Synthese und Komplexchemie funktionalisierter Tripod‐Liganden RC(CH₂PPh₂)₃

Abstract

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)

Spontaneous Si–C bond cleavage in (TriphosSi)-nickel complexes

“…The magnetic moments of complexes 7a and 7b were measured using the Evans method and found to be 1.9µ B and 1.7µ B respectively, which is in line with literature findings for Ni(I) complexes. 39 The Ni(I)-center is tetrahedrally coordinated by the κ 3 -bound Triphos Si ligand 1b and one bromide ligand. The phosphorus atoms are not equivalent, which is shown by the three observed Ni-P distances (2.246(2) Å, 2.258(2) Å and 2.219(2) Å).…”

“…Although a structurally related (Triphos C )Ni(I)-complex was previously reported by Huttner as well as Sacconi and coworkers, their synthetic procedure failed in our hands. 39,40 We subsequently attempted a different synthetic route towards such Ni(I)-complexes that allows for a simple straightforward gram scale synthesis. The reaction of 2a with cobaltocene gave the analogous C-derived Ni(I)-compound 7a and was confirmed by X-ray structure analysis (Scheme 3 and Fig.…”

Polydentate phosphines

“…Using tripodal complex ligand an iron complex [{(CH 3 ) 2 -CHCH 2 CH 2 C(CH 2 PPh 2 ) 3 } Fe(NCMe) 3 ][BF 4 ] 2 , which displays an octahedral geometry at the metal center, and the cobalt complex a fivecoordinate distorted square-pyramidal geometry was synthesized and analyzed [58]. The chiral tripodal ligand with three different donor groups [59], L = CH 3 C(CH 2 PR 2 )(CH 2 PR 0 2 ) (CH 2 PR 00 2 ), with R = 2-tolyl, R 0 = /4-tolyl, R 00 = Ph was used to obtain the complexes [(L)Fe(NCMe) 3 (Fig.…”

Tripodal Phosphane Ligands with Novel Linker Units and Their Rhodium Complexes as Building Blocks for Dendrimer Catalysts

“…[11] If performed in batch reactors, this requires catalysts which retain their original activity after separation and reintroduction to a catalytic conversion. The dendrimer catalysts cat3 and cat4 were found to be isolable (removal of the solvent and reaction product under vacuum) after a complete conversion and re-usable for a subsequent cycle without significant decrease in activity during the first three cycles of catalyst isolation and reintroduction to a new batch of substrates.…”

“…[3Ϫ7,11Ϫ16] Previously published syntheses of such derivatives partially suffer from the nontolerance of certain functional groups (e.g. C-C multiple bonds) [11] or the fact that the phosphanyl groups are introduced at a very early stage of the reaction sequence, making subsequent work up more difficult. [12Ϫ16] Moreover, if expensive (chiral) phosphanyl functions are to be introduced in an early reaction step of the synthetic pathway [17] the loss of phosphane during the overall sequence may be considerable.…”