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42‐ and 46‐Membered phosphorus‐based macrocycles were obtained in a [2+2] condensation of PhP(O)[N(Me)NH2]2 with dialdehydes. These macrocycles were isolated in a pure form after preparative thin layer chromatography and were characterized by multinuclear NMR and mass spectroscopy. The FAB mass spectra of these macrocycles revealed parent ion (M+1) peaks in good intensity.

1,3-Bis(3-butylimidazolium-1-yl)benzene diiodide (1) was reacted with Li(2,2,6,6-tetramethylpiperidine) yielding the free bis-carbene, 1,3-bis(3-butylimidazol-2-ylidene-1-yl)benzene (3), which has been spectroscopically characterized. Combining the free bis-carbene with [Rh(COD)Cl]2 yielded the corresponding di-Rh bis(N-heterocyclic carbene) complex (4) that was structurally characterized. The di-Rh bis-carbene complex was found to exhibit complex solution 13C and 1H NMR spectra that have been assigned as a mixture of diastereomers. The crystal structure of the di-Rh bis-carbene compound 4 was composed of a pair of enantiomeric atropisomers. The diastereomeric atropisomers were assigned as the source of the spectral complexities. The di-Rh di-carbene complex 4 and the CCC–NHC Rh pincer complex 2 were applied as catalysts in hydrosilylation reactions of terminal and internal alkynes. Both catalysts are highly active, regioselective, stereoselective, and chemoselective: terminal alkynes give predominantly the β-(Z) isomer and internal alkynes afford the β-(E) isomer in chloroform or benzene. One of the strongest attributes of the catalyst systems is that the results were achieved without exclusion of air and without purification of commercially available reagents.

A general solution to the preparation of pincer complexes that require the formation of two N-heterocyclic carbenes (NHC’s) and the activation of an aryl C–H bond is reported. The reaction of a phenylene-bridged bis(imidazolium) salt with Zr(NMe2)4 generated the requisite CCC–NHC Zr pincer complex, which has been characterized by X-ray crystallography. Subsequent manipulation of the Zr coordination sphere by reaction with MeI demonstrated the robustness of the ligand geometry at Zr and led to the isolation and structural characterization of a CCC–NHC Zr triiodide pincer complex. A variation of the methodology has been applied to a saturated NHC analog to produce the corresponding CCC–NHC Zr pincer complex. Importantly, it has been found that CCC–NHC Zr pincer complexes can be generated in situ and transmetallated with an appropriate Rh source to generate CCC–NHC Rh pincer structures. These two methodologies, metallation of CCC–NHC precursors with transition metal amido complexes combined with transmetallation, hold great promise for opening general synthetic pathways to a wide variety of transition metal CCC–NHC pincer complexes.

Reactions of N-methylhydrazine with chlorocyclophosphazenes, N3P3Cl6 (1), N3P3(OPh)Cl5 (2), gem-N3P3Ph2Cl4 (3), spiro-N3P3(O2C12H8)2Cl2 (4), N3P3(OPh)5Cl (5), and diphenylphosphinic chloride, Ph2P(...

The cyclophosphazene hydrazide gem-N3P3Ph2[N(Me)NH2]4 was reacted with o-hydroxybenzaldehyde to afford the multisite coordination ligand gem-N3P3Ph2[N(Me)N═CHC6H4-2-OH]4 (LH4). The latter reacted with copper(II) salts to afford a novel tetranuclear copper assembly {N3P3Ph2[N(Me)N═CHC6H4-2-O]4Cu2}2, which contains, remarkably, 15 contiguous inorganic rings.

The reactions of n-butylstannonic acid and di n-butyltinoxide with ferrocene monocarboxylic acid have been studied. In the former reaction a hexameric compound, [n-BuSn(O)OC(O)C5H4FeC5H5]6 has been isolated in a quantitative yield. In the latter reaction a tetrameric compound [{n-Bu2SnO2C(C5H4FeC5H5}2O}]2 has been isolated. In contrast to the drum like structure of the former compound, the latter has a ladder like arrangement. Both [n-BuSn(O)OC(O)C5H4FeC5H5]6 and [{n-Bu2SnO2C(C5H4FeC5H5)}2O]2 are electro-chemically robust and show a single oxidation peak in the cyclic voltammetric experiment corresponding to the simultaneous oxidation of six and four ferrocene substituents respectively. The hydrazine substituted cyclophosphazenes, N3P3[N(Me)NH2]6, gem-N3P3Ph2[N(Me)NH2]4, and gem-N3P3(O2C12H8)2[N(Me)NH2]2, are readily condensed with ferrocene carboxaldehyde, C5H5FeC5H4CHO, to afford the corresponding cyclophosphazenes linked to the ferrocenyl moiety through the hydrazone linkage, N3P3[N(Me)N=CHC5H4FeC5H5]6...