBu4]2[Pt(C6F5)2(micro-mtpO)](2).0.5(toluene), and [NBu4][Pt(C6F5)2(mtpO)(HmtpO)] have been established by X-ray diffraction. Values of IC50 were calculated for the new platinum complexes cis-[Pt(C6F5)2(HmtpO)2] and [Pt(dmba)(PPh3)(HmtpO)]ClO4 against a panel of human tumor cell lines representative of ovarian (A2780 and A2780 cisR), lung (NCI-H460), and breast cancers (T47D). At 48 h incubation time, both complexes were about 8-fold more active than cisplatin in T47D and show very low resistance factors against an A2780 cell line, which has acquired resistance to cisplatin. The DNA adduct formation of cis-[Pt(C6F5)2(HmtpO)2] and [Pt(dmba)(PPh3)(HmtpO)]ClO4 was followed by circular dichroism and electrophoretic mobility. Atomic force microscopy images of the modifications caused by these platinum complexes on plasmid DNA pB R322 were also obtained.     

Synthetic,structural, electrochemical,and theoretical studies of heterometallic aggregates with a [Pt(2)(mu-S)(2)M] core (M = Hg,Au)

Novel electroactive multimetallic compounds based on the [Pt(2)(mu(2)-S)(2)M] core, viz. [Pt(2)(PPh(3))(4)(mu(3)-S)(2)HgFc]PF(6) (1) [Fc = (eta(5)-C(5)H(4))Fe(eta(5)-C(5)H(5))] and [Pt(2)(PPh(3))(4)(mu(3)-S)(2)Hg(2)Fc'](PF(6))(2) (2) [Fc' = Fe(eta(5)-C(5)H(4))(2)], have been synthesized under the guide of electrospray mass spectrometry. The electrochemistry of these ferrocene funtionalized compounds together with the reported [Pt(2)(PPh(3))(4)(mu(3)-S)(2)HgPPh(3)](PF(6))(2) (3), [Pt(2)(PPh(3))(4)(mu(2)-S)(mu(3)-S)HgPh]PF(6) (4), and [Pt(2)(PPh(3))(4)(mu(2)-S)(mu(3)-S)AuPPh(3)]PF(6) (5) have been investigated using cyclic voltammetry and DFT calculations. These results point to a prominent ligand-based oxidation.     

Ten-vertex iron-monocarbollide complexes: synthesis and reactivity of the anion [4,9-{Fe(CO)4}-9,9,9-(CO)3-arachno-9,6-FeCB8H11]-

The reagent [arachno-4-CB8H14] reacts with [Fe3(CO)12] in tetrahydrofuran (THF) at reflux temperatures, followed by addition of [N(PPh3)2]Cl, to afford [N(PPh3)2][4,9-{Fe(CO)4}-9,9,9-(CO)3-arachno-9,6-FeCB8H11] (3). In the anion of 3, one iron atom is part of the open CBBFeBB face of a 10-vertex {arachno-9,6-FeCB8} cage, to which the second iron atom is attached via an Fe-Fe bond and an additional exo-polyhedral Fe-B sigma bond. Upon heating 3 in refluxing toluene, the closed 10-vertex species [N(PPh3)2][2,2,2-(CO)3-closo-2,1-FeCB8H9] (4) is obtained, whereas the isomeric compound [N(PPh3)2][6,6,6-(CO)3-closo-6,1-FeCB8H9] (5) is isolated upon heating [closo-4-CB8H9]- and [Fe3(CO)12] in refluxing THF with subsequent addition of [N(PPh3)2]Cl. Protonation of 3 using CF3SO3H in CH2Cl2 gives the charge-compensated compound [4,9-{Fe(CO)4}-4-(mu-H)-9,9,9-(CO)3-arachno-9,6-FeCB8H11] (6), in which the B-Fe sigma bond of the precursor has been converted to a B-H right harpoon-up Fe linkage. In contrast, 3 with {M(PPh3)}+ gives the trimetallic species [1,3,4,9-{MFe(CO)4(PPh3)}-1,3-(mu-H)2-9,9,9-(CO)3-arachno-9,6-FeCB8H9] (M = Cu (7), Ag 8) in which the three metal centers form a V-shaped M-Fe-Fe unit. Compound 6 reacts with PEt3 in the presence of Me(3)NO to yield [4,9-(PEt3)2-9,9-(CO)2-nido-9,6-FeCB8H10] (9). In the latter, the formerly exo-polyhedral {Fe(CO)4} fragment has been replaced by a PEt3 ligand, with a second PEt3 substituting one CO group at the remaining cluster iron vertex. The novel structural features of compounds 3-9 have been confirmed by single-crystal X-ray diffraction studies.     

Synthesis of TiRru2 heterobimetallic and TiRuM (M = Rh, Rr, Pd, Pt) heterotrimetallic sulfido clusters from a hydrosulfido-bridged titanium-ruthenium complex

Treatment of the hydrosulfido-bridged titanium-ruthenium heterobimetallic complex [Cp2Ti(mu2-SH)2RuCl(eta5-C5Me5)] (1; Cp = eta5-C5H5) with an excess of triethylamine followed by addition of [RuCl2(PPh3)3] and [[(cod)M]2(mu2-Cl)2] (M = Rh, Ir; cod = 1,5-cyclooctadiene) led to the formation of the TiRu2 and TiRuM mixed-metal sulfido clusters [(CpTi)[(eta5-C5Me5)Ru][Ru(PPh3)2](mu3-S)2(mu2-Cl)2] (3) and [(CpTi)[(eta5-C5Me5)Ru][M(cod)](mu3-S)2(mu2-Cl)] (M = Rh (4a), Ir (4b)), respectively. On the other hand, the reactions of 1 with [M(PPh3)4] (M = Pd, Pt) afforded the TiRuM trinuclear clusters [(CpTiCl)[(eta5-C5Me5)Ru][M(PPh3)2](mu3-S)(mu2-S)(mu2-H)] (M = Pd (5a), Pt (5b)) with an unprecedented M3(mu3-S)(mu2-S) core. The detailed structures of these triangular clusters 3-5 have been determined by X-ray crystallography. Crystal data: 3, triclinic, P1, a = 12.448(4) A, b = 12.773(4) A, c = 17.270(4) A, alpha = 100.16(2) degrees, beta = 99.93(2) degrees, gamma = 114.11(3) degrees, V = 2373(1) A(3), Z = 2; 4a, triclinic, P1, a = 7.714(2) A, b = 11.598(3) A, c = 14.802(4) A, alpha = 80.46(2) degrees, beta = 82.53(2) degrees, gamma = 71.47(2) degrees, V = 1234.0(6) A3, Z = 2; 4b, triclinic, P1, a = 7.729(1) A, b = 11.577(2) A, c = 14.766(3) A, alpha = 80.14(1) degrees, beta = 82.71(1) degrees, gamma = 71.55(1) degrees, V = 1231.1(4) A3, Z = 2; 5a, monoclinic, P2(1)/c, a = 11.259(4) A, b = 16.438(4) A, c = 26.092(5) A, beta = 102.23(3) degrees, V = 4719(2) A(3), Z = 4; 5b, monoclinic, P2(1)/n, a = 11.369(2) A, b = 16.207(3) A, c = 26.116(2) A, beta = 102.29(1) degrees, V = 4701(1) A3, Z = 4.     

Cubane-type heterometallic sulfido clusters: incorporation of two metal fragments into a dinuclear ReS(mu-S)2ReS core affording bimetallic M2Re2(mu 3-S)4 clusters (M = Ru,Pt, Cu) or trimetallic MM'Re2(mu 3-S)4 clusters via incomplete cubane-type MRe2(mu 3-S)(mu 2-S)3 intermediates (M = Ru,Rh, Ir; M' = Mo,W, Pd,Ru, Rh)

Reactions of a dirhenium tetra(sulfido) complex [PPh(4)](2)[ReS(L)(mu-S)(2)ReS(L)] (L = S(2)C(2)(SiMe(3))(2)) with a series of group 8-11 metal complexes in MeCN at room temperature afforded either the cubane-type clusters [M(2)(ReL)(2)(mu(3)-S)(4)] (M = CpRu (2), PtMe(3), Cu(PPh(3)) (4); Cp = eta(5)-C(5)Me(5)) or the incomplete cubane-type clusters [M(ReL)(2)(mu(3)-S)(mu(2)-S)(3)] (M = (eta(6)-C(6)HMe(5))Ru (5), CpRh (6), CpIr (7)), depending on the nature of the metal complexes added. It has also been disclosed that the latter incomplete cubane-type clusters can serve as the good precursors to the trimetallic cubane-type clusters still poorly precedented. Thus, treatment of 5-7 with a range of metal complexes in THF at room temperature resulted in the formation of novel trimetallic cubane-type clusters, including the neutral clusters [[(eta(6)-C(6)HMe(5))Ru][W(CO)(3)](ReL)(2)(mu(3)-S)(4)], [(CpM)[W(CO)(3)](ReL)(2)(mu(3)-S)(4)] (M = Rh, Ir), [(Cp*Ir)[Mo(CO)(3)](ReL)(2)(mu(3)-S)(4)], [[(eta(6)-C(6)HMe(5))Ru][Pd(PPh(3))](ReL)(2)(mu(3)-S)(4)], and [(Cp*Ir)[Pd(PPh(3))](ReL)(2)(mu(3)-S)(4)] (13) along with the cationic clusters [(Cp*Ir)(CpRu)(ReL)(2)(mu(3)-S)(4)][PF(6)] (14) and [(Cp*Ir)[Rh(cod)](ReL)(2)(mu(3)-S)(4)][PF(6)] (cod = 1,5-cyclooctadiene). The X-ray analyses have been carried out for 2, 4, 7, 13, and the SbF(6) analogue of 14 (14') to confirm their bimetallic cubane-type, bimetallic incomplete cubane-type, or trimetallic cubane-type structures. Fluxional behavior of the incomplete cubane-type and trimetallic cubane-type clusters in solutions has been demonstrated by the variable-temperature (1)H NMR studies, which is ascribable to both the metal-metal bond migration in the cluster cores and the pseudorotation of the dithiolene ligand bonded to the square pyramidal Re centers, where the temperatures at which these processes proceed have been found to depend upon the nature of the metal centers included in the cluster cores.     

Simple preparations of Pd6Cl12, Pt6Cl12, and Qn[Pt2Cl8+n], n=1, 2 (Q=TBA+, PPN+) and structural characterization of [TBA][Pt2Cl9] and [PPN]2[Pt2Cl10].C7H8

The hexanuclear Pd6Cl12, i.e., the crystal phase classified as beta-PdCl2, was obtained by reacting [TBA]2[Pd2Cl6] with AlCl3 (or FeCl3) in CH2Cl2. The action of AlCl3 on PtCl42-, followed by digestion of the resulting solid in 1,2-C2H4Cl2 (DCE), CHCl3, or benzene, produced Pt6Cl12.DCE, Pt6Cl12.CHCl3, or Pt6Cl12.C6H6, respectively. Treating [TBA]2[PtCl6] with a slight excess of AlCl3 afforded [TBA][Pt2Cl9], whose anion was established crystallographically to be constituted by two "PtCl6" octahedra sharing a face. Dehydration of H2PtCl6.nH2O with SOCl2 gave an amorphous compound closely analyzing as PtCl4, reactive with [Q]Cl in SOCl2 to yield [Q][Pt2Cl9] or [Q]2[Pt2Cl10], depending on the [Q]Cl/Pt molar ratio (Q=TBA+, PPN+). A single-crystal X-ray diffraction study has shown [PPN]2[Pt2Cl10].C7H8 to contain dinuclear anions formed by two edge-sharing PtCl6 octahedra.     

Structural, dynamic, and theoretical studies of [AunPt2(PPh3)4(mu-S)2-n(mu 3-S)nL][PF6]n [n = 1, L = PPh3; n = 2, L = Ph2PCH2PPh2, (C5H4PPh2)2Fe

Three heterometallic Au-Pt complexes [Pt2(PPh3)4(mu-S)(mu 3-S)Au(PPh3)][PF6] (2), [Pt2(PPh3)4(mu 3-S)2Au2(mu-dppm)]-[PF6]2 (3), and [Pt2(PPh3)4(mu 3-S)2Au2(mu-dppf)][PF6]2 (4) have been synthesized from Pt2(PPh3)4(mu-S)2 (1) [dppm = Ph2PCH2PPh2; dppf = (C5H4PPh2)2Fe] and characterized by single-crystal X-ray crystallography. In 2, the Au(I) atom is anchored on only one of the sulfur centers. In 3 and 4, both sulfur atoms are aurated, showing the ability of 1 to support an overhead bridge structure, viz. [Au2(P-P)], with or without the presence of Au-Au bond. The change of dppf to dppm facilitates such active interactions. Two stereoisomers of complex 3 (3a,b) have been obtained and characterized by single-crystal X-ray crystallography. NLDFT calculations on 2 show that the linear coordination mode is stabilized with respect to the trigonal planar mode by 14.0 kJ/mol. All complexes (2-4) are fluxional in solution with different mechanisms. In 2, the [Au(PPh3)] fragment switches rapidly between the two sulfur sites. Our hybrid MM-NLDFT calculations found a transition state in which the Au(I) bears an irregular trigonal planar geometry (delta G++ = 19.9 kJ/mol), as well as an intermediate in which Au(I) adopts a regular trigonal planar geometry. Complexes 3a,b are roughly diastereoisomeric and related by sigma (mirror plane) conversion. This symmetry operation can be broken down to two mutually dependent fluxional processes: (i) rapid flipping of the dppm methylene group across the molecular plane defined by the overhead bridge; (ii) rocking motion of the two Au atoms across the S...S axis of the (Pt2S2) core. Modeling of the former by molecular mechanics yields a steric barrier of 29.0 kJ/mol, close to that obtained from variable-temperature 31P(1Hz) NMR study (33.7 kJ/mol). In 4, the twisting of the ferrocenyl moiety across the S...S axis is in concert with a rocking motion of the two gold atoms. The movement of dppf is sterically most demanding, and hence, 4 is the only complex that shows a static structure at lower temperatures. Pertinent crystallographic data: (2) space group P1, a = 15.0340(5) A, b = 15.5009(5) A, c = 21.9604(7) A, alpha = 74.805(1) degrees, beta = 85.733(1) degrees, gamma = 78.553(1) degrees, R = 0.0500; (3a) space group Pna2(1), a = 32.0538(4) A, b = 16.0822(3) A, c = 18.9388(3) A, R = 0.0347; (3b) space group Pna2(1), a = 31.950(2) A, b = 16.0157(8) A, c = 18.8460(9) A, R = 0.0478; (4) space group P2(1)/c, a = 13.8668(2) A, b = 51.7754(4) A, c = 15.9660(2) A, beta = 113.786(1) degrees, R = 0.0649.     

Acetonimine and 4-imino-2-methylpentan-2-amino platinum(II) complexes: synthesis and in vitro antitumor activity

The reaction of [Pt(dmba)(PPh3)Cl] [where dmba = N,C-chelating 2-(dimethylaminomethyl)phenyl] with aqueous ammonia in acetone in the presence of AgClO4 gives the acetonimine complex [Pt(dmba)(PPh3)(NH=CMe2)]ClO4 (1). The reaction of [Pt(dmba)(DMSO)Cl] with aqueous ammonia in acetone in the presence of AgClO4 gives a mixture of [Pt(dmba)(NH=CMe2)2]ClO4 (2) and [Pt(dmba)(imam)]ClO4 (3a) (where imam = 4-imino-2-methylpentan-2-amino). [Pt(dmba)(DMSO)Cl] reacts with [Ag(NH=CMe2)2]ClO4 in a 1:1 molar ratio to give [Pt(dmba)(DMSO)(NH=CMe2)]ClO4 (4). The reaction of [Pt(dmba)(DMSO)Cl] with 20% aqueous ammonia in acetone at 70 degrees C in the presence of KOH gives [Pt(dmba)(CH2COMe)(NH=CMe2)] (5), whereas the reaction of [Pt(dmba)(DMSO)Cl] with 20% aqueous ammonia in acetone in the absence of KOH gives [Pt(dmba)(imam)]Cl (3b). The reaction of [NBu4]2[Pt2(C6F5)4(mu-Cl)2] with [Ag(NH=CMe2)2]ClO4 in a 1:2 molar ratio produces cis-[Pt(C6F5)2(NH=CMe2)2] (6). The crystal structures of 1 x 2 Me2CO, 2, 3a, 5, and 6 have been determined. Values of IC50 were calculated for the new platinum complexes against a panel of human tumor cell lines representative of ovarian (A2780 and A2780 cisR) and breast cancers (T47D). At 48 h incubation time complexes 1, 4, and 5 show very low resistance factors against an A2780 cell line which has acquired resistance to cisplatin. 1, 4, and 5 were more active than cisplatin in T47D (up to 30-fold in some cases). The DNA adduct formation of 1, 4, and 5 was followed by circular dichroism and electrophoretic mobility.     

Cluster core controlled reactions of substitution of terminal bromide ligands by triphenylphosphine in octahedral rhenium chalcobromide complexes

Reactions of rhenium chalcobromides Cs4[{Re6(mu3-S)8}Br6].2H2O, Cs3[{Re6(mu3-Se)8}Br6].2H2O, Cs3[{Re6(mu3-Q)7(mu3-Br)}Br6].H2O (Q = S, Se), and K2[{Re6(mu3-S)6(mu3-Br)2}Br6] with molten triphenylphosphine (PPh3) have resulted in a family of novel molecular hybrid inorganic-organic cluster compounds. Six octahedral rhenium cluster complexes containing PPh3 ligands with general formula [{Re6(mu3-Q)8-n(mu3-Br)n}(PPh3)4-nBrn+2] (Q = S, n = 0, 1, 2; Q = Se, n = 0, 1) have been synthesized and characterized by X-ray single-crystal diffraction and elemental analyses, 31P{1H} NMR, luminescent measurements, and quantum-chemical calculations. It was found that the number of terminal PPh3 ligands in the complexes is controlled by the composition and consequently by the charge of the cluster core {Re6Q8-nBrn}n+2. In crystal structures of the complexes with mixed chalcogen/bromine ligands in the cluster core all positions of a cube [Q8-nBrn] are ordered and occupied exclusively by Q or Br atoms. Luminescence characteristics of the compounds trans-[{Re6Q8}(PPh3)4Br2] and fac-[{Re6Se7Br}(PPh3)3Br3] (Q = S, Se) have been investigated in CH2Cl2 solution and the broad emission spectra in the range of 600-850 nm were observed.     

Assembly of a heterometallic polynuclear Sn(IV)-Cu(I) cluster based on Sn(edt)2 (edt = ethane-1,2-dithiolate) as a metalloligand

Reaction of [Cu(PPh3)2(MeCN)2]ClO4 (1) and Sn(edt)2 (edt = ethane-1,2-dithiolate) in dichloromethane afforded a novel compound [Sn3Cu4(S2C2H4)6(mu3-O)(PPh3)4](ClO4)2 x 3 CH2Cl2 (2), which is the first example of the heptanuclear Sn(IV)-Cu(I) oxosulfur complex with a bottle-shaped cluster core. Complex 2 gives a blue-green luminescent emission in the solid state. Crystallographic data for 2: C87H90Cl8Cu4O9P4S12Sn3, trigonal, space group R3, M = 2682.02, a = 18.156(2) A, b = 18.156(2) A, c = 54.495(10) A, gamma = 120 degrees, V = 15558(4) A3, Z = 6 (T = 130.15 K).     

Preparation and substitution chemistry of [Bu4N]2[W6Cl8(p-OSO2C6H4CH3)6]. A useful precursor for pseudohalide, acetate, and organometallic complexes containing the [W6Cl8](4+) core

The tosylate (p-toluenesulfonate) cluster [Bu4N]2[W6Cl8(p-OSO2C6H4CH3)6] (1) has been prepared and characterized by IR and NMR spectroscopy, elemental analysis, and an X-ray crystal structure. This cluster complex is shown to be a useful starting material for the preparation of pseudohalide clusters, [Bu4N]2[W6Cl8(NCQ)6] (Q = O (2), S (3), and Se (4)), in high yields. Cluster 1 also serves as a precursor to the new cluster compounds: [Bu4N]2[W6Cl8(O2CCH3)6] (5), [Bu4N]2[W6Cl8((mu-NC)Mn(CO)2(C5H5))6] (6), [W6Cl8((mu-NC)Ru(PPh3)2(C5H5))6][ p-OSO2C6H4CH3]4 (7), and [W6Cl8((mu-NC)Os(PPh3)2(C5H5))6][ p-OSO2C6H4CH3]4 (8). X-ray crystal structures are reported for 1, 4, and 5.     

Synthesis, structural characterization, and photophysical properties of palladium and platinum(II) complexes containing 7,8-benzoquinolinate and various phosphine ligands

A series of mononuclear cyclometalated benzo[h]quinolinate platinum and palladium(II) complexes with phosphine ligands, namely, [M(bzq)ClL] (L=PPh2H, Pt 1, Pd 2; PPh2CCPh, Pt 3, Pd 4), [Pt(bzq)(PPh2H)(PPh2CCPh)]ClO4 5, [Pt(bzq)(PPh2C(Ph)=C(H)PPh2)]ClO4 6, and [Pt(bzq)(CCPh)(PPh2CCPh)] (7a, 7b), were synthesized. The X-ray crystal structures of 1, 6.CH3COCH3.1/2CH3(CH2)4CH3, and 7b.CH3COCH3 have been determined. In 1, the metalated carbon atom and the P atom are mutually cis, whereas in 7b they are trans located. For complex 6, C and N are crystallographically indistinguishable. Reaction of [Pt(bzq)(mu-Cl)]2 with PPh2H and excess of NEt3 leads to the phosphide-bridge platinum dimer [Pt(bzq)(mu-PPh2)]2 8 (X-ray). Moderate pi-pi intermolecular interactions and no evident Pt-Pt interactions are found in 1, 7b, and in 8. All of the complexes exhibit absorption bands at high energy due to the intraligand transitions (1IL pi --> pi) and absorptions at lower energy which are attributed to MLCT (5d) pi --> pi (CLambdaN) transition. Platinum complexes show strong luminescence in both solid state and frozen solutions. The influence of the coligands on the photophysics of the platinum complexes has been examined by absorption and emission spectroscopy.     

Synthesis of acetimino complexes of Pt(II) and Pt(IV) and the first heteronuclear mu-acetimido complexes

The reactions of [Ag(NH=CMe2)2]ClO4 with cis-[PtCl2L2] in a 1:1 molar ratio give cis-[PtCl(NH=CMe2)(PPh3)2]ClO4 (1cis) or cis-[PtCl(NH=CMe2)2(dmso)]ClO4 (2), and in 2:1 molar ratio, they produce [Pt(NH=CMe2)2L2](ClO4)2 [L = PPh3 (3), L2= tbbpy = 4,4'-di-tert-butyl-2,2'-dipyridyl (4)]. Complex 2 reacts with PPh3 (1:2) to give trans-[PtCl(NH=CMe2)(PPh3)2]ClO(4) (1trans). The two-step reaction of cis-[PtCl2(dmso)2], [Au(NH=CMe2)(PPh3)]ClO4, and PPh3 (1:1:1) gives [SP-4-3]-[PtCl(NH=CMe2)(dmso)(PPh3)]ClO4 (5). The reactions of complexes 2 and 4 with PhICl2 give the Pt(IV) derivatives [OC-6-13]-[PtCl3(NH=CMe2)(2)(dmso)]ClO4 (6) and [OC-6-13]-[PtCl2(NH=CMe2)2(dtbbpy)](ClO4)2 (7), respectively. Complexes 1cis and 1trans react with NaH and [AuCl(PPh3)] (1:10:1.2) to give cis- and trans-[PtCl{mu-N(AuPPh3)=CMe2}(PPh3)2]ClO4 (8cis and 8trans), respectively. The crystal structures of 4.0.5Et2O.0.5Me2CO and 6 have been determined; both exhibit pseudosymmetry.     

New palladium(II) and platinum(II) complexes with the model nucleobase 1-methylcytosine: antitumor activity and interactions with DNA

Palladium and platinum complexes with the model nucleobase 1-methylcytosine (1-Mecyt) of the types [Pd(N-N)(C6F5)(1-Mecyt)]ClO4 [N-N = bis(3,5-dimethylpyrazol-1-yl)methane (bpzm), bis(pyrazol-1-yl)methane (bpzm), N,N,N',N'-tetramethylethylenediamine (tmeda), or 2,2'-bipyridine (bpy)] and [M(dmba)(L')(1-Mecyt)]ClO4 [dmba = N,C-chelating 2-(dimethylaminomethyl)phenyl; L' = PPh(3) (M = Pd or Pt), DMSO (M = Pt)] have been obtained. Palladium and platinum complexes of the types cis-[M(C6F5)2(1-Mecyt)2] (M = Pd or Pt) and cis-[Pd(L')(C6F5)(1-Mecyt)2]ClO4 (L' = PPh(3) or t-BuNC) have also been prepared. The crystal structures of [Pd(bpzm)(C6F5)(1-Mecyt)]ClO4, [Pt(dmba)(DMSO)(1-Mecyt)]ClO4, cis-[Pd(C6F5)2(1-Mecyt)2], and cis-[Pd(t-BuNC)(C6F5)(1-Mecyt)2]ClO4 have been established by X-ray diffraction. There is extensive hydrogen bonding (N-H...O, C-H...F or C-H...O) in all the compounds. There are also intermolecular pi-pi interactions between pyrimidine rings of adjacent chains in [Pd(C6F5)2(1-Mecyt)2]. DNA adduct formation of the new complexes synthesized was followed by circular dichroism and electrophoretic mobility. Atomic force microscopy images of the modifications caused by the complexes on plasmid DNA pBR322 were also obtained. Values of IC(50) were also calculated for the new complexes against the tumor cell line HL-60. At a short incubation time (24 h) almost all new complexes were more active than cisplatin.     

New palladium(II) and platinum(II) complexes with 9-aminoacridine: structures, luminiscence, theoretical calculations, and antitumor activity

The new complexes [Pd(dmba)( N10-9AA)(PPh 3)]ClO 4 ( 1), [Pt(dmba)( N9-9AA)(PPh 3)]ClO 4 ( 2), [Pd(dmba)( N10-9AA)Cl] ( 3), and [Pd(C 6F 5)( N10-9AA)(PPh 3)Cl] ( 4) (9-AA = 9-aminoacridine; dmba = N,C-chelating 2-(dimethylaminomethyl)phenyl) have been prepared. The crystal structures have been established by X-ray diffraction. In complex 2, an anagostic C-H...Pt interaction is observed. All complexes are luminescent in the solid state at room temperature, showing important differences between the palladium and platinum complexes. Complex 2 shows two structured emission bands at high and low energies in the solid state, and the lifetimes are in agreement with excited states of triplet parentage. Density functional theory and time-dependent density functional theory calculations for complex 2 have been done. Values of IC 50 were also calculated for the new complexes 1- 4 against the tumor cell line HL-60. All of the new complexes were more active than cisplatin (up to 30-fold in some cases). The DNA adduct formation of the new complexes synthesized was followed by circular dichroism and electrophoretic mobility. Atomic force microscopy images of the modifications caused by the complexes on plasmid DNA pB R322 were also obtained.     

Alkynyldiphenylphosphine d8 (Pt, Rh, Ir) complexes: contrasting behavior toward cis-[Pt(C6F5)2(THF)2

The synthesis and characterization of a series of mononuclear d(8) complexes with at least two P-coordinated alkynylphosphine ligands and their reactivity toward cis-[Pt(C(6)F(5))(2)(THF)(2)] are reported. The cationic [Pt(C(6)F(5))(PPh(2)C triple-bond CPh)(3)](CF(3)SO(3)), 1, [M(COD)(PPh(2)C triple-bond CPh)(2)](ClO(4)) (M = Rh, 2, and Ir, 3), and neutral [Pt(o-C(6)H(4)E(2))(PPh(2)C triple-bond CPh)(2)] (E = O, 6, and S, 7) complexes have been prepared, and the crystal structures of 1, 2, and 7.CH(3)COCH(3) have been determined by X-ray crystallography. The course of the reactions of the mononuclear complexes 1-3, 6, and 7 with cis-[Pt(C(6)F(5))(2)(THF)(2)] is strongly influenced by the metal and the ligands. Thus, treatment of 1 with 1 equiv of cis-[Pt(C(6)F(5))(2)(THF)(2)] gives the double inserted cationic product [Pt(C(6)F(5))(S)mu-(C(Ph)=C(PPh(2))C(PPh(2))=C(Ph)(C(6)F(5)))Pt(C(6)F(5))(PPh(2)C triple-bond CPh)](CF(3)SO(3)) (S = THF, H(2)O), 8 (S = H(2)O, X-ray), which evolves in solution to the mononuclear complex [(C(6)F(5))(PPh(2)C triple-bond CPh)Pt(C(10)H(4)-1-C(6)F(5)-4-Ph-2,3-kappaPP'(PPh(2))(2))](CF(3) SO(3)), 9 (X-ray), containing a 1-pentafluorophenyl-2,3-bis(diphenylphosphine)-4-phenylnaphthalene ligand, formed by annulation of a phenyl group and loss of the Pt(C(6)F(5)) unit. However, analogous reactions using 2 or 3 as precursors afford mixtures of complexes, from which we have characterized by X-ray crystallography the alkynylphosphine oxide compound [(C(6)F(5))(2)Pt(mu-kappaO:eta(2)-PPh(2)(O)C triple-bond CPh)](2), 10, in the reaction with the iridium complex (3). Complexes 6 and 7, which contain additional potential bridging donor atoms (O, S), react with cis-[Pt(C(6)F(5))(2)(THF)(2)] in the appropriate molar ratio (1:1 or 1:2) to give homo- bi- or trinuclear [Pt(PPh(2)C triple-bond CPh)(mu-kappaE-o-C(6)H(4)E(2))(mu-kappaP:eta(2)-PPh(2)C triple-bond CPh)Pt(C(6)F(5))(2)] (E = O, 11, and S, 12) and [(Pt(mu(3)-kappa(2)EE'-o-C(6)H(4)E(2))(mu-kappaP:eta(2)-PPh(2)C triple-bond CPh)(2))(Pt(C(6)F(5))(2))(2)] (E = O, 13, and S, 14) complexes. The molecular structure of 14 has been confirmed by X-ray diffraction, and the cyclic voltammetric behavior of precursor complexes 6 and 7 and polymetallic derivatives 11-14 has been examined.     

Gold and silver complexes with the ferrocenyl phosphine FcCH2PPh2

Linear gold(I) and silver(I) complexes with the ferrocenyl phosphine FcCH2PPh2 [Fc = (eta5-C5H5)Fe(eta5-C5H4)] of the types [AuR(PPh2CH2Fc)], [M(PPh3)(PPh2CH2Fc)]OTf, and [M(PPh2CH2Fc)2]OTf (M = Au, Ag) have been obtained. Three-coordinate gold(I) and silver(I) derivatives of the types [AuCl(PPh2CH2Fc)2] and [M(PPh2CH2Fc)3]X (M = Au, X = ClO4; M = Ag, X = OTf) have been obtained from the corresponding gold and silver precursors in the appropriate molar ratio, although some of them are involved in equilibria in solution. The crystal structures of [AuR(PPh2CH2Fc)] (R = Cl, C6F5), [AuL(PPh2CH2Fc)]OTf (L = PPh3, FcCH2PPh2), [Au(C6F5)3(PPh2CH2Fc)], and [Ag(PPh2CH2Fc)3]OTf have been determined by X-ray diffraction studies.     

Synthesis and reactivity of bridging and terminal hydrosulfido palladium and platinum complexes. Crystal structures of [NBu4]2[(Pt(c6F5)2(mu-SH)]2], [Pt(C6F5)2(PPh3)[S(H)AgPPh3]], and [Pt(C6F5)2(PPh3)[S(AuPPh3)2]

The reactions of the hydroxo complexes [M(2)R(4)(mu-OH)(2)](2)(-) (M = Pd, R = C(6)F(5), C(6)Cl(5); M = Pt, R = C(6)F(5)), [[PdR(PPh(3))(mu-OH)](2)] (R = C(6)F(5), C(6)Cl(5)), and [[Pt(C(6)F(5))(2)](2)(mu-OH)(mu-pz)](2-) (pz = pyrazolate) with H(2)S yield the corresponding hydrosulfido complexes [M(2)(C(6)F(5))(4)(mu-SH)(2)](2-), [[PdR(PPh(3))(mu-SH)](2)], and [[Pt(C(6)F(5))(2)](2)(mu-SH)(mu-pz)](2-), respectively. The monomeric hydrosulfido complexes [M(C(6)F(5))(2)(SH)(PPh(3))](-) (M = Pd, Pt) have been prepared by reactions of the corresponding binuclear hydrosulfido complexes [M(2)(C(6)F(5))(4)(mu-SH)(2)](2-) with PPh(3) in the molar ratio 1:2, and they can be used as metalloligands toward Ag(PPh(3))(+) to form the heterodinuclear complex [(C(6)F(5))(2)(PPh(3))[S(H)AgPPh(3)]], and toward Au(PPh(3))(+) yielding the heterotrinuclear complexes [M(C(6)F(5))(2)(PPh(3))[S(AuPPh(3))(2)]]. The crystal structures of [NBu(4)](2)[[Pt(C(6)F(5))(2)(mu-SH)](2)], [Pt(C(6)F(5))(2)(PPh(3))[S(H)AgPPh(3)]], and [Pt(C(6)F(5))(2)(PPh(3))[S(AuPPh(3))(2)]] have been established by X-ray diffraction and show no short metal-metal interactions between the metallic centers.