CH CHCH Research Articles

Crystal structure of trans-2,4-bis(sec-butyl)-2,4-bis((2-methyl-1-thioxo)butylsulfanyl)-1,3-dithietane, C2S2(C4H9)2(C4H9CS2)2

C20H36S6, monoclinic, P121/n1 (no. 14), a = 12.008(3) A, b = 6.050(2) A, c = 17.858(5) A, = 99.34(2)°, V = 1280.2 A, Z = 2, Rgt(F) = 0.050, wRref(F) = 0.080, T = 293 K. Source of material 2-methylbutanedithioic acid was prepared according to a previously described procedure [1,2]. Reaction of the dithioacid with BF3 · Me2O, as it is the case for branched dithioacids [3] caused the evolution of H2S and produced the dithietane species. So 2.34 g (0.05 mol) of CH3CH2CH(CH3)CS2H was dissolved in 20 mL hexane. Boron trifluoride dimethyletherate (3.42 g, 0.03 mol) was then added. The mixture was cooled to 253 K. After two weeks, crystals of crude dithietane were collected by filtration. Good quality crystals for X-ray diffraction analysis were obtained by slow evaporation from an acetone solution. Discussion The tetrahedral unit C1-S2-C2 located close to the centre of symmetry and shares an edge (S2-S2 ) with its centrosymmetrical one. At the centre of the molecule, this condensation creates an almost regular square plane built by S2 and C1 and their centrosymmetrical ones with the S2–C1–S2 angle being 94.57(3)°. The tetrahedral unit C1-S2-C2 is mainly characterized by three very similar C—S distances ranging from 1.832(2) A to 1.842(2) A and one C1—C2 distance of 1.539(3) A. In spite of this apparent distortion the average angle C2–C1–S in this tetrahedron, 114.3°, is not far from the theoretical value for a regular tetrahedron in the other organic entities of the arrangement. The observed interatomic distances and bond angles are in accordance with all values previously reported [4]. Z. Kristallogr. NCS 220 (2005) 541-542 541 © by Oldenbourg Wissenschaftsverlag, Munchen Crystal: yellow prism, size 0.40 × 0.45 × 0.44 mm Wavelength: Mo K radiation (0.7107 A) : 5.36 cm−1 Diffractometer, scan mode: Enraf-Nonius CAD4, 2 max: 59.92° N(hkl)measured, N(hkl)unique: 4172, 4061 Criterion for Iobs, N(hkl)gt: Iobs > 3 (Iobs), 2503 N(param)refined: 118 Programs: SIR92 [5], teXsan [6], ORTEP-3 [7] Table 1. Data collection and handling. H(1) 4e 1.2257 −0.0010 0.9336 0.066 H(2) 4e 1.1951 0.3892 0.9384 0.083 H(3) 4e 1.0983 0.3568 0.8703 0.083 H(4) 4e 1.3258 0.3138 0.8691 0.175 H(5) 4e 1.2410 0.4595 0.8158 0.175 H(6) 4e 1.2398 0.2048 0.8057 0.175 H(7) 4e 1.1301 −0.0819 0.8152 0.084 H(8) 4e 1.0173 −0.0027 0.8378 0.084 H(9) 4e 1.0747 −0.2165 0.8733 0.084 H(10) 4e 1.3506 0.2761 1.1726 0.103 H(11) 4e 1.5378 0.1776 1.1996 0.140 H(12) 4e 1.5114 −0.0319 1.1499 0.140 H(13) 4e 1.5796 0.2293 1.0762 0.141 H(14) 4e 1.4930 0.4019 1.0956 0.141 H(15) 4e 1.4522 0.2005 1.0447 0.141 H(16) 4e 1.4112 0.0705 1.2864 0.133 H(17) 4e 1.3700 −0.1441 1.2430 0.133 H(18) 4e 1.2836 0.0356 1.2572 0.133 Table 2. Atomic coordinates and displacement parameters (in A). Atom Site x y z Uiso

Mesostructured Crystalline Ceria with a Bimodal Pore System Using Block Copolymers and Ionic Liquids as Rational Templates

A concept is shown to fabricate mesoporous ceria thin films with a crystalline framework and a bimodal pore size distribution by evaporation-induced self-assembly followed by a suitable temperature treatment and template removal strategy. The use of a suitable block copolymer ((CH2CH2CH2(CH)CH2CH3)79(OCH2CH2)89OH), “KLE”) and an ionic liquid template (leading to pores 3 nm in diameter) generated a bimodal pore system of deformed spherical mesopores of ca. 6 nm × 16 nm with the smaller pores being located in the matrix between the larger ones. The porosity was studied by a combination of quantitative SAXS analysis, physisorption, AFM, and TEM, introducing a general methodology for a quantitative structural characterization of such films.

Measurement of photolysis branching ratios of 2-bromopropane at 234 and 267 nm

The photolysis branching ratios of 2-bromopropane have been investigated near 234 and 267 nm using resonance-enhanced multiphoton ionization with time of flight mass spectrometry. Bromine fragments monitored in this study were produced via direct dissociation of 2-bromopropane, represented by CH 3CHBrCH 3 → CH 3CHCH 3 + Br( 2P 3/2)/Br*( 2P 1/2). The branching ratios at two different excitation wavelengths were measured to be 0.534 and 0.244, respectively. The results indicated that the Br( 2P 3/2) dominated the dissociation process and the branching ratios exhibited an increasing trend with photon energy increase. Through ab initio calculation, we proposed a possible photodissociation mechanism of 2-bromopropane.

Design, Synthesis, and Chemistry of Sterically Nondemanding Primary Bisphosphines1

Design and synthesis of chelating bisphosphines functionalized with the smallest chemical unit "H" on the P(III) centers ((PH(2)CH(2))(2)CHCH(2)NHPh (4) and (PH(2)CH(2))(2)CHCONHPh (5)) are described. Studies demonstrating that no bulky chemical substituents are necessary to offer thermal/oxidative stability to the -PH(2) groups in 4 and 5 are described. The H atoms around the P(III) centers in 5 (or 4) concur limited/no steric influence, but yet the phosphines manifest high nucleophilicity to coordinate strongly with W(0) and Re(I). The studies include synthesis and X-ray structural characterization of an air-stable primary bisphosphine (5) and its transition-metal chemistry with W(CO)(6) and Re(CO)(5)Br to produce the complexes (eta(2)-(PH(2)CH(2))(2)CHCONHPh)W(CO)(4) (6) and (eta(2)-(PH(2)CH(2))(2)CHCONHPh)Re(CO)(3)Br (7), respectively.

Low-temperature EPR and quantum chemical study of lactone radical cations and their transformations

Radical cations of a number of lactones ( β-butyro-, γ-butyro-, γ-valero-, δ-hexano-, δ-valero- and ε-capro-) were radiolytically generated in CF 3CCl 3 matrix and investigated by EPR spectroscopy. The primary radical cation of the 4-membered ring β-butyrolactone is unstable even at 77 K and undergoes spontaneous ring opening and fragmentation, leading to the deprotonated neutral (CH 2CHCH 2) radical. The stability of the primary carbonyl-centred radical cations of the 5-, 6- and 7-membered lactone rings towards intramolecular H-shift from the C1 in α-position to carbonyl oxygen depends primarily on the ring size, which determines the activation energy of the transformation and distance L(H–O) of the carbonyl oxygen to the nearest H-atom on the ring. The larger the ring, the smaller the L(H–O) and also activation energy of the H-shift, making the transformation of the primary radical cation more feasible. The quantum chemical calculations facilitated the interpretation of the EPR spectra of the secondary radical cations.

Characterization of alkanethiol/ZnO structures by X-ray photoelectron spectroscopy

1-Propanethiol (CH 3CH 2CH 2SH) was connected with O-polar zinc oxide (ZnO) surfaces toward biofunctional devices. X-ray photoelectron spectroscopy (XPS) measurement revealed that the S O bonds were formed between 1-propanethiol and ZnO layers. Although the surface coverage of the molecule is less than a few percent, 1-propanethiol/ZnO structures were stable even at thermal treatment of 400 °C.

Adsorption and reaction of 1,3-butadiene on Pt(1 1 1) and Sn/Pt(1 1 1) surface alloys

Temperature-programmed desorption (TPD), Auger electron spectroscopy (AES), and low-energy electron diffraction (LEED) were used to study the chemistry of 1,3-butadiene (H 2C CHCH CH 2, C 4H 6) on Pt(1 1 1) and p(2 × 2)-Sn/Pt(1 1 1) and (√3 × √3)R30°-Sn/Pt(1 1 1) surface alloys. All chemisorbed 1,3-butadiene completely dehydrogenated to H 2 and surface carbon on Pt(1 1 1). Alloying Sn on Pt(1 1 1) can completely inhibit this decomposition and 1,3-butadiene reversibly adsorbs and desorbs from the two Sn/Pt(1 1 1) alloys under UHV conditions. The desorption activation energy of 1,3-butadiene on the (2 × 2) and (√3 × √3)R30°-Sn/Pt(1 1 1) surface alloys is 88 and 75 kJ/mol, respectively. These values are good estimates of the adsorption energies, and also place lower limits on the activation energy barrier for dissociating vinylic C–H bonds on the (2 × 2) and √3 surface alloys. Even though 1,3-butadiene is much more strongly chemisorbed than 1-butene (H 2C CHCH 2CH 3, C 4H 8) on the (2 × 2)-Sn/Pt(1 1 1) alloy, 1,3-butadiene is less reactive than 1-butene because there are no allylic β-CH bonds in 1,3-butadiene as there are in 1-butene.

Sphingolipids as coenzymes in anion transfer and tumor death

Many kinds of natural sphingolipids and their analogs stimulate or inhibit a wide assortment of biochemical phenomena and enzymes. The puzzle considered here is: how can these lipids control so many different kinds of processes? In almost every study in which a structural comparison was made, an allylic alcohol moiety [–CHCH–CH(OH)–] was found to be an essential feature of the sphingolipid. Many of those stimulations lead to cell death, emphasizing the importance of allylic sphingolipid structure in the design of chemotherapeutic agents. The proposal offered here is that these lipids function as coenzymes, in which the allylic moiety acts as an anion transferring agent, forming transient phosphate or acyl or peptidyl esters for the synthesis or hydrolysis of phosphoproteins, proteins, and phospholipids. Sphingolipids that inhibit these reactions may simply displace the active sphingolipids from their sites in the enzymes’ active regions, or bind to the enzymes’ allosteric region. This kind of competition could act as a major homeostatic control mechanism. Some of the allylic sphingolipids also generate reactive oxygen, possibly by oxidation of the allylic alcohol group. This explains the need to control redox-controlling metabolites in sphingolipid-controlled processes (e.g., glutathione). Many anticancer drugs that produce apoptosis in tumors possess an allylic alcohol residue, affect protein phosphorylation, and produce reactive oxygen species. They may be therapeutically useful because they control the action of sphingolipids as anion transfer agonists or inhibitors.

Spectroscopic studies of binary liquid mixtures of alkoxyethanols with substituted and cyclic amides at 298.15 K

The study of the effect of simultaneous presence of ether (–O–) and (–OH) groups on the excess thermodynamic properties and the corresponding behaviour of alkoxyethanols in binary mixtures is of great relevance in understanding the nature of interactions. The IR spectra have been measured for binary mixtures of 2-propoxyethanol, CH 3CH 2CH 2OCH 2CH 2OH or 2-isopropoxyethanol, (CH 3) 2CHOCH 2CH 2OH with N, N-dimethyl formamide HCON(CH 3) 2, N, N-dimethyl acetamide, CH 3CON(CH 3) 2 2-pyrrolidinone, ▪ and N-methyl-2-pyrrolidinone, ▪ at 298.15 K. The shifts in the C O and O H stretch have been used to interpret the excess molar volumes, V m E, and excess free energy of activation for viscous flow, Δ G* E. The effects of the specific interactions on the dependence of these properties on the position of the methyl group in 2-propoxyethanol and 2-isopropoxyethanol and the influence of N, N-disubstituted and cyclic amides have been discussed in the light of IR measurements.

The Keggin structure complex of carbenium ions: hydrothermal synthesis and characterization of [CH 3CHCH 3] 3[PMo 12O 40

A novel Keggin unit containing n-propylcarbocation complex, [CH 3CHCH 3] 3[PMo 12O 40], was synthesized by a hydrothermal method in the presence of CuCl 2. X-ray structure analysis has confirmed the presence of the [CH 3CHCH 3] + cations in [CH 3CHCH 3] 3[PMo 12O 40]. Its structure was also characterized by thermogravimetric analysis.

Novel fluorinated polymers by radical polyaddition: Inspiration and progress

AbstractThe story of the outset and the growth of radical polyaddition of bisperfluoroisopropenyl derivatives [CF2C(CF3)R C(CF3) CF2] with several organic compounds possessing carbon–hydrogen bonds is described. The reaction afforded novel fluorinated polymers bearing such organic segments in polymer main chains as 1,4‐dioxane, diethyl ether, dimethoxyethane, 18‐crown‐6, triethylamine, glutaraldehyde, and alkanes which have never been supposed as direct starting compounds for preparation of polymers. The facile method for preparation of fluorinated hybrid polymers bearing alkylsilyl groups was developed with diethoxydimethylsilane and silsesquioxanes. Taking advantage of the high reactivity of the perfluoroisopropenyl group as a radical acceptor, self‐polyaddition and cyclopolymerization were investigated. Triethysilyl perfluoroisopropenyl ether [CF2 C(CF3)OSi(C2H5)3] was proved to be the most probable candidate for self‐polyaddition. Cyclopolymerization of perfluoroisopropenyl vinylacetate [CF2C(CF3) OCO CH2CH CH2] was investigated to afford polymers possessing five‐membered‐ring units in main chains. The interconversion of the unstable fluorinated carbon radical and the stable hydrocarbon radical had an important role in the reaction. The radical addition reaction presented herein may be developed for preparation of a wide variety of novel fluorinated polymers and organic compounds possessing functional groups. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4101–4125, 2004

C4H8[rad]+ isomerizations by theory

Structures, energies and reaction coordinates for much of the C4H8+ potential surface were obtained by ab initio and density functional theories. Most C4H8+ isomers are demonstrated to be mutually accessible below the threshold for the lowest energy dissociation, consistent with inferences from earlier experimental data. The “virtual intermediates” (point that reactions pass through corresponding to a conventional structure but lacking a corresponding potential minimum) CH3+CHCH2CH2 and +CH2CH(CH3)CH2 are found to be very important in C4H8+ rearrangements. CH3+CHCH2CH2 is accessed from the 1-butene cation by a 1,4- and a 1,2-H-shift, the 2-butene cation by a 1,2-H-shift and the 1-methylcyclopropane cation by ring opening. All reactions through CH3+CHCH2CH2 begin or end with a 1,2-H-shift going to or from the 1-butene ion. The 1-butene cation appears to form rather than the more stable 2-butene cation because the minimum energy pathways down from higher energy transition states go to the 1-butene cation side of the transition state that connects the 1-butene and the 2-butene ions. Perhaps charge localization on the CH carbon directs these pathways to the 1-butene cation by a carbocation-like rearrangement. Predicted competition between 1,3- and consecutive 1,2-transfers across double bonds, despite 1,2-shifts being energetically strongly favored over 1,3-shifts in other systems, is another interesting feature of C4H8+ reactions. The lowest energy isomerization found in this work was a 1,5-H-shift in the 1-pentene ion. In contrast to CH3+CH CH2CH2, CH3+CHCH2CH2CH2 appears to inhabit a potential energy minimum, albeit a shallow one. The order of the critical energies for different ring sized transfers is 1,4 > 1,3 ≅ 1,2 > 1,5 in the CnH2n+ ions examined, differing from the order 1,3 > 1,4 > 1,2 > 1,5 established for other homologous series of aliphatic radical cations.

Diastereoselective Synthesis of the Indenylruthenium(II) Complexes [Ru(η5-C9H7){κ3(P,C,C)-Ph2P(CH2CRCH2)}(PPh3)][PF6] (R = H, Me): Enantiofacial Coordination, Hemilabile Properties, and Diastereoselective Nucleophilic Additions to κ3(P,C,C)-Allylphosphine Ligands

The mixed-phosphine complexes [Ru(η5-C9H7)Cl{κ1(P)-Ph2P(CH2CRCH2)}(PPh3)] (R = H (1a), Me (1b)) are prepared by phosphine exchange reactions (1:1 molar ratio) of [Ru(η5-C9H7)Cl(PPh3)2] with the corresponding allylphosphines Ph2P(CH2CRCH2) in refluxing THF. The reaction of 1a with sodium methoxide in methanol yields the hydride derivative [Ru(η5-C9H7)H{κ1(P)-Ph2P(CH2CHCH2)}(PPh3)] (1c). The treatment of complexes 1a and 1b with NaPF6 in methanol diastereoselectively affords the cationic complexes [Ru(η5-C9H7){κ3(P,C,C)-Ph2P(CH2CRCH2)}(PPh3)][PF6] (R = H (2a), Me (2b)) in good yield. An X-ray crystal structure determination of complex 2a shows that the si enantiofacial coordination of the olefin group accompanies the R relative configuration of the metal center. No epimerization process has been observed. Olefin exchange substitution reactions of complex 2a with MeCN and BzCN (1:1.5 molar ratio) in refluxing CH2Cl2 yield the cationic complexes [Ru(η5-C9H7)(NCR){κ1(P)-Ph2P(CH2CHCH2)}(PPh3)][PF6] (R = Me (3a), Bz (3b)). Similarly, the neutral complexes [Ru(η5-C9H7)(N3){κ1(P)-Ph2P(CH2CRCH2)}(PPh3)] (R = H (4a), Me (4b)) are obtained by the treatment of complexes 2a,b with sodium azide in THF/MeOH at room temperature. The addition of lithium carbanions LiR‘ (R‘ = Me, nBu) to solutions of complexes 2a,b in tetrahydrofuran results in regio- and stereoselective exo addition at the Cβ atom of the coordinated allylic group, affording the ruthenacyclopentane complexes [Ru(η5-C9H7){κ2(P,C)-Ph2P{CH2C(R)(R‘)CH2}}(PPh3)] (R = H, R‘ = Me (5a), nBu (5b); R = Me, R‘ = Me (6a), nBu (6b)) in 80−95% yield. Similarly, the complexes [Ru(η5-C9H7){κ2(P,C)-Ph2P{CH2CH(R)CH2}}(PPh3)] (R = H (5c), Me (6c)) are formed by the reaction of equimolar mixtures of complexes 2a,b with Li[B(C2H5)3H]. The molecular structure and relative configurations RRuS/SRuR of the new stereogenic atoms of complex 5b have been determined by X-ray diffraction. Kinetic studies on the substitution reaction of complex 2a with CD3CN in CDCl3 indicate that the olefin exchange occurs via parallel first-order (dissociative) and second-order (associative) pathways and highlight the intermediacy of a transient coordinatively unsaturated species, formed by olefin dissociation before attack of the nitrile.

Introduction of a phosphorus ylide moiety into [η 2-(ω-hydroxy)alkenyl]chromium(0) carbene complexes with Ph 3PCCO and consecutive Wittig alkenations with 2-alkynals. Part 12: the chemistry of metallacyclic alkenylcarbene complexes

Ketenylidenetriphenylphosphorane, Ph 3PCCO ( 2), reacts selectively with the ω-hydroxy group of the alkene–carbene complexes (OC) 4CrC(η 2-NMeCH 2CHCHCH 2OH)R 1 ( 1) (R 1=Me: ( 1a); Ph: ( 1b)) to give the acyl ylide terminated complexes (OC) 4CrC[(4,5-η 2)-NMeCH 2CHCHCH 2O(O)C–CHPPh 3]R 1 ( 3) (R 1=Me: ( 3a); Ph: ( 3b)). Complexes 3 undergo Wittig alkenation reactions with aldehydes such as 2-alkynals, R 2–CC–CHO (R 2=H, SiMe 3, Ph), to give the corresponding 4 Z, 9 E-dien-11-ynes (OC) 4CrC[(4,5-η 2)-NMeCH 2CHCHCH 2O(O)C– CH CH–CC–R 2]R 1 ( 4– 6) (R 1=Me, R 2=H, SiMe 3, Ph: ( 4a– 6a); R 1=Ph, R 2=H, SiMe 3, Ph: ( 4b– 6b)). All complexes were characterized in solution by one- and two-dimensional NMR spectroscopy ( 1H, 13C, 29Si, 31P, 1H/ 1H COSY, 13C/ 1H HETCOR, 31P/ 31P EXSY).

Density functional study of n-propyltrichlorogermane and n-propyltrichlorostannane

The IR and Raman spectra of n-propyltrichlorogermane (PTCG), CH 3CH 2CH 2GeCl 3, and n-propyltrichlorostannane (PTCS), CH 3CH 2CH 2SnCl 3, were measured in the liquid and solid states. The fundamental vibrations were assigned with the aid of a density functional theory (DFT) method using gaussian 98. For the calculation of the DFT method, the B3LYP/6-31G* and the 6-311+G** levels were used for C, H, Cl and Ge atoms and the B3LYP/CEP-31G level for Sn atom. The trans ( T) and gauche ( G) forms around the central C–C bond coexisted in the liquid state for both the molecules. While, the T form existed in the solid state for PTCG and the G form existed for PTCS. From the temperature dependent measurements of the Raman spectra in the liquid state, the enthalpy differences were found to be Δ H( G− T)=0.26±0.03 kcal mol −1 with the T form being more stable for PTCG and to be Δ H( G− T)=−0.03±0.01 kcal mol −1 with the G form being slightly stable for PTCS, respectively. However, the energy differences between the forms calculated by the DFT method showed that the T form was more stable than the G form for both the molecules.

Conformation analysis of 1,4-pentadien-3-yl radicals by ab initio and DFT methods

1,4-Pentadien-3-yl radical is the simplest acyclic hydrocarbon radical having five conjugated pi-electrons. In this work the 1,4-pentadien-3-yl (CH 2CHCH ∗CHCH 2) is studied by different level of theoretical methods (UB3LYP, UHF and UMP2 as well) with conformation and energy aspect. All of potential energy surfaces show that three different minima can exist. According to energy calculations with B3LYP/6-31G(d), B3LYP/6-311+G(3df,2p), BH and HLYP/6-311+G(3df,3p) and G3MP2 quantum chemistry models, relative energies of the E,Z and the Z,Z structure of 1,4-pentadien-3-yl radical with respect to the E,E structure of 1,4-pentadien-3-yl are 10.0±0.7 and 26.9±1.9 kJ mol −1, respectively.

Hydrothermal synthesis and structural characterization of novel organically templated zincophosphites: [C 6H 4(CH 2NH 3) 2]·[Zn 3(HPO 3) 4] and [CH 3CH 2CH 2NH 3] 2·[Zn 3(HPO 3) 4

Two novel organically templated zincophosphites, [C 6H 4(CH 2NH 3) 2]·[Zn 3(HPO 3) 4] and [CH 3CH 2CH 2NH 3] 2·[Zn 3(HPO 3) 4] have been synthesized under hydrothermal conditions with different template 1,3-Bis(aminomethyl)benzene and propylamine, and characterized by single-crystal X-ray diffraction. [C 6H 4(CH 2NH 3) 2]·[Zn 3(HPO 3) 4] crystallizes in the monoclinic space group P2 1/ c, with cell parameters, a=9.5467(10) Å, b=26.405(2) Å, c=7.9946(8) Å, and β=99.472(2)°. [CH 3CH 2CH 2NH 3] 2·[Zn 3(HPO 3) 4] crystallizes in the orthorhombic space group Pccn, with cell parameters, a=9.8162(15) Å, b=23.284(4) Å, and c=8.9306(12) Å. Two compounds consist of vertex linking of ZnO 4 tetrahedral and [HPO 3 2−] pseudopyramidal units. They have similar inorganic frameworks with the same compositions. They are both built up from two-dimensional layers with four- and eight-membered rings and one-dimensional chains composed of four-memberd rings, but their layered structures are different due to the influence of corresponding organic template. To our knowledge, [C 6H 4(CH 2NH 3) 2]·[Zn 3(HPO 3) 4] is the first mention of a zinc phosphite material with an aromatic template. Two compounds were also characterized by IR spectroscopy, thermogravimetric and differential thermal analyses, and proton-decoupled 31P MAS solid-state NMR spectroscopy.

Synthesis and reactivity of a tethered diene cyclopentadiene, (C 5Me 4H)SiMe 2(CH 2CHCHCHCH 2), and its alkali metal salts

(C 5Me 4H)SiMe 2Cl reacts with (THF)KCH 2CHCHCHCH 2 to form (C 5Me 4H)SiMe 2(CH 2CHCHCHCH 2) ( 1). Compound 1 reacts with KH and n-BuLi to make M(C 5Me 4)SiMe 2(CH 2CHCHCHCH 2), M=K, 2; Li, 3, respectively. Carbon–silicon cleavage occurs when 1 reacts with K to form (C 5Me 4H)K, which crystallizes from dimethoxyethane as [(C 5Me 4H)K(DME)] x . This potassium salt has an extended structure which generates bent metallocene (C 5Me 4H) 2K(DME) sub-structures which have 133.9° ring centroidKring centroid angles. Compound 1 reacts with TiCl 4 to make (C 5Me 4H)TiCl 3 ( 5), which has a piano stool structure.

Synthesis of [TpRu(CO)(PPh 3)] 2(μ-CHCHCHCHC 6H 4CHCHCHCH) from Wittig reactions

Treatment of [Ru(CHCHCH 2PPh 3)X(CO)(PPh 3) 2] + (X=Cl, Br) with KTp (Tp=hydridotris(pyrazolyl)borate) and NaBPh 4 produced [TpRu(CHCHCH 2PPh 3)(CO)(PPh 3)]BPh 4. Reaction of RuHCl(CO)(PPh 3) 3 with HCCCH(OEt) 2 produced Ru(CHCHCH(OEt) 2)Cl(CO)(PPh 3) 2, which reacted with KTp to give TpRu(CHCHCHO)(CO)(PPh 3). Treatment of [TpRu(CHCHCH 2PPh 3)(CO)(PPh 3)]BPh 4 with NaN(SiMe 3) 2 and benzaldehyde produced TpRu(CHCHCHCHPh)(CO)(PPh 3). The later complex was also produced when TpRu(CHCHCHO)(CO)(PPh 3) was treated with PhCH 2PPh 3Cl/NaN(SiMe 3) 2. The bimetallic complex [TpRu(CO)(PPh 3)] 2(μ-CHCHCHCHC 6H 4CHCHCHCH) was obtained from the reaction of [TpRu(CHCHCH 2PPh 3)(CO)(PPh 3)]BPh 4 with NaN(SiMe 3) 2 and terephthaldicarboxaldehyde.

Hexanuclear copper(II) complex of a novel poly(pyridine) ligand exhibiting unique long distance ferromagnetic interactions through a nitrato-O,O ′ bridge

A novel hexanuclear copper complex [Cu 6(NO 3) 12(opytrizediam) 2(H 2O)][(CH 3) 2CO] 0.5(CH 3CH 2CH 2OH) 0.5 ( 1) with a NO 3 bridge has been synthesized by reaction of Cu(NO 3) 2 · 3H 2O with the new potentially octadentate ligand opytrizediam in n-propanol/acetone solution (opytrizediam= N, N ′-{2,4-di[(di-pyridin-2-yl)amine]-1,3,5-triazine} ethylenediamine). A single-crystal X-ray diffraction analysis showed the presence of six structurally different copper centres. The coordination spheres of four copper(II) ions are best described as square-pyramidal CuN 2O 3 chromophores while the two other copper(II) ions are in a trigonal-bipyramidal CuN 4O environment. Variable-temperature studies on 1 revealed a unique ferromagnetic coupling of two copper(II) ions bridged by a didentate nitrate anion and separated by a distance of 6.391(6) Å, with J=8.6(1) cm −1.