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The coordination abilities of the novel N,N'-diphosphino-silanediamine ligand of formula SiMe(2)(NtolPPh(2))(2) (SiNP, 1) have been investigated toward rhodium, and the derivatives [RhCl(SiNP)](2) (2), [Rh(SiNP)(COD)][BF(4)] (3), and Rh(acac)(SiNP) (4) have been synthesized. The stability of the dinuclear frame of [RhCl(SiNP)](2) (2) toward incoming nucleophiles has been shown to be dependent on their π-acceptor ability. Indeed, the mononuclear complexes RhCl(SiNP)(L) (L = CO, 5; CN(t)Bu, 6) have been isolated purely and quantitatively upon reaction of 2 with CO and CN(t)Bu, respectively. Otherwise, PPh(3) and RhCl(SiNP) equilibrate with Rh(Cl)(SiNP)(PPh(3)) (7). Carbon electrophiles such as MeI and 3-chloro-1-proprene afforded the oxidation of rhodium(I) to rhodium(III) and the formation of RhCl(2)(η(3)-C(3)H(5))(SiNP) (8) and Rh(Me)(I)(SiNP)(acac) (10), respectively. The methyl derivative 10 is thermally stable and does not react either with CO or with CN(t)Bu even in excess. Otherwise, RhCl(2)(η(3)-C(3)H(5))(SiNP) (8) is thermally stable but reacts with CO, affording 3-chloro-1-proprene and RhCl(SiNP)(CO) (5). Finally, upon reaction of Rh(acac)(SiNP) (4) and 3-chloro-1-proprene, RhCl(acac)(η(1)-C(3)H(5))(SiNP) (9a) and [Rh(acac)(η(3)-C(3)H(5))(SiNP)]Cl (9b) could be detected at 233 K. At higher temperatures, 9a and 9b smoothly decompose, affording the dinuclear derivative [RhCl(SiNP)](2) (2) and the CC coupling product 3-allylpentane-2,4-dione.

The challenge to realize polymetallic assemblies of unambiguous structure and stereochemistry, in which the nature of the intervalence transition (IT) is rationalized, has been faced by investigating the syn and anti isomers of η6-Cr(CO)3{η5-[(2-ferrocenyl)indenyl]Rh(CO)2} and their mixed-valence cations. Crystallographic studies and DFT calculations provide a detailed description of the structural and electronic features of these complexes, evidencing a significant difference in geometrical distortions and frontier MO composition between syn and anti isomers. Mixed-valence cations are generated and monitored by low-temperature spectroelectrochemistry in the visible, IR, and near-IR regions. The IT bands in the near-IR spectra are rationalized in the framework of Marcus−Hush theory and at quantum chemistry level by density functional theory. Noteworthy, the results reported provide rare experimental evidence that the presence of a third metal center (Rh) increases the metal−metal (Fe−Cr) interaction with ...

The [2+2] compartmental macrocyclic complexes [Ln(H 2 -L)-(N0 3 )], where H 2 -L is the cyclic Schiff base, derived from the condensation of 2,6-diformyl-4-chlorophenol (H-L A ) or 2,6-diformyl-4-methylphenol (H-L B ) and N,N-bis(2-aminoethyl)-2-hydroxybenzylamine·3HCl (HA'·3HCl), contains a free N 3 0 3 coordination chamber and can act as a ligand toward an identical or a different lanthanide(III) ion and a d transition metal(II) ion to give the related f,f homodinuclear [Ln 2 (L)-(X) 2] and f,f' heterodinuclear [LnLn'(L)(X) 2 ] or d,f heterodinuclear [LnM(L)(X)] complexes. They have been characterized by ESEM-EDS, ESI-MS, and IR and 1 H and 13 C NMR spectroscopy. The X-ray single-crystal analysis of the [2+1] acyclic complex [Lu 2 (L') 2 ], derived from partial hydrolysis of the related [2+2] homodinuclear complex [Lu 2 (L)(Cl) 2 ], followed by the loss of one lutetium(III) ion with the free formyl groups turning into diacetal ones, is also reported.

The reactivity of the cyclic primary aliphatic amines cyclopropyl-, cyclopentyl- and cyclohexylamine with cis- and trans-[PtCl 2 (NCMe) 2 ], under the same experimental conditions, is compared. Whereas cis-[PtCl 2 (NCMe) 2 ] yields the neutral diamidine compounds, the reactions with trans-[PtCl 2 (NCMe) 2 ] take place either with addition or substitution processes yielding the neutral diamidine complexes trans-[PtCl 2 (Amidine) 2 ], the monocationic trans-[PtCl(Amine)(Amidine) 2 ]Cl and the dicationic trans-[Pt(Amine) 2 (Amidine) 2 ]Cl 2 salts. An NMR and ESI study indicate that the main species formed is the monocationic trans-[PtCl(Amine)(Amidine) 2 ]Cl complex. The X-ray structure of trans{PtCl 2 {N(H)=C(CH 3 )NHCHCH 2 CH 2 } 2 ] is reported and its supramolecular arrangement is described.

New copper(I) complexes containing the water soluble N-methyl-1,3,5-triaza-7-phosphaadamantane (mPTA) phosphine have been synthesized by ligand-exchange reactions starting from [Cu(CH(3)CN)(4)][BF(4)] or [Cu(CH(3)CN)(4)][PF(6)] precursors and (mPTA)X (X=CF(3)SO(3), I). Depending on the ligand counter ion, the hydrophilic [Cu(mPTA)(4)][(CF(3)SO(3))(4)(BF(4))] 3a and [Cu(mPTA)(4)][(CF(3)SO(3))(4)(PF(6))] 3c complexes or the iodine-coordinated [Cu(mPTA)(3)I]I(3)4 species were obtained respectively and fully characterized by spectroscopic methods. Single crystal structural characterization was undertaken for [Cu(mPTA)(3)I]I(3).H(2)O, 4.H(2)O, and [Cu(mPTA)(4)][(CF(3)SO(3))(2)(BF(4))(3)] .0.25H(2)O, 3b.0.25H(2)O, the latter obtained by crystallization of [Cu(mPTA)(4)][(CF(3)SO(3))(4)(BF(4))] 3a. The cytotoxicity of analogous tetrahedral homoleptic Cu(I) derivatives [Cu(PTA)(4)](BF(4)) 1, [Cu(PTAH)(4)][Cl(4)(BF(4))] 2, [Cu(mPTA)(4)][(CF(3)SO(3))(4)(BF(4))] 3a and [Cu(mPTA)(4)][(CF(3)SO(3))(4)(PF(6))] 3c was evaluated against a panel of several human tumor cell lines. All the complexes showed in vitro antitumor activity comparable to that of the reference metallodrug cisplatin. Tests performed on cisplatin sensitive and resistant cell lines showed that against human ovarian 2008/C13(*) cell line pair, the resistance factor of copper derivatives was roughly 7-fold lower than that of cisplatin, whereas against human cervix cancer A431/A431-Pt cell line pair it was about 2.5-fold lower. These results, confirming the circumvention of cisplatin resistance, support the hypothesis that phosphine copper(I) complexes follow different cytotoxic mechanisms than do platinum drugs.

A series of heterobimetallic η 6 -[(ferrocenyl)indene]-Cr(CO) 3 complexes differing for the position of the ferrocenyl group, 1-(ferrocenyl)indene and 2-(ferrocenyl)indene, and the degree of indene methylation (tetramethyl- and hexamethyl-) have been prepared and studied with the aim to stabilise the mono- and dications generated by chemical and electrochemical oxidation, and at same time to tune the metal–metal electronic coupling in the mixed-valence cations. The magnitude of electronic delocalisation and spin density in the cations have been monitored by means of optical techniques (UV–Vis, near-IR, mid-IR) and EPR spectroscopy. The results have been rationalised in the framework of Marcus-Hush theory and at quantum chemistry level by DFT and TD-DFT methods, establishing that a metal-to-metal electronic coupling occurs the magnitude of which depends on the degree of indene methylation.

Mixed-valence compounds, which have at least two redox sites in different oxidation states linked by a bridging ligand that promotes electron transfer from one site to the other, are excellent benchmarks for the study of intramolecular electron transfer (1). Transition metal complexes that display multielectron redox chemistry are therefore attracting much interest due to their potential applications in molecular materials for catalysis and electronics (2). In particular, compounds containing multiple ferrocene (Fc) units are suitable models since these units display versatile organic chemistry and a well-defined redox behavior (3-5). Although there have been many reports of biferrocenyl complexes,(1c, 3, 5) experimental (6) and theoretical (7) studies on oligoferrocene systems are relatively scarce despite their potential to highlight those factors that influence the mechanistic pathway of intercomponent electron transfer.

The reaction of cis - and trans -[PtCl 2 (NCCH 2 Ph) 2 ] with a 5-fold excess of MeNH 2 and Me 2 NH in CH 2 Cl 2 at −10 °C affords in high yield the bis-amidine derivatives cis - and trans -[PtCl 2 { Z -N(H) C(NHMe)CH 2 Ph} 2 ] ( 1a , 2a ) and cis - and trans -[PtCl 2 { E -N(H) C(NMe 2 )CH 2 Ph} 2 ] ( 3a , 4a ), respectively. The complexes were characterized by means of elemental analysis, multinuclear NMR and FT-IR techniques. The X-ray diffraction analysis was carried out for trans -[PtCl 2 { Z -N(H) C(NHMe)CH 2 Ph} 2 ] ( 2a ). Moreover, the in vitro cytotoxicity for the new derivatives was evaluated in a wide panel of human tumor cell lines.

The new sodium bis(1-methyl-1 H -imidazol-2-ylthio)acetate, Na[( S -tim) 2 CHCO 2 ], has been prepared in ethanol solution using 2-mercapto-1-methylimidazole, dibromoacetic acid and NaOH. New di- and tri-organotin(IV) derivatives have been synthesized from reaction between SnR n Cl 4− n (R = Ph, Cy and n Bu, n = 2–3) acceptors and Na[( S -tim) 2 CHCO 2 ]. Complexes of the type {[κ 1 O -( S -tim) 2 CHCO 2 ]SnR 3 } and related decarboxylated species {[κ 2 N , N -( S -tim) 2 CH 2 ]SnR 2 Cl 2 } have been obtained and characterized by elemental analyses, FT-IR, ESIMS and multinuclear ( 1 H, 13 C and 119 Sn) NMR spectral data. The adduct {κ 1 O -[( S -tim) 2 CHCO 2 ]Sn(H 2 O)(C 4 H 9 ) 3 } was characterized by single crystal X-ray studies. The dichloromethane reaction solution of {κ 1 O -[( S -tim) 2 CHCO 2 ]Sn(C 6 H 5 ) 3 } was re-crystallized and the decarboxylated species {[( S -tim) 2 CH 2 ]SnCl(H 2 O)(C 6 H 5 ) 3 } was obtained as a crystalline solid and characterized by X-ray crystallography.

The high yield synthesis of 3- and 4-(pentafluorosulfanyl)benzoic acid derivatives is described starting from the NO2-derivatives, which are reduced to the corresponding anilines. Then the NH2– group is converted to bromide and subsequently to the HC O moiety. The benzaldeydes are then oxidised to the corresponding benzoic acids. The X-ray structure of 3–SF5–C6H4–COOH is also reported.

A family of (ferrocenyl)indenes, (2-ferrocenyl)indene, (2-ferrocenyl)tetramethylindene, (2-ferrocenyl)hexamethylindene, (3-ferrocenyl)indene, and (3-ferrocenyl)hexamethylindene, and the corresponding monooxidized cations have been prepared. The results of a structural and spectroelectrochemical study are discussed. The availability of pairs of isomers with known geometries and differently methylated indenes allowed the detailed investigation of how slight geometric and electronic modifications affect their physical properties. The molecular structures have been determined by X-ray diffraction and compared with the fully optimized structures calculated with state-of-the-art DFT methods. Calculated and crystallographic structures agree in establishing the dependence of the orientation of the indene moiety and the ferrocenyl cyclopentadienyl rings on the degree of methylation. The UV-vis spectra and in particular the appearance upon oxidation of a new near-IR absorption, whose energy and intensity increase with the degree of methylation and cyclopentadienyl-indene planarity, are rationalized in the framework of the Hush theory and at quantum chemistry level by DFT and TD-DFT calculations.

The extent of metal-metal electronic coupling was quantified for a series of syn and anti stereoisomers of (FeCp)(2)-, (RhL(2))(2)- and (FeCp)(RhL(2))- (L(2)=1,5-cyclooctadiene (cod), L=CO) as-indacenediide mixed-valent ions by spectroelectrochemical and DFT studies. The effect of the syn/anti orientation of the metal units with respect to the planar aromatic ligand indicates that electron transfer occurs through the bridge rather than through space. The nature of the metal was found to be crucial: while homobimetallic diiron species are localised valence-trapped ions (Class II), the dirhodium analogues are almost delocalised mixed-valent ions (borderline and Class III). Finally, despite their redox asymmetry, even in the heterobimetallic iron-rhodium as-indacenediide complexes, strong metal-metal coupling is present. In fact, oxidation of the iron centre is accompanied by electron transfer from rhodium to iron and formation of a reactive 17-electron rhodium site. syn and anti Fe-Rh as-indacenediide complexes are rare examples of heterobimetallic systems which can be classified as borderline Class II/Class III species.

New silver(I) complexes have been synthesised from the reaction of AgNO3, monodentate PR3 (PR3 = P(o-tolyl)3, P(m-tolyl)3, P(p-tolyl)3, P(p-C6H4F), SeP(C6H5)3) or bidentate tertiary (dppe = bis(diphenylphosphane)ethane, dppf = 1,1′-bis(diphenylphosphane)ferrocene) phosphanes and potassium dihydrobis(3-nitro-1,2,4-triazolyl)borate, K[H2B(tzNO2)2]. These compounds have been characterized by elemental analyses, FT-IR, ESI-MS and multinuclear (1H and 31P) NMR spectral data. The adduct {[H2B(tzNO2)2]Ag[P(m-tolyl)3]2} has been characterized by single crystal X-ray studies. In the former, the H2B(tzNO2)2 acts as a monodentate ligand utilizing the coordinating capability of only one of the additional (exo-) ring nitrogens to complete the coordination array about the silver atom.

Homogeneous ethylene and propylene polymerisation with new mixed-ligand chloroalcoholate of hafnocene was investigated. The catalytic activity of the complex was studied in comparison with Cp2HfCl2 pre-treated with 2-methyladamantan-2-ol in different molar ratios. The addition of the bridged alicyclic alcohol to the metallocene does not deactivate the catalytic system, but results similar to those obtained with the corresponding mixed-ligand hafnocenes were obtained. The voluminous alcoholato-moiety makes part of the [MAdO–MAO]− counter-ion where it promotes regioerrors in the growing polymer chain. The X-ray structure of new complex was determined.

Novel palladium(II) complexes with oxazolin-2-ylidene ligands have been synthesized via direct reaction of palladium acetate and oxazolium salts, prepared in turn by alkylation of oxazole with methyl iodide or benzylic bromides. The resulting complexes have been characterized and used as catalysts in Heck coupling reactions of aryl bromides, where they exhibit remarkable catalytic activity, higher than that of the closely related bis-imidazolin-2-ylidene and bis-benzothiazolin-2-ylidene complexes.

The reaction of Cr(η6-CH3C6H5)2 with dbcpH−NO2 (dbcpH−NO2 = 1-benzoyl-3-nitro-6-hydroxy-6-phenyl fulvene) proceeds with the evolution of dihydrogen and formation of the ionic derivative [Cr(η6-CH3C6H5)2][dbcp−NO2] (dbcp−NO2 = 1,2-dibenzoyl-4-nitro-cyclopentadienyl anion) which was characterized by X-ray diffraction, electrochemical and EPR techniques. The cation [Cr(η6-CH3C6H5)2]+, which in the solid state presents an unprecedented cis-eclipsed arrangement of the arene rings, undergoes a chemically reversible, one-electron reduction to the corresponding neutral derivative.

The new sodium bis(2-pyridylthio)acetate ligand, Na[(pyS) 2 CHCO 2 ], has been prepared in ethanol solution using 2-mercaptopyridine, dibromoacetic acid and NaOH. New mono- and di-organotin(IV) derivatives containing the anionic bis(2-pyridylthio)acetate have been synthesized from reaction between SnR n Cl 4− n (R = Me, Ph and n Bu, n = 1–2) acceptors and Na[(pyS) 2 CHCO 2 ]. Mono-nuclear complexes of the type {[(pyS) 2 CHCO 2 ]R n SnCl 4− n −1 } have been obtained and characterized by elemental analyses, FT-IR, ESI-MS, multinuclear ( 1 H and 119 Sn) NMR spectral data and X-ray crystallography. ESI-MS spectra of methanol solution of the complexes show the existence of hydrolysed species. Attempts to crystallize the dimethyltin(IV) derivative ( 3 ), from acetonitrile solution yield the dimeric dicarboxylatotetramethyldistannoxane ( 8 ), which was characterized by single crystal diffraction analysis.

Thin film depositions of metallic silver were performed by the MOCVD (Metal Organic Chemical Vapor Deposition) technique on glass substrate using, as precursors, the two new compounds (1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)(2,2’-bipyridine)silver(I), [Ag(hfac)(bipy)] (1), and (1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)(N,N,N’,N’-tetramethylethylenediamine)silver(I), [Ag(hfac)(tmeda)] (2). Both silver compounds were characterized by single crystal X-ray diffraction measurements, indicating that 1 exists as a dimeric species, and 2 as polymeric chains. The films were analysed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) revealing, a high crystallinity and fairly good quality with little carbon and oxygen contamination when using the tetramethylethylenediamine derivative

The functionalised diaminodimethylsilanes SiMe2[NH(CH2)nX]2 (X = NMe2, n = 2, H2L1; n = 3, H2L2; X = OMe, n = 2, H2L3; n = 3, H2L4) have been synthesised by aminolysis of SiMe2Cl2 with NH2(CH2)nX, and their ligating ability towards zirconium(IV) has been investigated. The syntheses of [ZrY2(L)] (Y = Cl, NMe2, Me; L = L1, L2, L3, L4) are reported and the solid-state structures of some selected compounds determined by X-ray crystallography. In addition, the solution molecular structures of all the metal derivatives have been elucidated by variable-temperature multinuclear 1D/2D NMR spectroscopy, and the dynamics have been investigated in some selected cases. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

2-(Azidomethyl)phenyl isocyanide, 2-(CH2N3)C6H4NC (AziNC), coordinates to some cationic Pt(II) and Pd(II) species to afford isocyanide complexes of the type trans-[MCl(AziNC)(PPh3)2][BF4] (M=Pt, l; Pd, 2). AziNC is coordinated also in some neutral Pt(II) and Pd(II) species such as [MCl2(AziNC)2] (M=Pt, 3; Pd, 4) derived from the reactions of 2 equiv. of AziNC with [PtCl2(COD)] and [PdCl2(MeCN)2], respectively. Complexes 1 and 2 react with 1 equiv. of PPh3 affording the heterocyclic carbene complexes trans-[MCl{ (H)}(PPh3)2][BF4] (M=Pt, 5; Pd, 6). Complexes 3 and 4 react with 1 equiv. of PPh3 displacing the isocyanide with the formation of the complexes cis-[MCl2(AziNC)(PPh3)] (M=Pt, 7; Pd, 8). These latter ones react with 2 equiv. of PPh3 affording as the final products the cationic carbene species trans-[MCl{ (H)}(PPh3)2][Cl] (M=Pt, 9; Pd, 10). Complex 5 was also characterized by single crystal X-ray diffraction. The carbene complex is square-planar and the angle formed between the platinum square plane and the heterocyclic carbene ligand is 87.9(2)°. The C(1)–N(1) and C(1)–N(2) bond distances in the latter of 1.32(2) and 1.30(2) A, respectively, are short for a single bond and indicate extensive π-bonding between the nitrogen atoms and the carbene carbon.

An improved synthesis of platinum acetate is reported in detail. This tetrameric complex reacts with PPh3 or P � /n-Bu3 at room temperature to give the thermodynamically unstable bis-substituted trans -[Pt(OAc)2L2] complexes, which are not easily accessible via other routes. The structure of the new compound trans -[Pt(OAc)2(PPh3)2] has been determined by X-ray analysis. # 2003 Elsevier B.V. All rights reserved.

The new η 2 -formamidinyl Zr complex Zr(NMeCyc) 2 [C(NAr)NMeCyc] 2 (1) (Ar = 2,6-dimethylphenyl, Cyc = cyclohexyl) was prepared upon double insertion of 2,6-dimethyl phenyl isocyanide in the Zr-N bond of Zr(NMeCyc) 4 . 1 wasthen converted into Zr(OC 6 F 5 ) 2 [C(NAr)N-MeCyc] 2 (2) and ZrCl 2 [C(NAr)NMeCyc] 2 (3) by reacting it with C 6 F 5 OH and [NHMe 3 ]Cl, respectively. The crystal structure of 1 was established by X-ray analysis. All the complexes have been tested as catalysts for the polymerization of ethylene and 1-hexene in the presence of [NHMe 2 Ph][B(C 6 F 5 ) 4 ] as cocatalyst.

Lanthanide(III) complexes with composition Ln(nic)(H 2 O) n (pic) 3 (nic) (Ln=Pr, Nd n =8; Tm n =7) (pic=picrate, nic=nicotinamideN-O) were obtained by reaction of the hydrated lanthanide picrate with nicotinamideN-oxide in ethanol. They were characterized by elemental analysis and IR spectra. The molecular structures of Pr, Nd and Tm complexes were established by X-ray crystallography. Different triclinic phases have been detected for the isostructural Nd and Pr derivatives. They are nine coordinated to eight water molecules and a monodentate nic ligand while the apparently isomorphous Tm derivative looses a water molecule with a eight coordination number and a coordination geometry changing from tricapped trigonal prism (Pr, Nd) to square antiprismatic.

The silicon compounds SiMe2(NRR′)2 [NRR′ = NMe2 (1), NEt2 (2), NC4H8 (3), NHEt (4), NHiPr (5), NHtBu (6), NMeBu (7)] have been synthesised via aminolysis of the dichloro species SiMe2Cl2 and their ligating ability has been investigated towards zirconium(IV). The dimer zirconium compound {Zr[(NiPr)2SiMe2]2}2 (8) has been synthesised by reacting ZrCl4 with the lithium salt Li2[(NiPr)2SiMe2] and its molecular structure has been determined in the solid state by X-ray diffraction analysis. The reaction of ZrCl4 with SiMe2(NRR′)2 yields the Lewis adducts ZrCl4[(NRR′)2SiMe2] [NRR′ = NMe2 (10), NC4H8 (11), NHEt (12), NHiPr (13), NHtBu (14), NMeBu (15)]. On the other hand, the mixed amido derivative Zr(NMe2)3(NHMe)[(NtBu)SiMe2(NHtBu)] (9) has been obtained from the reaction of Zr(NMe2)4 with SiMe2(NHtBu)2. The solution molecular structure and dynamics of the zirconium derivatives have been elucidated by 1D and 2D multinuclear NMR spectroscopy.

The synthesis and the X-ray structure of the two pseudotetrahedral Zn(II) zwitterionic complexes: trichloro(1-methylpiperazin-1-ium-N4)zinc(II), [ZnCl3(H2Meppz)], and trichloro(1,4-dimethylpiperazin-1-ium-N4)zinc(II), [ZnCl3(HMe2ppz)], are described [(H2Meppz)+=1-methylpiperazin-1-ium monocation and (HMe2ppz)+=1,4-dimethylpiperazin-1-ium monocation]. [ZnCl3(H2Meppz)] and [ZnCl3(HMe2ppz)] complexes are isomorphous and isostructural, respectively, to the [CoCl3(H2Meppz)] and [CoCl3(HMe2ppz)] complexes, already reported in literature by us. Both complexes present a very uncommon and distorted tetrahedral aminotrichlorozinc(II), NZnCl3, group, where N is a nitrogen atom of an aliphatic amine. So far this group has been found only in the (1,3,5,7-tetraazaadamantane)trichloro-zincate(II) anion [{(CH2)6N4}ZnCl3]−. The bulky ZnCl3 group present in [ZnCl3(HMe2ppz)], is coordinated to the axial position of the piperazine ring instead of the less hindered equatorial position, as found in the analogous [CoCl3(HMe2ppz)] complex. An extended hydrogen bond network is present in the crystals of both the complexes but, while the [ZnCl3(H2Meppz)] complex shows nearly linear N+H⋯Cl intermolecular hydrogen bonds, the [ZnCl3(HMe2ppz)] complex shows a perfectly symmetrical (imposed by space group symmetry) Download : Download full-size image ZnNCl three-centre intermolecular hydrogen bond. The solid state infrared spectra of both the compounds are discussed in agreement with the hydrogen bond network present in the crystals.

Lanthanide(III) complexes of six-nitrogen-donor macrocyclic ligands carrying a benzyl-type group, CH2C6H4X (X=H, OH, or NH2), at each di-imine side chain were synthesized by the metal-templated, cyclic Schiff-base condensation of 2,6-diacetylpyridine with substituted S- or R,S-1,2-diaminopropanes. The complexes were obtained as mixtures of constitutional isomers and stereoisomers, which were identified by 1H NMR spectra and separated by fractional crystallization. The molecular structure of the 11-coordinate complex [La(NO3)2(H2O)(C36H38N6)](NO3)(H2O) was established by X-ray crystallography.

The reactions of cis-[PtCl2(NCMe)2] with a fivefold excess of the primary aliphatic amines RNH2 (R=Me, Et, Pri, But) in CH2Cl2 at −10 °C afford in high yield the bis-amidine complexes cis-[PtCl2{ZN(H)C(NHR)Me}2], where both amidine ligands assume the Z configuration. The corresponding reactions of trans-[PtCl2(NCMe)2] with RNH2 (R=Me, Et, But) give a mixture of the bis-amidine trans-[PtCl2{ZN(H)C(NHR)Me}2] and the mono-amidine trans-[PtCl2(NCMe){ZN(H)C(NHR)Me}] derivatives, which could be isolated as pure products operating with a platinum nitrile complex:amine molar ratio of 1:50 or 1:1, respectively. The reaction of trans-[PtCl2(NCMe)2] with a 50-M excess of PriNH2 affords the bis-amidine bis-amine dicationic complex trans-[Pt(H2NPri)2{ZN(H)C(NHPri)Me}2]Cl2, which has been characterized also by X-ray diffraction analysis. The reactions of cis- and trans-[PtCl2(NCMe)2] with the secondary aliphatic amines R′R″NH yield the bis-amidine complexes cis- and trans-[PtCl2{EN(H)C(NR′R″)Me}2] (R′, R″=Et) and/or cis- and trans-[PtCl(NCMe){EN(H)C(NR′R″)Me}2] (R′, R″=Et; R′=Me, R″=But), where the amidine ligands have the E configuration. The compound trans-[PtCl2(NCMe){EN(H)C(NMeBut)Me}] has been characterized by single crystal X-ray diffraction. All the complexes have been characterized by IR, 1H and 13C NMR spectroscopies. The Z or E configuration of the amidine ligand can be readily deduced by 1H NMR data.

Complexes of Ca(II) and Sr(II) with six-nitrogen-donor macrocyclic ligands carrying a methyl group at each diimine side-chain were synthesized by the metal-templated condensation of 2,6-diacetylpyridine with R-, S-, or R,S-1,2-diaminopropane. The complexes exist as stereoisomers as well as constitutional isomers, which can be identified by 1H NMR spectra and separated by fractional crystallization. The molecular structure of the eight-coordinate complex [Sr(CF3SO3)2(C24H30N6)] was established by X-ray crystallography.

The compounds [quinolinium]4[Bi2Cl10] (1), [isoquinolinium]4[Bi2Cl10].2H2O (2) and [8-hydroxyquinolinium]4[BiCl6]·Cl·2H2O (3) have been obtained by reacting bismuthate oxide and the appropriate base in HCl acid medium. The crystal structures of 1 and 2 consist of quinolinium and isoquinolinium cations, respectively, interacting through hydrogen bonding with [Bi2Cl10]4− dimers. The different degree of interactions in the two derivatives causes significant differences in the bond distances of the anions. The crystal structure of 3 is made of [BiCl6]3− and Cl− anions and 8-hydroxyquinolinium cations. Hydrogen bond interactions including the N-bonded and O-bonded H atoms together with an interstitial chlorine atom stabilize the entire crystal structure.

The reaction of cis-[PtCl2(NCMe)2] with a 5-fold excess of Me2NH in CH2Cl2 at −10°C affords in high yield the bis-amidine complex cis-[PtCl2{E-N(H)C(NMe2)Me}2] (E,E-2), where both the amidine ligands assume the E configuration. E,E-2 was characterized by X-ray structure analysis, NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS). The corresponding reactions of trans-[PtCl2(NCMe)2] with Me2NH gave the bis-amidine complex trans-[PtCl2{E-N(H)C(NMe2)Me}2] (E,E-3) and the mono-amidine derivative trans-[PtCl2{E-N(H)C(NMe2)Me}(NCMe)] (E-4).

The complexes trans-[FeH(NCR)(dppe)2][BF4] (1) (R=NH2, NMe2, NEt2 or NC(NH2)2; dppe=Ph2PCH2CH2PPh2) and trans-[FeL(NCR)(depe)2]Yn (R=NH2, NMe2, NEt2 or NC(NH2)2; depe=Et2PCH2CH2PEt2; Y=BF4 or BPh4; (2), L=Br, n=1; (3), L=NCR, n=2) have been prepared by treatment of trans-[FeHCl(dppe)2] (in THF and in the presence of Tl[BF4]) or trans-[FeBr2(depe)2] (in MeOH and in the presence of [NBu4][BF4] or Na[BPh4]), respectively, with the appropriate cyanamide. NMR and Mossbauer spectral, as well as FAB mass spectrometric data are reported. Mossbauer partial isomer shift (PIS) and partial quadrupole splitting (PQS) parameters have been estimated for the cyanamide and dppe ligands and rationalised, with the overall IS and QS, in terms of π- and σ-electronic effects, the cyanamides behaving as more effective σ-donors and weaker π-acceptors than organonitriles. FAB MS fragmentation patterns are also proposed. The crystal structures of 1 (R=NH2) and 3 (R=NEt2, Y=BF4) are reported.

The complex [CrCl 3 (THF) 3 ] reacts with Li(CH 2 CH 2 CH 2 NMe 2 ) in THF at room temperature (r.t.) to form the tetranuclear complex [Cr 4 (CH 2 CH 2 CH 2 NMe 2 ) 4 (μ 4 -O)(μ-Cl) 6 ] ( 1 ) where each chromium atom has a distorted octahedral coordination geometry with an oxygen atom shared among the four metal ions.

The crystal and molecular structures of [(phenH)2Cl][Cr2(CO)10(μ-H)] (1) and [K(phen)2][Cr2(CO)10(μ-H)] (2) have been determined by single crystal X-ray diffraction. The availability of the potassium cation for the carbonyl oxygens coordination influences the conformation of the anion in 2 as demonstrated by the comparison with the non-coordinating [(phenH)2Cl] cation in 1 and with literature data.

The crystal structures of two stereoisomers of tetraphenyl- and pentaphenyl-substituted cyclopentenes 1 and 2 have been determined by X-ray analysis. An envelope conformation 1E has been ascertained for the cis isomer 1a, whereas the cis, cis isomer 2a, which crystallizes in two different space groups, P1¯ and P21/n, displays a twisted 2T1 conformation. The phenyl substituents are all tilted with respect to the cyclopentene ring in both structures. Compound 1a crystallizes in the space group P21/a with a = 18.553(3), b = 6.006(2), c = 19.355(5), β = 102.67(4)°, and V = 2104.2(g) A3 for Z = 4; compound 2a I crystallizes in P21/n with a = 10.064(2), b = 20.756(5), c = 12.245(3) A, β = 95.21(2)°, and V = 2547(1) A3 for Z = 4; compound 2aII crystallizes in P1¯ with a = 10.117(3), b = 11.750(2), c = 12.359(2) A, α = 111.25(2), β = 94.84(2), γ = 108.78(2)°, and V = 1262.3(6) A3 for Z = 2.

The new solid-state complex {[Hf(NEt2)2Cl2(DME)] (DME = 1,2-dimethoxyethane)}, intermediate in the synthesis of the new bis-diethylamide bis-isopropoxy hafnium (IV) complex [Hf(NEt2)2(OiPr)2], has been synthesized, isolated and characterized by NMR spectroscopy and X-ray diffraction. The crystal structure showed the metal to be hexa-coordinated with a distorted octahedral geometry. Catalytic tests for the polymerization of ethylene have been carried out using this intermediate with [(NHMe2Ph)B(C6F5)4] as cocatalyst. The obtained polymer had a high molecular weight and a high melting point, characteristic of a high density polyethylene (HDPE).

3,3′-(1,2-ethanediyl)bis[2-substituted-1,3-thiazolidin-4-one] derivatives display different biological activities depending on the configuration of the 2,2′ centers and on the substitution at C2, C2′. In this context, 3,3′-(1,2-ethanediyl)bis[2-(2′-(5′-methyl)thienyl)-1,3-thiazolidin-4-one] (6b) and 3,3′-(1,2-ethanediyl)bis[2-(3′-pyridyl)-1,3-thiazolidin-4-one] (8b) have been prepared. Their structural and conformational features, which can be related to the biological activity, have been investigated by X-ray diffraction and molecular modeling techniques.

The reaction between bismuthate oxide and phen (1,10-phenanthroline) in acid medium led to the isolation of the unusual [(PhenH)(PhenH2)][BiCl6]·2H2O derivative, which has been characterized by X-ray analysis and IR spectroscopy. The compound crystallizes in the triclinic space group \([\text[P\bar 1]]\) with a = 8.313(2), b = 9.349(2), c = 9.807(3) A, α = 86.39(3), β = 110.27(3) and γ = 106.48(3)°. The crystal structure is made of [BiCl6]3− anions and [(PhenH)(PhenH2)]3+ cations. A network of hydrogen bond interactions involving the two clathrated water molecules, the phenanthroline moiety and the chlorines characterizes the entire structure.

The diazonium salts obtained from 2-amino-N-methyl-N-(1-phenyl-3-methylpyrazol-5-yl)benzamide were reacted with cuprous oxide or copper at 5 or 25 °C under different pH conditions. Cuprous oxide at 25 °C and pH 6.25 yielded the racemic epimers (3′SR,4′RS)- and (3′SR,4′SR)-4′-hydroxy-2′,4′-dihydro-2,5′-dimethyl-2′-phenylspiro[isoindoline-1,3′-3′H-pyrazol]-3-ones 2 and 10 respectively, (RS)-2′,4′-dihydro-2,5′-dimethyl-2′-phenylspiro[isoindoline-1,3′-3′H-pyrazole]-3,4′-dione 9 and N-methylphthalimide 8. The thermal transformation of 2 and 10 into the potentially pharmacologically active 3-methyl-1-phenyl[2]benzopyrano[4,3-c]pyrazol-5(1H)-one 4 was strongly dependent on the structure of the two epimers. When 1 was reacted with cuprous oxide or copper sulfate and sodium halide (chloride or bromide), in the presence of ascorbic acid as initiator, a mixture of epimers (3′SR,4′RS)- and (3′SR,4′SR)-4′-chloro(or bromo)-2′,4′-dihydro-2,5′-dimethyl-2′-phenylspiro[isoindoline-1,3′-3′H-pyrazol]-3-ones 6b and 7b (or 6c and 7c) was obtained. The same epimers were obtained when the diazonium halides (chloride and bromide) 1b,c obtained from 2-amino-N-methyl-N-(1-phenyl-3-methyl-1H-pyrazol-5-yl)benzamide were treated with the appropriate classical Sandmeyer catalysts. The formation of the spiro compounds is based on consecutive Pschorr and Sandmeyer reactions. The X-ray crystal structures of the epimers 2 and 10 have been determined, confirming the given formulations.

The cyanoguanidine complex cis-[Pt(NCNC(NH2)2)2(PPh3)2][BPh4]2, prepared by reacting cis-[PtCl2(PPh3)2] with cyanoguanidine in the presence of Na[BPh4], readily reacts with methanol to give cis-[(PPh3)2PtNHC(OMe) = NC(NH2) = NH)] [BPh4] containing a novel type of azametallcycle whose molecuar structure is established by X-ray crystallography. Its formation involves metal-promoted nucleophilic addition of the alcohol to the cyano group of a cyanoguanidine ligand, combined with deprotonation of the guanidine unit which then chelates the Pt(II) centre.

The interaction of several β-diketones [pentane-2,4-dione, 1,3-diphenylpropane-1,3-dione, 1,1,1-trifluoro-4(2-thienyl)butane-2,4-dione] and their sodium salts with complexes of the type [ML(CH3COO)2]X·n(H2O), where M is LaIII, EuIII or YIII, L is the macrocyclic ligand C22H26N6, X is Cl− or CH3COO− and n is 4–9, was investigated in solution by NMR and luminescence spectroscopy. A number of crystalline ∗ML∗-(β-diketonate) complexes were isolated and characterized; the structure of one member of the series, [EuL(CH3COO)∗(C6H5CO)2CH∗](CH3COO) · 6(H2O), was established by X-ray crystallography. The structure is ionic; the 10-coordinate EuIII is bonded to the six nitrogens of the macrocyclic ligand, two oxygens of a bidentate acetate and two oxygens of the chelating β-diketonate. The coordinated acetate and the β-diketonate are situated on opposite sides of the ∗EuL∗ macrocycle; an uncoordinated acetate provides charge neutrality.

The syntheses of the ligand bis(benzylamide)diethylenetriaminepentaacetic acid (BBA-DTPA) and its Gd(III) and Lu(III) complexes are reported. The solid state structure of Lu(III) BBA-DTPA was determined in a single crystal X-ray diffraction study. The lutetium ion adopts a mine-coordinate geometry, which is best described as a distorted tricapped prism. Eight coordination sites are occupied by the ligand (three nitrogen atoms, two carboxamide oxygens and three carboxylate oxygens) and the ninth site is occupied by the oxygen atom of a water molecule. The VT 13 C NMR spectra of Lu(III) BBA-DTPA are consistent with the presence of three isomers in solution. Water proton relaxation rates have shown that Gd(III) BBA-DTPA displays an analogous behaviour to that observed for other Gd(III) complexes of related bisamide derivatives of DTPA. The solubility of Gd(III) BBA-DTPA has been markedly improved by the presence of an excess of hydroxypropyl-β-cyclodextrin. The thermodynamic stability of the inclusion complex has been evaluated by measuring the proton relaxation enhancement upon addition of β-cyclodextrin.

The compound bis[η-(1,3,3,5,5-pentamethylcyclohexyl)-cyclopentadienyl] zirconium dichloride has been prepared and the crystal structure determined. The compound together with the cocatalyst methylaluminoxane will catalyse the polymerisation of the ethene and propene.

Two β-ketoiminato complexes of zirconium, di[bis-trifluoroacetylacetone-ethylenediiminato]zirconium Zr(enTFA2)2 (1), and di[bis-trifluoroacetylacetone-trimethylenediiminato]zirconium, Zr(trimenTFA2)2 (2), have been obtained in high yield from the reaction of ZrCl4 and the sodium salt of the corresponding Schiff base. The compounds have been characterized by elemental analysis, NMR, mass spectrometry and X-ray structure determination. The coordination geometry around the zirconium atom is a dodecahedron in 1 and a square antiprism in 2. The increase of the aliphatic bridging chain of the ligand does not produce significant changes in the ZrOav bond distances [2.101(2) in 1 and 2.086(4) A in 2] while the ZrNav bond distances are lengthened [2.432(4) in 1 and 2.491(5) A in 2].

The reactions of the nitrile complexes cis- and trans-[PtCl2(NCR)2] (R = Me, Et, CH2Ph, Ph) with an excess of ethanethiol, EtSH, in the presence of a catalytic amount of n-BuLi in tetrahydrofuran (THF), afforded in good yield the bis-imino thioether derivatives cis-[PtCl2{E-N(H)?C(SEt)R}2] (R = Me (1), Et (2), CH2Ph (3), Ph (4)) and trans-[PtCl2{E-N(H)?C(SEt)R}2] (R = Me (5), Et (6), CH2Ph (7), Ph (8)). The imino thioether ligands assumed the E configuration corresponding to a cis addition of the thiol to the nitrile triple bond. The spectroscopic properties of these complexes have been reported along with the molecular structures of 1, 2, and 7 as established by X-ray crystallography which indicated that these compounds exhibit square-planar coordination geometry around the platinum center. Four N-H···Cl intermolecular contacts (N-H···Cl ca. 2.5-2.7 Å) between each chlorine atom and the N-H proton of the imino thioether ligand gave rise to "dimers" Pt2Cl4L4 (L = imino thioether) formed by two PtCl2L2 units. The cytotoxic properties of these new platinum(II) complexes were evaluated against various human cancer cell lines. Among all derivatives, trans-[PtCl2{E-N(H)?C(SEt)CH2Ph}2] showed the greatest in vitro cytotoxic activity being able to decrease cancer cell viability roughly 3-fold more effectively than cisplatin.

The cyclic five-membered platinum(II) oxycarbene complex trans-[Pt(Me){CCH(p-tolyl)CH2CH2O}(PPh3)2][BF4] (1) can be prepared in good yield under very mild conditions either by reaction of trans-[Pt(Me)(C⋮C-p-tolyl)(PPh3)2] with oxirane in the presence of 1 equiv of HBF4 or by reaction of the cationic solvato complex trans-[Pt(Me)(PPh3)2(solv)][BF4] with oxirane and 1.5 equiv of p-tolylacetylene. The X-ray crystal structure of 1 is reported.

White prismatic crystals of formula Sb(dpk.OCH 3 )(O 2 C 6 H 4 ) were synthesized from the reaction of Sb(O 2 C 6 H 4 )F and dpk in methanol solution. The complex has been characterized by X-ray crystallography and Mossbauer spectroscopy. The crystal structure is characterized by a previously unknown O⊃N coordinating mode of the dpk. OCH 3 ligand. The Sb ion coordination geometry is of the AX 4 Y 2 E type, with four primary bonds due to the chelation of the dpk. OCH 3 and of the catecholato ligands, while the two secondary contacts with the oxygens of a catecholate and two dpk. OCH 3 ligands of adjacent molecules determine the chain formation.

In the β form of tris(thiocyanato-N)[2,7,13,18-tetramethyl-3,6,14,17,23,24-hexaazatricyclo[17.3.1.1 8,12 ]-tetracosa-1(23),2,6,8(24),9,11,13,17,19,21-decaene-N 3 ,N 6 ,N 14 ,N 17 ,N 23 ,N 24 ]europium, the nine-coordinate Eu III ion is bound to the N atoms of three monodentate isothiocyanate ligands and to the six N atoms of the macrocyclic ligand L (C 22 H 26 N 6 ), which has an 18-membered six-N-atom donor cavity, with a coordination geometry analogous to that of the α form.

The synthesis of homoleptic and heteroleptic alkylindium derivatives (generally as diethyl ether adducts) was carried out in high yields from InI3. The nuclear magnetic resonance and mass spectra of the compounds MenInEt3−n (n = 0, 1, 2, or 3) and of their trideuteromethyl analogues showed that both heteroleptic Me2InEt and MeInEt2 exist as single compounds, although disproportionation to InMe3 and InEt3 has been observed at temperatures slightly higher than room temperature. The crystal structure of unusual diphosphine-bridged adduct, [(InMe3)diphos(Me2InEt)] · [(InMe3)diphos(InMe3)], (diphos = (C6H5)2PCH2CH2P(C6H5)2 is reported.

The TDCO thiocyanate complexes Eu(NCS)3 TDCO and Yb(NCS)3TDCO (TDCO = 1,7,10,16-tetraoxa-4,13-diazacyclooctadecane) have been synthesised and their X-ray structure determined. Both are monoclinic with 4 neutral molecules in the unit cell of dimensions a = 16.438(4), b = 15.211(3), c = 9.334(2) A , β = 90.37(3)°, V = 2333.8(9) A 3 , space group P2t/n for Eu and a = 17.481(3), b = 8.020(2), c = 18.056(3) A , β = 118.12(3)°, V = 2232.6(9) A 3 , space group P2t/c for Yb. They consist of nine-coordinated metal centres linked to six donor atoms of the macrocyclic ligand and to three monodentate isothiocyanate ligands situated on opposite sides of the macrocycle. The two structures present different conformations of the TDCO ligand. The mean bond lengths are EuO 2.56(2), YbO 2.498(9), EuN(ring) 2.60(1); YN(nng) 2.518(8) and EuN(CS) 2.44(1), YbN(CS) 2.365(9) A consistent with the difference in the Eu and Yb ionic radii.

The crystal and molecular structure of the [5S,15S] isomer of the [LaL(NCS)3] complex (L=C26H30N6) was determined by single crystal X-ray diffraction analysis. The compound crystallizes in the orthorhombic space group P212121 witha=13.647(4),b=19.504(4),c=11.606(4)A. The 9-coordinate La(III) is bound to the N atoms of three monodentate isothiocyanates and to the six N atoms of the macrocycle ligand L, which has an 18-membered, six-nitrogen donor cavity and two peripheral −CH3 substituents.