Polymerization of propadiene. IV. Kinetics and mechanism of polymerization under the influence of rhodium(I) complexes

The kinetics and mechanisms of propadiene polymerization under the influence of [Rh(CO)₂Cl]₂, Rh(CO)₂P(C₆H₅)₃Cl, Rh(CO)₃Cl are reported. The reaction rates are first-order in Rh(CO)₂P(C₆H₅)₃Cl and Rh(CO)₃Cl and half-order in [Rh(CO)₂Cl]₂. They are second-order in the substrate for Rh(CO)₃Cl and [Rh(CO)₂Cl]₂ and first-order for Rh(CO)₂P(C₆H₅)₃Cl. The data are interpreted in terms of a common intermediate mechanism. The formation of this common intermediate is the rate-determining step. A solvent effect is also discussed.     

Electrochemical Properties of Ru Polypyridyl Phosphonates

[Ru(bpyPO₃H₂)(bpy)Cl]Cl (bpyPO₃H₂=6,6’-bipyridin-2-yl)phosphonic acid) and [Ru(tpy)(MepyPO₃H₂)Cl]Cl (MepyPO₃H₂=(pyridin-2-ylmethyl)phosphonic acid) were synthesized and characterized spectroscopically and electrochemically. Each compound was found to exhibit proton-coupled electron transfer (PCET). In the case of [Ru(bpyPO₃H₂)(bpy)Cl]Cl, a Ru(V/IV) couple was detected at 1.4 V vs. NHE. Each complex was tested for its ability to catalyze C−H bond oxidation using a variety of sacrificial oxidants, and it was found that under aqueous conditions [Ru(bpyPO₃H₂)(bpy)Cl]Cl oxidizes secondary C−H bonds using sodium periodate (NaIO₄) as the primary oxidant.     

Comparison of molecular structure and 35Cl nuclear quadrupole coupling tensors in 2,3,6-trichlorophenyl acetate

The crystal structure of 2,3,6-Cl₃C₆H₂OCOCH₃ was determined at room temperature; C⁵_2h-P2₁/c; Z=4. ³⁵Cl Zeeman split NQR at 294K shows, that the EFG tensors are mainly determined by the CCl bonds. φ_zz for the three Cl atoms is nearly parallel to the directions CCl. The asymmetry parameter of the EFG's are 0.1423 for Cl(2), 0.1037 for Cl(3) and 0.1015 for Cl(6). φ_xx of Cl(2), Cl(3) and Cl(6) is almost perpendicular to the ring plane. The NQR results are discussed with respect to the molecular structure. Temperature dependences of ³⁵Cl NQR resonances are reported for the range 77≦ T/K≦ 300.     

3‐Rhoda‐1,2‐diazacyclopentanes: A Series of Novel Metallacycle Complexes Derived From CN Functionalization of Ethylene

Rh‐containing metallacycles, [(TPA)Rh^III(κ²‐(C,N)‐CH₂CH₂(NR)₂‐]Cl; TPA=N,N,N,N‐tris(2‐pyridylmethyl)amine have been accessed through treatment of the Rh^I ethylene complex, [(TPA)Rh(η²‐CH₂CH₂)]Cl ([ 1 ]Cl) with substituted diazenes. We show this methodology to be tolerant of electron‐deficient azo compounds including azo diesters (RCO₂N?NCO₂R; R=Et [ 3 ]Cl, R=iPr [ 4 ]Cl, R=tBu [ 5 ]Cl, and R=Bn [ 6 ]Cl) and a cyclic azo diamide: 4‐phenyl‐1,2,4‐triazole‐3,5‐dione (PTAD), [ 7 ]Cl. The latter complex features two ortho‐fused ring systems and constitutes the first 3‐rhoda‐1,2‐diazabicyclo[3.3.0]octane. Preliminary evidence suggests that these complexes result from N–N coordination followed by insertion of ethylene into a [Rh]?N bond. In terms of reactivity, [ 3 ]Cl and [ 4 ]Cl successfully undergo ring‐opening using p‐toluenesulfonic acid, affording the Rh chlorides, [(TPA)Rh^III(Cl)(κ¹‐(C)‐CH₂CH₂(NCO₂R)(NHCO₂R)]OTs; [ 13 ]OTs and [ 14 ]OTs. Deprotection of [ 5 ]Cl using trifluoroacetic acid was also found to give an ethyl substituted, end‐on coordinated diazene [(TPA)Rh^III(κ²‐(C,N)‐CH₂CH₂(NH)₂‐]⁺ [ 16 ]Cl, a hitherto unreported motif. Treatment of [ 16 ]Cl with acetyl chloride resulted in the bisacetylated adduct [(TPA)Rh^III(κ²‐(C,N)‐CH₂CH₂(NAc)₂‐]⁺, [ 17 ]Cl. Treatment of [ 1 ]Cl with AcN?NAc did not give the Rh?N insertion product, but instead the N,O‐chelated complex [(TPA)Rh^I ( κ²‐(O,N)‐CH₃(CO)(NH)(N?C(CH₃)(OCH?CH₂))]Cl [ 23 ]Cl, presumably through insertion of ethylene into a [Rh]?O bond.     

Preparation and characterization of diruthenium(II,III) compounds containing terminal olefin groups

4-Vinylbenzoic acid reacted with Ru₂(D(3,5-Cl₂Ph)F)₃(OAc)Cl and cis-Ru₂(D(3,5-Cl₂Ph)F)₂(OAc)₂Cl (D(3,5-Cl₂Ph)F is N,N′-bis(3,5-dichlorophenyl)formamidinate) to yield Ru₂(D(3,5-Cl₂Ph)F)₃(4-vinylbenzoate)Cl (1) and cis-Ru₂(D(3,5-Cl₂Ph)F)₂(4-vinylbenzoate)₂Cl (2), respectively. Ru₂(D(3,5-Cl₂Ph)F)₃(OAc)Cl reacted with 5-hexenoic acid and 6-heptenoic acid to afford Ru₂(D(3,5-Cl₂Ph)F)₃(5-hexenoate)Cl (3) and Ru₂(D(3,5-Cl₂Ph)F)₃(6-heptenoate)Cl (4), respectively. All new compounds were characterized using voltammetric and Vis–NIR spectroscopic techniques, and the structures of 1 and 2 were also established through X-ray single crystal diffractions.     

Molecular structures of (SiCl3)2CH2 and (SiCl3)2CCl2 as studied by electron diffraction

An electron diffraction analysis of the molecular structures of 1,1,1,3,3,3-hexachloro-1,3-disilapropane and octachloro-1,3-disilapropane has been carried out. Deviations from the staggered conformation are indicated. The data may be approximated by models with C₂ symmetry and a small tilt of the SiCl₃ groups. The main bond lengths (r_g) and bond angles obtained for (SiCl₃)₂ CH₂ are: SiCl, 202.7(4); SiC, 186.6(6); CH, 109.8(24) pm, ClSiCl, 107.9(1); SiCSi, 118.3(7)°; and for (SiCl₃)₂CCl₂: SiCl, 202.0(4); SiC, 190.2(9); CCl, 179.6(9) pm; ClSiCl, 109.5(1); SiCSi, 120.6(9); ClCCl, 110.9(16); SiCCl, 106.3(3)°.     

Synthesis and characterization of transition metal complexes of a new bidentate ligand {2-(diphenylphosphino)ethyl}benzylamine

A new bidentate ligand {2-(diphenylphosphino)ethyl}benzylamine(DPEBA) was synthesized and characterized based on the IR, mass and ¹H, ¹³C and ³¹P NMR spectra. Various complexes of platinum group metal ions and Ni(II) and Co(II) ions with the ligand were synthesized. Reaction of RuCl₂(PPh₃)₃ or RuCl₂(Me₂SO)₄ with the ligand DPEBA, resulted in formation of a penta-coordinate, Ru(II) species of the composition [RuCl(DPEBA)₂]Cl. Carbonylation of [RuCl(DPEBA)₂]Cl gave an octahedral carbonyl complex of the type [RuCl(CO)(DPEBA)₂]Cl. The reaction of RuCl₃·3H₂O or RuCl₃(AsPh₃)₂MeOH with a twofold excess of the ligand gave an octahedral Ru(III) cationic species [Ru(DPEBA)₂Cl₂]Cl. Carbonylation of the Ru(III) complex gave rise to a carbonyl complex [RuCl(CO)(DPEBA)₂]Cl₂. The ligand DPEBA reacts with cobalt(II) chloride in methanol to give the 1 : 1 complex [Co(DPEBA)Cl₂]. A series of Rh(I) complexes [Rh(DPEBA)₂Cl], [ RhCl(CO)(DPEBA)] and [Rh(DPEBA)₂]Cl were synthesized by the reaction of DPEBA with RhCl(PPh₃)₃, RhCl(CO)(PPh₃)₂ and [Rh(COD)Cl]₂, respectively. Reaction of [Ir(COD)Cl]₂ and IrCl(CO)(PPh₃)₂ with the ligand DPEBA, gave the square-planar complexes [Ir(DPBA)₂]Cl and [Ir(DPEBA)(CO)Cl], respectively. Octahedral cationic complexes of the type [M(DPEBA)₂Cl₂]Cl (M = Rh(III), Ir(III)) were synthesized by the reaction of the ligand DPEBA and rhodium and iridium trichlorides. Reaction of NiCl₂·6H₂O with DPEBA in 1 : 2 molar equivalents, in boiling butanol gave an octahedral neutral complex [Ni(DPEBA)₂Cl₂] which readily rearranges to the square-planar complex [Ni(DPEBA)₂]Cl₂ in methanol. Reaction of Pd(II) and Pt(II) chlorides with DPEBA gave square-planar, cationic complexes of the type [M(DPEBA)₂Cl]Cl (M = Pd, Pt). All the complexes were characterized on the basis of their analytical and spectral data.     

cis-Di­chloro­bis­(triethyl­arsine)­platinum(II) and cis-di­chloro­bis­(triethyl­phosphine)­platinum(II)

The crystal structure of cis-[PtCl₂(C₆H₁₅As)₂], (I), is isostructural with a previously reported structure of cis-[PtCl₂(C₆H₁₅P)₂], (II). A new polymorph of (II) is also reported here. Selected geometrical parameters in the arsine complex are Pt—Cl 2.3412 (12) and 2.3498 (13), Pt—As 2.3563 (6) and 2.3630 (6) Å, Cl—Pt—Cl 88.74 (5), As—Pt—As 97.85 (2), and Cl—Pt—As 171.37 (4) and 177.45 (4)°. Corresponding parameters in the phosphine complex are Pt—Cl 2.364 (2) and 2.374 (2), Pt—P 2.264 (2) and 2.262 (2) Å, Cl—Pt—Cl 85.66 (9), P—Pt—P 98.39 (7), and Cl—Pt—P 170.26 (7) and 176.82 (8)°.     

An FTIR study of the Cl atom-initiated oxidation of CH2Cl2 and CH3Cl

The Cl atom-initiated oxidation of CH₂Cl₂ and CH₃Cl was studied using the FTIR method in the photolysis of mixtures typically containing Cl₂ and the chlorinated methanes at 1 torr each in 700 torr air. The results obtained from product analysis were in general agreement with those reported by Sanhueza and Heicklen. The relative rate constant for the Cl atom reactions of CH₂Cl₂ and CH₃Cl was determined to be k(Cl +CH₃Cl)/k(Cl + CH₂Cl₂) = 1.31 ± 0.14 (2σ) at 298 ± 2 K.     

Binuclear iron(III) compounds with bidentate bases

Summary Binuclear iron(III) derivatives, Fe₂Cl(anth)₅, Fe₂Cl(salH)₅, Fe₂Cl(acac)₅ and Fe₂Cl(quin)₅ · quinH have been prepared by reacting Fe₂Cl(OH)₂(AcO)₃ · 2AcOH with anthranilic acid (anthH), salicylic acid (salH₂), acetylacetone (acacH) and 8-hydroxyquinoline (quinH), respectively. These compounds have been characterised by molecular weight, conductance, i.r. spectral, magnetic susceptibility and Mössbauer measurements.     

Gas electron diffraction study of the molecular structure of NbCl4

The structure of the NbCl₄ molecule is studied experimentally by the synchronous electron diffraction and mass spectrometry methods. The model molecular geometries of C_2v, C_3v, D_2d, and T_d symmetries are verified. The advantages of the tetrahedral model over the other models are established. The thermally averaged parameters of the effective configuration of the NbCl₄ molecule are as follows: r_g(Nb?Cl)=2.279(5) Å, l(Nb?Cl)=0.073(2) Å, r_g(Cl?Cl)=3.692(17) Å, l(Cl?Cl)=0.275(11) Å, ∠_g(Cl-Nb-Cl)=108.2(5)°, and δ(Cl?Cl)=0.030(19) Å.     

Über polygermane: XVI. Synthese α,ω-dichlorierter polygermane Cl(Ph2Ge)nCl (n = 2,3,4) durch germylen-einschub

The germylene Ph₂Ge of Ph₂GeHCl and Net₃ inserts in excess Ph₂GeHCl and forms polygermanes Cl(Ph₂Ge)_nH. This one-pot reaction and subsequent chlorination to Cl(Ph₂Ge)_nCl has been optimized. Increasing amounts of NEt₃ step up the yields of higher polygermanes. The ¹³C NMR phenyl signals for C(ipso) shift to low field with increasing chain length. The crystal structures of Cl(Ph₂Ge)_3,4Cl (R = 0.072 and 0.087) have been determined. The position of Cl(Ph₂Ge)₄Cl is split off by disorder (main molecule 82%, side molecule 18%). Two crystallographically different molecules of the trigermane are present; the ClGe₃Cl chain contains anti-gauche and gauche-gauche conformation respectively (distances GeGe 241.3–243.7 pm, angles GeGeGe 110.4 and 116.7°). The ClGe₄Cl chain is centrosymmetric and has all-anti conformation (distances GeGe 245.0 and 244.2 and 244.2 pm, angle GeGeGe 116.2°).     

Geometries,vibrational frequencies,and electron affinities of X2Cl (X=C,Si,Ge) clusters

Ab initio quantum chemical calculations have been performed on X₂Cl^? and X₂Cl (X = C, Si, Ge) clusters. The geometrical structures, vibrational frequencies, electronic properties and dissociation energies are investigated at the Hartree–Fock (HF), Møller–Plesset second‐ and fourth‐order (MP2, MP4), CCSD(T) level with the 6‐311+G(d) basis set. The X₂Cl (X = C, Si, Ge) and X₂Cl^? (X = Si, Ge) take a bent shape obtained at the ground state, while C₂Cl^? has a linear structure. The impact on internal electron transfer between the X₂Cl and the corresponding anional clusters is studied. The three different types of electron affinities (EAs) at the CCSD(T) are reported. The most reliable adiabatic electronic affinities, obtained at the CCSD(T)/cc‐pvqz level of theory, are predicted to be 3.30, 2.62, and 1.98 eV for C₂Cl, Si₂Cl, and Ge₂Cl, respectively. The calculated EAs of C₂Cl and Ge₂Cl are in good agreement with theoretical results reported. The correlation effects and basis sets effects on the geometrical structures and dissociation energies are discussed. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

Nitrosyltechnetium(I) Complexes with 2‐(Diphenylphosphanyl)aniline

[Tc^I(NO)Cl(H₂L1)₂]⁺ cations (H₂L1 = 2‐(diphenylphosphanyl)aniline) are formed during reactions of H₂L1 with (NBu₄)[Tc(NO)Cl₄(MeOH)] or (NH₄)TcO₄/HCl/NH₂OH mixtures. Different isomers were isolated depending on the counterions and solvents used. The technetium(I) complexes cis‐NO,Cl,trans‐P,P‐[Tc^I(NO)Cl(H₂L1)₂]Cl, trans‐NO,Cl,cis‐P,P‐[Tc^I(NO)Cl(H₂L1)₂]₂(TcCl₆), and trans‐NO,Cl,trans‐P,P‐[Tc^I(NO)Cl(H₂L1)₂](PF₆) were isolated in crystalline form and studied by spectroscopic methods and X‐ray crystallography. DFT calculations show that there are only minor energy differences between the three isomers and the formation of the individual compounds is most probably strongly influenced by interactions with solvents and counterions.     

Preparation,structures, and properties of nickel complexes containing 2,6-bis[4′,4′-dimethyloxazolin-2′-yl]pyridine,a pincer ligand

Five- and six-coordinate nickel complexes [(Dm-Pybox)NiCl₂], [(Dm-Pybox)Ni(H₂O)Cl₂], [(Dm-Pybox)Ni(H₂O)₂Cl]Cl (2a), and [(Dm-Pybox)Ni(MeOH)₂Cl]Cl (2b), where Dm-Pybox is 2,6-bis[4′,4′-dimethyloxazolin-2′-yl]pyridine, have been isolated and structurally characterized by single crystal X-ray diffraction. The solid state structures of 2a and 2b feature different modes of non-covalent interactions, C–H?Cl, C–H?O and O–H?Cl interactions. Spectroscopic and analytical methods, UV–vis and thermogravimetric analyses were done to further investigate chemical properties of the complexes.     

FTIR study of the Cl- and Br-atom initiated oxidation of trichloroethylene

The Cl- and Br- initiated oxidations of CHCl(DOUBLEBOND)CCl₂ in 700 torr of air at 296 K have been studied using a Fourier transform infrared spectrometer. Rate constants k(Cl+CHCl(DOUBLEBOND)CCl₂)=(7.2±0.8)×10⁻¹¹ and k(Br+CHCl(DOUBLEBOND)CCl₂)=(1.1±0.4)×10⁻¹³ cm³ molecule⁻¹ s⁻¹ were determined using a relative rate technique with ethane and ethylene as references, respectively. The major products observed were CHXClC(O)Cl, (X=Cl or Br), CHClO, and CCl₂O. Combining results obtained for the Cl-initiated oxidation of CHCl₂(SINGLEBOND)CHCl₂, we deduced that Cl-addition on trichloroethylene occurs via channel 1a, Cl+CHCl(DOUBLEBOND)CCl₂→ CHCl₂(SINGLEBOND)CCl₂, (100±12)%. Self-reaction of the subsequently generated peroxy radicals CHCl₂(SINGLEBOND)CCl₂O₂ leads to CHCl₂CCl₂O radicals which were found to decompose via channel 8a, CHCl₂C(O)Cl+Cl, (91±11)% of the time, and channel 8b, CHCl₂+CCl₂O, (9±2)%. The reaction Br+CHCl(DOUBLEBOND)CCl₂→CHBrCl(SINGLEBOND)CCl₂ (17a) accounted for ≥(96±11)% of the total reaction. Decomposition of the CHBrCl(SINGLEBOND)CCl₂O radicals proceeds (≥93±11)% via CHBrClC(O)Cl+Cl. As part of this work, k(Cl+CHCl₂C(O)Cl)=(3.6±0.6)×10⁻¹⁴ and k(Cl+CHCl₂(SINGLEBOND)CHCl₂)=(1.9±0.2)×10⁻¹³ cm³ molecule⁻¹ s⁻¹ were measured. Errors reported above include statistical uncertainties (2σ) and estimated systematic uncertainties. © 1997 John Wiley & Sons, Inc. Int J Chem Kinet: 29: 695–704, 1997.     

Übergangsmetall—silyl-komplexe: VI. CH3/Cl-Austausch bei der reaktion vonR3PAuCH3 mit chlorsilanen

The reaction of R₃PAuCH₃ (R₃P = TolPh₂P or Me₂PhP) with organosilicon halides HSiR₂Cl (HSiPh₂Cl, HSiMeCl₂, HSiMe₂Cl) yields R₃PAuCl and the corresponding methylated silanes HSiR₂CH₃ by CH₃/Cl exchange. Oxidative addition of the SiH group of several H-silanes to the gold center is not observed.     

Some highly fluorinated acyclic,cyclic, and polycyclic derivatives of Cl2NCF2CF2NCl2 and Cl2CNCCl2CCl2NCCl2

When Cl₂NCF₂CF₂NCl₂ is heated with CF₂CFX (X = Cl, F) ClXCFCF₂N(Cl)CF₂CF₂N(Cl)CF₂CXClF (X = Cl, 2 ; F, 3 ) is formed. Mercury extracts chlorine fluoride from 2 and 3 to form new polyfluorobisazomethines, ClXCFCF₂NCFCFNCF₂CXClF (X = Cl, 4 ; F, 5 ). Photolysis of the product obtained from CCl₂NCCl₂CCl₂NCCl₂ with ClF, CF₂ClN(Cl)CF ClCFClN(Cl)CF₂Cl ( 6 ) gives another bisazomethine, CF₂ClNCFCFNCF₂Cl ( 7 ) with concomitant loss of Cl₂. At 25°C, in the presence of CsF, 4 and 5 are cyclized to give (X = Cl, 8 ; F, 9 ), and 7 forms a bicyclic derivative at 100°C, ( 1 ). Addition of chlorine fluoride to 8 and to 1 produces ( 10 ) and ( 14 ), respectively. Photolysis of 10 results in the loss of CFCl₃ to form ( 11 ), and 14 loses Cl₂ and dimerizes to the hydrazine ( 15 ). The further addition of ClF to 11 gives rise to ( 12 ) which when photolyzed at 3000 Å forms a second cyclic hydrazine, ( 13 ).     

Interconversion of Metallabenzenes and Cyclic η2‐Allene‐Coordinated Complexes

Treatment of the osmabenzene [Os{CHC(PPh₃)CHC(PPh₃)CH} Cl₂(PPh₃)₂]Cl ( 1 ) with excess 8‐hydroxyquinoline produces monosubstituted osmabenzene [Os{CH C(PPh₃) CHC(PPh₃)CH}(C₉H₆NO)Cl(PPh₃)]Cl ( 2 ) or disubstituted osmabenzene [Os{CHC(PPh₃)CHC(PPh₃)CH} (C₉H₆NO)₂]Cl ( 3 ) under different reaction conditions. Osmabenzene 2 evolves into cyclic η²‐allene‐coordinated complex [Os{CH?C(PPh₃)CH=(η²‐C?CH₂)}(C₉H₆NO)(PPh₃)₂]Cl ( 4 ) in the presence of excess PPh₃ and NaOH, presumably involving a P? C bond cleavage of the metallacycle. Reaction of 4 with excess 8‐hydroxyquinoline under air affords the S_NAr product [(C₉H₆NO)Os{CHC(PPh₃)CHCHC} (C₉H₆NO)(PPh₃)]Cl ( 5 ). Complex 4 is fairly reactive to a nucleophile in the presence of acid, which could react with water to give carbonyl complex [Os{CH?C(PPh₃)CH?CH₂}(C₉H₆NO) (CO)(PPh₃)₂]Cl ( 6 ). Complex 4 also reacts with PPh₃ in the presence of acid and results in a transformation to [Os {CHC(PPh₃)CHCHC}(C₉H₆NO)Cl (PPh₃)₂]Cl ( 7 ) and [Os{CH?C(PPh₃) CH=(η²‐C?CH(PPh₃))}(C₉H₆NO) Cl(PPh₃)]Cl ( 8 ). Further investigation shows that the ratio of 7 and 8 is highly dependent on the amount of the acid in the reaction.     

PNPP Hydrolysis Catalyzed by Manganese(III) Complexes with Crowned Salicylaldimine Schiff Base Ligand

Four manganese(III) complexes (MnL¹Cl, MnL²Cl, MnL⁴₂Cl, MnL⁵₂Cl) with a crowned salicylaldimine Schiff base ligand have been synthesized and employed as models to mimic hydrolase in the hydrolysis of p-nitrophenyl picolinate (PNPP). The kinetics and mechanism of catalytic PNPP hydrolysis have been investigated. The kinetic mathematical model of PNPP cleavage catalyzed by these complexes has been proposed. The effects of the ligand structure and crown ether ring in complexes, and the reactive temperature on the rate of catalytic PNPP hydrolysis have been also examined. The results show that compared with the crown-free analogous MnL³Cl and MnL⁶₂Cl, the crowned Schiff base manganese(III) complexes, MnL¹Cl, MnL²Cl, MnL⁴₂Cl and MnL⁵₂Cl, exhibit more high catalytic activity, which follow the order: MnL¹Cl >MnL²Cl >MnL⁴₂Cl >MnL⁵₂Cl >MnL³Cl >MnL⁶₂Cl; the pseudo-first-order-rate (k_obs) for the PNPP hydrolysis catalyzed by the complex MnL¹Cl containing three crown ether rings is highest among six complexes and is 1.81 times that of MnL³Cl, 1.49 × 10³ times that of spontaneous hydrolysis of PNPP, respectively, at pH = 7.00, [S] = 2.0 × 10⁻⁴ mol dm⁻³.