Synthesis and Complex Chemistry of Functionalised Tripod Ligands RC(CH2PPh&* Malonic ester 1 is alkylated and converted into the triols ligand ?a. In addition, the tripod ligands ?a and ?c have been RC(CH20H), (5). These are easily converted into the corre-further characterized by the syntheses and X-ray analyses of sponding functionalised tripodal ligands RC(CH2PPh2), (?) the nickel complex [ (?a)NiCl] (8a), the iron complex Ziel unserer Untersuchungen war es daher, zunachst geeignete Synthesen zu funktionalisierten Triolen RC(CH20H)3 zu entwickeln, die eine groI3e Variationsbreite des Restes R zulassen. Die Triole RC(CH20H), sollten dann in einer einfachen Reaktionsfolge in die funktionalisierten Tripod-Liganden RC(CHzPR;)3 umgewandelt werden, wobei zunachst nur die Liganden rnit R' = Ph dargestellt wurden. Ergebnisse und DiskussionUm ein im Rest funktionalisiertes Triol zu erhalten, werden zunachst primare Akylbromide RBr [R = C6H5CH2, C12H25Br, (CH3)2CH(CH2)2Br] mit einem Aquivalent Natrium-diethylmalonat, NaHC(C0zEt)2, zu den monoalkylierten Malonestern (2) umgesetzt (Schema 1). Die Malonester 2 werden deprotoniert und rnit Benzyl (chlormethy1)

The tripod ligands R C H ,C (C H 2 PPh2 ) 3 react with (C H 3 CN )6Fe(BF4 ) 2 to yield the tripod-F e(II) complexes R C H 2 C (C H 2 PPh2 )3 F e(C H 3 CN)3 (BF4 ) 2 (R = H, la; R = Ph, lb ). The octa hedral low spin F e(II) com pounds are shown by cyclic voltam m etry to undergo reversible one electron oxidation at +1.47 V (vs. SCE) to give the corresponding F e(III) derivatives.In a similar way (C H 3 CN )6Co(BF4 ) 2 reacts with the same tripod ligands to produce the tripod-Co(II) complexes R C H 2 C(CH 2 PPh2 )3 Co(CH 3 CN)2 (BF4 ) 2 (R = H, 2a; R -Ph, 2b). The com pounds are param agnetic (2a, g = 2.123; 2b, g = 2.129). The structure of complex 2bshows that the tripod ligand is facially coordinated with one longer (233.1 pm) and two shorter (about 222 pm) C o -P bonds. Reversible reduction is found for 2 a at -0 .3 0 V by cyclic voltammetry. The com pounds have been characterized by spectroscopic and analytical tech niques including X-ray analyses.

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Durch photochemische Umlagerung von Hecogeninacetat (1) zum ungesättigten Aldehyd 5 und anschließende Prins‐Reaktion sind die 14β‐Hydroxysteroide 7a und 10a bequem zugänglich. Die Konfiguration an C‐13 und C‐14 bei 7a, 10a und 9a wurde chemisch und mit Hilfe spektroskopischer Methoden (1H‐NMR, 13C‐NMR und CD) abgeleitet.

Tripod Rhodium COD Complexes: Synthesis, Structure, Dynamics and Catalysis The reaction of the tripod ligands R′C(CH2PR2)3 (1a–c) and X2POCH[CH2P(Ph)2]2 (2a–c) with [RhI(COD)Cl]2] is investigated. It yields tripod rhodium COD complexes [(1a–c)RhI(COD)]Y (3a–c) and [(2a–c)RhI(COD)]Y [4a–c; Y = B(Ph)4, PF6]. The tripod ligand is coordinated by all three donor groups in each case, irrespective of the different donor capabilities of the coordinating groups. The solid state structure of compounds 3a–c and 4a is determined by X‐ray analysis. The observed coordination polyhedra delineate the variation from the idealized trigonal bipyramide to an idealized quadratic pyramide. In solution the analysis of the NMR spectra shows a rapid intramolecular interconversion according to a turnstile pseudo rotation. The complexes 3a and 4a are found to be catalysts for the hydrogenation of prochiral olefines.