Crystal Structures Of 1a Research Articles

Synthesis, characterization, DNA-binding study and anticancer properties of ternary metal(ii) complexes of edda and an intercalating ligand

A series of ternary metal(ii) complexes {M(phen)(edda); 1a (Cu), 1b (Co), 1c (Zn), 1d (Ni); H(2)edda = N,N(')-ethylenediaminediacetic acid} of N,N'-ethylene-bridged diglycine and 1,10-phenanthroline were synthesized and characterized by elemental analysis, FTIR, UV-visible spectroscopy and magnetic susceptibility measurement. The interaction of these complexes with DNA was investigated using CD and EPR spectroscopy. MTT assay results of 1a-1c , screened on MCF-7 cancer cell lines, show that synergy between the metal and ligands results in significant enhancement of their antiproliferative properties. Preliminary results from apoptosis and cell cycle analyses with flow cytometry are reported. seems to be able to induce cell cycle arrest at G(0)/G(1). The crystal structure of 1a is also included.

Two new N-heterocyclic carbene silver(I) complexes with the π–π stacking interactions

The precursors bis[ N-(alkyl)benzimidazoliumylmethyl]durene halide ( 1a: alkyl = C 2H 5, halide = Br −; 1b: alkyl = n-C 4H 9, halide = Cl −; durene = 1,2,4,5-tetramethylbenzene) and their two new NHC silver(I) complexes [Durene(CH 2BimyEtAgBr) 2] ( 2a) and [Durene(CH 2Bimy n BuAgCl) 2] ( 2b) (Bimy = benzimidazol-2-ylidene) have been prepared and characterized. In the crystal structures of 2a and 2b the aromatic π–π stacking interactions are observed.

Two Routes of Electrophilic Addition and Unexpected Cluster Core Transformation in the Reactions of the K2[Fe3(μ3‐Q)(CO)9] (Q = Se, Te) Clusters with iPr2PCl

AbstractThe reactions of the K2[Fe3(μ3‐Q)(CO)9] (Q = Se (K2[1a]), Te (K2[1b])) clusters with iPr2PCl in THF lead to the formation of mixtures of two products: [{Fe2(CO)6(μ‐PiPr2)}2(μ4,η2‐Q2)] (2a, 2b) and [Fe3(μ3‐Q)(μ‐PiPr2)2(CO)7] (3a, 3b). The compounds 3a and 3b are the products of addition of two {PiPr2}+ units to two Fe‐Fe edges of the initial cluster accompanied by the elimination of two CO‐ligands. The compounds 2a and 2b are the products of the initial cluster core fragmentation followed by assembling of the diiron fragments via Q–Q bond formation.In contrast to that the reaction of K2[1a] with iPr2PCl in CH2Cl2 leads mostly to the electrophilic insertion of {PiPr2}+ into the Se–Fe bond and formation of [(μ‐H)Fe3(μ3,η2‐SePiPr2)(CO)9] (4a). Reaction of K2[1b] with iPr2PCl in CH2Cl2 leads primarily to unstable unidentified products, although 2b and 3b in minor amounts present in the reaction solution. The crystal structures of 2a, 2b, 3a and 4a were determined by single‐crystal X‐ray diffraction.

Synthesis and Catalytic Applications of Chiral Hydridoiridium(III) Complexes with Diamine/Bis(monophosphane) and Diamine/Diphosphane Coordination

AbstractThe P2/N2‐coordinated cis‐dihydridoiridium(III) chelate complexes (OC‐6‐13)‐[IrH2(H2N∩NH2)(PR3)2]BF4 [PR3 = PPh3, H2N∩NH2 = 1,2‐(H2N)2C6H4 (1a); (1R,2R)‐(H2N)2C6H10 {(R,R)‐dach} (1b); (R)‐2,2′‐diamino‐1,1′‐binaphthyl {(R)‐dabin} (1c); PR3 = PiPr3, H2N∩NH2 = (R,R)‐dach (2a), (R)‐dabin (2b); PR3 = PCy3, H2N∩NH2 = (R)‐dabin (3)] were obtained by treating the respective diamine ligands with labile precursors such as [IrH2(OCMe2)2(PPh3)2]BF4, [(η4‐1,5‐C8H12)Ir(PPh3)2]BF4, or [IrH5(PR3)2]/HBF4 (R = iPr, Cy). While oxidative addition of HCl to [(η4‐1,5‐C8H12)Ir{(S,S)‐bdpcp}]BF4 [(S,S)‐bdpcp = (1S,2S)‐(Ph2P)2C5H8] yields the usual mononuclear adduct [(η4‐1,5‐C8H12)Ir(H)(Cl){(S,S)‐bdpcp}]BF4 (4), similar treatment of [(η4‐1,5‐C8H12)Ir{(R)‐binap}]BF4 furnishes the triply chlorido‐bridged diiridium complex [{(R)‐binap}2Ir2H2(μ‐Cl)3]BF4 (5). Opening of the μ‐Cl bridges of 5 by N,N nucleophiles was used to synthesise the three diamine/(R)‐binap complexes [Ir(H)(Cl)(H2N∩NH2){(R)‐binap}]BF4 [H2N∩NH2 = (1R,2R)‐H2NCH(Ph)CH(Ph)NH2 {(R,R)‐dpen} (6a), (R,R)‐dach (6b), and H2NCMe2CMe2NH2 {tmen} (6c). Whereas the dihydrides [IrH2{(R,R)‐dach}(PR3)2]BF4 and [IrH2{(R)‐dabin}(PR3)2]BF4 (R = iPr, Ph) are only poor (pre)catalysts for the enantioselective hydrogenation of acetophenone, complexes 6a–c catalyze the formation of 1‐phenylethanol in good enantiomeric excess [eemax = 82–84 % (S)] in the presence of base. The crystal structures of 1a, 4, and 5 have been determined. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Synthesis, Characterization, and Reactivity of Niobium and Tantalum Complexes Bearing Metal−Nitrogen Bonds. X-ray Molecular Structure of [Nb(C5H4SiMe3){NH(CH2)2-η-NH2}Cl3] and the Novel Tetranuclear Niobium Oxo Derivative [{Nb(C5H4SiMe3)Cl(μ2-O)}4(Cl)2(μ3-O)

The reaction of the cyclopentadienyl-silyl-amido titanium compound [Ti{η5-C5H4SiMe2-η-N(CH2)2-η-NH2}Cl2] with group 5 metal monocyclopentadienyl complexes [MCpRCl4] (M = Nb, Ta; CpR = C5H4SiMe3 (Cp‘), C5Me5 (Cp*)) afforded the heterobimetallic complexes [TiCl2{η5-C5H4SiMe2-η-N(CH2)2-κ-NH2}MCpRCl4] (M = Nb, CpR = Cp‘, 2a; Cp*, 2b; M = Ta, CpR = Cp‘, 3a; Cp = Cp*, 3b). Compounds 2 evolve at room temperature to give a three-component mixture, the chlorosilyl-substituted cyclopentadienyl titanium compound [Ti(η5-C5H4SiMe2Cl)Cl3], the corresponding mononuclear amido-amino, [NbCpR{NH(CH2)2-η-NH2}Cl3] (CpR = Cp‘, 4a; Cp*, 4b), and the dinuclear imido niobium complexes [{NbCpRCl2}2(μ-N(CH2)2-η-N)] (CpR = Cp‘, 5a; Cp*, 5b). In contrast, the analogue tantalum complexes thermally degraded, when CpR = Cp‘ at normal temperature, whereas when CpR = Cp* at temperatures higher than 50 °C, they gave a unique tantalum complex, the corresponding mononuclear amido-amino derivative [TaCpR{NH(CH2)2-η-NH2}Cl3] (CpR = Cp‘, 6a; Cp*, 6b). Alternatively, these group 5 complexes were prepared by direct reaction of the monocyclopentadienyl derivatives with the corresponding organic diamine, in the appropriate proportion and reaction conditions. Tantalum amino adducts were observed as intermediate species in the course of such reactions, and even the dinuclear derivative [{TaCp*Cl4}2(μ-NH2(CH2)2NH2)] (8) could be isolated. Hydrolysis of the dinuclear imido complex 5a yielded the tricyclic tetranuclear niobium oxo derivative [{NbCp‘Cl(μ2-O)}4(Cl)2(μ3-O)] (9), which displays an asymmetrical structure as a consequence of the triply connected oxygen site. These compounds were characterized by elemental analysis and NMR spectroscopy, and the crystal structures of 4a and 9 were determined by X-ray diffraction methods.

Sterically hindered and completely arrested nitrogen inversion in pyrazolidines

Syntheses of trans-1,2-di- tert-butylpyrazolidine 1, d, l- and semi- meso-1,2-diisopropyl-3,5-dimethylpyrazolidines, 2a and 2b, respectively, have been developed. Activation parameters of the nitrogen inversion in 1 (Δ G ≠ = 123 kJ mol −1 at 110 °C, Δ H ≠ = 114 kJ mol −1, Δ S ≠ = −15 J K −1 mol −1) have been determined. The steric veto of the nitrogen inversion in 2a has been confirmed. Chemical transformations of 1 have been studied, and the crystal structures of 2a·picrate and 2b·HCl determined.

Zirconium(IV) Tris(phosphinoamide) Complexes as a Tripodal‐Type Metalloligand: A Route to Zr–M (M = Cu, Mo, Pt) Heterodimetallic Complexes

AbstractTreatment of ZrCl4 with 3 equiv. of Li(PPh2NR) (R = tBu, iPr) gives tris(phosphinoamide)zirconium complexes, (PPh2NR)3ZrCl [R = tBu (1a), iPr (1b)], in high yield. Crystal structures of 1a,b show that three phosphorus atoms are coordinated to the zirconium center in the solid state, whereas variable temperature NMR studies indicate a reversible coordination/dissociation process of three phosphorus atoms in the solution state. Reaction of 1a,b with CuCl give rise to the formation of Zr–Cu heterodimetallic complexes, ClCu(Ph2PNR)3ZrCl [R = tBu (2a), iPr (2b)]. The molecular structures of 2a,b show that the Cu atom adopts a pseudotetrahedral coordination geometry with tripodal phosphorus moieties and a chlorine atom, whereas the ligand arrangement around the Zr atom is trigonal bipyramidal with the linear Cl–Zr–Cu axis at the apical site. A Zr–Mo heterodimetallic complex, (CO)3Mo(Ph2PNiPr)3ZrCl (3), is synthesized from 1b and Mo(CO)3(CH3CN)3, in which the ligands around the Mo center are arranged octahedrally, and three phosphorus moieties are coordinated in the fac‐P3 fashion. The reaction of 1b with a square planar PtII precursor, such as (COD)PtCl2, is unique and gives (κ2‐Ph2PNiPr)Pt(Ph2PNiPr)2ZrCl3 (4), which is the first example of a Zr–Pt zwitterionic heterodimetallic complex. The reaction involves intramolecular migration of two chlorine atoms from Pt to Zr as well as that of a Ph2PNiPr moiety from Zr to Pt.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

New N-heterocyclic carbene silver(I) and mercury(II) 2-D supramolecular layers by the π–π stacking interactions

The precursor 1-(9-anthracenylmethyl)-3-alkylbenzimidazolium chlorides ( 1a, alkyl = C 4H 9, 1b, alkyl = C 6H 13) and their three new NHC silver(I) and mercury(II) complexes {[1-(9-anthracylmethyl)-3-alkylbimy]MCl} 2 ( 2a, alkyl = C 4H 9, M = Ag; 2b, alkyl = C 6H 13, M = Ag; 3a, alkyl = C 4H 9, M = Hg; bimy = benzimidazol-2-ylidene) have been prepared and characterized. The crystal structures of 2a, 2b and 3a showed that 2-D supramolecular layers are formed by both benzimidazole ring head to tail π–π stacking interactions and anthracene ring face-to-face π–π stacking interactions.

Synthesis, Structure, and Luminescence of Di- and Trinuclear Palladium/Gold and Platinum/Gold Complexes with (2,7-Di-tert-butylfluoren-9-ylidene)methanedithiolate,1

Acetone solutions of [Au(OClO3)(PCy3)] react with complexes [M{S2C=(t-Bu-fy)}2]2- [t-Bu-fy=2,7-di-tert-butylfluoren-9-ylidene; M=Pd (2a), Pt (2b)] or [M{S2C=(t-Bu-fy)}(dbbpy)] [dbbpy=4,4'-di-tert-butyl-2,2'-bipyridyl; M=Pd (3a), Pt (3b)] to give the heteronuclear complexes [M{S2C=(t-Bu-fy)}2{Au(PCy3)}2] [2:1 molar ratio; M=Pd (4a), Pt (4b)], [M{S2C=(t-Bu-fy)}(dbbpy){Au(PCy3)}]ClO4 [1:1 molar ratio; M=Pd (5a), Pt (5b)], or [M{S2C=(t-Bu-fy)}(dbbpy){Au(PCy3)}2](ClO4)2 [2:1 molar ratio; M=Pd (6a), Pt (6b)]. The crystal structures of 3a, 4a, 4b, 5b, and 6a have been solved by single-crystal X-ray studies and, in the cases of the heteronuclear derivatives, reveal the formation of short Pd...Au or Pt...Au metallophilic contacts in the range of 3.048-3.311 A. Compounds 4a and b and 5a and b undergo a dynamic process in solution that involves the migration of the [Au(PCy3)]+ units between the sulfur atoms of the dithiolato ligands. The coordination of 2a and b and 3a and b to [Au(PCy3)]+ units results in important modifications of their photophysical properties. The dominant effect in the absorption spectra is an increase in the energy of the MLCT (4a and b) or charge transfer to diimine (5a, b, 6a, b) transitions because of a decrease in the energies of the mixed metal/dithiolate HOMOs. The Pd complexes 2a and 4a are luminescent at 77 K, and the features of their emissions are consistent with an essentially metal-centered 3d-d state. The Pt/Au complexes are also luminescent at 77 K, and their emissions can be assigned as originating from a MLCT triplet state (4b) or a mixture of charge transfer to diimine and diimine intraligand pi-pi* triplet states (5b and 6b).

Monoarylplatinum(II) Complexes with a 2-Phenylpyridyl Ligand and Coordinated Solvent, [Pt(Ar)(Phpy)(solv)] (Phpy = 2-phenylpyridyl; solv = NCCH3, dmso). Preparation from [Pt(Ar)2(solv)2], Structures, and Chemical Properties

Diarylplatinum(II) complexes, [Pt(Ar)2(dmso)2] (Ar = C6H3Me2-3,5 (1a), C6H3(CF3)2-3,5 (1b), Ph (1c); dmso = dimethyl sulfoxide) and [Pt{C6H3(CF3)2-3,5}2(NCCH3)2] (2b), were prepared and fully characterized. Heating mixtures of 2-phenylpyridine (PhpyH) with the complexes in solution at 50 °C caused coordination of PhpyH and its cyclometalation accompanied by elimination of arene to produce monoarylplatinum(II) complexes with a solvent ligand, [Pt(Ar)(Phpy)(dmso)] (Ar = C6H3Me2-3,5 (3a), C6H3(CF3)2-3,5 (3b), Ph (3c)) and [Pt{C6H3(CF3)2-3,5}(Phpy)(NCCH3)] (4b). The rate of the reactions decreased in the order 1a > 1c > 2b > 1b. Crystal structures of 3a,c and 1H NMR spectra of the complexes showed that the aryl ligand and phenyl group of the Phpy ligand occupied cis positions. A diarylplatinum complex with a monodentate phenylpyridyl ligand, [Pt(C6H3Me2-3,5)2(CF3PhpyH)(dmso)] (5), was isolated and characterized using X-ray crystallography. The neutral arylplatinum(II) complex 4b underwent exchange of the acetonitrile ligand more easily than the cationic complex, [Pt{C6H3(CF3)2-3,5}(bpy)(NCCH3)]+, because of the C-bonded phenyl group of the Phpy ligand had a greater trans effect than the N-bonded pyridyl group of bpy. Oxidative addition of I2 to 3a,b and 4b readily gave Pt(IV) dimeric complexes with bridging iodo ligands, [(Pt(Ar)(Phpy)I)2(μ-I)2] (Ar = C6H3Me2-3,5 (7a), C6H3(CF3)2-3,5 (7b)). The dimeric structure of 7b was confirmed using X-ray crystallography.

Synthesis and structural characterization of two novel N -heterocyclic carbene complexes of Rh(I)

Two new N-heterocyclic carbene (NHC) ligands with p-methylphenyl and p-methoxyphenyl substituents on 4,5-positions and methoxyethyl pendants on N atoms of the imidazole ring were complexed together with cyclooctadiene and an iodide ion to Rh(I) to give 4a and 4b, respectively. The complexes were characterized by elemental analyses, NMR and IR spectroscopy. In addition, molecular and crystal structure of 4a was determined by single-crystal X-ray methods. In 4a the rhodium ion has distorted square planar coordination geometry chelating with cyclooctadiene (COD) ligand. Molecules of 4a form polymeric chains along the c axis through C–H ··· I hydrogen bonds.

2- N-(Quinoline-8-yl)iminomethylphenolate – A (ONN)-tridentate ligand system in silicon complex chemistry

Condensation of salicylic aldehyde with 8-aminoquinoline afforded (ONN)-tridentate ligand 2- N-(quinoline-8-yl)iminomethylphenol ( 1), which was obtained as a crystalline solid for the first time and characterized by X-ray diffraction. Reaction between 1 and phenyltrichlorosilane in the presence of triethylamine results in the formation of the 1:1 chelate complex dichloro-[2- N-(quinoline-8-yl)imino-methylphenolato]-phenylsilane ( 2a) bearing a hexacoordinate silicon atom. The crystal structure of 2a ∗CHCl 3 reveals a rare coordination pattern: Although carrying two chlorine atoms, the hexacoordinate Si atom coordinates the tridentate ligand’s imine N atom in the trans position to the phenyl group. Silylation of 1 with hexamethyldisilazane and synthesis of dichloro-[2- N-(quinoline-8-yl)iminomethylphenolato]-methylsilane ( 2b) yielded few crystals of [2- N-(quinoline-8-yl)iminomethylphenolato]-salicylaldiminato-methylsiliconium chloride ( 2b′) as byproduct. 2b′ is the first structurally characterized main group element complex of salicylaldimine. This bidentate ligand exhibits an unusually strong N → Si coordination.

Crystal Structures of Tetrakis‐(4‐chlorophenylthio)‐butatriene and Tetrakis‐(tert‐butylthio)‐butatriene

Tetrakis‐(4‐chlorophenylthio)‐butatriene (3a) and tetrakis‐(tert‐butylthio)‐butatriene (3b) were synthesized, and their crystal structures were determined. The compound 3a is monoclinic, space group P21/c, a=6.9785(8), b=8.6803(9), c=22.884(2) Å, β=93.887(6)o, V=1383.0(3) Å3, Z=2. The compound 3b is monoclinic, space group P21/n, a=11.0615(6), b=10.8507(4), c=11.2717(6) Å, β =116.427(2)o, V=1211.5(1) Å3, Z=4. The title compounds 3a and 3b reside on an inversion center so that only half of the molecule is crystallographically unique. Both compounds are not planar. The crystal structures of 3a and 3b have cumulated double bonds. The C7–C8–C8i and C5–C6–C6i angles that show the linearity in both structures, respectively, are 176.4(3)° in 3a and 175.6(2)° in 3b.

Preparation and Structure of New Phenylplatinum Complexes Containing Silsesquioxane as a Monodentate or Bidentate Ligand

Incompletely condensed silsesquioxanes, R7Si7O9(OH)3 (R = cyclo-C5H9, iso-C4H9), react with trans-[PtI(Ph)(L)2] (L = PEt3, PMe2Ph) at room temperature in the presence of Ag2O to yield platinum complexes with a monodentate O-coordinated silsesquioxane, trans-[Pt{O10Si7R7(OH)2}(Ph)(L)2] (1a: R = cyclo-C5H9; L = PEt3, 1b: R = iso-C4H9; L = PEt3, 2a: R = cyclo-C5H9; L = PMe2Ph, 2b: R = iso-C4H9; L = PMe2Ph). Reactions of silsesquioxanes with trans-[PtI(Ph)(PPh3)2] in the presence of Ag2O at 55 °C afford unexpected Pt−Ag heterobimetallic complexes, [Pt{O11Si7R7(OH)(AgPPh3)}(Ph)(PPh3)] (3a: R = cyclo-C5H9, 3b: R = iso-C4H9), and a hydroxo-bridged dinuclear platinum complex, anti-[{PtPh(PPh3)}2(μ-OH)2] (4). These complexes were isolated and characterized by X-ray crystallography and 1H, 31P, 29Si, and 13C NMR spectroscopy. The crystal structures of 3a and 3b show a square-planar coordination around the Pt center bonded to Ph, PPh3, and bidentate O,O-coordinated silsesquioxane. One of the coordinated oxygen...

Preparation, reactivity and tautomeric preferences of novel (1H-quinolin-2-ylidene)propan-2-ones

1,1-Difluoro-3-(1H-quinolin-2-ylidene)propan-2-one 1a, 1,1,1-trifluoro-3-(1H-quinolin-2-ylidene)propan-2-one 1b, 1,1,1-trifluoro-3-(4-chloro-1H-quinolin-2-ylidene)propan-2-one 1c and 1,3-dibromo-1,1-difluoro-3-(2-quinolyl)propan-2-one 2 are prepared and characterized by various spectroscopic techniques. The crystal structure of 1a is determined by X-ray diffraction. Furthermore, a series of previously known non-halogenated (1H-quinolin-2-ylidene)propan-2-ones 1d-1h are oxidized with AgBrO3 in the presence of AlCl3. In all cases, 2-(1-bromo-1-chloromethyl)quinoline 3 is obtained in high yield. The bromination order and sites of 1a are analyzed based on ab initio MP2 and DFT calculations for the molecule and its anions.

Gyroscope-like Molecules Consisting of PdX2/PtX2 Rotators Encased in Three-Spoke Stators: Synthesis via Alkene Metathesis, and Facile Substitution and Demetalation

Reactions of trans-MCl2(P((CH2)6(CH=CH2)3)2 (M = a, Pd; b, Pt) and Grubbs' catalyst, followed by hydrogenation (ClRh(PPh3)3), give the title compounds trans-MCl2(P((CH2)14)3P) (2a, 37%; 2b, 43%). These react with LiBr, NaI, and KCN to give the corresponding MBr2, MI2, and M(CN)2 species (58-99%). 13C NMR data show that the MX2 moieties rapidly rotate within the diphosphine cage on the NMR time scale, even at -120 degrees C. The reaction of 2b and KSCN gives separable Pt(SCN)2 and Pt(SCN)(NCS) species (5b, 27%; 6b, 30%), and that with Ph2Zn gives a PtPh2 species (7b, 55%). NMR data for 5b-7b show that MX2 rotation is no longer rapid. Reactions of 2b with excess NaCCH or KCN afford the free dibridgehead diphosphine P((CH2)14)3P (66-83%), presumably as an "in/in" isomer, as addition of PtCl2 regenerates 2b. The crystal structures of 2a and 7b are analyzed with respect to MX2 rotation.

Ligand Bridged Heterodinuclear Transition Metal Complexes – Syntheses, Structures and Electrochemical Investigations

AbstractThe syntheses of the homo‐ and hererobimetallic compounds [Ln1M(η5‐C5H4)CMe2(η5‐C9H6)2MLn] (2a‐5d), [(C9H7)CMe2(η5‐C5H4)Fe(η5‐C5H4)CMe2(η5‐C9H6)2MLn] (6a‐c), and [(η5‐C5H4)CMe2(η5‐C9H6)2MLn]2Fe (7a‐b) are reported with 1MLn = Rh(cod) 2, Ir(cod) 3, Mn(CO)3 4 and FeCp 5, 2MLn = Rh(cod) a, Ir(cod) b, Mn(CO)3 c and FeCp d, respectively. Crystal structures of 3a, 3b and 5c are described showing two different ligand conformations in form of two rotamers. The energetic difference between these both rotamers is insignificant small in the gas phase according to DFT calculations. The rotation barrier for the species has been determined to 23 kJ/mol. According to the absence of intermolecular interactions in the solid state, the preference for one of the conformers is deduced from packing effects. All complexes are investigated by cyclic voltammetry. The shift of the redox potentials with respect to the mononuclear reference systems is a suitable tool to determine intermetallic electronic interaction. For some compounds, the normal behaviour with an increasing separation of the redox potentials is observed. A second group of complexes shows the opposite behaviour with a decreasing in the potential differences. A mechanism of intramolecular catalytic oxidation is supposed for that species.

New diruthenium vinyliminium complexes from the insertion of alkynes into bridging aminocarbynes

Primary alkynes R′C CH [R′ = Me 3Si, Tol, CH 2OH, CO 2Me, (CH 2) 4C CH, Me] insert into the metal–carbon bond of diruthenium μ-aminocarbynes [Ru 2{μ-CN(Me)(R)}(μ-CO)(CO)(MeCN)(Cp) 2][SO 3CF 3] [R = 2,6-Me 2C 6H 3 (Xyl), 1a; CH 2Ph (Bz), 1b; Me, 1c] to give the vinyliminium complexes [Ru 2{μ-η 1:η 3-C(R′) CHC N(Me)(R)}(μ-CO)(CO)(Cp) 2][SO 3CF 3] [R = Xyl, R′ = Me 3Si, 2a; R = Bz, R′ = Me 3Si, 2b; R = Me, R′ = Me 3Si, 2c; R = Xyl, R′ = Tol, 3a; R = Bz, R′ = Tol, 3b; R = Bz, R′ = CH 2OH, 4; R = Bz, R′ = CO 2Me, 5a; R = Me, R′ = CO 2Me, 5b; R = Xyl, R′ = (CH 2) 4C CH, 6; R = Xyl, R′ = Me, 7a; R = Bz, R′ = Me, 7b; R = Me, R′ = Me, 7c]. The related compound [Ru 2{μ-η 1:η 3-C[C(Me) CH 2] CHC N(Me)(Xyl)}(μ-CO)(CO)(Cp) 2][SO 3CF 3], ( 9) is better prepared by reacting [Ru 2{μ-CN(Me)(Xyl)}(μ-CO)(CO)(Cl)(Cp) 2] ( 8) with AgSO 3CF 3 in the presence of HC CC(Me) CH 2 in CH 2Cl 2 at low temperature.In a similar way, also secondary alkynes can be inserted to give the new complexes [Ru 2{μ-η 1:η 3-C(R′) C(R′)C N(Me)(R)}(μ-CO)(CO)(Cp) 2][SO 3CF 3] (R = Bz, R′ = CO 2Me, 11; R = Xyl, R′ = Et, 12a; R = Bz, R′ = Et, 12b; R = Xyl, R′ = Me, 13). The reactions of 2– 7, 9, 11– 13 with hydrides (i.e., NaBH 4, NaH) have been also studied, affording μ-vinylalkylidene complexes [Ru 2{μ-η 1:η 3-C(R′)C(R″) C(H)N(Me)(R)}(μ-CO)(CO)(Cp) 2] (R = Bz, R′ = Me 3Si, R″ = H, 14a; R = Me, R′ = Me 3Si, R″ = H, 14b; R = Bz, R′ = Tol, R″ = H, 15; R = Bz, R′ = R″ = Et, 16), bis-alkylidene complexes [Ru 2{μ-η 1:η 2-C(R′)C(H)(R″)CN(Me)(Xyl)}(μ-CO)(CO)(Cp) 2] (R′ = Me 3Si, R″ = H, 17; R′ = R″ = Et, 18), acetylide compounds [Ru 2{μ-CN(Me)(R)}(μ-CO)(CO)(C CR′)(Cp) 2] (R = Xyl, R′ = Tol, 19; R = Bz, R′ = Me 3Si, 20; R = Xyl, R′ = Me, 21) or the tetranuclear species [Ru 2{μ-η 1:η 2-C(Me)CCN(Me)(Bz)}(μ-CO)(CO)(Cp) 2] 2 ( 23) depending on the properties of the hydride and the substituents on the complex. Chromatography of 21 on alumina results in its conversion into [Ru 2{μ-η 3:η 1-C[N(Me)(Xyl)]C(H)C CH 2}(μ-CO)(CO)(Cp) 2] ( 22). The crystal structures of 2a[CF 3SO 3] · 0.5CH 2Cl 2, 12a[CF 3SO 3] and 22 have been determined by X-ray diffraction studies.

Organoplatinum Polymorphs with Varying Molecular Conformation, Intermolecular Interaction, and Luminescence

Two mononuclear organoplatinum complexes based on the 2,2'-dipyridylamino derivative ligands (2,2'-dipyridylamino)phenyl triphenyl methane (dm) and (2,2'-dipyridylamino)phenyl triphenyl silane (dsi) with the formula PtPh 2 (dm) (1) and PtPh 2 (dsi) (2), respectively, have been synthesized. Both 1 and 2 have been found to form two polymorphs concomitantly: a colorless blue-luminescent form A (space group I4 1 /a) (1A and 2A) and a yellow nonluminescent form B (space group P2 1 /c) (1B and 2B). The crystal structures of 1A, 1B, and 2A were determined by single-crystal X-ray diffraction analyses. The CPh 3 group was found to display different conformations in the crystal lattices of 1A and 1B. Considerable variations in intermolecular interactions were also observed for the crystals of 1A and 1B. 2A was found to be isostructural to 1A. Spectroscopic study (UV-vis and luminescence) and molecular orbital calculations (Gaussian98) were performed to understand the color and luminescent differences between 1A and 1B. Intermolecular π-π stacking interactions between a phenyl of the CPh 3 group and the pyridyl of the 2,2'-dipyridylamino group were found to be the most likely cause for the absence of emission in the crystals of 1B.

4-Methoxy- and 4-cyano-substituted lithium aryloxides: electronic effects of substituents on aggregation

The para-substituted lithium aryloxides [{4-NC-C6H4OLi.(Pyr)2}2.Pyr] 1a, [{4-NC-C6H4OLi.(THF)2}2] 1b, [{4-MeO-C6H4OLi.Pyr}4] 2a, [4-MeO-C6H4OLi.(THF)n] 2b, [{4-NC-2,6-(t-Bu)2-C6H2OLi.(Pyr)2}infinity] 3a, [{4-NC-2,6-(t-Bu)2-C6H2OLi.(THF)2}infinity] 3b, [{4-MeO-2,6-(t-Bu)2-C6H2OLi.Pyr}2.(Pyr)2] 4a, and [4-MeO-2,6-(t-Bu)2-C6H2OLi.(THF)n] 4b were prepared by the direct deprotonation of the corresponding phenol with an alkyllithium base (BuLi or MeLi) in the appropriate solvent, either pyridine or THF. All compounds were characterized by 1H and 13C NMR spectroscopy, and the crystal structures of 1a, 1b, 2a, 3a, 3b and 4a were elucidated. The cyano derivatives 1a and 1b adopt discrete tetrasolvated Li2O2 ring dimers whereas the methoxy analogue 2a crystallizes as a tetrasolvated molecular tetramer with a pseudo cubic Li4O4 core. The sterically encumbered cyano derivatives 3a and 3b form isostructural 1D polymeric chains of monomers via bridging of the phenolate ligands through Li...NC and Li-O contacts. In comparison, the crystal structure of the methoxy counterpart 4a is a disolvated molecular Li2O2 ring dimer. Solution NMR spectroscopic studies of 1-4 in d5-pyridine and d8-THF indicate that the methoxy complexes are more highly aggregated than the cyano derivatives, consistent with the solid-state studies. Ab initio molecular orbital calculations at the HF/6-31G* level of theory indicate that the origin of the aggregation state variations between the cyano and methoxy complexes is due to electronic effects.