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The well-defined piano-stool iron(II) complex (Cp-NHC)Fe(CO)I bearing a bidentate cyclopentadienyl-functionalised N-heterocyclic carbene ligand is shown to catalyse the reduction of ketones under mild conditions (1-2 h at room temperature) when combined with catalytic amounts of potassium tert-butoxide, and using PhSiH and the inexpensive and less reactive polymethylhydrosiloxane as reducing agents. The stoichiometric reaction of (Cp-NHC)Fe(CO)I with potassium tert-butoxide generates an iron-hydroxo complex, which seems to be the active species in the reduction of ketones. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Highlights: [•] The potential energy surface of Cp2Pd2(BO)2 has 11 low energy structures. [•] These Cp2Pd2(BO)2 structures includes both perpendicular and coaxial structures. [•] Several Cp2Pd2(BO)2 structures have the BO group directly bonded to a Cp carbon atom. [•] A highly favored coaxial Cp2Pd2(μ-BF)2 structure is found. [Copyright &y& Elsevier]

Abstract: Reaction of CpRu(cod)Cl with phenylacetylene and AcOH gives an unusual binuclear ruthenium complex CpRu(μ-σ,η3:η3,σ-C6H3Ph3)RuCp (5, 58% yield) with a bridging acyclic flyover ligand C6H3Ph3. Under similar conditions [CpRu(MeCN)3]+ undergoes an unexpected cleavage of Cp ligand giving 4,7-diphenyl-3a,7a-dihydroindene (6, 65% yield). In sharp contrast, the pentamethylated congeners Cp*Ru(cod)Cl and [Cp*Ru(MeCN)3]+ react with phenylacetylene and AcOH in catalytic fashion giving 1,4-diphenyl-1-acetoxy-1,3-butadiene. The structures of 5 and 6 were established by X-ray diffraction. The mechanism of Cp ligand cleavage was proposed on the basis of DFT calculations. [Copyright &y& Elsevier]

Abstract: Treatment of [FeCp(CO)2Cl] with 1 equiv of the amidophosphine ligands Li[R2PNR′] (R = Ph, iPr, R′ = iPr, tBu, Cy) afforded complexes of the type [FeCp(CO)(κ2(C,P)-(C O)–NiPr-PPh2)] (1a), [FeCp(CO)(κ2(C,P)-(C O)-NtBu-PPh2)] (1b), and [FeCp(CO)(κ2(C,P)-(C O)-NCy-PiPr2)] (1c) in 40–50% yields. Complex 1a was also formed when [FeCp(CO)2(PPh2NHiPr)]+ (2) was reacted with 1 equiv of KOtBu. These complexes feature a four-membered carboxamido-phospha-ferracycle as a result of an intramolecular nucleophilic attack of the amidophosphine ligand on coordinated CO. Upon treatment of 1a with the electrophile [Me3O]BF4 the aminocarbene complex [FeCp(CO)(κ 2(C,P) C(OMe)-NiPr-PPh2)]+ (3) was obtained bearing an aza-phospha-carbene moiety. Upon treatment of cis,trans,cis-[Fe(CO)2(Ph2PNHiPr)2(Br)2] (4a) and cis,trans,cis-[Fe(CO)2(Ph2PNHtBu)2(Br)2] (4b) with KOtBu the carboxamido-phospha-ferracycles trans-[Fe(CO)2(κ2(C,P)-(C O)-NiPr-PPh2)(Ph2PNHiPr)Br] (5a) and trans-[Fe(CO)2(κ2(C,P)-(C O)-NtBu-PPh2)(Ph2PNHtBu)Br] (5b) were formed in moderate yield. Finally, representative structures were determined by X-ray crystallography. [Copyright &y& Elsevier]

Abstract: Anticancer activity of the new [Ru(η5-C5H5)(PPh3)(Me2bpy)][CF3SO3] (Me2bpy = 4,4′-dimethyl-2,2′-bipyridine) complex was evaluated in vitro against several human cancer cell lines, namely A2780, A2780CisR, HT29, MCF7, MDAMB231 and PC3. Remarkably, the IC50 values, placed in the nanomolar and sub-micromolar range, largely exceeded the activity of cisplatin. Binding to human serum albumin, either HSA (human serum albumin) or HSAfaf (fatty acid-free human serum albumin) does not affect the complex activity. Fluorescence studies revealed that the present ruthenium complex strongly quench the intrinsic fluorescence of albumin. Cell death by the [Ru(η5-C5H5)(PPh3)(Me2bpy)][CF3SO3] complex was reduced in the presence of endocytosis modulators and at low temperature, suggesting an energy-dependent mechanism consistent with endocytosis. On the whole, the biological activity evaluated herein suggests that the complex could be a promising anticancer agent. [Copyright &y& Elsevier]

The reaction of Mo2Ir2(μ-CO)3(CO)7(η5-C5H5)2 and Ir(CCCH2OH)(CO)(PPh3)3 in refluxing toluene gives the molybdenum–iridium cluster MoIr2(μ3-η2-C6H4)(μ-PPh2)(μ-CO)2(CO)4(η5-C5H5) (1) in low yield. Mo2Ir2(μ-CO)3(CO)6(PPh3)(η5-C5H5)2 (2) is a possible intermediate en route to 1; reaction of Mo2Ir2(μ-CO)3(CO)7(η5-C5H5)2 and Ir(CCCH2OH)(CO)(PPh3)3 in refluxing dichloromethane affords low yields of 2, and thermolysis of the latter in refluxing toluene gives modest yields of 1. A structural study reveals that 1 consists of a triangular MoIr2 core with a molybdenum-bound cyclopentadienyl group, two terminal carbonyls at each of the iridium atoms, one carbonyl bridging each of the Mo–Ir bonds, and a PPh2 moiety spanning the Ir–Ir linkage. The cluster coordination sphere is completed by a face-capping benzyne ligand that ligates η1- to each iridium atom and η2- to the group 6 metal. A structural study of 2 confirms the tetranuclear Mo2Ir2 core with molybdenum-bound cyclopentadienyl groups, six terminal and three-edge-bridging carbonyls, the latter deployed about an MoIr2 face, and a triphenylphosphine ligand ligated axially with respect to the carbonyl-bridged plane. Reaction of 1 with PPh3 in refluxing toluene gives MoIr2(μ3-η2-C6H4)(μ-PPh2)(μ-CO)2(CO)3(PPh3)(η5-C5H5) (3) in low yield. While X-ray structural authentication of 3 has thus far proven elusive, theoretical studies indicate that an equatorially substituted structure is favored energetically over the axially-substituted isomer by around 20 kJ mol−1, but this energy difference is not sufficiently large so as to exclude formation of the axial isomer experimentally. [Copyright &y& Elsevier]

Abstract: Trimethylsilylcyclopentadienes bearing alkoxysilyl functionality, C5H4(SiMe3)(SiMe2OR), where R is Me (2), i-Pr (3) and t-Bu (4), were prepared and characterized. Methoxy derivative 2 reacts with TiCl4 giving unstable [Ti(η 5-C5H4SiMe2OMe)Cl3] (5), which is slowly transformed to chlorosilyl complex [Ti(η 5-C5H4SiMe2Cl)Cl3] (6) and a mixture of cyclopentadienyltitanium(IV) methoxides on heating. Fully alkoxylated derivatives of the type [Ti(η 5-C5H4SiMe2OR)(OR)3] [R = Me (7), i-Pr (8), t-Bu (9)] and {Ti[η 5-C5H4SiMe(OMe)2](OMe)3} (10), were synthesized in low-to-moderate yields from respective chlorosilylcyclopentadienyltitanium trichlorides. All prepared alkoxysilyl compounds were characterized by spectroscopic techniques including 29Si NMR. Polymerization activity of 7–10 in the presence of methylaluminoxane was determined and compared with [TiCp(OMe)3] and corresponding trimethylsilyl-substituted compounds [Ti(η 5-C5H4SiMe3)(OR)3], where R is Me, i-Pr and t-Bu. The highest conversion of styrene has been observed in systems based on [Ti(η 5-C5H4SiMe3)(OMe)3], [TiCp(OMe)3] and [Ti(η 5-C5H4SiMe3)(OBu t )3], respectively. The new alkoxysilyl compounds 7–10 have significantly lower activity of 500–1800 kg of polystyrene/(mol Ti mol styrene h). All prepared polystyrenes showed both high melting point and high degree of syndiotacticity as determined by DSC and NMR measurements. [Copyright &y& Elsevier]

Abstract: Ruthenium complexes hold great potential as alternatives to cisplatin in cancer chemotherapy. We present results on the in vitro antitumor activity of an organometallic ‘RuIICp’ complex, [RuIICp(bipy)(PPh3)][CF3SO3], designated as TM34 (PPh3 = triphenylphosphine; bipy = 2,2′-bipyridine), against a panel of human tumor cell lines with different responses to cisplatin treatment, namely ovarian (A2780/A2780cisR, cisplatin sensitive and resistant, respectively), breast (MCF7) and prostate (PC3) adenocarcinomas. TM34 is very active against all tumorigenic cell lines, its efficacy largely surpassing that of cisplatin (CisPt). The high activity of TM34 towards CisPt resistant cell lines possibly suggests a mechanism of action distinct from that of CisPt. The effect of TM34 on the activity of the enzyme poly(ADP-ribose) polymerase 1 (PARP-1) involved in DNA repair mechanisms and apoptotic pathways was also evaluated, and it was found to be a strong PARP-1 ruthenium inhibitor in the low micromolar range (IC50 =1.0±0.3μM). TM34 quickly binds to human serum albumin forming a 1:1 complex with a conditional stability constant (log K′~4.0), comparable to that of the RuIII complex in clinical trial KP1019. This indicates that TM34 can be efficiently transported by this protein, possibly being involved in its distribution and delivery if the complex is introduced in the blood stream. Albumin binding does not affect TM34 activity, yielding an adduct that maintains cytotoxic properties (against A2780 and A2780cisR cells). Altogether, the properties herein evaluated suggest that TM34 could be an anticancer agent of highly relevant therapeutic value. [Copyright &y& Elsevier]

The reaction of [CpRu(CHCN)][PF], [Cp*RuCl], and [CpRuCl] n with 1,3-diformylindene results in the predominant formation of zwitter-ionic arene-cyclopentadienyl complexes {η-1,3-(CHO)CH}RuCp (Cp = CH), {η-1,3-(CHO)CH}RuCp* (Cp* = CMe), and {η-1,3-(CHO)CH}RuCp (Cp = CMeCF), respectively. The ruthenocenes {η-1,3-(CHO)CH}RuCp, {η-1,3-(CHO)CH}RuCp*, and {η-1,3-(CHO)CH}RuCpF were synthesized by the reaction of 1,3-diformylindenyl potassium with [CpRu(CHCN)][PF], [Cp*RuCl], and [CpRuCl]. [ABSTRACT FROM AUTHOR]

Synthesis and characterization of a series of 1,3- and 1,2-cyclopentadienyl disubstituted derivatives of η5-CpCo(η4-C4Ph4) has been described. The 1,3- and 1,2-cyclopentadienyl diester derived cobalt sandwich compounds {η5-C5H3[C(O)OMe]2}Co(η4-C4Ph4) were prepared by literature procedure and were separated by column chromatography. The reduction of these diester derivatives using LiAlH4 gave the bis(hydroxymethyl) derivatives, [1,3-η5-C5H3(CH2OH)2] Co(η4-C4Ph4) 1 and [1,2-η5-C5H3(CH2OH)2]Co(η4-C4Ph4) 2 which were oxidized to the dialdehydes [1,3-η5-C5H3(CHO)2]Co(η4-C4Ph4) 3 and [1,2-η5-C5H3(CHO)2]Co(η4-C4Ph4) 4 by using tetrapropylammonium perruthenate along with N-methyl morpholine oxide. Reaction of the dialdehydes with (chloromethyl)triphenylphosphonium chloride/n-BuLi followed by elimination of HCl using n-BuLi resulted in the 1,2- and 1,3-cyclopentadienyl disubstituted dialkynes [1,3-η5-C5H3(C≡CH)2]Co(η4-C4Ph4) 5 and [1,2-η5-C5H3(C≡CH)2]Co(η4-C4Ph4) 6. The reactions of 1 and 2 with NaN3 in acetic acid resulted in the bis(azidomethyl) derivatives [1,3-η5-C5H3(CH2N3)2]Co(η4-C4Ph4) 7 and [1,2-η5-C5H3(CH2N3)2]Co(η4-C4Ph4) 8. Heating of bis(hydroxymethyl) compounds 1 and 2 in acetic acid at 85–90°C resulted in the formation of bis(2-acetoxymethyl) derivatives [1,3-η5-C5H3(CH2OAc)2]Co(η4-C4Ph4) 9 and [1,2-η5-C5H3(CH2OAc)2]Co(η4-C4Ph4) 10. The reactions of 1 and 2 with thiophenol in the presence of trifluoroacetic acid in dichloromethane gave bis(phenylmethyl thioether) derivatives 11 [1,3-η5-C5H3(CH2SPh)2]Co(η4-C4Ph4) and [1,2-η5-C5H3(CH2SPh)2]Co(η4-C4Ph4) 12. The click reaction of the 1,2-dialkyne 6 with benzyl azide resulted in the 1,2-bis(triazole) derivative 13. The 1,3-diazide 8 was reduced to bis(aminomethyl) derivative [1,3-η5-C5H3(CH2NH2)2]Co(η4-C4Ph4) 14. Condensation of the 1,3-dialdehyde 3 with aniline resulted in the 1,3-bis(phenylimino) derivative 15. All the new compounds synthesized in this study were characterized by 1H and 13C NMR, FT-IR, HRMS, CHN analysis. The compounds 2–6, 8 and 10 have also been structurally characterized by single crystal X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

Abstract: A series of allyl molybdenum [(η 3-C3H5)Mo(CO)2L2Cl], [(η 3-C3H4COOMe)Mo(CO)2L2Br], cyclopentadienyl molybdenum [(η 5-C5H4R)Mo(CO)2L2][BF4] (R = H, 4-MeOC6H4CH2, 3,4,5-(MeO)3C6H2CH2), indenyl molybdenum [(η 5-C9H6R)Mo(CO)2L2][BF4] (R = H, 4-MeOC6H4CH2) and cyclopentadienyl tungsten compounds [(η 5-C5H5)W(CO)2L2][BF4], where L2 is N,N′-chelating ligand, were synthesized and characterized. The in vitro assay on human leukemia cells MOLT-4 has shown that the substitution in the π-ligand has lower effect of on cytotoxicity than exchange of the N,N′-chelating ligand. Nevertheless, even this modification can lead to considerable enhance of cytotoxicity as was evidenced on the series of the indenyl molybdenum(II) compounds. [Copyright &y& Elsevier]

Abstract: The dicarboxylic diester of the cyclobutadiene linked dimeric cobalt sandwich compound, {[η5-C5H4(C(O)OMe)]Co(η4-C4Ph3)}2 on controlled reduction with LiAlH4 gave the bis(hydroxymethyl) compound {[η5-C5H4(CH2OH)]Co(η4-C4Ph3)}2 1 in 98% yield. The diester was also reduced to the dimethyl derivative {[η5-C5H4(Me)]Co(η4-C4Ph3)}2 2 using LiAlH4 and AlCl3. Compound 1 was reacted with NaN3 in acetic acid at 50 °C to get the diazido methyl derivative {[η5-C5H4(CH2N3)]Co(η4-C4Ph3)}2 3 whereas the bis (2-acetoxy methyl) derivative {[η5-C5H4(CH2OC(O)Me]Co(η4-C4Ph3)}2 4 was obtained in almost quantitative yield by heating compound 1 with acetic acid at 80–85 °C. Click reaction of compound 3 with phenylacetylene resulted in the bis triazole derivative {[η5-C5H4(CH2N3C2HPh)]Co(η4-C4Ph3)}2 5 whereas reduction of 3 with LiAlH4 gave the bis (aminomethyl) compound {[η5-C5H4(CH2NH2)]Co(η4-C4Ph3)}2 6. The diacetyl derivative [{η5-C5H4[C(O)Me]}Co(η4-C4Ph3)}]2 7 was prepared by the reaction of in-situ generated {η5-C5H4[C(O)Me]}Co(PPh3)2, diphenyl acetylene and diphenyl diacetylene in 2:1:3 molar ratio in 42% yield. A novel dimeric derivative having two different functional groups on the cyclopentadienyl rings [{η5-C5H4[C(O)OMe]}Co(η4-C4Ph3)][{η5-C5H4[C(O)Me]}Co(η4-C4Ph3)] 8 was synthesized in 52% yield by reacting the ethynyl ester {η5-C5H4[C(O)OMe]}Co[η4-C4Ph3(Ch {η5-C5H4[C(O)Me]}Co(PPh3)2 and diphenyl acetylene in 1:2:3 molar ratio. Structural studies on compounds 1–4, 7 and 8 indicated that the two cobalt sandwich units were oriented almost anti to each other whereas compound 3 had the two cyclobutadiene rings oriented at an angle of 55.7(1)° to each other. The identity of compounds 5 and 6 was confirmed by 1H NMR, 13C NMR, IR and mass spectrometry. [Copyright &y& Elsevier]

Abstract: A new family of “RuCp” (Cp=η5-C5H5) derivatives with bidentate N,O and N,N′-heteroaromatic ligands revealed outstanding cytotoxic properties against several human cell lines namely, A2780, A2780CisR, HT29, MCF7, MDAMB231, and PC3. IC50 values were much lower than those found for cisplatin. Crystal structure of compound 4 was determined by X-ray diffraction studies. Density functional theory (DFT) calculations performed for compound 1 showed electronic flow from the ruthenium center to the coordinated bidentate ligand, in agreement with the electrochemical studies and the existence of a metal-to-ligand charge-transfer (MLCT) band evidenced by spectroscopic data. [Copyright &y& Elsevier]

Abstract. The cyclopentadienyl-substituted iron-bismuth complexes [{Cp(CO)2Fe}BiCl2] ( 1), [{Cp(CO)2Fe}BiBr2] ( 2), [{Cp′′(CO)2Fe}BiBr2] ( 3) and [{Cp*(CO)2Fe}BiBr2] ( 4) were prepared with high yields starting from [Cpx(CO)2Fe]2 [Cpx = C5H5 (Cp), C5H3-1, 3- tBu2 (Cp′′), C5Me5 (Cp*)] and the corresponding bismuth halides. The single crystal X-ray structure analyses of compounds 2- 4 are reported. Comparison of their solubility demonstrates that the steric hindrance in this type of compounds is only slightly higher for compound 3 compared with compound 2 but significantly lower compared with the Cp* derivative 4. Compounds 1- 4 react with nucleophililic reagents such as KO tBu, NaOCH2CH2OCH3, and NaOSiMe3 as well as with water in the presence of an amine to give a mixture of [{Cpx(CO)2Fe}Bi X] ( X = Cl, Br) and [{Cpx(CO)2Fe}3Bi]. In case of a reaction with nBu4NCl and DMAP (dimethylaminopyridine) no such dismutation is observed. Instead the complexes [{Cp(CO)2Fe}BiBr2(DMAP)2] ( 5), [N nBu4]2[{{Cp(CO)2Fe}BiBr3}2] ( 6) and [N nBu4]2[{{Cp(CO)2Fe}BiCl3}2] ( 7) were isolated and characterized by single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

Late transition-metal complexes bearing linked cyclopentadienyl/indenyl-carboranyl ligands were synthesized and their reactivities were examined. Reaction of Li2[Me2C(L)(C2B10H10)] (L = C5H4, C9H6, Me2NCH2CH2C5H3) with MCl2(PPh3)2 in Et2O afforded [η5:σ-Me2C(C5H4)(C2B10H10)]M(PPh3) (M = Co ( 4), Ni ( 5)), [η5:σ-Me2C(C9H6)(C2B10H10)]M(PPh3) (M = Co ( 6), Ni ( 7)), and [η5:σ-Me2C(Me2NCH2CH2C5H3)(C2B10H10)]Ni(PPh3) ( 8). Treatment of 4 or 5 with 2,6-dimethylphenylisocyanide, N-heterocyclic carbene (NHC), PCy3, or 1,2-bis(diphenylphosphino)ethane (dppe) gave the corresponding PPh3 displacement complexes [η5:σ-Me2C(C5H4)(C2B10H10)]M(2,6-Me2C6H3NC) (M = Co ( 9), Ni ( 10)), [η5:σ-Me2C(C5H4)(C2B10H10)]M[1,3-(2,6- i-Pr2C6H3)2C3N2H2] (M = Co ( 11), Ni ( 12)), [η5:σ-Me2C(C5H4)(C2B10H10)]Ni(PCy3) ( 13), or {[η5:σ-Me2C(C5H4)(C2B10H10)]Co}2(dppe) ( 14), respectively. These complexes were characterized by various spectroscopic techniques and elemental analyses. The molecular structures of 4- 14 were further confirmed by single-crystal X-ray analyses. [ABSTRACT FROM AUTHOR]

A new Schiff base, (pyridin-2-yl)-N-(3,5-di(pyridin-2-yl)-4H-1,2,4-triazol-4-yl)methanimine, (L), was synthesized. Reaction of [(η6-arene)Ru(µ-Cl)Cl]2 and [Cp*M(µ-Cl)Cl]2 (M = Rh and Ir) with one equivalent of L in the presence of NH4PF6 in methanol yielded dinuclear complexes, [(η6-arene)2Ru2(L-OH)Cl](PF6)2 {arene = C6H6 (1), p-iPrC6H4Me (p-cymene) (2) and C6Me6 (3)}, and [Cp*2M2(L-OH)Cl](PF6)2 [M = Rh (4) and Ir (5)], respectively, leading to the formation of five new chiral complexes with –OH on the azomethine carbon. L is a pentadentate ligand where one of the metal centers is coordinated to two nitrogen atoms in a bidentate chelating fashion while the other metal is bonded tridentate to three nitrogen atoms. Although the ligand is neutral before coordination, after complexation it is anionic (uni-negative) with negative charge on the azo nitrogen {see the structures: N(5) in 2[PF6]2 and N(3) for 4[PF6]2}. The complexes have been characterized by various spectroscopic methods including infrared and 1H NMR and the molecular structures of the representative complexes are established by single-crystal X-ray diffraction studies. [ABSTRACT FROM AUTHOR]

Abstract: Reactions of [(η 5-R)Rh(CO)2] (R = cp, ind) with water-soluble phosphines (L = 1,3,5-triaza-7-phosphaadamantane and tris(2-cyanoethyl)phosphine) give the new rhodium(I) complexes of the types [Rh(η 5-cp)(CO)(PTA)] (1), [Rh(η 5-cp)(CO)(P(CH2CH2CN)3)] (2), [Rh(η 5-ind)(CO)(PTA)] (3) and [Rh(η 5-ind)(CO)(P(CH2CH2CN)3)] (4) in isolated yields of 52–75%. All these compounds have been fully characterized by IR, 1H, 31P{1H} and 13C{1H} NMR, FAB-MS spectroscopies and elemental analyses. Reactivity for the substitution of phosphine is greater for [(η 5-ind)Rh(CO)(L)] comparing to [(η 5-cp)Rh(CO)(L)] because of a flexibility of the indenyl ligand to undergo facile η 5–η 3 coordinative isomerizations. The obtained complexes are active catalyst precursors for the dehydrogenation of propan-2-ol, octane and cyclooctane under photoassisted conditions without any organic hydrogen transfer acceptors, giving TOFs of 26–56 using 3 as precatalyst. [Copyright &y& Elsevier]

Abstract: The present work deals with the investigation of the thermal properties of two volatile rhenium compounds Re2(CO)10 and Re(CO)3(C5H5). The thermal behaviour of Re(CO)3(C5H5) in the condensed phase is studied by means of thermogravimetry and differential scanning calorimetry. Thermal decomposition of the vapour of Re2(CO)10 and Re(CO)3(C5H5) is studied in vacuum and in the presence of hydrogen and water vapour by means of in situ high-temperature mass spectrometry. The routes of vapour decomposition on a heated surface are proposed. Using Knudsen’s effusion method with mass spectrometric registration of the composition of the gas phase, and the flow method, temperature dependences of saturated vapour pressure were measured; thermodynamic parameters of the sublimation of complexes were calculated. For Re2(CO)10 we specified the data on the saturated vapour pressure using two independent methods within the temperature range below the phase transformations of the compound and the start of decomposition of complex vapour: =(95.5±2.3)kJ·mol−1, =(188.3±7.0)J·mol−1 ·K−1 (effusion method), =(93.6±1.7)kJ·mol−1, =(187.5±5.0)J·mol−1 ·K−1 (flow method). For Re(CO)3(C5H5) the thermodynamic characteristics were determined for the first time: =(85.2±1.0)kJ·mol−1, =(173.6±2.7)J·mol−1 ·K−1 (flow method). [Copyright &y& Elsevier]

Abstract: Two crystalline complexes of bis(η 1-methylcyclopentadienyl)zinc, [Zn(C5H4Me)2(py)2] (1), where py is pyridine, and [Zn(C5H4Me)2(teeda)], 2, where teeda is N,N,N′,N′-tetraethylethylenediamine have been isolated. The crystal structures of 1 and 2 are the first crystal structures for Zn(C5H4Me)2 complexes reported in the literature; both structures display η 1-coordination of the methylcyclopentadienyl ring to zinc, and both compounds display chirogenic α-carbon atoms. While 1 forms racemic crystals, 2 undergoes spontaneous resolution and crystals of 2 are thus enantiomerically pure. 1H NMR showed that Zn(C5H4Me)2 is stereochemically labile in solution with only one signal for the Cp-protons. This fact opens up the possibility for total spontaneous resolution and absolute asymmetric synthesis. [Copyright &y& Elsevier]

Abstract: Coordination chemistry may be used to synthesise large molecules with a closed cavity of molecular dimensions and of roughly equal size in three dimensions. The systems discussed here will involve polytopic ligands linked into spherical shapes by metal coordination. After discussing general strategies for their synthesis using the coordinate bond, studies on systems possessing five-fold symmetry are discussed. This is particularly favourable for the formation of spherical molecules, and some of the problems of multicomponent self-assembly are discussed. After reviewing some recent work, it is suggested that either the combination of three-fold symmetry with four-fold or five-fold symmetry is particularly suitable for sphere formation. [Copyright &y& Elsevier]

Abstract: Methylthiophene-fused or dimethylthiophene-fused trimethylcyclopentadienyltitanium trichloride complexes, (η5-Me4RC7S)TiCl3 (R = Me or H), are prepared, from which a chloride ligand is replaced with 2,6-diisopropylphenoxy, di(tert-butyl)ketimide, or tri(tert-butyl)phosphinimide ligand to yield (η5-Me4RC7S)TiXCl2 (11, R = Me, X = iPr2C6H3O–; 12, R = H, X = iPr2C6H3O–; 13, R = Me, X = tBu2C = N–; 14, R = H, X = tBu2C = N–; 15, R = Me, X = tBu3P = N–; 16, R = H, X = tBu3P = N–). The molecular structures of 11, 14, and 16 are confirmed by X-ray crystallography. The Cp(centroid)–Ti–N angles of 11, 14, and 16 (119.83°, 111.98°, and 125.34°, respectively) are significantly larger than the corresponding angle observed for the related thiophene-fused and tetrahydroquinaldine-linked cyclopentadienyl complex (1), [(η5-(Me4C7S)-(2-MeC9H9N-κN)]TiMe2 (106.6°). The phenoxy complexes 11 and 12 show negligible activity, while the ketimido and phosphinimido complexes 13–16 exhibit good activities (5–20 × 106 g/molTi h) for ethylene/1-octene copolymerization. The ketimido-complexes 13 and 14 are able to incorporate a high amount of 1-octene (15–16 mol%), while the phosphinimido-complexes 15 and 16 are not as capable (8 mol% 1-octene) under the identical polymerization conditions. The catalytic performance of 13–16 is inferior to 1 in terms of activity and comonomer incorporation. [Copyright &y& Elsevier]

Abstract: The Cp2Rh2(CO) n (n = 4, 3, 2, 1) derivatives have been examined by density functional theory using the BP86 and MPW1PW91 functionals. The known tricarbonyl Cp2Rh2(CO)3 is predicted to have a singly bridged structure with a predicted Rh–Rh single bond distance of ∼2.70 Å in close agreement with the experimental value of 2.68 Å, determined by X-ray crystallography. In contrast to the cobalt analog, no evidence for a triply bridged Cp2Rh2(μ-CO)3 structure was found. The known dicarbonyl Cp2Rh2(CO)2 is predicted to have a doubly bridged structure with a predicted Rh bond distance of 2.58 Å in close agreement with the experimental Rh bond distance of 2.564 Å, found by X-ray crystallography for the permethylated derivative (η5-Me5C5)2Rh2(μ-CO)2. The monocarbonyl Cp2Rh2(CO) is predicted to have a four-electron donor bridging carbonyl group with a Rh–O distance of ∼2.5 Å and a Rh bond distance of ∼2.54 Å. This differs from Cp2Co2(CO) which was previously predicted to have only a two-electron donor bridging carbonyl group with a long Co⋯O distance and a short Coce of ∼2.0 Å suggesting a formal triple bond. For Cp2Rh2(CO)4 doubly bridged trans and cis isomers were found within ∼1.0 kcal/mol in energy with non-bonding Rh⋯Rh distances of ∼3.2 Å. However, these Cp2Rh2(CO)4 isomers are predicted to be unstable with respect both to CO loss to give Cp2Rh2(CO)3 and to fragmentation into two CpRh(CO)2 units. [Copyright &y& Elsevier]

Abstract: The cyclopentadiene/cyclopentadienyl system forms a critical part in the oxidation chemistry of aromatic fuel components used in surrogate fuels and the importance of the cyclopentadienyl radical in poly-aromatic hydrocarbon (PAH) growth has also been noted due to its site dependent reactivity. The latter aspect has been subject to a number of studies along with the initial pyrolysis steps. By contrast, few studies have been performed of the corresponding oxidation chemistry under conditions of relevance to combustion applications. Thermochemical data for oxidation reactions featuring the cyclopentadienyl radical with O, OH, HO2 and O2 were determined at the G3B3 and G4/G4MP2 levels in combination with an analysis of internal rotations using density functional theory and with the Jahn–Teller effect treated as a pseudo-rotation. The calculated potential energy surfaces were subsequently used in a consistent manner for the determination of pressure dependent reaction rate parameters through the Rice–Ramsperger–Kassel–Marcus/master-equation approach with Eckart quantum tunnelling corrections applied to reactions involving hydrogen transfers. The accuracy of the method was further investigated by comparisons of computed rate parameters for pyrolysis reactions with alternative determinations. The resulting chemistry was incorporated into an evaluation framework for the study of cyclopentadiene oxidation using recent experimental flow reactor data and principal uncertainties in reaction pathways assessed. [Copyright &y& Elsevier]

Abstract: Treatment of CpZrCl3 with 1 equiv of 2-(2H-benzo[d][1,2,3]triazol-2-yl)-4,6-di-tert-pentylphenol (LigH) in THF or toluene affords the monomeric complex C31H41Cl2N3O2Zr (1) or the dimeric complex C54H66Cl4N6O2Zr2 (2), respectively. THF can transform the dimeric 2 into monomeric 1 within a few minutes at room temperature. The reaction between LigH and 2 equiv of CpZrCl3 gave the novel dinuclear complex C32H38Cl5N3OZr2 (3), linked by three bridging chlorides. The monomeric complex C44H56Cl2N6O2Zr (4), containing two Lig and two Cl ligands, could be obtained by the reaction between 2 equiv of LigH and Zr(NMe2)4 in toluene and subsequent addition of Me3SiCl. The molecular structures of the complexes were determined by the single crystal X-ray crystallographic method. In the presence of methylalumoxane (MAO) as a cocatalyst, the four complexes synthesized were highly active for the polymerization of ethylene. [Copyright &y& Elsevier]

lthough organometallic compounds of Cu(I) have been known for some time, including cyclopentadienyl derivatives of the type CpCuL (Cp = η-cyclopentadienyl ligand; L = phosphine or CO), organometallic compounds of copper in higher formal oxidation states are essentially unknown except for a few alkylcopper(III) and allylcopper(III) derivatives, only stable at very low temperatures. Theoretical studies on the cyclopentadienyl derivatives CpCuCl ( n = 1, 2, 3) indicate a preference for structures with terminal Cp rings and bridging Cl atoms up to a maximum of two of the latter. However, CpCuCl ( n = 1, 2, 3) structures with bridging Cp rings are found at only slightly higher energies. The lowest energy doublet mixed Cu(II/III) oxidation state CpCuCl structure with a single bridging Cl atom can be formally derived from the lowest energy doublet Cu(I/II) mixed oxidation state CpCuCl structure by oxidative addition of Cl. [ABSTRACT FROM AUTHOR]

Organometallic complexes containing non-reducing monosaccharide ligands represent a small but challenging field in modern chemistry. For the main part these compounds serve as reagents and catalysts for specific applications in enantio-selective conversions, e.g., intramolecular hydroaminations, Pauson-Khand reactions and allylic alkylations, and aminations. Furthermore, transfer-hydrogenations as well as reductions can be performed by these complexes. Medicinal applications such as anticancer and anti-inflammatory active compounds, carbon monoxide-releasing molecules and radio-pharmaceutics are also among these particular applications. Therefore, the monosaccharides have been featured with various functional and thus coordinating groups and have been established in pure organometallic chemistry. Aspects in syntheses, characterizations, molecular structures and applications of these types of sugar complexes are arranged into four groups of classical organometallic ligands: cyclopentadienyl, carbonyl, hydrocarbyl and unsaturated hydrocarbyl ligands. However, this field has not yet been investigated systematically, but structural and reactivity tendencies have clearly loomed. [ABSTRACT FROM AUTHOR]

Abstract: The U4+ cyclooctatetraenyl complex, [(C5Me5)(C8H8)U]2(μ-C8H8), 1, reacts with two equiv of 4,4′-dimethyl-2,2′-bipyridine (Me2bipy) and 2 equiv of 2,2′-bipyridine (bipy) to form 2 equiv of (η5-C5Me5)(η8-C8H8)U(Me2bipy-κ 2N,N′) and (η5-C5Me5)(η8-C8H8)U(bipy-κ 2N,N′), respectively. X-ray crystallography, infrared spectroscopy, and density functional theory calculations indicate that the products are best described as U4+ complexes of bipyridyl radical anions. Hence, only one of the (C8H8)2− ligands in 1 acts as a reductant and delivers 2 electrons per equiv of 1. Since the reduction potentials of uncomplexed (C8H8)2−, Me2bipy, and bipy are −1.86, −2.15, and −2.10V vs SCE, respectively, it is likely that prior coordination of the bipyridine reagents enhances the electron transfer. [ABSTRACT FROM AUTHOR]

Abstract: Tantalum nitride based thin films have been deposited on p-Si (100) and SiO2/Si by thermal Atomic Layer Deposition (ALD) using either the Ta(=N t Bu)(NEt2)3 or a derivative, in which one dialkylamido ligand is substituted by a η5-cyclopentadienyl (η5-Cp), as metal organic precursors with ammonia as reducing agent. TaNxCy self-limiting temperature dependent ALD growth was achieved for the TaCp(=N t Bu)(NEt2)2/NH3 process with a growth rate of 0.51–0.91Å cycle−1 in the 400–425°C temperature range while between 240 and 280°C, the growth of TaN based films from the Ta(=N t Bu)(NEt2)3 was accompanied by a partial decomposition of the precursor. The η5-cyclopentadienyl type compound allows lower nitrogen content in the precursor and thereafter in the deposited film. Although N/Ta ratio is close to one at temperatures of 390 and 400°C, as analyzed by Rutherford Back Scattering and Nuclear Reaction Analysis, films were amorphous independently of the deposition temperature. Since Ta–C bonds are present in the Cp derivative, the TaCp(=N t Bu)(NEt2)2 tends more likely to form tantalum carbide compared to Ta(=N t Bu)(NEt2)3, which leads to lower thin film resistivity. For both precursors, employed in their respective ALD window, films were smooth with a root-mean-square roughness close to 1nm. [ABSTRACT FROM AUTHOR]

Reaction of the [Rh(η-CMe)(NCMe)] ( 1) dication with the hexaosmium [Os(CO)] ( 2) dianion leads to the initial formation of [Os(CO)Rh(η-CMe)] ( 3). This cluster readily adds CO to form [Os(CO)Rh(η-CMe)] ( 4) which has been characterised crystallographically. 3 also adds dihydrogen to give [OsH(CO)Rh(η-CMe)] ( 5) and undergoes a substitution reaction with PPh to form [Os(CO)(PPh)Rh(η-CMe)] ( 6). With the [Ru(CO)] ( 7) dianion, [Rh(η-CMe)(NCMe)] ( 1) reacts to form three mixed-metal clusters [Ru(CO)Rh(η-CMe)] ( 8), [Ru(CO)Rh(η-CMe)] ( 9) and [Ru(CO)Rh(η-CMe)] ( 10). The clusters have been characterised spectroscopically and the structures of 8 and 10 have been confirmed crystallographically. The cluster 8 undergoes a substitution reaction with P(OMe) to form the disubstituted product [Ru(CO)(P(OMe))Rh((η-CMe)] ( 11) which has also been characterised crystallographically. [ABSTRACT FROM AUTHOR]

Abstract: A quite general approach for the preparation of η5- and η6-cyclichydrocarbon platinum group metal complexes is reported. The dinuclear arene ruthenium complexes [(η6-arene)Ru(μ-Cl)Cl]2 (arene=C6H6, C10H14 and C6Me6) and η5-pentamethylcyclopentadienyl rhodium and iridium complexes [(η5-C5Me5)M(μ-Cl)Cl]2 (M=Rh and Ir) reacts with two equivalents of the ligands 2-chloro-3-(pyrazolyl)quinoxaline (L1 ) and di-(2-pyridyl)amine (L2 ) in presence of NH4PF6 to afford the corresponding mononuclear complexes of the type [(η6-arene)Ru(L1)Cl]PF6 {arene=C6H6 (1), C10H14 (2) and C6Me6 (3)}, [(η6-arene)Ru(L2)Cl]PF6 {arene=C6H6 (4), C10H14 (5) and C6Me6 (6)}, and [(η5-C5Me5)M(L1)Cl]PF6 {M=Rh (7), Ir (8)} and [(η5-C5Me5)M(L2)Cl]PF6 {M=Rh (9), Ir (10)}. However the mononuclear η5-cyclopentadienyl analogues such as [(η5-C5H5)Ru(PPh3)2Cl], [(η5-C5H5)Os(PPh3)2Br], [(η5-C5Me5)Ru(PPh3)2Cl] and [(η5-C9H7)Ru(PPh3)2Cl] complexes react in presence of one equivalent of ligands 2-chloro-3-(pyrazolyl)quinoxaline (L1 ) and di-(2-pyridyl)amine (L2 ) and one equivalent of NH4PF6 in methanol yielded mononuclear complexes [(η5-C5H5)Ru(PPh3)(L1)]PF6 (11), [(η5-C5H5)Os(PPh3)(L1)]PF6 (12), [(η5-C5Me5)Ru(PPh3)(L1)]PF6 (13) and [(η5-C9H7)Ru(PPh3)(L1)]PF6 (14) and [(η5-C5H5)Ru(PPh3)(L2)]PF6 (15), [(η5-C5H5)Os(PPh3)(L2)]PF6 (16), [(η5-C5Me5)Ru(PPh3)(L2)]PF6 (17) and [(η5-C9H7)Ru(PPh3)(L2)]PF6 (18) respectively. These compounds have been systematically characterized by IR, NMR and mass spectrometry. The molecular structures of 2, 4 and 15 have been established by single crystal X-ray diffraction study and some of the representative complexes have also been studied by UV–visible spectroscopy. The crystal packing diagram of complex 4 reveals that the cation [(η6-C6H6)Ru(L2)Cl]+ is engaged in non-covalent interaction. This compound gives rise to a 1D helical architecture along the ‘a’ axis via intermolecular NCl hydrogen bonds. [Copyright &y& Elsevier]

Abstract: Three new mixed salicylaldiminato cyclopentadienyl zirconium complexes Cp′[2-Bu t -6-(C6H11NCH)C6H3O]ZrCl2 (Cp′= n BuC5H4 (3a), t BuC5H4 (3b) and Me4C5H (3c)) were prepared and the structure of complex 3c was confirmed by X-ray diffraction analysis. All of the three complexes showed high activities for ethylene homopolymerization with the activation of methylaluminoxane, and 3a showed the highest activity up to 1.15×106 g PE/mol Zrh for ethylene homopolymerization at 70°C. The 13C NMR spectrum showed that the obtained polymer is linear polyethylene. Complexes 3a–c also catalysed ethylene/1-hexene copolymerization with high activities from 6.29×105 to 12.3×105 g Copolymer/mol Zrh and with 0.89–1.39% 1-hexene incorporation level. In addition, the influence of the substituted alkyl on Cp on the catalytic behavior of corresponding zirconium complexes was discussed. [Copyright &y& Elsevier]

Abstract: The new ansa-titanocene dichloride [{(SiMePh)(η5-C5H4)2}TiCl2] (1) was prepared by one pot reaction, whereas synthesis of its methylated analogue [{(SiMePh)(η5-C5Me4)2}TiCl2] (3) was performed in two steps with isolation of corresponding silane intermediate SiMePh(HC5Me4)2 (2). The reaction of 1 and 3 with TiCl4 afforded the dinuclear complexes [(SiMePh){(η5-C5R4)TiCl3}2] (R=H (4) and R=Me (5)). The catalysts formed from 4 and 5 after their activation with excess MAO exhibited a modest activity in ethylene polymerization. The polymer products consisted of high molar mass linear polyethylenes with a broad molar mass distribution. The presence of three paramagnetic titanium species in the mixture 4/MAO was revealed by EPR spectroscopy. All new prepared compounds 1–5 were characterized by multinuclear NMR, EI-MS, IR, and solid-state structures of 1, 3 and 5 were determined by X-ray single crystal diffraction. [Copyright &y& Elsevier]

Abstract: Dicyclopentadienyl-(2-oxo-4-((2,6-di-isopropylphenyl)imido)pentane)-aluminum, Cp2Al(ket), crystallizes in monoclinic system in P21/c space group symmetry as a monomeric four-coordinate chelate complex with cyclopentadienyl ligands η 1(σ) and η 1(π) bonded to the aluminum center. Crystal structure analysis supported with the Hirshfeld surface analysis allowed to identify the most significant intermolecular interactions. They pointed out that both cyclopentadienyl ligands are engaged in C–H…π hydrogen bonds as π-acceptors. These directional intermolecular forces are crucial for the molecular arrangement in crystal and give rise to a supramolecular layer structure. The layer shows the symmetry of p2111 layer group. The presence of the intramolecular offset π-stacking between the cyclopentadienyl and chelate rings was also detected. [Copyright &y& Elsevier]

Abstract: A quite general approach for the preparation of η5-and η6-cyclichydrocarbon platinum group metal complexes is reported. The dinuclear arene ruthenium complexes [(η6-arene)Ru(μ-Cl)Cl]2 (arene=C6H6, C10H14 and C6Me6) and η5-pentamethylcyclopentadienyl rhodium and iridium complexes [(η6-C5Me5)M(μ-Cl)Cl]2 (M=Rh, Ir) react with 2equiv. of 4-amino-3,5-di-pyridyltriazole (dpt-NH2) in presence of NH4PF6 to afford the corresponding mononuclear complexes of the type [(η6-arene)Ru(dpt-NH2)Cl]PF6 {arene=C10H14 (1), C6H6 (2) and C6Me6 (3)} and [(η6-C5Me5)M(dpt-NH2)Cl]PF6 {M=Rh (4), Ir (5)}. However, the mononuclear η5-cyclopentadienyl analogues such as [(η5-C5H5)Ru(PPh3)2Cl], [(η5-C5H5)Os(PPh3)2Br], [(η5-C5Me5)Ru(PPh3)2Cl] and [(η5-C9H7)Ru(PPh3)2Cl] complexes react in presence of 1equiv. of dpt-NH2 and 1equiv. of NH4PF6 in methanol yielded mononuclear complexes [(η5-C5H5)Ru(PPh3)(dpt-NH2)]PF6 (6), [(η5-C5H5)Os(PPh3)(dpt-NH2)]PF6 (7), [(η5-C5Me5)Ru(PPh3)(dpt-NH2)]PF6 (8) and [(η5-C9H7)Ru(PPh3)(dpt-NH2)]PF6 (9), respectively. These compounds have been totally characterized by IR, NMR and mass spectrometry. The molecular structures of 4 and 6 have been established by single crystal X-ray diffraction and some of the representative complexes have also been studied by UV–Vis spectroscopy. [Copyright &y& Elsevier]

Abstract: Chemical implantation of Group 4 cations [Ti(III), Ti(IV), Zr(IV), Hf(IV)] has been carried out under mild conditions by the reaction of polycyclopentadienyl- (MCp n ; M=Ti, n =3, 4; M=Zr, Hf, n =4), mixed cyclopentadienyl/N,N-dialkylcarbamato (ML x (O2CNEt2) y ; M=Ti, L=Cp, C5Me5 (Cp*), x =2, y =1; M=Hf, L=Cp, x =1, y =3), and N,N-dialkylcarbamato (M(O2CNR2) n , M=Ti, n =3, R= i Pr; M=Ti, Hf, n =4, R=Et; M=Zr, n =4, R= i Pr) derivatives, with the silanol groups of amorphous silica. Cyclopentadiene/pentamethylcyclopentadiene and/or carbon dioxide and the secondary amine are released in the process. The amount of implanted cations depends on the metal and on the ligands, the pentamethylcyclopentadienyl complex being less reactive than the unsubstituted congener. The starting complexes and the final products have been characterized by EPR or by 13C CP-MAS NMR spectroscopy. [Copyright &y& Elsevier]

Abstract: Although f element chemistry has progressed enormously since the time when it was investigated by F.H. Spedding, much still remains to be discovered in this area. This address will describe some recent developments in a fundamental type of f element reaction, reduction, that show just how much new chemistry is still to be discovered in a heavily studied area of f element chemistry that was thought to be mature. This lecture should serve to encourage new efforts to challenge conventional ideas in other “mature” areas of f element science and technology. For 90 years, lanthanide-based reduction chemistry was accomplished with just three divalent ions, Eu2+, Yb2+, and Sm2+. Now there are many new ways to accomplish molecular reductive chemistry equivalent to that of the traditional Ln2+ ions, but with all the metals in the lanthanide series, La–Lu. Several years ago such an idea would have been unthinkable. This lecture will describe the development of these new types of reduction and their implications in both lanthanide and actinide chemistry. [Copyright &y& Elsevier]

Abstract: Ruthenium complexes [(η 5-C5H5)Ru(κ 1-P-PPh2Py)(PPh3)Cl] (1) and [(η 5-C5H5)Ru(κ 2-P-N-PPh2Py)(PPh3)]+ (1a) containing diphenyl-2-pyridylphosphine (PPh2Py) are reported. Coordinated PPh2Py in the complex [(η 5-C5H5)Ru(κ 1-P-PPh2Py)(PPh3)Cl] (1) exhibits monodentate behavior. In presence of NH4PF6 in methanol at room temperature it afforded chelated complex [(η 5-C5H5)Ru(κ 2-P,N-PPh2Py)(PPh3)]+ (1a). Further, 1 reacted with various species viz., CH3CN, NaCN, NH4SCN and NaN3 to afford cationic and neutral complexes [(η 5-C5H5)Ru(κ 1-P-PPh2Py)(PPh3)L]+ and [(η 5-C5H5)Ru(κ 1-P-PPh2Py)(PPh3)L] [L=CH3CN (1b); CN− (1c); N3 − (1d) and SCN− (1e)] and it’s reaction with N,N-donor chelating ligands dimethylglyoxime (H2dmg) and 1,2-phenylenediamine (pda) gave cationic complexes [(η 5-C5H5)Ru(κ 1-P-PPh2Py)(κ 2-N-N)]PF6 [κ 2-N-N =dmg (1f) and pda (1g)]. The complexes 1–1g have been characterized by physicochemical techniques and crystal structures of 1, 1a, 1c, 1e and 1f have been determined by single crystal X-ray analyses. Catalytic potential of the complex 1 has been evaluated in water under aerobic conditions. It was observed that the complex 1 selectively catalyzes reduction of aldehyde into alcohol. [Copyright &y& Elsevier]

Abstract: The synthesis of a series of rhodium and iridium complexes bearing bulky cyclopentadienyl or hydro(trispyrazolyl)borate ligands is described. The rhodium cyclopentadienyl and hydrotris(pyrazolyl)borate diene compounds, [(η5-C5Me4Bu t )Rh(η4-2,3-MeRC4H4] (R=H, 1; Me, 2) and TpMsRh(η4-2,3-MeRC4H4) (R=H, 3; Me, 4; TpMs is hydrotris(3-mesitylpyrazol-1-yl)borate), respectively, have been prepared from the corresponding Rh(I) diene precursors and Zn(C5Me4Bu t )2 (for 1 and 2), or TlTpMs (for 3 and 4), as effective C5Me4Bu t or TpMs transfer reagents. In contrast with these results, attempts to obtain a bis(ethylene) derivative of the TptolIr(I) unit (Tptol stands for hydrotris(3-p-tolylpyrazol-1-yl)borate) have provided instead the Ir(III) complex [(κ 4 -N,N′,N″,C-Tptol)-Ir(C2H5)(C2H4)] (5), whose formation requires C–H bond activation of a molecule of ethylene and of one of the Tptol p-tolyl substituents. In refluxing toluene 5 experiences metalation of a second p-tolyl substituent to give [(κ 5-N,N′,N″,C,C′-Tptol)-Ir(C2H4)] (6), which features unusual κ5-Tptol coordination. The latter compound reacts with carbon monoxide to yield the corresponding carbonyl, 7. [Copyright &y& Elsevier]

Abstract: The mononuclear complexes [(η6-arene)Ru(ata)Cl]PF6 {ata =2-acetylthiazole azine; arene=C6H6 [(1)PF6]; p-iPrC6H4Me [(2)PF6]; C6Me6 [(3)PF6]}, [(η5-C5Me5)M(ata)]PF6 {M=Rh [(4)PF6]; Ir [(5)PF6]} and [(η 5-Cp)Ru(PPh3)2Cl] {η 5-Cp=η 5-C5H5 [(6)PF6]; η 5-C5Me5 (Cp∗) [(7)PF6]; η 5-C9H7 (indenyl); [(8)PF6]} have been synthesised from the reaction of 2-acetylthiazole azine (ata) and the corresponding dimers [(η6-arene)Ru(μ-Cl)Cl]2, [(η5-C5Me5)M(μ-Cl)Cl]2, and [(η5-Cp)Ru(PPh3)2Cl], respectively. In addition to these complexes a hydrolysed product (9)PF6, was isolated from complex (4)PF6 in the process of crystallization. All these complexes are isolated as hexafluorophosphate salts and characterized by IR, NMR, mass spectrometry and UV–Vis spectroscopy. The molecular structures of [2]PF6 and [9]PF6 have been established by single-crystal X-ray structure analyses. [Copyright &y& Elsevier]

Abstract: 9-Nickelafluorenyllithium (1) reacted with iodine and then with various Cp x M complexes (Cp x =Cp, Cp∗, M=Na, Mg, Li) in different solvents. The products (π-allyl complexes), isolated from these reactions, were formed via addition of the biphenyl ligand to the Cp ring originally bonded to the Ni atom. Stereospecifity of the reactions depended on the used solvent. π-Allyl compounds 2, 3 and 4 were characterized by X-ray single crystal analysis. [Copyright &y& Elsevier]

Abstract: The reaction of [C5H4(CH2) n X]Tl (1: n =2, X=NMe2, OMe, CN; n =3, X=NMe2) with [(η6-C6H6)RuCl(μ-Cl)]2, 2, afforded the sandwich compounds [{η5-C5H4(CH2) n X}Ru(η6-C6H6)]PF6, 3, and [η5-C5H4(CH2)nX]2Ru, 4. Photolytic cleavage of 3 in acetonitrile afforded the tethered products [{η5:κN-C5H4(CH2) n X}Ru(CH3CN)2]PF6, 5. [Copyright &y& Elsevier]

Abstract: Reaction of (4-nBu-C6H4)5CpH (=CpBIGH) with KH in THF and subsequent recrystallization from hexane/Et2O gave the solvent-free product CpBIGK in good crystalline yield (55%). Crystal structure determination revealed the one-dimensional coordination polymer [CpBIGK] ∞ . Despite the steric bulk of the CpBIG ligands, the chains are not perfectly linear. They can be pictured as an array of highly symmetric sandwiches bridged by K+ ions at an angle of 167.7(2)°. The C–K bond distances are much shorter than those in other cyclopentadienyl potassium complexes. This is explained by networks of attractive C–H⋯C(π) interactions between neighbouring CpBIG ligands. In all cases the C–H donors and C acceptors are represented by the ortho-CH units in the aryl substituents. The C–H···C(π) networks within the supersandwich are less distinct than those observed in the metallocene sandwich complexes M (M=Ca, Sr, Ba, Yb, Sm). Significant out-of-plane bending of the aryl substituents indicates that, within the supersandwich chain, pairs of tighter C–H⋯C(π) networks exist. Large displacement factors for the K+ ions are explained by assuming induced polarization of these soft metals. This results in enforcement of the CpBIG–K interactions. [Copyright &y& Elsevier]

Abstract: The mononuclear η5-cyclopentadienyl complexes [(η5-C5H5)Ru(PPh3)2Cl], [(η5-C5H5)Os(PPh3)2Br] and pentamethylcyclopentadienyl complex [(η5-C5Me5)Ru(PPh3)2Cl] react in the presence of 1eq. of the tetradentate N,N′-chelating ligand 3,5-bis(2-pyridyl)pyrazole (bpp-H) and 1eq. of NH4PF6 in methanol to afford the mononuclear complexes [(η5-C5H5)Ru(PPh3)(bpp-H)]PF6 ([1]PF6), [(η5-C5H5)Os(PPh3)(bpp-H)]PF6 ([2]PF6) and [(η5-C5Me5)Ru(PPh3)(bpp-H)]PF6 ([3]PF6), respectively. The dinuclear η5-pentamethylcyclopentadienyl complexes [(η5-C5Me5)Rh(μ-Cl)Cl]2 and [(η5-C5Me5)Ir(μ-Cl)Cl]2 as well as the dinuclear η6-arene ruthenium complexes [(η6-C6H6)Ru(μ-Cl)Cl]2 and [(η6-p-iPrC6H4Me)Ru(μ-Cl)Cl]2 react with 2eq. of bpp-H in the presence of NH4PF6 or NH4BF4 to afford the corresponding mononuclear complexes [(η5-C5Me5)Rh(bpp-H)Cl]PF6 ([4]PF6), [(η5-C5Me5)Ir(bpp-H)Cl]PF6 ([5]PF6), [(η6-C6H6)Ru(bpp-H)Cl]BF4 ([6]BF4) and [(η6-p-iPrC6H4Me)Ru(bpp-H)Cl]BF4 ([7]BF4). However, in the presence of 1eq. of bpp-H and NH4BF4 the reaction with the same η6-arene ruthenium complexes affords the dinuclear salts [(η6-C6H6)2Ru2(bpp)Cl2]BF4 ([8]BF4) and [(η6-p-iPrC6H4Me)2Ru2(bpp)Cl2]BF4 ([9]BF4), respectively. These compounds have been characterized by IR, NMR and mass spectrometry, as well as by elemental analysis. The molecular structures of [1]PF6, [5]PF6 and [8]BF4 have been established by single crystal X-ray diffraction studies and some representative complexes have been studied by UV–vis spectroscopy. [Copyright &y& Elsevier]

Abstract: The synthesis and characterization of a class of group 4 metal derivatives based on the silyl-linked bis(amidinate) ligands [SiMe2{NC(Ph)N(2,6-R2Ph)Li}2] [L1 (R=H) and L2 (R=Me)] are described. The metal salts coordinated with cyclopentadienyl were used in order to increase the steric hindrance and lower the Lewis acidity of metal centers, which could prevent the N-ligands from rearranging. The tetradentate ligands L1 and L2 reacted with TiCl2(C5H5)2 to give compounds 1 and 2 in tridentate and bidentate bonding modes, respectively. Treatment of the ligand L1 with ZrCl3(C5H5) produced the half-sandwich zirconium complex 3. Reactions of the ligands with ZrCl2(C5H5)2 afforded zirconium compounds 4 and 5, demonstrating the same geometry as 1. Comparing these analogous molecular structures, it suggests that the coordination modes of the N-ligands are variable according to the properties of the metal centers as well as the bulky hindrance of the terminal groups on the seven-membered N–C–N–Si–N–C–N backbone. [Copyright &y& Elsevier]

[Display omitted] • The systematic study of the series of cyclopentadienyl borohydride Ln3+ complexes. • Five different structural types of cyclopentadienyl Neodymium borohydride complexes. • Different complex cyclopentadienylborohydride lanthanide anions. • Neodymium cyclopentadienylborohydrides initiate ε-caprolactone polymerization. A series of mono-, bis- and tris(cyclopentadienyl) complexes of La, Nd and Tb with borohydride ligand were synthesized and structurally characterized. Various structural types of complex anions and cations containing cyclopentadienyl and borohydride ligands in the coordination sphere of Ln3+ have been studied by single-crystal X-ray diffraction. Five different structural types of Cp-lanthanide borohydrides were found for neodymium: {CpNd(BH 4) 2 } in [(CpNd(BH 4) 2 (THF) 2 ] (2Nd) ; {Cp 2 Nd(BH 4) 2 }− in [Cp 2 Nd(BH 4) 2 ][Na(18-crown-6)(THF) 2 ] (3Nd) ; {Cp 2 Nd(BH 4)} in [Cp 2 Nd(BH 4)(THF)] (4Nd) ; {CpNd(18-crown-6)(BH 4)}+ in [Cp 2 Nd(BH 4) 2 ] 2 [CpNd(18-crown-6)(BH 4)][Na(18-crown-6)(THF) 2 ] (6Nd) ; {Cp 3 Nd(BH 4)}− in [Cp 3 Nd(BH 4)][Na(18-crown-6)(THF) 2 ] (8Nd). Complex anions {Cp 2 Nd(BH 4) 2 }− and {Cp 3 Nd(BH 4)}− are able to replace each other in the crystal lattice. Mono- and bis(cyclopentadienyl)borohydride complexes of neodymium effectively initiate ε-caprolactone polymerization. [ABSTRACT FROM AUTHOR]

Abstract: The dimerization of 6,6-dimethylfulvene with Ni(cod)2 yields the 4,4,8,8-tetramethyl-3a,4,7a,8-tetrahydro-s-indacene isomer (1a). Heating a solution of 1a converts it to the 1,4,5,8 (1b) and 1,4,7,8 (1c) tetrahydro-s-indacene isomers. The activation energy for the isomerization is 23(1)kcal/mol. 1b and 1c can be deprotonated with n-BuLi and the reaction of the dianion with [ClIr(C2H4)2]2 gives two isomers, cis-[(η5-C5H3)(CMe2)Ir(C2H4)2]2 (cis-2) and trans-[(η5-C5H3)(CMe2)Ir(C2H4)2]2 (trans-2). Reaction of 1b and 1c with RhCl3 · xH2O in refluxing methanol yields a red-orange solid, which was consistent with the empirical formula, [(C5H3)(CMe2)RhCl2] n (3). Reaction of 3 with C2H4 in a Na2CO3/ethanol mixture afforded cis-[(η5-C5H3)(CMe2)Rh(C2H4)2]2 in 5% yield. [Copyright &y& Elsevier]

Abstract: A new class of (CH2) n -bridged indenyl-pyrazoles [4-{Ind-(CH2) n }-RR′PzH] (Ind=1H-inden-3-yl, n =1–3, RR′Pz=3,5-disubstituted pyrazolato) were synthesized. Reactions of the indenyl-functionalized pyrazoles with nickelocene in refluxing toluene afforded trimetallic and dimetallic cyclopentadienyl nickel(II) complexes, i.e., [CpNi{4-(Ind-(CH2) n )-RR′Pz}2]2Ni and [CpNi{4-(Ind-(CH2) n )-RR′Pz}]2, depending on the steric hindrance from the 3,5-disubstituents on the pyrazolato rings. In the CpNi(II) complexes, pyrazolato ligands exhibit μ-η1:η1 coordination to the metal centers and the indenyl moieties demonstrate no interaction with the metals. All the indenyl-pyrazoles and their complexes were characterized by spectroscopic and analytical methods including X-ray crystallographic study. [Copyright &y& Elsevier]