HC CR Research Articles

Au9Ag6(CCR)10(DPPM)2Cl2](PPh4): a four-electron cluster with a bi-decahedral twisted metal core.

The assembly of cluster units in a distinct manner can give rise to nanoclusters exhibiting unique geometrical structures and properties. Herein, we present a one-pot synthesis and structural characterization of a AuAg alloy cluster, [Au9Ag6(CCR)10(DPPM)2Cl2](PPh4), denoted as Au9Ag6 (where HCCR is 3,5-bis(trifluoromethyl)phenylacetylene, and DPPM is bis(diphenylphosphino)methane). Single-crystal X-ray diffraction data analysis reveals that Au9Ag6 features a distinctive Au7Ag6 bi-decahedral core, formed by a twisted assembly of two Au4Ag3 decahedra sharing one vertex. The Au4Ag3 building blocks are bridged by two gold atoms on opposite sides of the bi-decahedral core. The Au9Ag6 cluster is monoanionic and it is stabilized by two chloride, two DPPM and ten alkynyl ligands. This cluster represents the first instance of a cluster of clusters built upon decahedral units.

Alkyne to carbyne coupling reactions of the unsaturated methoxycarbyne-bridged complex [Mo 2(η 5-C 5H 5) 2(μ-COMe)(μ-PCy 2)(CO) 2

The 32-electron complex [Mo 2Cp 2(μ-COMe)(μ-PCy 2)(CO) 2] (Cp = η 5-C 5H 5) reacts at 333 K with terminal alkynes HC CR to give the corresponding derivatives [Mo 2Cp 2{μ-κ 2:η 3-CRCHC(OMe)}(μ-PCy 2)(CO) 2], (R = p-tol, CO 2Me), with good yields. These compounds are both obtained selectively as trans-dicarbonyl isomers and display a propenyl-ylidene type ligand bridging the dimetal centre, derived from the specific coupling of the alkyne to the carbyne ligand through the terminal carbon atom of the alkyne. The reaction with the internal alkyne (MeO 2C)C C(CO 2Me) gives the related derivative [Mo 2Cp 2{μ-κ 2:η 3-C(CO 2Me)C(CO 2Me)C(OMe)}(μ-PCy 2)(CO) 2], but now this product is obtained as an equimolar mixture of the corresponding trans- and cis-dicarbonyl isomers. The structures of the new compounds are discussed on the basis of the available spectroscopic data in solution and an X-ray diffraction analysis of the product derived from p-tolylacetylene (Mo−Mo = 2.8646(8) Å).

Reactivity of the N-heterocyclic carbene complexes [Ru(IMes) 2(CO)HX] (X = OH, Cl) with alkynes

Treatment of the 16-electron hydroxy hydride complex [Ru(IMes) 2(CO)H(OH)] ( 1, IMes = 1,3-bis-(2,4,6-trimethylphenyl)imidazol-2-ylidene) with HC CR affords the alkynyl species [Ru(IMes) 2(CO)H(C CR)] (R = Ph 3, SiMe 3, 4) and [Ru(IMes) 2(CO)(C CR) 2] (R = Ph, 5). Deuterium labelling studies show that the mono-alkynyl complexes are formed via hydrogen transfer from a coordinated alkyne ligand to Ru–OH, while bis-alkynyl formation is proposed to take place through hydrogen transfer to Ru–H. Both 3 and 5 readily coordinate CO to give the corresponding dicarbonyl species 6 and 7. Addition of HC CPh to the hydride chloride precursor [Ru(IMes) 2(CO)HCl] ( 2) results in a different reaction pathway involving alkyne insertion into the Ru–H bond to yield the alkenyl chloride complex [Ru(IMes) 2(CO)(CH CHPh)Cl] 8. Complexes 3– 8 have been structurally characterised by X-ray crystallography.

2,2′-Bipyrimidine transition metal complexes: Synthesis, reaction chemistry and solid state structures

2,2′-Bipyrimidine metal complexes with Ti, Mo, Fe, Ru, Pt, Ag, and Cu transition metal atoms have been synthesized and structurally characterized. These molecules were prepared by following synthesis methodologies. The reaction of 2,2′-bipyrimidine ( 1; bipym) with {[Ti](μ-σ,π-C CSiMe 3) 2}AgOTf ([Ti] = (η 5-C 5H 4SiMe 3) 2Ti, OTf = OSO 2CF 3) ( 2) in a 1:1 molar ratio gave [{[Ti](μ-σ,π-C CSiMe 3) 2}Ag(bipym)]OTf ( 3) which on further treatment with another equivalent of 2 produced [({[Ti](μ-σ,π-C CSiMe 3) 2}Ag) 2(μ-1,2,3,4-bipym)](OTf) 2 ( 4). As consequence thereof, the coordination number of Ag(I) was changed from 3 to 4. A platinum–bipym complex with two acetylide substituents was accessible by the gradual reaction of 1 with K 2[PtCl 4] ( 5) and two equivalents of HC CR ( 7a, R = SiMe 3; 7b, R = Fc; 7c, R = Rc; Fc = (η 5-C 5H 4)(η 5-C 5H 5)Fe; Rc = (η 5-C 5H 4)(η 5-C 5H 5)Ru) in di- iso-propylamine and in presence of [CuI]. Originating from cis-[(bipym)Pt(C CR) 2] ( 8a, R = SiMe 3; 8b, R = Fc; 8c, R = Rc) diverse multinuclear complexes with two, three or four different transition metals could be obtained. These are: [((CO) 4Mo)(μ-1,2,3,4-bipym)Pt(C CFc) 2] ( 10), [(AgClO 4)(μ-1,2,3,4-bipym){[Pt(μ-σ,π-C CFc) 2]AgOClO 3}] ( 12), [(McC C) 2Pt(μ-1,2,3,4-bipym)({[Ti](μ-σ,π-C CSiMe 3) 2}M)]X ( 15a, Mc = Fc, M = Cu, X = PF 6; 15b, Mc = Rc, M = Cu, X = PF 6; 15c, Mc = Fc, M = Ag, X = ClO 4), and [(McC C) 2Pt(μ-1,2,3,4-bipym)PtCl 2] ( 17). Like other organometallic Pt–Ag tweezer complexes, compound 12 decomposed to give FcC C–C CFc ( 13). During prolonged stirring of 15a and 15b, respectively, [(McC C) 2Pt(μ-1,2,3,4-bipym)({[Ti](μ-σ,π-C CSiMe 3)(μ-σ,π-C CH)}M)]X ( 15′a, M = Cu, X = PF 6; 15′b, M = Cu, X = PF 6) was formed. The structures of 8b, 8c, 15a′, and 15b′ in the solid state are reported. All complexes exhibit the anticipated planar dinuclear Pt–M structure (M = Pt, Cu, Ag) with the 2,2′-bipyrimidine unit in a μ-1,2,3,4-bridging mode. Electrochemical investigations were carried out with 8a, 8b, and 8c and show that no significant influence of R on the bipym redox potentials exists. The typical redox behavior for the bipym, ferrocene, ruthenocene units and platinum were observed.

Activation of C–CN bond of propionitrile: An alternative route to the syntheses of 5-substituted-1 H-tetrazoles and dicyano-platinum(II) species

Reaction of trans-[Pt(N 4CR) 2(PPh 3) 2] 1 (R = Me 1a, Et 1b, Ph 1c, CH 2CH 2Ph 1d) with propionitrile under reflux gives trans-[Pt(CN) 2(PPh 3) 2] 2 along with 5-substitued-1 H-tetrazoles N 4CR 3 (R = Me 3a, Et 3b, Ph 3c, CH 2CH 2Ph 3d) in moderated to good yield, respectively. Treatment of cis-[Pt(N 3) 2(PPh 3) 2] 5 with alkynes HC CR′ 6 (R′ = Ph 6a, p-MeC 6H 4 6b) under focused microwave irradiation leads, upon azide replacement, to the formation of the dialkynyl complexes trans-[Pt(C CR′) 2(PPh 3) 2] 7 (R′ = Ph 7a, p-MeC 6H 4 7b) which also furnish the dicyano-platinum complex 2 in refluxing propionitrile. In both cases, the reactions leading to the formation of 2 proceed via an unusual oxidative addition, involving NC–C bond cleavage of two propionitrile molecules, and a reductive elimination process.

Low-Carbohydrate Diet Versus Caloric Restriction: Effects on Weight Loss, Hormones, and Colon Tumor Growth in Obese Mice

Our objective was to compare the effects of a low-carbohydrate diet to a high-carbohydrate/calorie-restricted diet on weight loss, hormones, and transplanted colon tumor growth. Eighty male C57BL/6 mice consumed a diet-induced obesity regimen (DIO) ad libitum for 7 weeks. From Weeks 8 to 14, the mice consumed a 1) DIO diet ad libitum (HF); 2) low-carbohydrate diet ad libitum (LC); 3) high-carbohydrate diet ad libitum (HC); or 4) HC calorie restricted diet (HC–CR). MC38 cells were injected at Week 15. At the time of injection, the HC–CR group displayed the lowest body weight (25.5 ± 0.57 g), serum insulin-like growth factor I (IGF-I; 135 ± 56.0 ng/ml), and leptin (1.0 ± 0.3 ng/ml) levels. This group also exhibited the longest time to palpable tumor (20.1 ± 0.9 days). Compared to the HF group, the HC group exhibited lower body weight (39.4 ± 1.4 vs. 32.9 ± 0.7 g, respectively), IGF-I (604 ± 44.2 vs. 243.4 ± 88.9 ng/ml, respectively), and leptin (15.6 ± 2.2 vs. 7.0 ± 0.7 ng/ml, respectively) levels but similar tumor growth. IGF-I levels were lower in the LC group (320.0 ± 39.9 ng/ml) than the HF group, but tumor growth did not differ. These data suggest LC diets do not slow colon tumor growth in obese mice.

Synthesis and reactivity of hydride and dihydrogen complexes of ruthenium with tris(pyrazolyl)borate and phosphite ligands

Chloro phosphite complexes RuClTpL(PPh 3) ( 1a, 1b) [L = P(OEt) 3, PPh(OEt) 2] and RuClTp[P(OEt) 3] 2 ( 1c) [Tp = hydridotris(pyrazolyl)borate] were prepared by allowing RuClTp(PPh 3) 2 to react with an excess of phosphite. Treatment of the chloro complexes 1 with NaBH 4 in ethanol yielded the hydride RuHTpL(PPh 3) ( 2a, 2b) and RuHTp[P(OEt) 3] 2 ( 2c) derivatives. Protonation reaction of 2 with Brønsted acids was studied and led to thermally unstable (above 10 °C) dihydrogen [Ru(η 2- H 2)TpL(PPh 3)] + ( 3a, 3b) and [Ru(η 2-H 2)Tp{P(OEt) 3} 2] + ( 3c) complexes. The presence of the η 2-H 2 ligand is indicated by short T 1 min values and J HD measurements of the partially deuterated derivatives. Aquo [RuTp(H 2O)L(PPh 3)]BPh 4 ( 4), carbonyl [RuTp(CO)L(PPh 3)]BPh 4 ( 5), and nitrile [RuTp(CH 3CN)L(PPh 3)]BPh 4 ( 6) derivatives [L = P(OEt) 3] were prepared by substituting H 2 in the η 2-H 2 derivatives 3. Vinylidene [RuTp{ C C(H)R}L(PPh 3)]BPh 4 ( 7, 8) (R = Ph, t Bu) and allenylidene [RuTp( C C CR1R2)L(PPh 3)]BPh 4 ( 9– 11) complexes (R1 = R2 = Ph, R1 = Ph R2 = Me) were also prepared by allowing dihydrogen complexes 3 to react with the appropriate HC CR and HC CC(OH)R1R2 alkynes. Deprotonation of vinylidene complexes 7, 8 with NEt 3 was studied and led to acetylide Ru(C CR)TpL(PPh 3) ( 12, 13) derivatives. The trichlorostannyl Ru(SnCl 3)TpL(PPh 3) ( 14) compound was also prepared by allowing the chloro complex RuClTpL(PPh 3) to react with SnCl 2 · 2H 2O in CH 2Cl 2.

Vinyl and carbene ruthenium(II) complexes from hydridoruthenium(II) precursors.

The reactions of the hydrido compounds [RuHCl(CO)(L)2][L = PiPr3 (1), PCy3 (2)] with HC(triple bond)CR (R = H, Ph, tBu) afforded by insertion of the alkyne into the Ru-H bond the corresponding vinyl complexes [RuCl(CHCHR)(CO)(L)2], 3-8, which upon protonation with HBF4 gave the cationic five-coordinated ruthenium carbenes [RuCl(CHCH2R)(CO)(L)2]BF4, 9-14. Subsequent reactions of the carbene complexes with PR3(R = Me, iPr) and CH3CN led either to deprotonation and re-generation of the vinyl compounds or to cleavage of the ruthenium-carbene bond and the formation of the six-coordinated complexes [RuCl(CO)(CH3CN)2(PiPr3)2]BF4, 17, and [RuH(CO)(CH3CN)2(PiPr3)2]X, 18a,b. The acetato derivative [RuH(2-O2CCH3)(CO)(PCy3)2], 19, also reacted with acetylene and phenylacetylene by insertion to yield the related vinyl complexes [Ru(CHCHR)(kappa2-O2CCH3)(CO)(PCy3)2], 20, 21, of which that with R = H was protonated with HBF4 to yield the corresponding cationic ruthenium carbene 22. With [RuHCl(H2)(PCy3)2], 25, as the starting material, the five-coordinated chloro(hydrido)ruthenium(II) compounds [RuHCl(PCy3)(dppf)], 26(dppf = [Fe(eta5-C5H4PPh2)2]), [RuHCl[Sb(CH2Ph)3](PCy3)2], 27, and [RuHCl(CH3CN)(PCy3)2], 30, were prepared. The reactions of 27 with HCCR (R = H, Ph) gave the hydrido(vinylidene) complexes [RuHCl(CCHR)(PCy3)2], 28 and 29, whereas treatment of 30 with HC(triple bond)CPh afforded the vinyl compound [RuCl(CHCHPh)(CH3CN)(PCy3)2], 31. The molecular structures of 11(R = tBu, L = PiPr3) and 26 were determined crystallographically.

Dynamic (hyper)polarizability calculations for polymers with linear and cyclic π-conjugated elementary cells

Static and dynamic (hyper)polarizabilities for polymers built up from HCCR with RH, OH, F have been calculated with the perturbed coupled Hartree–Fock method. At this level polyacetylene (PA) has the highest polarizability, but the inclusion of the electron correlation correction interchanges the ordering and the fluorinated system becomes the most polarizable one. This shows that these contributions cannot be neglected. We have investigated the series of polymers arising from the cyclic five-membered molecules pyrrole, furane, and thiophene and in addition polyparaphenylene (PPh) and polyaniline (PAn). The basis set dependence and the effect of the number of neighbors interaction have been studied. It turns out that polythiophene (PTh) is easier to polarize than polyparaphenylene, polypyrrole (PPy) and polyfurane (PFu). The correlation contribution does not change the sequence. Polyaniline in its neutral all- trans configuration shows the highest static and dynamic polarizabilities due to the very extended π-electron system of the elementary cell. In addition, the static and dynamic polarizabilities of the constituent molecules pyrrole, furane, thiophene and benzene have been calculated for comparison with the corresponding polymers.

New reactions of 1-alkynes catalyzed by transition metal complexes.

Recently discovered catalytic reactions with ruthenium and lanthanide metal complexes have extended the scope of 1-alkynes as useful reagents. The specific formation of aryl-substituted (Z)-1,3-enzymes via the dimerization of HC(triple bond) CR(1) (R(1) = aryl) has been attained using dimeric lanthanide complexes, the catalytic activity of which appears to be unaffected by time. The dimerization of HC(triple bond) CR(2) (R(2) = t-Bu, SiMe(3)) catalyzed by Ru(cod)(cot)/PR(3) or RuH(2)(PPh(3))(3) produces a good yield of butatrienes (Z)R(2)CH=C=C=CHR(2) with a high degree of selectivity. Under certain conditions, HC(triple bond) C=SiMe(3) dimerizes to yield exclusively (Z)-M(3)Si-C(triple bond) C-CH=CH-SiMe(3). The hydration of HC(triple bond)CR(3) (R(3) = alkyl, aryl) catalyzed by RuCl(2)/PR'(3) or CpRuCl(PR"(3))(2) has realized the first example of anti-Markovnikov regioselectivity in an addition reaction of water that produces aldehydes R(3)CH(2)bond;CHO. The application of this reaction to propargylic alcohols has lead to their formal isomerization to alpha,beta-unsaturated aldehydes. In contrast, the addition of amines R(4)bond;NH(2) (R(4) = aryl) to HCtbond;CR(5) (R(5) = alkyl, aryl) conforms to Markovnikov's rule to produce ketimines R(5)bond;(C=NR(4))bond;CH(3) when catalyzed by a Ru(3)(CO)(12)/additive. Since the reaction can be performed in air without the need for any solvents, it enables the practical synthesis of aromatic ketimines, which are difficult to prepare by conventional methods. The synthesis of indoles using deactivated anilines is one practical application of this reaction. The mechanisms of some of these reactions have been analyzed in detail with the aid of theoretical calculations.

Addition of diazoalkanes to alkyne(pentacarbonyl)–chromium and –tungsten — formation of 3 H-pyrazole complexes

Photolysis of [M(CO) 6] (M=Cr, W) in CH 2Cl 2 at −78 °C generates [(CO) 5M(CH 2Cl 2)]. Subsequent sequential reaction of [(CO) 5M(CH 2Cl 2)] with terminal alkynes, HCCR (R=COOMe, Ph, p-Tol), and diazoalkanes, R 1(R 2)CN 2 (R 1=Me, Et, Ph; R 2=Me, Et) affords 3 H-pyrazole complexes, [(CO) 5M– NN–C(R)C(H)–C (R 1)(R 2)]. These complexes are derived from addition of diazoalkanes to alkyne complex intermediates, [(CO) 5M(HCCR)]. Their vinylidene tautomers, [(CO) 5MCC(R)H], present in solution in equilibrium with the alkyne complexes, do not react. Likewise, isolable disubstituted vinylidene complexes, [(CO) 5MCC(R‘)R*], do not add diazoalkanes.

1H, 13C and 29Si NMR study of acetylide and parallel alkyne substituted Ru 3 and Os 3 clusters derived from HCCR (R=SiMe 3, SiPh 3 and CMe 3). X-ray crystallographic study of [(μ-H)M 3(CO) 9(CCR)] (M=Ru, R=SiMe 3, SiPh 3; M=Os, R=SiPh 3, CMe 3) and [Ru 3(μ-CO)(CO) 9(HCCR)] (R=CMe 3)

A series of alkyne parallel μ 3-η 2-(//) substituted trinuclear cluster derivatives has been synthesized, containing the alkynes (HCCR, R=SiMe 3, SiPh 3 and tBu) coordinated to Ru 3 and Os 3 units and then converted into the corresponding chemically related acetylide derivatives. A 1H, 13C and 29Si NMR study was carried out for all the complexes and the results are also analyzed in comparison with results of Extended Hückel Molecular Orbital calculations carried out on the complexes and the free alkynes. In the acetylide derivatives, 13C 1H and 187Os 1H couplings involving the hydride, were measured. The 13C 29Si couplings for all the derivatives which contain silicon shows the changes in hybridization of the C β. The structures of [(μ-H)Ru 3(CO) 9(CCR)] (R=SiMe 3 and SiPh 3) and [(μ-H)Os 3(CO) 9(CCR)] (R=SiPh 3 and CMe 3) and [Ru 3(CO) 10(HCCR)] (R=CMe 3) were determined by single crystal X-ray diffraction methods.

Synthesis, characterization and crystal structures of alkyl-, alkynyl-, alkoxo- and halo-magnesium amides

In our experiments, 1:1 stoichiometric reaction between MgR 2 and diphenylamine produced the monomeric heteroleptic alkylmagnesium amides [RMgNPh 2(THF) 2] [R=Et 1 and i Pr 2]. Adding the stronger donor solvent HMPA (HMPAhexamethyl-phosphoramide) to compound 1 caused disproportionation resulting in a bisamidomagnesium compound [Mg(NPh 2) 2(HMPA) 2] 3. The stoichiometric reaction between bis(diisopropylamido)-magnesium and different substituted acetylenes HCCR in THF solution produced two dimeric amidomagnesium acetylide compounds [(RCC)Mg(μ-N i Pr 2)(THF)] 2 [R=Ph 4, R=SiMe 3 5]. When the differently sized secondary amines, HNEt 2 and HN(SiMe 3) 2, were reacted with Grignard reagent EtMgBr, they produced diethylamino-bridging and bromo-bridging Hauser base [BrMg(μ-NEt 2)(HMPA)] 2 6 and [(Me 3Si) 2NMg(μ-Br)(OEt 2)] 2 7, respectively. Unexpectedly, the reaction of MgEt 2 and HN(SiMe 3) 2 in refluxing THF produced [(Me 3Si) 2NMg(μ-OEt)(THF)] 2 8. Additionally, we synthesized the first trinuclear magnesium compound [( t BuCC)(THF)Mg(μ-CC t Bu)(μ-N i Pr 2)Mg(μ-CC t Bu)(μ-N i Pr 2)Mg(THF)(CC t Bu)] 9, which exhibited both an electron-rich bridging ligand N i Pr 2 and electron-deficient bridging ligand CC t Bu. All of these new compounds ( 1– 9) were characterized by 1H-, 13C-, 31P-NMR, IR spectroscopy, mass spectrometry and X-ray crystallography.

CpCo(CO) 2-catalysed cyclotrimerisation of alkynes in supercritical carbon dioxide

The reactivity of mono-substituted HCCR (R=Ph, a; CH 2OH, b; CH 2CH 2CH 2CH 3, c) and di-substituted RCCR (R=CH 2CH 3, d; CO 2CH 3, e; Ph, f) acetylenes was studied in supercritical carbon dioxide (scCO 2) using the easily available complex CpCo(CO) 2 as catalyst. The reaction of phenylacetylene produced a mixture of the isomeric cyclotrimers 1,3,5- ( 2a) and 1,2,4-triphenylbenzene ( 2a′), in a 1:5 ratio, and traces of cobaltcyclopentadienone complexes CpCo(η 4-C 4H 2[Ph] 2CO) ( 6a, mixture of isomers). The possible product formed by the incorporation of CO 2 to alkynes, i.e. diphenylpyrone ( 7a) was not observed. The reaction of the cobaltacyclopentadiene complex CpCo(1.4-σ-C 4[Ph] 4)(PPh) 3 ( 8f), in scCO 2, was performed. No insertion of CO 2 into the CoC σ-bond to form tetraphenylpyrone ( 7f) by reductive elimination was observed, instead the cobaltcyclobutadiene complex CpCo(η 4-C 4[Ph] 4) ( 9f) was formed. In the reactions with other alkynes, lower yields were obtained in general, except in the cyclotrimerisation of the highly activated alkyne, propargyl alcohol ( b). Reaction of the non-activated alkynes, 1-hexyne ( c) and 3-hexyne ( d), produced complex mixtures of cobalt complexes in low yield in which the alkyne was coordinated to cobalt. Finally, the highly hindered diphenylacetylene ( f) gave a mixture of the known complexes CpCo(η 4-C 4[Ph] 4) ( 9f) and CpCo(η 4-C 4[Ph] 4CO) ( 6f) in agreement with the results observed in conventional organic solvents.

Synthesis and reactivity of neutral vinylidene and σ-alkynyl complexes containing the hemilabile ligand Ph2PCH2CH2OMe

Abstract RuTp(COD)Cl reacts readily with Ph2PCH2CH2OMe to give the neutral complex RuTp(κ2(P,O)-Ph2PCH2CH2OMe)Cl (2) which transforms with terminal alkynes HCCR (R=Ph, n-Bu, C6H9) and carbon monoxide, respectively, into the neutral vinylidene complexes RuTp(κ1(P)-Ph2PCH2CH2OMe)(Cl)(CCHR) (3a–c) and RuTp(κ1(P)-Ph2PCH2CH2OMe)(Cl)(CO) (4). The κ1(P) bonding mode of the phosphinoether testifies to its hemilabile nature. Complex 3a reacts with lithium diisopropylamide to give the neutral α-acetylide complex RuTp(κ2(P,O)-Ph2PCH2CH2OMe)(CCPh) (5) which couples with stoichiometric amounts of HCCPh to give RuTp(κ1(P)-Ph2PCH2CH2OMe)(C(Ph)CHCCPh) (6), featuring a σ,η2-bound enynyl ligand. Treatment of 3a with AgCF3SO3 affords the cationic vinylidene complex [RuTp(κ2(P,O)-Ph2PCH2CH2OMe)(CCHPh)]CF3SO3 (7). Complex 5 is found to catalyze the dimerization of HCCR (RPh, SiMe3, n-Bu, t-Bu, C6H9) to give enynes. The structures of 3a, 4, 5 and 7 have been determined by X-ray crystallography.

Solution and solid–gas reactivity of unsaturated [RuCp(tmeda)] + (tmeda=Me 2NC 2H 4NMe 2)

The coordinatively unsaturated complex [RuCp(tmeda)] + has been prepared by the reaction of [RuCp(tmeda)Cl] with NaBAr′ 4 (Ar′=3,5-C 6H 3(CF 3) 2) in fluorobenzene. The PF 6 − salt of [RuCp(tmeda)] + is prepared by heating [RuCp(tmeda)(CH 3CN)]PF 6 at 150°C under reduced pressure (10 −2 atm). The X-ray crystal structure of [RuCp(tmeda)] + as the BAr′ 4 salt has been determined showing the absence of any agostic interactions between ruthenium and the CH bonds of the diamine ligand, and only minor deviations from the planar geometry at Ru. [RuCp(tmeda)] + reacts readily with the gases H 2, CH 2CH 2, CHFCH 2, HCCH, CO, HCl, N 2, and O 2 at low temperature to give [RuCp(tmeda)(η 2-H 2)] +, [RuCp(tmeda)(η 2-CH 2CH 2)] +, [RuCp(tmeda)(η 2-CHFCH 2)] +, [RuCp(tmeda)(η 2-HCCH)] +, [RuCp(tmeda)(CO)] +, [RuCp(tmeda)(H)(Cl)] +, [RuCp(tmeda)(N 2)] +, and [RuCp(tmeda)(O 2)] +. The reactions of [RuCp(tmeda)][BAr′ 4] with the above gases have also been carried out as solid–gas reactions. Treatment of [RuCp(tmeda)] + with the terminal acetylenes HCCR (R=Bu t , SiMe 3) results in the formation of the vinylidene complexes [RuCp(tmeda)(CCHR)] +. In the case of R=SiMe 3 upon treatment with HCl, the parent vinylidene complex [RuCp(tmeda)(CCH 2)] + is formed. [RuCp(tmeda)(η 2-HCCH)] + and [RuCp(tmeda)(CCH 2)] + are not interconvertable for kinetic reasons. Furthermore, [RuCp(tmeda)] + reacts slowly with both CH 2Cl 2 and CH 2Br 2 to give the carbene complex [RuCp(tmeda)(CH 2)] + involving double CX bond activation.

Reactions of the cluster complex [Ru5(μ5-C2)(μ-SMe)2(μ-PPh2)2(CO)11] with terminal alkynes HCCR (R = Ph, But or SiMe3)

Reaction of the dicarbon-containing complex [Ru5(µ5-C2)(µ-SMe)2(µ-PPh2)2(CO)11] 1 with monosubstituted alkynes HCCR (R = Ph, But or SiMe3) yielded [Ru5(µ5-CCCHCR)(µ-SMe)2(µ-PPh2)2(CO)10] (R = Ph, But or SiMe3) in which the Ru5 pentagon in 1 is retained. Coupling of the C2 and alkyne moieties forms a CCCHCR ligand which in combination with one Ru atom forms a metallacycle. The unsubstituted terminal carbon has a strong carbidic interaction with four of the Ru atoms. Carbonylation of the R = Ph and SiMe3 complexes yields [Ru5(µ5-CCCHCR)(µ-SMe)2(µ-PPh2)2(CO)11] (R = Ph or SiMe3), in which one Ru atom has been extruded from the cluster, although retained by co-ordination to bridging PPh2, SMe and hydrocarbon ligands. A minor product in each case was identified as [Ru5{µ5-CC[C(O)SMe]CHCR}(µ-SMe)(µ-PPh2)2(CO)10 (R = Ph or SiMe3). Here, the organic ligand is formed by combination of the CCCHCR ligand with CO and one of the SMe groups and is attached to an Ru5 core with an open-envelope conformation. Pyrolysis of [Ru5(µ-CCCHCR)(µ-SMe)2(µ-PPh2)2(CO)11] afforded [Ru5(µ5-CCCHCR)(µ-SMe)2(µ-PPh2)2(CO)10] and [Ru5(µ5-CCCHCR)(µ3-SMe)(µ-SMe)(µ-PPh2)2(CO)9] (R = Ph or SiMe3), in which one SMe group becomes triply bridging. The complex [Ru5{µ5-CC(CHCSiMe3)C(=CHSiMe3)CO}(µ-SMe)2(µ-PPh2)2(CO)8], in which the organic ligand, formed by combination of CO, HC2SiMe3 and CCHSiMe3 molecules, is attached to the opposite side of the open-envelope cluster from that in [Ru5{µ5-CC[C(O)SMe]CHCR}(µ-SMe)(µ-PPh2)2(CO)10], has also been isolated. The structures of five complexes were determined from single-crystal X-ray studies.

π-conjugated poly(monosubstituted) acetylenes containing Sn(II) and Sn(IV) species: investigation with laser ionization mass spectrometry

Polyenes [HCCR] n (R=Ph, C 13H 9O), namely polyphenylacetylene (PPA) and polyethynylfluorenol (PEFl) containing Sn(II) and Sn(IV) in the polymer matrix, have been investigated using laser ionization mass spectrometry. The positive ion mass spectra show that carbon clusters linked to Sn, i.e. SnC n H + ( n=1–25) are formed for PPA, while a higher degree of fragmentation occurs for PEFl which gives SnC n H + ( n=1–8). The species SnCl 3 − is found in the negative ion patterns of the two polymers, regardless of whether the dopant was SnCl 2 or SnCl 4. This result suggests a lower stability of the tin complexes, formed by interaction with the polymer matrix, with respect to the iron chlorides or polyiodides species found in the LMS spectra of PPA/FeCl 3 and PPA/I 2, respectively, previously studied.

Synthesis and reactivity of Ru(II) complexes containing the phosphino-amine Ph 2PCH 2CH 2NMe 2

RuCl 3 · 3H 2O reacts with 2 equiv. of Ph 2PCH 2CH 2NMe 2 in the presence of Zn to the neutral complex Ru( κ 2(P,N)-Ph 2PCH 2CH 2NMe 2) 2Cl 2 ( 1). Alternatively, 1 is also obtained by the reaction of RuCl 2(PPh 3) 3 with 2 equiv. of Ph 2PCH 2CH 2NMe 2. Compound 1 crystallizes in the space group P2 1 (No. 4) with a = 11.009(3), b = 11.007(4), c = 16.999(4) A ̊ , β = 106.22(2)° and Z = 2. The hemilabile nature of the Ph 2PCH 2CH 2NMe 2 ligand in 1 is revealed by the reaction with CO and HC  CPh affording complexes Ru( κ 2(P,N)-Ph 2PCH 2CH 2NMe 2)-( κ 1(P)-Ph 2CH 2NMe 2)(Cl 2(CO) ( 2) and Ru( κ 2(P,N)-Ph 2PCH 2CH 2NMe 2)( κ 1(P)-Ph 2PCH 2CH 2NMe 2)(Cl) 2(CCHPh) ( 3). Halide abstraction from 1 with NaBPh 4 affords the five-coordinate cationic complex [ Ru(κ 2 (P,N)-Ph 2 PCH 2 CH 2 NMe 2) 2 Cl] ′ [ BPh 4] ( 4) which crystallizes in the space group Pbca (No. 61) with a = 21.806(4), b = 19.683(4), c = 26.405(5) A ̊ , and Z = 8. Compound 4 reacts readily with CH 3CN, CO and HC  CR (R  Ph, SiMe 3, n-Bu) to give the cationic complexes [Ru( κ 2(P,N)-Ph 2PCH 2CH 2NMe 2) 2(Cl)(CCHR)] ( 5), [Ru( κ 2(P,N)-Ph 2PCH 2CH 2NMe 2) 2(Cl)(CCHR)] ( 7–9). Compound [Ru( κ 2(P,N)-Ph 2PCH 2CH 2NMe 2) 2(Cl)(CO)] ′ [BPh 4] ( 6a) one of the two stereosiomers 6a and 6b crystallizes in the space group P l (No. 2) with a = 11.637(3), b = 15.012(3), c = 15.306(3) A ̊ , α = 96.34(1), β = 98.32(1), γ = 98.731(1)° and Z = 2 and the isomeric compound 6b crystallizes in the space group P 2 1 c (No. 14) with a = 20.445(2), b = 14.198)2), c = 19.717(2), A ̊ , β = 94.66(1)° and Z = 4, 1 catalyzes the dimerization of HC  CPh to Z- and E-butenynes.

Novel trialkylstibane iridium(I) and iridium(III) complexes including the x‐ray crystal structure of five‐Coordinate [IrCl(C2H4)2(SbiPr3)2

AbstractThe reaction of [IrCl(C8H14)2]2 (2) with SbiPr3 in the presence of H2 yields the dihydridoiridium(III) complex cis,mer‐[IrH2Cl(SbiPr3)3] (3) which on treatment with CO and with HCCR (R = Ph, CO2Me) affords the octahedral derivatives [IrH2Cl(CO)(SbiPr3)2] (4) and [IrHCl(CCR)(SbiPr3)3] (5, 6), respectively. The stibane ligand trans to hydride in 5 and 6 is rather labile and, therefore, 5 and 6 react with pyridine to give [IrHCl(CCR)(py)(SbiPr3)2] (7, 8). Five‐coordinate bis‐(stibane)iridium(I) complexes [IrCl(C2H4)2(SbR3)2] (10–12) were prepared from [IrCl(C2H4)2]2 (9) and four equiv. of SbR3 (R = iPr, Me, Ph). The X‐ray crystal structural analysis of 10 reveals a distorted trigonal‐bipyramidal geometry around the metal center with one stibane ligand and the two olefinic ligands in the equatorial plane. Compound 10 reacts with NaC5H5 to yield [C5H5Ir(C2H4)(SbiPr3)] (13) and with different alkynes by partial or complete displacement of the ethene ligands to give trans‐[IrCl(PhCCPh)(SbiPr3)2] (14), [IrHCl(CCTol)(C2H4)(SbiPr3)2] (15), and trans‐[IrCl‐{CC(SiMe3)R}(SbiPr3)2] (16, 17), respectively.