Tadeusz Wilczewski

Cyclopentadienyl-ruthenium complexes : I. The reactivity of some π-cyclopentadienyl-bistriphenylphosphine-ruthenium(II) complexes

Abstract Several ruthenium complexes of the CpRuX(PPh3)2 type, where X = Cl, Br, I, NCS, NCO, CN, BH4, H, D, and some of the CpRuS2CZ(PPh3) type, where Z = NR2 or OR, were obtained. The hydride CpRuH(PPh3)2 was obtained in high yield by reaction of CpRuCl(PPh3)2 with ROM (R = alkyl, M = alkali metal). The other complexes were obtained by ligand exchange of the chloride or hydride with MX salts or HX acids, respectively. Reaction of chloride or hydride with cyclopentadiene led to ruthenocene. However, when pyrrole was used instead of cyclopentadiene, it was not possible to obtain azaruthenocene in this way.

Theoretical and experimental study of natural convection heat transfer from isothermal hemisphere

Abstract The simplified analytical solution and experimental study of laminar free convection heat transfer from an isothermal hemisphere in unlimited space have been presented. The solution is based on adaptation of the methods used for inclined isothermal plates. In the proposed solution the control surface of the hemisphere was considered as a small inclined surface. Inclination of this surface was not a constant one but it was a function of azimuth angle. The result of theoretical consideration is presented in the relation of Nusselt and Rayleigh numbers: Nu = 0.533 × Ra 1 4 . The comparison of theoretical solutions with experimental results presented in this paper and results of other authors shows good agreement. Copyright

Natural convection heat transfer from complex surface

Abstract The analytical solution of convective heat transfer from an isothermal complex surface in an unlimited space has been presented. The complex surface is represented by a horizontal ring of diameters D and d with hemispherical segment of diameter d in the centre. The shape of the complex surface was expressed by factor p = d/D. The presented solution has been verified experimentally on a set-up of diameter of 0.4 m and height of 0.5 m with surfaces of constant external diameter D = 0.06 m and various shape factor p = 0—round plate, 0.183, 0.233, 0.40, 0.483, 0.554, 0.650, 0.817 and 1.0—hemisphere. The tested fluid was glycerine. The comparison of theoretical and experimental results gives good agreement.

Cyclopentadienyl-ruthenium and -osmium complexes: VI. Formation and properties of dihydrido-(η-cyclopentadienyl)bis(triphenylphosphine)osmium(IV) cation. Reaction of hydrido(η-cyclopentadienyl)bis(triphenylphosphine)osmium(II) and dihydrido(η-cyclopentadienyl)bis(triphenylphosphine)osmium(IV) halogenates with HX acids, X2 dihalogeno and halogenated hydrocarbons☆

Several new compounds of the type [CpOsH2(PPh3)2]+ X−, where X = Cl, Br, I, I3, BPh4, p-toluenesulphonate, d(+)-campho-10-sulphonate, have been obtained in the form of ion pairs or salts. The above compounds form during oxidative addition by HX acids to CpOsH(PPh)3)2. The reactions are complete after several seconds, with a quantitative yield. This is in contrast to the behaviour of CpRuH(PPh3)2, where covalent CpRuX(PPh3)2 forms. Reactions of CpOsH(PPh3)2 with DCl acid (excess) gives [CpOsD2(PPh3)2]Cl, but no [CpOsHD(PPh3)2]Cl is formed. Refluxing CpOsBr(PPh3)2, in ethylene glycol for instance, gives a [CpOsH2(PPh3)2]+ cation as a result of the dehydrogenation of the glycol. Compounds of the type, [CpOsH2(PPh3)2]X, in solutions of polar solvents (MeOH) or halogenated hydrocarbons (e.g. CH2X2) undergo transformation to CpOsX(PPh3)2 during the reductive elimination process. In this way novel CpOsI(PPh3)2 has been obtained. In the case of the reaction of a mixture of HX + X2 with CpOsH(PPh3)2, [CpOsHBr(PPh3)2]Br3 (for Br2) and [CpOsH2(PPh3)2]I3 (for I2) have been obtained in the form of sparingly soluble ion pairs with yields of about 90%.

Cyclopentadienyl-ruthenium and -osmium complexes. III: Chemical mechanism of dissolution of chloro (η-cyclopentadienyl)-bis(triphenylphosphine) ruthenium(II) in polar solvents

Abstract The conversion of CpRuCl(PPh 3 ) 2 in boiling ethylene glycol within 90 h of reflux has been investigated. New complex cations in the form of their tetraphenylborates, for which the formulae [Cp 1 RuCl(PPh 3 )PPh 2 Cp 2 Ru(η-C 6 H 5 ) + and [CpRu(η-C 6 H 5 )PPh 2 ] + are proposed, were isolated. The former cation is also formed at lower temperatures during the reflux of CpRuCl(PPh 3 ) 2 methanol. The following process takes place: 2CpRuCl(PPh 3 ) 2 → [Cp 1 RuCl(PPh 3 )PPh 2 Cp 2 Ru(η-C 6 H 5 )] + + Cl − + 2PPh 3 . In the presence of dicyclopentadiene during the reflux of CpRuCl(PPh 3 ) 2 in high boiling polar solvents (ethylene glycol, dimethyl sulphoxide), ruthenocene is formed in a 90% yield. One of the cyclopentadienyl groups in ruthenocene originates from dicyclopentadiene. As a result of the reaction of CpRuCl(PPh 3 ) 2 and NaBPh 4 in a mixture of diglyme and methanol, a colourless, crystalline compound, CpRu(η-C 6 H 5 )BPh 3 , is obtained in a 50–60% yield.

Cyclopentadienyl-ruthenium and -osmium complexes: V. Synthesis, reactivity and crystal structure determination of carbonylchloro(η-cyclopentadienyl)-(triphenylphosphine)ruthenium(II)☆

Abstract CpRuCl(CO)PPh3 is formed as the result of refluxing CpRuCl(PPh3)2 in ethylene glycol (yield up to 15%). A dissociation process is postulated with liberation of one PPh3 molecule and simultaneous rearrangement of the cation formed earlier: [CpRu(CO)(PPh3)2]+ Cl− → CpRuCl(CO)PPh3 + PPh3. CpRuCl(CO)PPh3 reacts reluctantly with the alkoxy anion to give CpRuH(CO)PPh3, in contrast to CpRuCl(PPh3)2, which undergoes very facile transformation into CpRuH(PPh3)2. The structure of CpRuCl(CO)PPh3 has been determined by the single-crystal X-ray diffraction method. The compound is triclinic, space group P 1 , a 9.378(2), b 10.584(2), c 16.590(4) A, α 126.11(1), β 55.91(1), γ 101.49(1)°. The unit cell contains both R and S enantiomers. A shorter distance of the RuCl bond has been noted in CpRuCl(CO)PPh3 (2.396 A) in comparison with the RuCl distance in CpRuCl(PPh3)2 (2.453 A). This causes a diminishing tendency to lose a chloride ion and as a result, nucleophilic attack of RO− on CpRuCl(CO)PPh3.

Cyclopentadienyl-ruthenium and -osmium complexes: VII. Formation and properties of ion-pairs containing the dihydride (η-cyclopentadienyl)bis(triphenylphosphine)-ruthenium (IV) cation☆

The [CpRhH2(PPh3)2]+ cation in the simple and fast reaction of CpRuH(PPh3)2 with organic sulphonic acids in polar solvents (methanol, acetone) has been obtained in the form of ion-pairs. The reaction runs for several minutes, with practically quantitative yields. The dihydride complex cation obtained may be isolated from polar solutions as a sparingly soluble ion-pair [CpRhH2(PPh3)2][BPh4] with the tetrapehynborate anion. In the [CpRuH2(PPh3)2][sulphonate] ion-pairs a reduction-elimination process slowly proceeds with the formation of non-ionic compounds of the CpRu(sulphonate)(PPh3)2 type. Also, the effect of methyl substituents in the Cp-ring on shifts in the 31P NMR signals and MS(FD) investigations of the new compounds obtained have been described. Explanation of the new group signals in the MS(FD) spectra as originating from the fragments formed, containing two ruthenium atoms π-bonded to the phenyl ring of BPh4, i.e. [CpRu(η6-C6H5BPh2CpRu(η6-C6H5)]+, were proposed. In the case of compounds containing the PPh3 molecule, a similar phenomenon occurs. For fragments obtained in the MS(FD) spectra, the formula [RSO3CpRuPPh2CpRu(η6-C6H5)]+ was ascribed.

Cyclopentadienyl-ruthenium and -osmium complexes: IV. Separation and identification of ruthenocene-carboxylic and -boronic acids. Use and evaluation of the chromatographic test for the detection of complexing of alkali metal cations

Abstract Ruthenocene-mono- and -di-carboxylic acids have been separated and identified. The applicability range of the chromatographic test, previously used to detect the complexing phenomenon of alkali metal catins by crown ethers, has been determined. The performance of the test in the case of several new cyclopentadienyl ruthenium and osmium complexes, organic acids and compounds of the ionic-pair type containing a large BPh4− anion, has been investigated.

Cyclopentadienyl-ruthenium and -osmium complexes

Abstract Ruthenium and osmium complexes of the type CpMX(PPh 3 )L (M = Ru; X = Cl, H, S 2 COC 10 H 19 , S 2 COMe; L & PPh 3 and PHPh 2 ; M = Os, X = Cl, Br, I, H, D, xanthogenate, dithiocarbamate, BPh 4 , L = PPh 3 ). The compound CpOsCl(PPh 3 ) 2 is readily soluble in MeOH and in the solution the cation [CpOs(PPh 3 ) 2 ] + is present. Upon addition of NaBPh 4 a white compound CpOs(PPh 3 ) 2 BPh 4 immediately precipitates, which can not be solved in MeOH, contrary to the behaviour of the corresponding ruthenium compound.

Cyclopentadienyl-ruthenium and -osmium complexes IX. Cation formation of cyclopentadienylruthenium complex molecules by the CpRu+ cation during reflux in alcohols or glycols☆

Abstract Information from MS(FD) and (EI) investigations of compounds containing [CpRu] fragment is presented. In a few cases cation formation gives the new extended cations having m/e values above those of the starting parent ions, enlarged by a 167 unit. An analogous process, taking into account the final product, can occur during reflux of the starting compounds, e.g. CpRuX(PPh 3 ) 2 type (X = Cl, Br, I) in glycols or lowboiling alcohols. In the last case the access of oxygen, playing the role of the labilizing agent of the PPh 3 ligands, is necessary. The phosphorus NMR studies of the dinuclear cations [CpRuCl(PPh 3 )CpRu(η 6 -C 6 H 5 )PPh 2 ] + as well as the application of the rule on the effect of the methyl substituent at Cp-ring on changes in the phosphorus NMR spectra, are described in detail.