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One of the fastest growing areas in polymer science is the photovoltaic organic devices, which conjugated polymers are an important part of, since they constitute the core of bulk heterojunction active layer. In this work two benzodithiophene based polymers containing fluorinated and non-fluorinated benzothiadiazole units were successfully synthesized. It was observed that chain growth depends upon the nature of the electron deficient monomer, being fluorinated monomer able to produce higher chain size and distribution. Low band gap was obtained (1.71 and 1.72 eV for fluorinated and non-fluorinated polymers, respectively) as well as values of −3.78 and −3.66 eV for LUMO orbitals energy were estimated. The synthesized polymers presented degradation temperatures above 280 °C, which makes them able to be processed through roll-to-roll deposition techniques. Charge carriers mobilities are 4.6 × 10−6 and 1.0 × 10−5 cm2 V−1.s−1 for non-fluorinated and fluorinated polymers, respectively: this last higher charge carrier mobility was attributed to the interaction between the fluorine atoms and the adjacent aromatic sulfur, which according to other authors promotes planarity and consequently, it favors the charge carriers mobility. AFM images showed a higher roughness correlated with phase separation for fluorinated polymer; conduction paths with dimensions less than 25 nm were detected which is positive for future improvement of solar devices.

A series of ligands, consisting of Schiff bases and their reduced amine derivatives, was prepared by [2+1] condensation of 3-methoxy (or 3-ethoxy)-2-hydroxybenzaldehyde or 2-hydroxybenzaldehyde with 3,4-diaminobenzoic acid or 1,2-diaminobenzene, and by subsequent reduction with hydrogen or NaBH4. The complexation behavior of these ligands towards Cd(II), Pb(II) and Hg(II) salts was tested and the resulting complexes characterized by elemental analysis, IR and NMR spectroscopy, ESI-MS mass spectrometry and SEM–ESEM microscopy. Ligand-bearing silicas were prepared by the reaction of a carboxylic group at the periphery of the coordinating moiety of the Schiff bases or amine derivatives with functionalized silicas bearing NH2 or Cl groups. Ligand-bearing silicas were characterized by elemental analysis, IR spectroscopy and SEM–ESEM microscopy. Finally, the capability of these materials to sequestrate the above mentioned metal ions from water solutions was studied. Preliminary data on the selective recognition of mercury ions from cadmium and lead ions are reported.

RATIONALE To try to find a correlation between the antiproliferative activity of a series of [MI(P)4]+ complexes (M = Cu, Ag and Au; P = tertiary phosphine) and their stability at micromolar concentration under mass spectrometric conditions. METHODS [MI(P)4]+ complexes were investigated by positive ion electrospray ionization mass spectrometry with multiple collisional experiments using an ion trap mass spectrometer. RESULTS The displacement of P from native [MI(P)4]+, previously described for the copper derivative, is common for the triad complexes leading to the formation of [M(P)3]+ and [M(P)2]+ adducts. Further dissociation of [M(P)2]+ depends on the nature of the metal (Cu ~ Ag > Au). More labile [Cu(P)2]+ and [Ag(P)2]+ are more cytotoxic against HCT-15 human colon carcinoma cells compared to less labile [Au(P)2]+ species. CONCLUSIONS The dissociation of P ligand(s) from the [MI(P)4]+ complexes is the driving force for the triggering of the antiproliferative activity. The more favored is the displacement of P from the [M(P)2]+ active form, the more favored is in turn the possibility for the metal to interact with biological substrates related to cancer proliferation. Copyright © 2013 John Wiley & Sons, Ltd.

This article reports the synthesis of two bimetallic zinc(II) complexes containing phenoxy-imine ligands and their application as initiators of ring opening polymerization (ROP) of L-lactide (LA). The phenoxy-imine ligands were obtained from salicylaldehyde derivatives and 2,3,5,6-tetramethylphenylenediamine, yielding two bidentate regions per ligand. The reactions of both phenoxy-imine ligands with ZnEt2 in the presence of n-BuOH afforded [Zn2(L1)(OBu)2] and [Zn2(L2)(OBu)2], which were characterized by elemental analysis, Fourier transform infrared (FTIR) and 1H nuclear magnetic resonance (NMR) spectroscopy. In addition, the geometries of both complexes were investigated by DFT (B3LYP/LACVP**) calculations. [Zn2(L1)(OBu)2] and [Zn2(L2)(OBu)2] were tested as initiators of ROP of LA at 180 °C using different LA/Zn molar ratios, namely 500, 1000 and 2500. Both complexes showed good activity, resulting in conversions up to 96% in 2 h. The poly-LLA exhibited average molecular weight (Mw) ranging from 45,000-92,000, relatively low polydispersity (Mw/Mn = 1.6-2.0) and high stereoregularity with melting temperature Tm = 164 °C.

The films of magnesium boride were grown on Si(100) substrate by chemical vapor deposition, starting from the synthesis of the single-source precursor Mg(BH 4 ) 2 . The deposition time was varied to study its influence on the film composition. The chemical composition of produced samples was investigated by the XPS technique. The depth profiling of MgB x films was carried out by using Ar ion sputtering combined with cyclic XPS measurements. The contributions of different chemical species (boride and oxides) in the depth profiles were separated by peak-fitting analysis of photoelectron B 1s and Auger Mg KLL spectra. In order to determine the correct parameters of peak fitting, the reference samples of MgB 2 and MgO were studied as well. The produced samples were composed of MgB x film covered by an overlayer of magnesium and boron oxides, whose thickness was increasing with deposition time. The surface of the films was enriched with magnesium, while the volume was characterized by the B : Mg ratio exceeding 2. XPS results confirmed that the bulk decomposition of Mg(BH 4 ) 2 precursor was successful; therefore, some other phenomenon, such as Mg segregation, was responsible for the formation of MgB x films with x > 2. In addition, a prolonged deposition time resulted in a thicker surface overlayer of Mg and B oxides, but it did not change the stoichiometry of the boride film.

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.

Magnesium boride films are synthesized from Mg(BH4)2 by CVD. A new synthesis of the precursor is developed. Deposition time of the samples is varied to study its influence on film composition. The films are analyzed by means of X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The contributions of various chemical species (boride and oxides) in the depth profiles, carried out using Ar ion sputtering combined with cyclic XPS measurements, are separated by peak-fitting analysis of photoelectron B1s and Auger MgKLL spectra. The samples are composed of MgBx film covered by an overlayer of magnesium and boron oxides.

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.

The Heck reaction of aryl dibromides and n-butyl acrylate catalyzed by Pd(OAc)2/P(t-Bu)3 is a high yielding method to produce intermediates for dihydroindacene type ligands. The same synthetic strategy, extended to tribromides, represents a simple route also to tridentate ligands potentially useful in the stabilization of trimeric metal complexes and clusters.

In this communication we report the synthesis and characterization of the vanadium (III) alkoxide [V(OCMe(2)CH(2)OMe)(3)], which presents an appreciable volatility (55 degrees C/1.5 Torr), its successful use as MOCVD precursor for the deposition of pure VO(2) and V(2)O(5) films and the characterization of the films by means of Rutherford Backscattering Spectroscopy (RBS), X-Ray Diffraction (XRD) and Cyclic Voltammetry.

The Rh(COD) and Ir(COD) homobimetallic complexes of s-indacene-diide, 2,6-dimethyl-s-indacene-diide, as-indacene-diide, and 2,7-dimethyl-as-indacene-diide have been synthesized from the di-lithium salts of the dianions and metal dimers [M(μ-Cl)L2]2 (M = Rh, Ir; L2 = COD, NBD, (ethylene)2, (CO)2 as mixtures of syn and anti isomers. The syn/anti ratio depends on the nature of the ancillary ligands at the metal and on the s or as geometry of the bridging ligand. In the reaction of the 2,7-dimethyl-as-indacene-diide-[M(COD)]2 species with CO, the higher reactivity of the syn isomers has been justified on the basis of a greater instability of the ground state due to steric interactions between the COD groups. Bis-η1 metal-bonded intermediates have been identified in the carbonylation of iridium derivatives; on the other hand, the formation of the bis-η5 mixed complexes syn and anti-{2,7-dimethyl-as-indacene-diide-[Rh(COD)][Rh(CO)2]} and their reactivity strongly support the existence of metalmetal interaction in the rhodium derivatives.

The crystal and molecular structures of the iminophosphine o-(Ph2P)C6H4CH=NC6H4OMe-4 (1) and its palladium complexes [Pd(η3-C3H5){o-(Ph2P)C6H4CH=NC6H4OMe-p}]BF4 (2) and [Pd(η2-fn){o-(Ph2P)C6H4CH=NC6H4OMe-4}] [fn = fumaronitrile, (3)] have been determined by X-ray analysis. In the free ligand (1), the planar imino group of E configuration is oriented, relative to the PPh2 unit, so that the CH=N hydrogen atom points towards phosphorus, with the nitrogen atom on the opposite side. In (2) and (3) the iminophosphine behaves as a P,N-chelate ligand, this coordination mode being achieved by the imino group rotation of 169.3 ° and 145.3 °, respectively, around its bond with the ortho disubstituted phenyl ring. Complex (2) shows a structural disorder with two different orientations of the allyl ligand. The trigonal planar coordination around the central metal in complex (3) involves the P- and N-donor atoms of (1) and the η2-bound olefin, with a marked lengthening of the olefinic carbon-carbon bond. In both the complexes, the chelate six-membered ring of the iminophosphine with palladium is not coplanar with the N-Pd-P coordination plane, the imino carbon atom and the ortho disubstituted phenyl group lying on the same side out of the N-Pd-P plane, whereas the N-substituent and one of the PPh2 groups are on the opposite side. The 1H-n.m.r. spectra at low temperatures of (2) and (3), and of [Pd(η2-tmetc){o-(Ph2P)C6H4CH=NCMe3}] [tmetc = tetramethyl ethylenetetracarboxylate, (4)] are interpreted on the basis of a non-rigid conformation of the chelate iminophosphine, which undergoes a fast dynamic process whereby the N- and P-substituents move above and below the coordination plane.

Magnesium borohydride, Mg(BH4)2, a long-sought candidate for efficient hydrogen storage chemisorption technology, has been obtained in a pure and crystalline form by two new synthetic routes in a hydrocarbon solvent. A first synthetic approach involves a metathetical reaction between organometallic magnesium compounds; a second route consists of an insertion reaction of BH3 species, released from BH3.S(CH3)2, into the Mg-C bonds of MgR2, with complete replacement of R groups with BH4 groups. Both methods, based on commercially available reagents, afford identical, pure, polycrystalline materials, identified by X-ray diffraction as the so-called low-temperature hexagonal form of Mg(BH4)2, stable below 180 degrees C, recently shown to possess a complex, unpredictable, crystal structure.

Bidentate ‘PN’ and tetradentate ‘P2N2’ ligands from stable silver(1) complexes, which were characterized by NMR and IR spectroscopy. Conductivity measurements indicate an ionic nature of the compounds in solution. A thorough mass spectrometric study (electrospray ionization and fast atom bombardment) of these complexes and the corresponding Cu(1) analogues supports the NMR and IR structural information.

The crystal structures of [NiCl2(PMePh2) · (PNMe2)] · 1/2 CH2Cl2 (1), C33H33Cl2NNiP2 · ½ CH2Cl2, and [NiCl(PMePh2)(PNMe2)][PF6] (2), C33H34ClF6NNiP3, have been determined by X-ray diffraction. Complex 1 crystallises in the monoclinic space group P21/n, a = 11.305(6) Å, b = 17.620(9) Å, c = 18.061(9) Å, β = 90.48(4)°, V = 3597(3) Å3 and Z = 4. Refinement of 2508 observed reflections and 275 parameters converges to a conventional R of 0.051. The coordination around the Ni(II) centre is distorted trigonal bipyramidal with the two axial positions occupied by the phosphorus atom of the monodentate phosphine and the tertiary amine nitrogen of the bidentate PNMe2 chelate. The equatorial sites accommodate the remaining phosphorus of the amino-phosphine and two chlorine donors. Complex 2 crystallites in the orthorhombic space group Pbca, a = 18.61(1) Å, b = 15.42(1) Å, c = 23.25(2) Å, V = 6673(7) Å3 and Z = 8. Refinement of 2351 observed reflections and 347 parameters yields R = 0.051. A square planar geometry describes the coordination around the metal with the two phosphorus donors located in a mutual cis-arrangement. As expected on the basis of the different coordination number, all of the metal-donor distances decrease on going from 1 to 2, as evidenced, in particular, by the Ni–N bond which contracts from 2.325(8) Å to 2.056(8) Å.

To try to find a correlation between the antiproliferative activity of a series of [M(I)(P)4](+) complexes (M = Cu, Ag and Au; P = tertiary phosphine) and their stability at micromolar concentration under mass spectrometric conditions.[M(I)(P)4](+) complexes were investigated by positive ion electrospray ionization mass spectrometry with multiple collisional experiments using an ion trap mass spectrometer.The displacement of P from native [M(I)(P)4](+), previously described for the copper derivative, is common for the triad complexes leading to the formation of [M(P)3](+) and [M(P)2](+) adducts. Further dissociation of [M(P)2](+) depends on the nature of the metal (Cu ~ AgAu). More labile [Cu(P)2](+) and [Ag(P)2](+) are more cytotoxic against HCT-15 human colon carcinoma cells compared to less labile [Au(P)2](+) species.The dissociation of P ligand(s) from the [M(I)(P)4](+) complexes is the driving force for the triggering of the antiproliferative activity. The more favored is the displacement of P from the [M(P)2](+) active form, the more favored is in turn the possibility for the metal to interact with biological substrates related to cancer proliferation.

Fe2O3 thin films obtained by the sol-gel technique from ethanolic solutions of Fe(OEt)3 have been deposited on pure silica and heat treated at two different temperatures. Preliminary thermogravimetric (TG) measurements on the precursor were carried out in order to evaluate the weight loss as a function of temperature and heat-treatment time. Chemical characterization of the films was obtained by XPS and UV–VIS spectroscopies. The bulk of the film heated at 500 °C did not show residual carbon. The corresponding UV–VIS spectrum was well structured in the 15 000–50 000 cm–1 region due to charge-transfer and inner-oxygen transitions. XRD measurements showed an amorphous pattern for the sample heated at 200 °C, whereas a diffraction peak corresponding to haematite (α-Fe2O3) nanocrystals was observed for the film heated at 500 °C.

Several mixtures of LiBH4 and Mg(BH4)2 borohydrides in different stoichiometric ratios (1:0, 2:1, 1:1, 1:2, 0:1), prepared by high energy ball milling, have been investigated with X-ray powder diffraction and thermal programmed desorption (TPD) volumetric analysis to test the dehydrogenation kinetics in correlation with the physical mixture composition. Afterwards mixed and unmixed borohydrides were dispersed on high specific surface area ball milled graphite by means of the solvent infiltration technique. BET and statistical thickness methods were used to characterize the support surface properties, and SEM micrographs gave a better understanding of the preparation techniques. It has been observed by TPD volumetric measurements that the confinement of the reactive borohydrides on the nanoporous supports leads to a lower dehydrogenation temperature compared to unsupported borohydrides. Moreover, a further decrease of the dehydrogenation temperature has been observed by increasing the specific surface area of the support and the pores volume and by using the prepared mixtures instead of pure materials. The dehydrogenation process seems to be favoured by the heterogeneous nucleation on the graphite surface of decomposition products or intermediate phases from melted liquid borohydrides.

A series of ferrocenyl-based complexes of general structure [eta(5)-(2-ferrocenyl)indenyI]MLn [MLn = RuCp*, FeCp, IrCOD, Mn(CO)(3), and Cr(CO)(2)NO] were synthesized with the aim of tuning the effect of the nature of the second metal group MLn on the magnitude of the metal-metal electronic coupling in their mixed valence ions generated by electrochemical oxidation. The electronic interaction was probed by determining different and independent physical properties, the potential splitting in the cyclic voltammograms, and the IT bands in the near-IR spectra, which were rationalized in the framework of Marcus-Hush theory and at the quantum chemistry level by the density functional theory and TD density functional theory methods. On the basis of the obtained results, we were able to establish a trend based on the magnitude of the Fe-M electron transfer parameters H-ab and alpha ranging from weakly to moderately coupled mixed valence ions.

Magnesium borohydride, Mg(BH4)2, a long-sought candidate for efficient hydrogen storage chemisorption technology, has been obtained in a pure and crystalline form by two new synthetic routes in a hydrocarbon solvent. A first synthetic approach involves a metathetical reaction between organometallic magnesium compounds; a second route consists of an insertion reaction of BH3 species, released from BH3·S(CH3)2, into the Mg−C bonds of MgR2, with complete replacement of R groups with BH4 groups. Both methods, based on commercially available reagents, afford identical, pure, polycrystalline materials, identified by X-ray diffraction as the so-called low-temperature hexagonal form of Mg(BH4)2, stable below 180 °C, recently shown to possess a complex, unpredictable, crystal structure.

The present communication is focused on the synthesis of the versatile heterobimetallic LaCo(ODiEt)5 (ODiEt = OC(CH2CH3)2CH2OCH3) alkoxide compound and on its innovative and unprecedented use as single-source precursor in the preparation of LaCoO3 films by both sol–gel and Chemical Vapour Deposition techniques. Nanostructured LaCoO3 films characterized by thermal stability of the perovskite structure up to 900 °C have been obtained thus evidencing the versatility of the adopted source compound. Morphological analysis revealed that high-quality smooth, well-adherent and crack-free layers have been prepared.

A series of heterobimetallic complexes of general structure [RhL(2){eta(5)-(2-ferrocenyl)indenyl}] (L(2)=cod, nbd, L=CO; cod=cyclooctadiene; nbd=norbornadiene) has been synthesised with the aim of tuning the metal-metal interaction in their mixed-valence ions generated both by chemical and electrochemical oxidation, and the results are compared with those obtained for [RhL(2){eta(5)-(1-ferrocenyl)indenyl}] isomers. Crystallographic studies and DFT calculations provide a detailed description of the structural and electronic features of these complexes evidencing a significant difference in the extent of planarity of the flexible bridging ligand between the 1- and 2-ferrocenyl isomers. Independent experimental probes, in particular the potential splitting in the cyclic voltammograms and the IT bands in the near-IR spectra, are rationalised in the framework of Marcus-Hush theory and at quantum chemistry level by DFT and TD-DFT methods. These methods allow us to establish a trend based on the magnitude of iron-rhodium electronic coupling H(ab) ranging from valence trapped to almost delocalised ions. The quasi planar bridge and the olefin ancillary ligands make [Rh(nbd){eta(5)-(2-ferrocenyl)indenyl}](+) and [Rh(cod){eta(5)-(2-ferrocenyl)indenyl}](+) rare examples of heterobimetallic systems which can be classified as borderline Class II/Class III species.

The new β-diketonate complexes (hfac)2ZrCl2, (hfac)3ZrCl, hfac = hexafluoroacetylacetonate, and (thd)2ZrCl2, thd = 2,2,6,6-tetramethyl-3,5-heptanedionate, have been prepared in good yield by reacting the corresponding β-diketonate thallium complexes with ZrCl4 in stoichiometric amounts and they have been characterized by elemental analyses and NMR spectra. These complexes and the β-diketonate complexes (acac)2ZrCl2, (acac)3ZrCl and (thd)3ZrCl have been tested as catalysts in the polymerization of 1-hexene in the presence of N,N′-(dimethylanilinium)-tetrakis(pentafluorophenylborate) or ethyltrichloroacetate as co-catalysts at room temperature using ethyl aluminum sesquichloride as scavenger.

A neutral bidentate P,N-ligand combining a hard dimethylamino nitrogen and a soft phosphine phosphorus donor affords the neutral trigonal bipyramidal as well as the cationic square-planar nickel(II) complexes cis-[NiCl2(PMe2Ph)(PNMe2)] and [NiCl(PMe2Ph)(PNMe2)]PF 6, respectively. The latter species exhibits an appreciable catalytic activity in propylene oligomerization in the presence of Et2AlCl as co-catalyst

The reaction of (1-ferrocenyl)indenyl lithium, generated from (3-ferrocenyl)-indene (1) and n-butyl lithium in THF, with the dimers [Ir(μ-Cl)(cod)]2 and [Ir(μ-Cl)(coe)2]2 afforded the heterobimetallic [η5-(1-ferrocenyl)indenyl]–Ir(cod) (2) and [η5-(1-ferrocenyl)indenyl]–Ir(coe)2 (3) (cod=cycloocta-1,5-diene; coe=cyclooctene). The complex [η5-(1-ferrocenyl)indenyl]–Ir(CO)2 (4) was obtained from 3 by exchange reaction with CO at room temperature. In contrast, the carbonylation of 2 at low temperature produces the η1-(1-ferrocenyl)indenyl]–Ir(cod)(CO)2 intermediate stable up to room temperature. The elimination of COD to give 4 occurs at higher temperature than in the corresponding monometallic η1-indenyl–Ir(cod)(CO)2. The crystal structure of 4 showed that iron and iridium are disposed in a cisoid configuration favoured by a stabilising weak bond interaction between the hydrogens of the cyclopentadienyl (Cp) ring and iridium and its carbonyls. The results of the electrochemical oxidation of 4 support the existence of a significant chemical interaction between the two metals. The comparison with the voltammetric results of the isomorphous rhodium complex 6 evidences for 4 a slowing down of the kinetic of the metal–metal interaction, and the absence of the radical cation oxidation even at high potential.

The binuclear [η5-(1-ferrocenyl)indenyl]Rh(NBD) (1), [η5-(1-ferrocenyl)indenyl]Rh(COD) (1a), and [η5-(1-ferrocenyl)indenyl]Rh(CO)2 (2) complexes have been synthesized (NBD = norbornadiene; COD = cycloocta-1,5-diene). The crystal structure determination showed that the iron and rhodium nuclei are disposed in a transoid configuration in 1 probably to avoid steric repulsions. On the contrary, in 2 the metals are in a cisoid configuration due to the presence of stabilizing π-hydrogen bonds between the CO's and the hydrogens of the unsubstituted cyclopentadienyl ring. The results of the chemical and electrochemical oxidation of 2 are in favor of the existence of an effective interaction between the two metals.

The heterobimetallic CpFe(μ-η5: η5-as-indacenediide)RhL2 complexes (L2 = COD (2), NBD (3), (ethylene)2 (4)) have been obtained from metalation of the mononuclear lithium CpFe(η5-as-indacenediide) with [Rh(μ-Cl)L2]2. Mixtures of syn and anti heterobimetallic complexes were formed and fully characterized by 2D NMR spectroscopy. The reactivity at the rhodium center is greatly influenced by the presence of the ferrocenyl moiety. The voltammetric behavior and the optical spectra are in favor of the existence of significant electronic interactions between the two metals.

The cationic complexes [Pd(η 3 -allyl){Ph 2 P( o -C 6 H 4 NMe 2 )}]PF 6 ( 1 ) and [PdMe(PPh 3 ){Ph 2 P( o -C 6 H 4 NMe 2 )}]CF 3 SO 3 ·C 6 H 6 ( 2 ) catalyse, without any added phosphine, the telomerization reaction of 1,3-butadiene with methanol, showing high chemio- (>95%) and regioselectivity towards the linear 1-methoxy-2,7-octadiene (>93%).

New neutral pentacoordinate nickel(II) complexes of the type [NiCl2(PR3)(P∩N)] [PR3 = PMe3, PMe2Ph, PMePh2; P∩N = 2-(diphenylphosphanyl)aniline (P∩NH2), N-methyl-2-(diphenylphosphanyl)aniline (P∩NHMe), N,N-dimethyl-2-(diphenylphosphanyl)aniline (P∩NMe2)], as well as cationic tetracoordinate nickel(II) complexes of the type [NiCl(PR3)(P∩N)]+ have been synthesized and characterized both in the solid state and in solution. Interesting X-ray structural data have been collected for each class of compounds, which show, inter alia, that the pentacoordinate neutral complexes can be isolated in two different molecular forms, namely square-pyramidal or bipyramidal-trigonal.