An anti-Bredt N-heterocyclic carbene gold(I) chloride complex was synthesized by taking advantage of the reversible insertion of the free carbene into the NH bond of hexamethyldisilazane. This precatalyst promotes the parent hydrazine hydroamination of terminal alkynes at room temperature.

The ring-opening polymerization (ROP) behavior of a variety of substituted 1,1'-ethylenylferrocenes, or dicarba[2]ferrocenophanes, is reported. The electronic absorption spectra and tilted solid-state structures of the monomers rac-[Fe(eta(5)-C(5)H(4))(2)(CHiPr)(2)] (7), [Fe(eta(5)-C(5)H(4))(2)(C(H)MeCH(2))] (8), and rac-[Fe(eta(5)-C(5)H(4))(2)(CHPh)(2)] (9) are consistent with the presence of substantial ring strain, which was exploited to synthesize soluble, well-defined polyferrocenylethylenes (PFEs) [Fe(eta(5)-C(5)H(4))(2)(C(H)MeCH(2))](n) (12) and [Fe(eta(5)-C(5)H(4))(2)(CHPh)(2)](n) (13) through photocontrolled ROP. Polymer chain lengths could be controlled by the monomer-to-initiator ratio up to about 50 repeat units and, consistent with the "living" nature of the polymerizations, sequential block copolymerization with a sila[1]ferrocenophane led to polyferrocenylethylene-polyferrocenylsilane (PFE-b-PFS) block copolymers (14 and 15). PFE polymers 12 and 13 showed two reversible oxidation waves, indicative of appreciable FeFe interactions along the polymer backbone. The diblock copolymers were characterized by NMR spectroscopy, GPC analysis, and cyclic voltammetry.

The reaction of potassium hydrotris(methimazolyl)borate {KTm = HB(mt)(3)} with [{Rh(cod)(mu-Cl)}(2)] gave [Rh(cod)Tm] while the complexes [Rh(CO)(PR(3))Tm] (R = Ph or NMe(2)) and [Rh{P(OPh)(3)}(2)Tm] were isolated from light-sensitive [Rh(CO)(2)Tm], prepared in situ from KTm and [{Rh(CO)(2)(mu-Cl)}(2)], and PR(3) or P(OPh)(3) under CO. The complexes [Rh(cod)Tm] and [Rh(CO)(PR(3))Tm] (R = Ph or NMe(2)) adopt kappa(3)-S(2)H structures in the solid state but in all cases rapid dynamic exchange processes render the three mt rings equivalent in solution. Oxidation of [Rh(CO)(PPh(3))Tm] with [Fe(eta-C(5)H(5))(2)][PF(6)] in the presence of NHPr(i)(2) gave a mixture containing two monocationic rhodaboratranes. One is assigned as [Rh(CO)(PPh(3)){B(mt)(3)}][PF(6)] on the basis of IR and NMR spectroscopy, with boron trans to the phosphine ligand. The second, structurally characterised as [Rh(PPh(3)){B(mt)(3)}][PF(6)], has boron trans to an empty coordination site, vacated by CO. Similar oxidation of [Rh(cod)Tm] gave small quantities of the boron-fluorinated bis(scorpionate) [Rh{FB(mt)(3)}(2)][PF(6)].

n Pr] were prepared, and the electronic effects of co-ligands and alkoxy vs. aminocarbene substituents were investigated by spectroscopic and electrochemical methods. The molecular structures of complexes 1, 2 and 4-6 were confirmed by single crystal X-ray diffraction. The use of the complexes 1-8 as homogeneous catalysts for the hydroformylation of 1-octene was demonstrated, and the influence of the carbene substituents and co-ligands on the activity and regioselectivity of the catalysis evaluated. Finally, the stability of the Rh-Ccarbene bond of complex 1 under hydroformylation conditions was confirmed with 13 C NMR experiments.

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