Corrigendum to "Synthesis and Characterization of New Palladium(II) Thiosemicarbazone Complexes and Their Cytotoxic Activity against Various Human Tumor Cell Lines".

[This corrects the article DOI: 10.1155/2013/524701.].

Synthesis and Characterization of New Palladium(II) Thiosemicarbazone Complexes and Their Cytotoxic Activity against Various Human Tumor Cell Lines.

The palladium(II) bis-chelate complexes of the type [Pd(TSC(1-5))2] (6-10), with their corresponding ligands 4-phenyl-1-(acetone)-thiosemicarbazone, HTSC(1) (1), 4-phenyl-1-(2'-chloro-benzaldehyde)-thiosemicarbazone, HTSC(2) (2), 4-phenyl-1-(3'-hydroxy-benzaldehyde)-thiosemicarbazone, HTSC(3) (3), 4-phenyl-1-(2'-naphthaldehyde)-thiosemicarbazone, HTSC(4) (4), and 4-phenyl-1-(1'-nitro-2'-naphthaldehyde)-thiosemicarbazone, HTSC(5) (5), were synthesized and characterized by elemental analysis and spectroscopic techniques (IR and (1)H- and (13)C-NMR). The molecular structure of HTSC(3), HTSC(4), and [Pd(TSC(1))2] (6) have been determined by single crystal X-ray crystallography. Complex 6 shows a square planar geometry with two deprotonated ligands coordinated to Pd(II) through the azomethine nitrogen and thione sulfur atoms in a cis arrangement. The in vitro cytotoxic activity measurements indicate that the palladium(II) complexes (IC50 = 0.01-9.87 µM) exhibited higher antiproliferative activity than their free ligands (IC50 = 23.48-70.86 and >250 µM) against different types of human tumor cell lines. Among all the studied palladium(II) complexes, the [Pd(TSC(3))2] (8) complex exhibited high antitumor activity on the DU145 prostate carcinoma and K562 chronic myelogenous leukemia cells, with low values of the inhibitory concentration (0.01 and 0.02 µM, resp.).

Unprecedented bending and rearrangement of f-element sandwich complexes induced by superbulky cyclooctatetraenide ligands.

The use of the superbulky cyclooctatetraenide dianion ligand [C(8)H(6)(SiPh(3))(2)](2-) (= COT(BIG)) in organo-f-element chemistry leads to unprecedented effects such as the formation of a significantly bent anionic Ce(III) sandwich complex, a novel cerocene formed by sterically induced SiPh(3) group migration, as well as the first example of a bent uranocene.

Facile access to tetravalent cerium compounds: one-electron oxidation using iodine(III) reagents.

Readily accessible and easy-to-use phenyliodine(III) dichloride, PhICl(2), has been established as an innovative and superior reagent for the one-electron oxidation of cerium(III) complexes, comprising amide, amidinate, and cyclopentadienyl derivatives. Its use allowed the successful synthesis and structural characterization of the first members of three new classes of chloro-functionalized (organo)cerium(IV) compounds, including the long sought-after Cp(3)CeCl.

Encapsulation of cyclooctatetraenyl dianion in an unusual organic/inorganic lanthanide triple-decker sandwich complex.

Treatment of [(COT)Nd(THF)(2)(mu-Cl)](2) with dilithium tetraphenyldisiloxanediolate, (LiOSiPh(2))(2)O, in a molar ratio of 1 : 4 afforded the novel organic/inorganic triple-decker complex (mu-eta(8):eta(8)-COT)[Nd{(Ph(2)SiO)(2)O}(2){Li(THF)(2)}{Li(THF)}](2) (1) which was structurally characterized by X-ray diffraction.

Bis(1H-pyrazole-κN)bis-(2,4,6-tri-isopropyl-benzoato-κO)cobalt(II).

The title compound, [Co(C(16)H(23)O(2))(2)(C(3)H(4)N(2))(2)] or (C(3)H(4)N(2))(2)Co(O(2)CC(6)H(2) (i)Pr(3)-2,4,6), is a rare example of a tetra-coordinate cobalt(II) carboxyl-ate stabilized by ancillary N-heterocyclic ligands. The Co(II) ion resides on a crystallographic twofold axis so that the asymmetric unit comprises one half-mol-ecule. Due to the steric bulk of the 2,4,6-triisopropyl-phenyl substituents, the carboxyl-ate ligands are both coordinated in a monodentate fashion despite the low coordination number. The coordination geometry around the central Co(II) ion is distorted tetra-hedral with angles at Co ranging from 92.27 (18)° to 121.08 (14)°.

Tris(N,N'-diisopropyl-benzamidinato)cerium(III).

The title compound, [Ce(C(13)H(19)N(2))(3)], was obtained in moderate yield (67%) by treatment of anhydrous cerium trichloride with three equivalents of Li[PhC(N(i)Pr)(2)] in tetra-hydro-furan. It is the first homoleptic lanthanide complex of this amidinate ligand. The central Ce(III) ion is coordinated by three chelating benzamidinate anions in a distorted octa-hedral fashion, with Ce-N distances in the narrow range 2.482 (2)-2.492 (2) Å. The dihedral angles between the phenyl rings and the chelating N-C-N units are in the range 73.3-87.9°, thus preventing conjugation between the two π-systems. The mol-ecule is located on a twofold rotation axis, and one of the phenyl rings is equally disordered over two alternative symmetry-equivalent positions around this axis.

[N,N'-Bis(2,6-diisopropyl-phen-yl)methanimidamidato][η-1,4-bis-(tri-methyl-sil-yl)cyclo-octa-tetra-enyl](tetra-hydro-furan)-samarium(III) toluene monosolvate.

The title compound, [Sm(C(25)H(35)N(2))(C(14)H(24)Si(2))(C(4)H(8)O)]·C(7)H(8), was prepared by treatment of anhydrous samarium trichloride with a 1:1 mixture of in situ-prepared Li(DippForm) [DippFormH = N,N'-bis-(2,6-diisopropyl-phen-yl)methanimidamide] and Li(2)(COT'') [COT'' = 1,4-bis-(trimethyl-sil-yl)cyclo-octa-tetra-enyl] in tetra-hydro-furan (THF). Despite the presence of two very bulky ligands (COT'' and DippForm), the mol-ecule still contains one coordinated THF ligand. The overall coordination geometry around the Sm(III) atom resembles a three-legged piano-stool with the COT'' ligand being η(8)-coordinated and the DippForm(-) anion acting as an N,N'-chelating ligand [Sm-N = 2.5555 (15) and 2.4699 (15) Å]. The asymmetric unit also contains a disordered mol-ecule of toluene, the refined ratio of the two components being 0.80 (4):0.20 (4).

4-Thiolatobenzoate-bridged gold/zirconium complex and its mononuclear precursors.

The selective synthesis of a Au (I) complex of 4-mercaptobenzoic acid, namely, [Au(SC 6H 4-4-COOH)(PMe 2Ph)] ( 1), is reported. It shows interesting photoluminescence (PL) properties, for example, high PL quantum yield, multicomponent emission, and an unusually large PL lifetime. This complex was further applied as a metalloligand for the synthesis of [Cp* 2Zr{kappa (1) O-OOCC 6H 4-4-SAu(PMe 2Ph)}{kappa (2) O,O'-OOCC 6H 4-4-SAu(PMe 2Ph)}] ( 3), one of the rare Au (I)/Zr (IV) complexes. For the first time the exchange between the two ligands, which are bound in mono- and bidentate fashion, respectively, could be observed with the help of variable-temperature NMR spectroscopy. For the corresponding monometallic zirconocene complex [Cp* 2Zr(kappa (1) O-O 2CC 6H 4-4-SH)(kappa (2) O,O'-O 2CC 6H 4-4-SH)] ( 2) the activation parameters of this exchange could be determined by line shape analysis.

trans-Bis(perchlorato-κO)tetra-kis(1H-pyrazole-κN)copper(II).

The title compound, [Cu(ClO(4))(2)(C(3)H(4)N(2))(4)], was obtained unexpectedly by the reaction of copper(II) perchlorate hexa-hydrate with equimolar amounts of 1-chloro-1-nitro-2,2,2-tripyrazolylethane in methanol solution. The crystal structure comprises octa-hedrally coordinated Cu(2+) ions, located on an inversion centre, with four pyrazole ligands in the equatorial plane. The average Cu-N distance is 2.000 (1) Å. Two perchlorate ions are coordinated to copper in trans positions [Cu-O = 2.4163 (11) Å].

1,2,3,4-Tetra-methyl-cyclo-pent-2-ene-1,4-diol.

The title compound, C(9)H(16)O(2), crystallizes with two mol-ecules in the asymmetric unit. The structure displays inter-molecular O-H⋯O hydrogen bonding.

1,2,3-Triphenyl-1,2-dihydro-quinoxaline.

The title compound, C(26)H(20)N(2), first reported in 1891, was obtained as a by-product in the preparation of benzildianil from benzil and excess aniline. The dihedral angles between the fused benzene ring and the pendant phenyl rings are 17.93 (11), 53.18 (10) and 89.08 (12)°.

Unusual inorganic ring systems of scandium and yttrium containing group 13 Metals: coordination of monomeric Me(2)InOMe to yttrium.

Novel transformations of lanthanide(III) disiloxanediolates with group 13 metal trialkyls are reported. Treatment of the scandium metallacrown complex [{(Ph2SiO)2O}2{Li(DME)}2]ScCl.THF (1) with AlMe3 resulted in an Li-Al exchange reaction and the formation of the heterotrimetallic inorganic ring system [{(Ph2SiO)2O}2{Li(THF)2}AlMe2]ScCl.THF (2). The related yttrium metallacrown [{(Ph2SiO)2O}2{Li(THF)2}2]YCl.THF (3) reacts with InMe3 under the formation of the heterobimetallic Y/In disiloxanediolate complex [{(Ph2SiO)2O}2{InMe2(OMe)}2InMe2]Y (4). In the latter, two monomeric Me2InOMe ligands are stabilized through coordination to yttrium.

Structural varieties in heterobimetallic lanthanide disiloxanediolates: "inorganic metallocenes" versus in-plane metallacrowns.

The previously proposed concept of "inorganic metallocenes" of group 3 and rare-earth elements has been tested by preparing a series of novel disiloxanediolates with metals displaying different ionic radii. For the smaller scandium and yttrium, approximately planar arrangements of the disiloxanediolate frameworks with solvent and chloride ligands in trans positions were found. Thus, the compounds [{(Ph2SiO)2O}2{Li(DME)}2]ScCl(THF/DME) (2; DME=1,2-dimethoxyethane and THF=tetrahydrofuran) and [{(Ph2SiO)2O}2{Li(THF)2}2]YCl(THF) (3) can be described as heterobimetallic inorganic ring systems or metallacrown complexes with "in-plane" coordination of the metal. In contrast, "out-of-plane" geometries with cis coordination of additional ligands were identified in the praseodymium derivatives [{(Ph2SiO)2O}2{Li(THF)2}{Li(THF)}]Pr(micro-Cl)2Li(THF)2 (4) and [{(Ph2SiO)2O}2{Li(DME)}2]PrCl(DME) (5). These compounds can be viewed as analogues of the known metallocene derivatives (C5Me5)2Pr(micro-Cl)2Li(THF)2 and (C5Me5)2PrCl(THF). The molecular structures of 2-5 have been determined by X-ray diffraction.

Unprecedented examples of heterobimetallic cerium(IV) disiloxanediolates.

The first disiloxanediolate complexes of cerium(IV) are reported. Starting from the readily available precursor ((t)BuO)(3)Ce(IV)(NO(3))(THF)(2) (1), we prepared the novel heterobimetallic compounds [{(Ph(2)SiO)(2)O}{K(THF)(2)}](2)Ce(O(t)Bu)(2) (2) and [{(Ph(2)SiO)(2)O}(2){(DME)-KO(t)Bu}{(Ph(2)SiO(2))K}Ce](2) (3) and structurally characterized them by X-ray diffraction.

Synthesis and structures of heteroleptic silylenes.

The reaction of benzamidinato silicon trichloride [{PhC(NR)2}SiCl3] [R = Bu(t) (1), SiMe3 (2)] with 2 equiv of potassium in THF afforded mononuclear chlorosilylene [{PhC(NBu(t))2}SiCl] (3) and [{PhC(NSiMe3)2}2SiCl2] (4), respectively. Compound 4 was formed by the disproportionation of unstable [{PhC(NSiMe3)2}SiCl]. The reaction of [{PhC(NBu(t))2}SiCl3] (1) with 1 equiv of LiR (R = NMe2, OBu(t), OPr(i), PPr(i)2) in THF yielded [{PhC(NBu(t))2}SiCl2R] [R = NMe2 (5), OBu(t) (6), OPr(i) (7), PPr(i)2 (8)]. Treatment of 5-8 with 2 equiv of potassium in THF resulted in the novel heteroleptic silylene [{PhC(NBu(t))2}SiR] [R = NMe2 (9), OBu(t) (10), OPr(i) (11), PPr(i)2 (12)]. Compounds 4, 9, and 12 have been analyzed by X-ray crystallography.

Axial chirality and supramolecular interactions: the case of [(kappa2-P,P-[PPh2NMe]2CO)Cu(I)Cl]2.

The title compound [(kappa2-P,P-[PPh(2)NMe}2CO)Cu(I)Cl]2 (4) is readily formed by the reaction between (PPh2NMe)2CO and copper(I) chloride. Compound 4 forms a two-dimensional supramolecular network of Cu2Cl2-centered dimers that are linked by pi-pi interaction between the phenyl substituents on phosphorus in the solid state. Because of the nature of these pi-pi interactions, only one of the three possible enantiomers, the meso form, can be observed in the crystals.

(R/S)A2- or (R,S/S,R)p,p'-[Pd(kappa(2)-P,P-[P(OC6H3But2-2,4)2N(Me)C(O)N(Me)PPh(2)]Cl2]: chirality created by ring tilting.

The reaction of the unsymmetric bisphosphanyl urea ligand P(OC(6)H(3)Bu(t)(2)-2,4)(2)N(Me)C(O)N(Me)PPh(2) with [Pd(cod)Cl(2)] (cod = 1,5-cyclooctadiene) results in the chiral palladacycle (R,S)(A2)-[Pd(kappa(2)-P,P-[P(OC(6)H(3)Bu(t)(2)-2,4)(2)N(Me)C(O)N(Me)PPh(2)]Cl(2)]. The chirality of the title compound is caused by the tilting of the central, six-membered PdP(2)N(2)C ring along one of the two P-N vectors and comprises two chiral planes and one chiral axis.

Construction of extended networks with a trimeric pyrazole synthon.

A H-bonded pyrazole trimeric motif drives the self-association of bifunctional tetramethyl-4,4'-bipyrazole, yielding highly interpenetrated 3D frameworks and allowing the engineering by design of a novel supramolecular isomer.