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Treatment of [Rh(CO)2(η-C5Me5)] with [Mn(CO)2(thf)(η-C5H5)](thf = tetrahydrofuran) affords [MnRh(µ-CO)2(CO)2(η-C5H5)(η-C5Me5)], the structure of which has been determined by an X-ray diffraction study. The crystals are orthorhombic, space group Pnam(non-standard setting of Pnma, No. 62), in a unit cell with a= 16.851(12), b= 9.338(5), c= 11.566(9)A, U= 1 820(2)A3 at 220 K, and Z= 4. The structure was solved to R 0.057 (R′ 0.058) from 1 860 observable independent reflections [I 3.0σ(I)]. The molecule possesses C, symmetry; one terminal carbonyl ligand on each of the metal atoms, together with the Rh–Mn bond [2.703(2)A], define the mirror plane. The cyclopentadienyl ligand on the Mn atom is in a trans relationship to the pentamethylcyclopentadienyl ligand on the Rh atom and both lie astride (perpendicular to) the mirror plane. The two other carbonyl ligands are terminal to the Mn atom but are strongly semi-bridging to the Rh atom [Mn–C(9) 1.866(7), Rh–C(9) 2.172(7)A], and define planes which are nearly perpendicular to the mirror plane. A distortion of the Rh–C5 geometry towards a ‘diolefin’ type attachment is discussed.Reaction of [Rh(CO)2(η-C5Me5)] with [Fe2(CO)9] in thf affords the compounds [FeRh(µ-CO)2(CO)4(η-C5Me5)] and [Fe2Rh(µ-CO)2(CO)7(η-C5Me5)]. The latter is also formed, together with [FeRh2(µ3-CO)(µ-CO)2(CO)3(µ-C5Me5)2], on treatment of [Rh2(µ-CO)2(η-C5Me5)2] with excess [Fe2(CO)9].The trirhodium complex [Rh3(µ3-CO)(µ-CO)2(η-C5Me5)3] was obtained in high yield by pyrolysis of [Rh(CO)2(η-C5Me5)] and undergoes dynamic behaviour in solution. Protonation of the trirhodium cluster or [Rh2(µ-CO)2(η-C5Me5)2] affords quantitatively the cation [Rh3(µ-H)(µ3-CO)(µ-CO)2(η-C5Me5)3]+ which can be deprotonated with NaOMe in MeOH.

Electrochemical Voltage Spectroscopy (EVS), gravimetric EVS (GEVS) and in-situ UV-vis EVS have been performed on polypyrrole cells. Results indicate that EVS is limited because of the very slow diffusion of counter-ions within the polymer. GEVS results show that there is an increase in polymer mass upon oxidation and a decrease in polymer mass upon reducing the polymer to its neutral state thus indicating that anions are solely responsible for the countering of the polymer's charge under these experimental conditions.

The compounds [M2(CO)n(η-C5H5)2](M = Mo or W, n= 4 or 6) react with the alkylidynetungsten compound [W(CR)(CO)2(η-C5H5)](R = C6H4Me-4) in toluene at ca. 100 °C to give the trimetal complexes [M2W(µ3-CR)(CO)6(η-C5H5)3]. In contrast, [Cr2(CO)4(η-C5H5)2] and [W(CR)(CO)2(η-C5H5)] afford the µ-alkyne-ditungsten compound [W2(µ-RC2R)(CO)4(η-C5H5)2]. This reaction is catalysed by small quantities of the dichromium species, and a possible mechanism is proposed. The compound [Mo3(µ3-CR)(CO)6(r)-C5H5)3] was obtained in low yield from a complex mixture of products produced in the reaction of [Mo2(CO)4(η-C5H5)2] with [W(CR)Br(CO)4]. The 1H and 13C-{1H} n.m.r. data for the new compounds are reported and discussed.

The bimetal compound [RhW(µ-CR)(CO)3(η-C5H5)(η-C9H7)](R = C6H4Me-4, C9H7= indenyl) reacts with the alkynes R1CCR2(R1= R2= Ph or Me; R1= Ph, R2= H or Me) in toluene at ca. 50–80 °C to give the bridged complexes [RhW{µ-C(R)C(R1)C(R2)}(CO)2(η-C5H5)(η-C9H7)]. The molecular structure of the species obtained from PhCCPh was established by a single-crystal X-ray diffraction study. A Rh–W bond [2.754(1)A] is bridged by a three-carbon chain [mean C–C 1.439(8)A]. Whereas all the atoms of the chain are bound to the rhodium [2.105(6), 2.135(6), and 2.103(5)A], only the two end carbons are attached to the tungsten [2.175(5) and 2.196(6)A]. The tungsten atom carries two essentially orthogonal terminal carbonyl groups, as well as the cyclopentadienyl ring. The indenyl group is asymmetrically attached to the rhodium atom, with three short Rh–C [2.185(7), 2.198(7), and 2.204(7)A] and two long Rh–C [2.334(7) and 2.330(7)A] separations to the C5 ring, implying slippage towards an η3-bonding mode. Formation of [RhW{µ-C(R)C(Ph)C(Ph)}(CO)2(η-C5H5)(η-C5Me5)] from [RhW(µ-CR)(CO)3(η-C5H5)(η-C5Me5)] and PhCCPh requires forcing conditions (100 °C, 5 d in toluene), and side-reactions occur to yield hexaphenylbenzene, [Rh(CO)2(η-C5Me5)], and the tetraphenylcyclopentadienone complex [Rh(µ-C4Ph4CO)(η-C5Me5)]. The reaction between [RhW(µ-CR)(CO)3(η-C5H5)(η-C9H7)] and [W(CR)(CO)2(η-C5H5)] has also been investigated. With heptane as solvent, the products are the trimetal complex [Rh2W(µ3-CR)(µ-CO)(CO)2(η-C5H5)(η-C9H7)2], the alkyne-bridged complex [W2(µ-RC2R)(CO)4(η-C5H5)2], and a compound formulated as [W2{µ-C(R)C(O)C(R)}(CO)4(η-C5H5)2]. Spectroscopic data (i.r., 1H and 13C-{1H} n.m.r.) for the new compounds are reported and discussed.

Enneacarbonyldi-iron reacts at room temperature with the compounds [RhW(µ-CR)(CO)3(η-C5H5)-(η-C9H7)](R = C6H4Me-4) and [CoW(µ-CR)(CO)3(η-C5H5)(η-C5Me5)] to give the heteronuclear trimetallic complexes [RhFeW(µ3-CR)(µ-CO)(CO)5(η-C5H5)(η-C9H7)] and [CoFeW(µ3-CR)(µ-CO)(CO)5(η-C5H5)(η-C5Me5)], respectively. The structure of the rhodiumirontungsten compound was established by an X-ray diffraction study. Crystals are monoclinic, space group P21/c(no. 14), with Z= 4 in a unit cell of dimensions a= 9.018(2), b= 15.572(4), c= 18.503(6)A, β= 103.69(2)°. Intensities were measured at room temperature to 2θ= 50°, and the structure has been refined to R 0.032 (R′ 0.034) for 3 497 unique reflections. The metal triangle has separations Fe–Rh 2.583(1), Fe–W 2.772(1), and Rh–W 2.760(1)A, and is asymmetrically capped by the CC6H4Me-4 ligand [µ3-C–Fe 2.029(6), µ3-C–Rh 2.035(6), µ3-C–W 2.093(6)A]. One CO ligand bridges the Fe–Rh bond, while the other five are terminally bonded; two to the tungsten, and three to the iron. The Rh–C(indenyl) distances suggest a tendency for η3 bonding of the ligand. The compound [RhW(µ-CR)(CO)3(η-C5H5)(η-C9H7)] reacts with [Rh(CO)2(η-C9H7)] in toluene at 60 °C to give [Rh2W(µ3-CR)(µ-CO)(CO)2(η-C5H5)(η-C9H7)2], and a related cluster [Rh2W(µ3-CR)(µ-CO)(CO)2(η-C5H5)(η-C5Me5)2] can be obtained from [Rh2(µ-CO)2(η-C5Me5)2] and [W(CR)(CO)2(η-C5H5)]. The latter reaction also affords the dimetal species [RhW(µ-CR)(CO)3(η-C5H5)(η-C5Me5)]. At 60 °C in toluene, [W(CR)(CO)2(η-C5H5)] and [Ni2(µ-CO)2(η-C5H5)2] give a mixture of the compounds [Ni2W(µ3-CR)(CO)2(η-C5H5)3] and [W2(µ-RC2R)(CO)4(η-C5H5)2]. The same products are obtained from [Ni(η-C5H5)2] and [W(CR)(CO)2(η-C5H5)], but the latter with [Ni2(µ-Me3SiC2SiMe3)(η-C5H5)2] affords [Ni2W(µ3-CR)(CO)2(η-C5H5)3] only. Pathways for the formation of some of the complexes, including [W2(µ-RC2R)(CO)4(η-C5H5)2], are proposed, and 1H and 13C n.m.r. data for the various species are reported.

Methods for synthesis of cluster complexes containing triangular arrangements of metal atoms capped by alkylidyne ligands are reported, and such structures confirmed by X-ray diffraction studies on the compounds [FePtW(µ3-CC6H4Me-4)(CO)6(PEt3)(η-C5H5)] and [FeRhW(µ3-CC6H4Me-4)(µ2-CO)(CO)5(η-C5H5)(η-C9H7)].

The Coulombic efficiency, stability, constant-current discharge characteristics, energy density and the relation of cell potential to degree of reduction of a partly reduced polyacetylene cathode, [Na+y(CH)y–]x(y⩽ 0.10), in a cell of the type Na|NaPF6(tetrahydrofuran)|[Na+y(CH)y–]x have been investigated. By comparison with data obtained with a (Li+y(CH)y–]x electrode, thermodynamic properties, such as the relation of cell potential to degree of reduction at diffusion equilibrium, appear to be intrinsic to the reduced polyacetylene and independent of the countercation, whereas kinetic properties, such as the cell potential during constant-current electrochemical reduction, vary with the countercation. The electrochemical reduction of polyacetylene with the incorporation of potassium countercations has been accomplished in a K|K ClO4(tetrahydrofuran)|[K+y(CH)y–]x cell using a complexing agent to solubilize the KClO4 in the tetrahydrofuran. A convenient electrochemical method for incorporating organic countercations into polyacetylene is discussed, together with selected properties of a [(Bu4N)+y(CH)y–]x electrode.