No abstract

The complexes [Ti(n-C5H5)CI2L] (L = N-NPh or NPhNH2) have been shown by X-ray crystallography to contain side-on dinitrogen moieties, the former being the first example of this kind of co-ordination of a diazenido-ligand.

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.

An oily adduct obtained from triethyl phosphite and diethyl azodicarboxylate was regarded by Morrison [41 as (22), whereas Ginsburg et al. ill suggested an alternative structure. Interception of the precursor (21) by a cycloaddition process provides evidence in favor of (22). On slow addition of dimethyl azodicarboxylate to trimethyl phosphite and phenyl isocyanate in benzene, we were able to isolate (17) in 84% yield; the reaction probably proceeds via an intermediate analogous to (16) having OCH3 instead of CsH5 attached to the phosphorus.