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Graphical abstract Highlights • Trans-disubstituted diamido diamine cyclams support cationic zirconium complexes. • (Bn 2 Cyclam)ZrCl 2 reacts with silver salts to form either neutral or cationic species. • (Bn 2 Cyclam)Zr(C 6 F 5) 2 displays a fluxional behaviour in solution. • (Bn 2 Cyclam)ZrCl} 2 (k 2- N,N' -Bn 2 Cyclam) displays one terminal- and one bridging- cyclam. • [(ansa -η5:η5-Cp 2 CMe 2)ZrCl(HBn 2 Cyclam)] is the first mixed cyclam/cyclopentadienyl complex. Abstract (Bn 2 Cyclam)ZrCl 2 reacts with silver salts to form either neutral or cationic species depending on the nature of the counterion. The reaction of (Bn 2 Cyclam)ZrCl 2 with AgCF 3 COO affords (Bn 2 Cyclam)Zr(OCOCF 3) 2 while with AgPF 6 the cationic species [(Bn 2 Cyclam)ZrCl(CH 3 CN)]PF 6 is formed. Cations of formulas [(All 2 Cyclam)ZrX(L)]+ (X = Me, L = CD 2 Cl 2 ; X, L = η2-CH 2 Ph), [(MeAll 2 Cyclam)Zr(η2-CH 2 Ph)]+ and [(Bn 2 Cyclam)Zr(n Bu)(THF)]+ were prepared by abstraction of one alkyl ligand from (R 2 Cyclam)ZrX 2 (R = All, MeAll, Bn; X = Me, CH 2 Ph, n Bu) using B(C 6 F 5) 3 or [PhMe 2 NH][B(C 6 F 5) 4 ]. (Bn 2 Cyclam)Zr(C 6 F 5) 2 was obtained by reaction of (Bn 2 Cyclam)ZrCl 2 with 2 equiv. of MgBrC 6 F 5. The complex (Bn 2 Cyclam)ZrCl} 2 (k 2- N,N' -Bn 2 Cyclam) displaying a cyclam bridging ligand was obtained either from the 1:1 reaction of (Bn 2 Cyclam)ZrCl 2 with LiNiPr 2 and from the reaction of 2 equiv. of (Bn 2 Cyclam)ZrCl 2 with Li 2 (Bn 2 Cyclam).(THF) 2 in THF. The reaction of LiCpC(Me) 2 CpLi with (Bn 2 Cyclam)ZrCl 2 led to the formation of the mixed cyclam/cyclopentadienyl complex [(ansa -η5:η5-Cp 2 CMe 2)ZrCl(HBn 2 Cyclam)]. [ABSTRACT FROM AUTHOR]

This work describes a procedure giving cyclopentadienyl molybdenum(II) compounds bearing carboxylic acid function group. It involves synthesis of carboxylic acid ester functionalized cyclopentadienides, their coordination to molybdenum(II) precursor and saponification of ester function groups. The method is not limited only to compounds with the function group directly attached in the cyclopentadienyl ring but also to those functionalized in the side chain. The attempts to synthesize the indenyl analogues were only partially successful due to low stability in the saponification step. All reported structure types were elucidated from spectroscopic measurements and verified by X-ray crystallography. The second part of the work describes an effect of the outer-coordination sphere on cytotoxicity of the cationic molybdenum(II) compounds bearing N,N -chelating ligands. The cytotoxicity of the modified species bearing phenanthroline ligand toward human leukemia cells MOLT-4 (IC 50  = 10.5 ± 0.5 μmol l −1 ) is higher than reported for cisplatin (IC 50  = 15.8 ± 1.9 μmol l −1 ). [ABSTRACT FROM AUTHOR]

Treatment of the N -heterocyclic chlorophosphine precursor (PPP)Cl ( 1 ) with two equivalents of nickelocene (NiCp 2 ) affords the phosphorus-bridged dimer [(μ-PPP)Ni 2 Cp 2 ]Cl ( 2 ). In contrast, an equimolar mixture of 1 and NiCp 2 in the presence of PPh 3 generates a different product, (PP(C 5 H 5 )P)NiCl 2 ( 3 ), in which a cyclopentadienyl anion has migrated to the N -heterocyclic phosphenium center. The phosphorus-bound Cp ring in complex 3 has undergone a [1,5]-hydride shift to afford a vinylic C 5 H 5 − ring, and can be subsequently deprotonated to produce [(PP(C 5 H 4 )P)NiCl] ( 4 ). [ABSTRACT FROM AUTHOR]

[Display omitted] • Five novel compounds L 1 , L 4 , L 5 , L 9 and L 10 were synthesized via arylation of ferrocene by diazonium salt under phase transfer condition. • The cyclic voltammograms of compounds L 1 , L 4 , L 5 , L 9 and L 10 showed a clear well-defined redox peak in both conditions. • The calibration plots confirmed that L 1 , L 4, L 5 , L 9 , and L 10 showed reversible electron transfer processes and diffusion control processes. • The LUMO energy levels give better electrons transportation compare to the LUMO energy level of the conduction band edge of TiO 2. Five derivatives of 3-ferrocenylphenylimine were synthesized through arylation of ferrocene by diazonium salt under phase transfer conditions. Sn/HCl was used to reduce the nitro derivatives to ferrocenylanilines, which was followed by addition of aromatic aldehydes. The thus obtained compounds N-(2,3-dimethoxybenzylidene)-3-ferrocenylimine (L 1), N-(4-nitrobenzylidene)-3-ferrocenylimine (L 4), N-(2-thiophenecarboxbenzylidene)-3-ferrocenylimine (L 5), N-(3-nitrobenzylidene)-3-ferrocenylimine (L 9), and N-(2-furabenzylidene)-3-ferrocenylimine (L 10) showed similar UV–vis absorption spectra with the exception of L 4 which is the nitro-substituted benzylideneimine. Cyclic voltammetry of peak potential separation of the compounds under light and dark conditions was studied and the redox couple ferrocene/ferrocenium showed half-wave potentials around 0.05 V vs Ag/AgCl which is markedly higher than ferrocene. The dependence of the peak potentials and currents from the scan rates was studied in detail. While the energy of the highest occupied molecular orbital was obtained from the half-wave potential of the oxidation, the energy of the lowest unoccupied molecular orbital (LUMO) was estimated from the onset of the absorption spectra. The gaps range from 2.87 to 3.05 eV. [ABSTRACT FROM AUTHOR]

The cyclopentadienyliridium hydrides Cp 2 Ir 2 H n (Cp = η 5 -C 5 H 5 ; n = 6, 4, 2, 0), and CpIrH n ( n = 4, 2) related to the experimentally known pentamethyl cyclopentadienyliridium hydrides Cp ∗ 2 Ir 2 H n (Cp ∗ = η 5 -Me 5 C 5 ; n = 6, 2) and Cp ∗ IrH 4 have been investigated by density functional theory. The lowest energy Cp 2 Ir 2 H n ( n = 6, 4, 2) structures are predicted to have terminal Cp rings with the central Ir 2 unit bridged by two hydrogen atoms. For the hexahydride Cp 2 Ir 2 H 6 , such doubly bridged Cp 2 Ir 2 (μ-H) 2 H 4 structures are bent, leading to trans and cis structures of similar energies with an unbridged Cp 2 Ir 2 H 6 isomer lying only ∼4 kcal/mol above the bridged structures. This suggests fluxional behavior consistent with experimental data on the temperature dependence of the proton NMR spectrum of the closely related Cp ∗ 2 Ir 2 H 6 . The tetrahydride Cp 2 Ir 2 H 4 is predicted to undergo slightly exothermic disproportionation into Cp 2 Ir 2 H 6 + Cp 2 Ir 2 H 2 and thus not be a viable species. This is consistent with the failure to find any Cp ∗ 2 Ir 2 H 4 in the Cp ∗ 2 Ir 2 H n systems. The doubly bridged dihydride Cp 2 Ir 2 (μ-H) 2 is a particularly favorable species since it lies more than 18 kcal/mol in energy below any other isomer. Higher energy Cp 2 Ir 2 H n ( n = 4, 2) structures have one or two bridging Cp rings and exclusively terminal hydrogen atoms. Related structures are the lowest energy structures for the hydride-free Cp 2 Ir 2 . A higher energy Cp 2 Ir 2 structure consists of two CpIr units linked solely by an Ir–Ir bond. Analysis of the frontier molecular orbitals indicates this Ir–Ir bond to be the quadruple bond required to give each iridium atom the favored 18-electron configuration. However, this quadruple bond is a 2 σ + 2π bond with no δ components and thus differs from the σ + 2π + δ quadruple bond found in the long-known Re 2 Cl 8 2− . [ABSTRACT FROM AUTHOR]

The coordination chemistry of the previously neglected 2,4-di( tert -butyl)pentadienyl (Pdl′) ligand with transition metals is explored. Several open metallocenes [(η 5 -Pdl′) 2 M] (M = Ti ( 3 ), V ( 4 ) and Cr ( 5 )) were prepared and characterized by various spectroscopic techniques and X-ray diffraction. Attempts to prepare the open ferrocene [(η 5 -Pdl′) 2 Fe] were hampered by its high thermal instability, which leads to the formation of iron metal and 2,4,7,9-tetra- tert -butyl-1,3,7,9-decatetraene ( 2 ). Nevertheless, the half-open ferrocene [(η 5 -Pdl′)Fe(η 5 -Cp″)] (Cp″ = 1,2,4-(Me 3 C) 3 C 5 H 2 , 6 ) and mono(pentadienyl) iridium complex [(η 5 -Pdl′)Ir(η 4 -cod)] ( 9 ) were successfully synthesized. The electronic and molecular structures of the half-open ferrocene [(η 5 -Pdl′)Fe(η 5 -Cp″)] ( 6 ) and its closed analogue [(η 5 -Cp′)Fe(η 5 -Cp″)] ( 7 , Cp′ = 1,3-(Me 3 C) 2 C 5 H 3 ) were compared. Complex 6 is significantly more encumbered than 7 , as shown by the short Pdl′ cent –Fe distance. Clean oxidation of 6 and 7 can be accomplished electrochemically and chemically to give the half-open ferrocenium 6 + and closed ferrocenium 7 + , respectively, and in both cases steric strain is released upon oxidation. On heating of 6 + to 152 °C in the solid state H 2 and isobutene is eliminated to give [(η 5 -Cp′) 2 Fe] + ( 8 ). [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: 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: 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: 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: 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: 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: 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: 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: Complexes of ruthenium containing 2-furan- and 2-thiophene-thiolates with phosphine ligands have been prepared and characterized. The bis(triphenylphosphine) complexes CpRu(PPh3)2SR (R=C4H3O: Fu (1a), C4H3S: Thi (1b)) were prepared by the reaction of thiolato anions (FuS− or ThiS−) with CpRu(PPh3)2Cl. The one-pot reaction of CpRu(PPh3)2Cl, thiolato anions and L ligands gave CpRu(L)SR (L=bis(diphenylphosphino)methane: dppm (2); bis(diphenylphosphino)ethane: dppe (3)). The newly prepared complexes have been characterized by spectroscopic techniques (FT-IR, 1H NMR and 31P NMR) and by elemental analysis. The crystal structure of CpRu(dppe)SThi (3b) has been determined by X-ray diffraction. [Copyright &y& Elsevier]

The cyclopentadienyl osmium(II) complexes [(η5-C5H5)Os(PPh3)2X] [X = Br (1), CH3CN (2)] reacts with sodium azide (NaN3) to yield the corresponding azido complex [(η5-C5H5)Os(PPh3)2N3] (3). This undergoes [3+2] dipolar cycloaddition reaction with activated alkynes like dimethyl and diethyl acetylenedicarboxylate to yield triazolato complexes [(η5-C5H5)Os(PPh3)2{N3C2(CO2R)2}] [R = –CH2CH3 (4) and –CH3 (5)]. The complex 3 also reacts with nitriles such as tetracyanoethylene (TCE), fumaronitrile and p-nitrobenzonitrile to yield complexes of the type [(η5-C5H5)Os(PPh3)2{N4C2(CN)C(CN)2}] (6), [(η5-C5H5)Os(PPh3)2{N3C2HCN}] (7) and [(η5-C5H5)Os(PPh3)2{N4C(C6H4–p-NO2)}] (8). These complexes were fully characterized on the basis of microanalyses, FT-IR and NMR spectroscopic data. The molecular structure of the representative complex [(η5-C5H5)Os(PPh3)2{N3C2(CO2CH2CH3)2}] (4) was determined by single crystal X-ray analysis. [Copyright &y& Elsevier]

Abstract: One approach to the removal of sulfur-containing compounds from transportation fuels involves the coordination of such compounds to transition metal complexes. We report the design and synthesis of a complex (η5-C5H4CH2Ph)Ru(CO)2(η1(S)-DBT)+ that tests the concept that DBT binding through the sulfur can be augmented by π–π stacking interactions between a pendant phenyl group on the cyclopentadienyl ring and the DBT ligand. The crystal structure and kinetic binding studies of (η5-C5H4CH2Ph)Ru(CO)2(DBT)+ are reported and discussed. [Copyright &y& Elsevier]

Abstract: When the iron sulfide complexes (μ-S x )[CpFe(CO)2]2 (x =2,3) are treated with O-alkyl oxalyl chlorides ROCOCOCl the complexes CpFe(CO)2SCOCO2R (1) [R=Me (a), Et (b)] are obtained. Similarly, the complexes CpFe(CO)2SeCOCO2R (2) are obtained from the analogous iron selenide (μ-Se)[CpFe(CO)2]2 reaction with the same reagents. Treatment of the iron selenide with half equivalent of oxalyl chloride produces the dimeric complex [CpFe(CO)2SeCO]2 (3). The new complexes, 1, 2 and 3, have been characterized by elemental analyses, IR and 1H NMR spectroscopy. The solid state structures of 1a, 2a, 3 and [CpFe(CO)2SCO]2 (4) were determined by an X-ray crystal structure analysis. [Copyright &y& Elsevier]

Abstract: The reaction of cyanamide and its derivatives with the (η5-C5H5)Mn(CO)2(THF) and (η5-C5H4CH3)Mn(CO)2(THF) complexes affords the cyanamide substituted complexes of types (η5-C5H5)Mn(CO)2(NCN(R′)(R″)) (2a–d) and (η5-C5H4CH3)Mn(CO)2(NCN(R′)(R″)) (3a–e). All complexes were characterized by spectroscopy (1H, 13C NMR, IR), elemental and mass spectroscopy analysis. Complex 2b (η5-C5H5)Mn(CO)2(NCN(CH3)2) was additionally examined by single crystal X-ray structure determination. [Copyright &y& Elsevier]

Abstract: The reaction of Nd(OTf)3 (OTf=O3SCF3) with two molar equivalents of LiCp″ [Cp″=C5H3(SiMe3)2-1,3] in thf solution generated the blue, tetrametallic dimer [{Nd(η5-Cp″)2(μ2-κ2-O3SCF3)(μ3-κ3-O3SCF3)Li(thf)}2] (1a), which has been shown by X-ray crystallography to contain a tricyclic, ladder-like scaffold with Nd and Li cations and OTf anions at its core. Compound 1a was relatively labile, being readily cleaved by a variety of donor molecules. 18-Crown-6 efficiently encapsulated the lithium cation to yield the salt [Li(18-crown-6)][Nd(η5-Cp″)2(κ1-O3SCF3)(κ2-O3SCF3)] (2). Addition of N,N,N′,N′-tetramethylethylenediamine (tmeda) afforded the monomeric bimetallic [Nd(η5-Cp″)2(μ2-κ2-O3SCF3)2Li(tmeda)] (3), while the more rigid donor 2,2′-bipyridine (bipy) produced the neutral, Li-free complex [Nd(η5-Cp″)2(κ1-O3SCF3)(bipy)] (4). The molecular and crystal structures of 2–4, as well as that of1b, the unstable La analogue of 1a, have been determined by X-ray methods. [Copyright &y& Elsevier]

Abstract: The use of potassium osmate, K2[OsO2(OH)4], as a precursor for some cyclopentadienyl-osmium complexes is described. The X-ray structures of OsBr(PPh3)2Cp, OsCl(dppe)Cp and OsX(dppe)Cp∗ (X=Cl, Br) are reported. [Copyright &y& Elsevier]

Abstract: Thermolysis of [CpRuCl(PPh3)2] and NaS2CNPr2 or NaS2CNMeBu in methanol affords the ruthenium(II) dithiocarbamate complexes, [CpRu(PPh3)(S2CNPr2)] and [CpRu(PPh3)(S2CNMeBu)], which have been crystallographically characterized. A similar treatment of two equivalents of [CpRuCl(PPh3)2] with the bis(dithiocarbamate) ligand derived from 1,3-homopiperazine affords [{CpRu(PPh3)}2(μ-S2CNC5H10NCS2)]. [Copyright &y& Elsevier]

Abstract: The mixed ligand complexes [{Gd(OCMe2-i-Pr)2Cp}2], [{Sm(OCMe2-i-Pr)2Cp}2], and [Sm2(OCMe2-i-Pr)3Cp3] were synthesized by reacting [LnCp3] with HOCMe2-i-Pr. X-ray crystallographic studies show that the three complexes each have two bridging alkoxide ligands linking two metal atoms. The coordination geometries at the metals are distorted tetrahedral. [Copyright &y& Elsevier]

Abstract: Reaction of tBu2(Me3Si)C5H2Li with S2Cl2 leads to [tBu2(Me3Si)C5H2]2S2. This compound exists as a pair of diastereomers (1,2) with sulfur in an allylic position of the cyclopentadiene system. Each diastereomer exists as a racemate of RS,SR and RR,SS enantiomers, respectively. 1 rapidly, 2 slowly convert below room temperature to a pair of diastereomers (3,4) with sulfur in vinylic position. Again, each diastereomer exists as a racemate of RS,SR and RR,SS enantiomers. 3 and 4 are the stable constitutional isomers at ambient temperatures and do not interconvert. The structures of 2, 3 and 4 have been determined by single crystal X-ray diffraction. [Copyright &y& Elsevier]

Reaction of the disilylcyclopentadiene 1,1-[SiMe2(CH2CH＝CH2)]2C5H4 with NbCl5 gave the new allylsilyl-substituted monocyclopentadienyl niobium complex [Nb{η5-C5H4SiMe2(CH2CH＝CH2)}Cl4]. This compound was reacted with LiNHtBu or NH2tBu to give the imido derivative [Nb{η5-C5H4SiMe2(CH2CH＝CH2)}(NtBu)Cl2], which was further alkylated to the imido alkyl complexes [Nb{η5-C5H4SiMe2(CH2CH＝CH2)}(NtBu)R2] (R = Me, CH2Ph) and [Nb{η5-C5H4SiMe2(CH2CH＝CH2)}(NtBu)Cl (CH2Ph)]. Reaction of the imido complexes with the corresponding lithium cyclopentadienides gave the dicyclopentadienyl-imido complexes [M(η5-C5R5){η5-C5H4SiMe2(CH2CH＝CH2)}(NtBu)Cl] (M = Nb, Ta; R = H, Me). Metallocene dichlorides [M(η5-C5R5){η5-C5H4SiMe2(CH2CH＝CH2)}Cl2] (M = Nb, Ta; R = H, Me) were easily prepared by reduction with Na/Hg and simultaneous transmetallation of [Ta(η5-C5R5)Cl4] with Li[C5H4SiMe2(CH2CH＝CH2)] and of [Nb{η5-C5H4SiMe2(CH2CH＝CH2)}Cl4] with Li(C5R5). All of the new compounds have been characterized by elemental analysis, and IR and NMR spectroscopy. [Copyright &y& Elsevier]

Abstract: The reaction of CpCo(CO)2 with elemental sulfur yielded the new sulfur-rich compound Cp4Co4(μ3-S)(μ3-S2)3 (1). The structure of 1 contains a Co4S7 core composed of three μ3-disulfido ligands and one μ3-sulfido ligand. PEt3 abstracts sulfur from 1 to yield the new compound Cp4Co4(μ3-S)3(μ3-S2) (2). Compound 2 is also a cage compound, but it contains three μ3-sulfido ligands and only one μ3-disulfido ligand. Compound 2 is converted back to 1 by reaction with elemental sulfur. The selenium homologue Cp4Co4(μ3-Se)3(μ3-Se2) (3) was obtained from the reaction of CpCo(CO)2 with elemental selenium. The structures of 1, 2 and 3 were determined by single-crystal X-ray diffraction analyses. [Copyright &y& Elsevier]

The reactivity of the iron selenide complex (μ-Se)[CpFe(CO)2]2 toward chloroformates, ROCOCl, has been studied and the products CpFe(CO)2SeCO2R [R=Me (1), Et (2), iso-Bu (3), Ph (4), 2-C6H4Cl (5), 4-C6H4Cl (6), and 4-C6H4NO2 (7)] have been obtained. The novel complexes, 1–7, have been characterized by elemental analyses, IR and 1H NMR spectroscopy. The solid state structure of CpFe(CO)2SeCO2Et, 2, was determined by an X-ray crystal structure analysis. [Copyright &y& Elsevier]

A cyclopentadiene compound having methyl substituents on 1,3-positions, 1,3-Me2-2-CH2(OTHP)-C5H3 (3) is prepared from 2-bromo-3-methyl-2-cyclopenten-1-one ethylene ketal (1) in 48% overall yield. Addition of 2.5 equivalents of indenyllithium to 3 affords a methylene bridged 1,3-dimethylcyclopentadienyl indenyl compound, CH2(1,3-Me2C5H3)(C9H7) (5) in 72% yield. Reaction of dilithium salt of 5 with ZrCl2(NMe2)2 (DME) furnishes an ansa-zirconocene complex [CH2(1,3-Me2C5H2)(C9H6)]Zr(NMe2)2 (6), which is transformed cleanly to the dichloride complex, [CH2(1,3-Me2C5H2)(C9H6)]ZrCl2 (7), by treatment of Me3SiCl. Hydrogenation of 7 over PtO2 gives a tetrahydroindenyl complex [CH2(1,3-Me2C5H2)(C9H10)]ZrCl2 (8). Reaction of the dilithium salt of 5 with Ti(NMe2)2Cl2 does not provide the desired ansa-titanocene complex, but a dinuclear complex [(1,3-Me2C5H2)Ti(NMe2)2Cl]–CH2–[(C9H6)Ti(NMe2)Cl] (9) is obtained. The solid structures of 6 and 9 were determined by X-ray crystallography. The ethylene and ethylene/norbornene (co)polymerizations were studied with 7/MAO and 8/MAO. [Copyright &y& Elsevier]

Treatment of tris-cyclopentadienyl-ytterbium in thf with one equivalent of 2,6-di(tert-butyl)phenol, N,N-dimethyl-2-aminoethanol or N,N-diethyl-2-aminoethanol resulted in substitution of one cyclopentadienyl ligand and formation of [YbCp2(O-C6H3tBu-2,6)(thf)] (1), [{YbCp2(μ-OCH2CH2NMe2)}2] (2) or [{YbCp2(μ-OCH2CH2NEt2)}2] · (thf)2 (3), respectively. All compounds were characterised by spectroscopic and X-ray crystallographic techniques, the latter two also being studied by variable temperature 1H NMR spectroscopy. Compound (1) is mononuclear with the Yb centre bound by two η5-cyclopentadienyl ligands one O-bound thf and an O-bound phenoxy ligand. Compounds (2) and (3) are centrosymmetric dimers with the Yb centre bound by two η5-cyclopentadienyl ligands, while the bidentate ligands chelate the metal centre and also bridge to the adjacent Yb through the alkoxy oxygen atom. Variable temperature 1H NMR studies on compounds (2) and (3) show a solution-state equilibrium between the dimeric solid-state structure and one with the nitrogen atoms non-bound to Yb. [Copyright &y& Elsevier]

The dimer [Ir(μ-Cl)(C8H14)2]2 reacts with the ligands (S)-(C5H4CH2CH(Ph)PPh2)Li and (R)-(C5H4CH(Cy)CH2PPh2)Li to give (S)-[Ir(η5-C5H4CH2CH(Ph)PPh2-κP)(C8H14)] and (R)-[Ir(η5-C5H4CH(Cy)CH2PPh2-κP)(C8H14)], which upon treatment with CH3I at room temperature afford the cationic iridium(III) compounds (S,SIr)-[Ir(η5-C5H4CH2CH(Ph)PPh2-κP)(CH3)(C8H14)][I] as a single diastereomer, and (R)-[Ir(η5-C5H4CH(Cy)CH2PPh2-κP)(CH3)(C8H14)][I] as a 9:1 mixture of two diastereomers. If the oxidative addition reaction is performed at reflux in methylene chloride, the starting complexes convert to the neutral compounds (S)-[Ir(η5-C5H4CH2CH(Ph)PPh2-κP)(CH3)(I)] and (R)-[Ir(η5-C5H4CH(Cy)CH2PPh2-κP)(CH3)(I)] as 1.6:1 and 3.3:1 mixtures of diastereoisomers, respectively. Carbonyl iridium complexes are synthesized by reacting [IrCl(CO)(PPh3)2] with the ligands to afford (S)-[Ir(η5-C5H4CH2CH(Ph)PPh2-κP)(CO)] and (R)-[Ir(η5-C5H4CH(Cy)CH2PPh2-κP)(CO)]. They give upon treatment with CH3I the cationic species (S)-[Ir(η5-C5H4CH2CH(Ph)PPh2-κP)(CH3)(CO)][I] and (R)-[Ir(η5-C5H4CH(Cy)CH2PPh2-κP)(CH3)(CO)][I] as 1.6:1 and 3:1 mixture of diastereomers, respectively. No migratory-insertion of the methyl group into the carbonyl–metal bond has been observed even after prolonged heating. [Copyright &y& Elsevier]

The reaction of [Ru(η3:η3-C10H16)Cl2]2 (1) with the Cp-linked phosphine ligands Ln (C5H5&z.sbnd;CH2CHRPR′2; R=H, R′=Ph, n=1; R=Ph, R′=Ph, n=2), in a 5:1 mixture of acetonitrile–ethanol and in the presence of Li2CO3 and KPF6 affords the cationic half-sandwich ruthenium(II) complexes [{η5-C5H4&z.sbnd;CH2CHRPR′2-κP}Ru(CH3CN)2]·[PF6] (4) and (5). Both complexes have been characterized in the solid state by an X-ray structure analysis. In contrast, the reaction between 1 and L3 (R=Ph, R′=o-xylyl) affords the cationic sandwich compound [{η5:η6-C5H4&z.sbnd;CH2CHPhPR′2}Ru]·[PF6] (7), in which one arene substituent of the phosphine is η6-coordinated to the metal and the phosphorus remains pendant. Treatment of 5 with tertiary phosphines (PR″3, R″=i-Pr, Ph, Cy) affords a mixture of the diastereomers [L2Ru(CH3CN)PR″3]+. The diastereoselectivity observed depends on the steric bulkiness of the phosphines and on the reaction conditions. [Copyright &y& Elsevier]

Substitution of cyclopentadiene by one to three Me3Si or t-Bu groups allows the formation of mono- and biscyclopentadienylmono-, di-, and triselanes. [(Me3Si)3C5H2]2Se2 is the first biscyclopentadienyldiselane characterized by single crystal X-ray diffraction. Crystal structures are also presented to show that such compounds can function as ligands via selenium or the cyclopentadienyl moieties. [Copyright &y& Elsevier]

The photolytic CO-substitution reaction of the organoiron thiocarboxylate complexes CpFe(CO)2SCOR (R=CH3, 2-CH3C6H4, 2-NO2C6H4, 4-NO2C6H4, 3,5-(NO2)2C6H3) with diphosphines (Ph2P(CH2)nPPh2) [n=1 (dppm), n=2 (dppe), n=3 (dpppr), n=4 (dppb), n=5 (dppp), n=6 (dpph)] at room temperature using 1:2 (metal–ligand) molar ratio afforded exclusively the disubstituted complexes CpFe(Ph2P(CH2)nPPh2)SCOR when n=1, 2 and 3 and the monosubstituted analogs CpFe(CO)(Ph2P(CH2)nPPh2)SCOR when n=4, 5 and 6. This reaction was found to be strongly influenced by the backbone length of the diphosphine ligand, the nature of the R group of the thiocarboxylate moiety and the metal–ligand molar ratios. The crystal structure of CpFe(dppm)SCO(3,5-(NO2)2C6H3) was determined. [Copyright &y& Elsevier]