Synthesis and characterization of the macrocyclic complexes [Ni(Me2[14]dienatoN2P2)]PF6 and [Ni(Me2[16]dieneN2P2)](PF6)2. Crystal structure of [Ni(Me2[16]dieneN2P2)](PF6)2.0.5H2O

Palladium(II) and Platinum(II) Complexes of a Tetraphosphamacrocycle. X-ray Crystal Structures of Phosphorus Analogs of a (Tetramethylcyclam)metal Complex1

“…Preparation of Pd 2+ and Pt 2+ Complexes with Me 4 [14]aneP 4 ,− ,− Stelzer et al reported that [Pd(MeHPCH 2 CH 2 PHMe) 2 ]Cl 2 ( 5a ) reacts with diketones to form 2b and 2c in high yield. During the reaction, the deprotonated phosphorus atoms attack the carbonyl groups of the diketone, with the OH groups remaining at the position α to the phosphorus.…”

Chiral Macrocyclic N2P2 Ligands and Iron(II): A Marriage of Interest

“…The retrosynthetic approach shown in Scheme indicates the enantiomerically pure bis- ortho -formyl-substituted diphosphine ( S , S )- 8 as the synthon of choice to prepare C 2 -symmetric N 2 P 2 macrocycles by condensation with a variety of chiral diamines. As the previous examples of N 2 P 2 macrocycles have shown a strong preference for the meso form, − , it is crucial to control the stereogenic center on phosphorus at an early stage of the synthesis. To this goal, we have adapted Jugé’s approach, which is excellently suitable to control the stereochemistry on phosphorus by sequential and selective nucleophilic cleavage of the P–O and P–N bonds of (2 R ,4 S ,5 R )-3,4-dimethyl-2,5-diphenyl-1,3,2-oxazaphospholidine-2-borane ( 3 ) (formed as a single diastereoisomer from PhP(NEt 2 ) 2 and (−)-ephedrine) .…”

“…The synthesis of such macrocyclic N 2 P 2 ligands is challenging, though, because it requires the control of the configuration at phosphorus. In fact, only a few P-containing macrocycles have been prepared, and N 2 P 2 macrocycles are even rarer and mostly achiral (Chart ). − …”

“…The N 2 P 2 macrocycles C and D were prepared by template synthesis with nickel(II), , whereas E was prepared by double alkylation of deprotonated 1,2-bis(phenylphosphino)benzene under high-dilution conditions . In all cases, only the meso isomer of the ligand was obtained.…”

Iron Complexes with Chiral N/P Macrocycles as Catalysts for Asymmetric Transfer Hydrogenation

“…Thus, the nickel(II) complex of the 16‐membered macrocycle 11 was prepared from a linear, open‐chain N 2 O 2 P 2 ligand upon refluxing in the presence of Ni(OAc) 2 ⋅4 H 2 O as templating agent (a 14‐membered dienato analogue (not shown) was prepared similarly) . Although the open‐chain precursor was prepared as a mixture of the lk and ul diastereoisomers, only the Ni(II) complex containing the meso diastereoisomer of the macrocycle was isolated in 30 % yield . In the meso macrocycle, the six‐membered P−M−P chelate ring assumes a favorable chair conformation.…”