Multidentate 2-pyridyl-phosphine ligands - towards ligand tuning and chiralityElectronic supplementary information (ESI) available. CCDC 1505955-1505962. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6dt04390a

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 (R 2 N) x P(2-py) 3− x (2-py = 2-pyridyl) with alkyl as well as aryl alcohols result in the formation of (alkoxy)pyridyl-phosphines (RO) x P(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 (Et 2 N) 2 P(2-py), the stepwise introduction of alcohols enables the synthesis of racemic alkoxy-amino-phosphines (R 2 N)(RO)P(2-py), as well as alkoxy-phosphines (RO) 2 P(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) 2 P(2-py), in-corporating only one N donor atom, shows completely different coordination behaviour. The incorporation of a variety of alcohols into (amino)pyridyl-phosphine frameworks provides access to a library of multidentate (alkoxy)pyridyl-phosphines. Their coordination chemistry with Cu I is explored.