932712-36-2Relevant academic research and scientific papers
Multidentate 2-pyridyl-phosphine ligands-towards ligand tuning and chirality
Hanf,García-Rodríguez,Feldmann,Bond,Hey-Hawkins,Wright
, p. 814 - 824 (2017/01/29)
In the current work a range of multidentate pyridyl-phosphine ligands are synthesised with tuneable electronic and steric character, through the incorporation of a variety of alcohols into (amino)pyridyl-phosphine frameworks. The stoichiometric reactions of compounds of the type (R2N)xP(2-py)3?x (2-py = 2-pyridyl) with alkyl as well as aryl alcohols result in the formation of (alkoxy)pyridyl-phosphines (RO)xP(2-py)3?x (R = Me, 2-Bu, Ph). This synthetic procedure also allows the introduction of enantiomerically pure alcohols, like (R)-(?)-2-BuOH and (S)-(+)-2-BuOH, and as such provides a very convenient two-step route to chiral multidentate pyridyl-phosphine ligand sets. Using the bis-amino-phosphine (Et2N)2P(2-py), the stepwise introduction of alcohols enables the synthesis of racemic alkoxy-amino-phosphines (R2N)(RO)P(2-py), as well as alkoxy-phosphines (RO)2P(2-py) and therefore offers easy access to a library of different pyridyl-phosphine ligands. Coordination studies of the (amino)pyridyl-phosphines and (alkoxy)pyridyl-phosphines with copper(i) reveal that ligands with two N donor atoms form dimeric arrangements, while (PhO)2P(2-py), in-corporating only one N donor atom, shows completely different coordination behaviour.
Coordination chemistry of α-ω-bis(pyridylimine) ligands containing flexible linkers with copper(I)
Hu, Zhenzhong,Schneider, Celine M.,Price, Christina N.,Pye, Whitney M.,Dawe, Louise N.,Kerton, Francesca M.
, p. 1773 - 1782 (2012/05/20)
Copper(I) complexes of a series of six potentially tetradentate bis(pyridylimine) ligands were prepared, where the pyridylimine groups were separated by different linking units [in L1, CH2CH2CH 2(SiMe2O)20SiMe2CH 2CH2CH2; in L2, CH2CH 2CH2SiMe2OSiMe2CH2CH 2CH2; in L3, CH2CH2; in L4, CH 2(CH2)4CH2; in L5, CH 2(CH2)7CH2; in L6, CH 2CH2CH2OCH2CH2OCH 2CH2OCH2CH2CH2]. The solubilities of L1, L2 and [Cu(L2)](PF6) in supercritical carbon dioxide were determined. The coordination chemistry of L1-L2 with CuI was studied by UV/Vis, multinuclear NMR and IR spectroscopy, MALDI-TOF and ESI mass spectrometries and elemental analysis. These data suggested that [1+1] complexes had formed. Dicopper complexes of L3-L6 were prepared for comparison, and [Cu2(L5)2](PF6)2 characterized by single-crystal X-ray diffraction analysis. Close methylene C-H...π interactions are observed within the structure. PGSE NMR spectroscopy was used to determine the hydrodynamic radii of the species in solution and comparison of these data with computational models for the complexes was made. Freezing point depression measurements afforded molecular weights for solution-state species in agreement with the formulations proposed via NMR and mass spectrometric data. There is no evidence to support linear metallopolymer formation but data suggest that [2+2] and [1+1] metallomacrocyles were formed, with siloxane linking groups encouraging the formation of [1+1] species. Solid-state NMR spectroscopic data on [Cu(L1)](PF6) indicate the presence of two different environments for the PF6- anions.
