title: Multidentate 2-pyridyl-phosphine ligands - towards ligand tuning and chirality.
abstract: 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.
authors.affiliation: Chemistry Department, University of Cambridge, Lensfield Road, CB2 1EW, Cambridge, UK. dsw1000@cam.ac.uk.
authors.forename: S
authors.identifier: http://orcid.org/0000-0003-2624-7872
authors.initials: S
authors.lastname: Hanf
authors.affiliation: Chemistry Department, University of Cambridge, Lensfield Road, CB2 1EW, Cambridge, UK. dsw1000@cam.ac.uk.
authors.forename: R
authors.initials: R
authors.lastname: García-Rodríguez
authors.affiliation: Chemistry Department, University of Cambridge, Lensfield Road, CB2 1EW, Cambridge, UK. dsw1000@cam.ac.uk.
authors.forename: S
authors.initials: S
authors.lastname: Feldmann
authors.affiliation: Chemistry Department, University of Cambridge, Lensfield Road, CB2 1EW, Cambridge, UK. dsw1000@cam.ac.uk.
authors.forename: A D
authors.initials: AD
authors.lastname: Bond
authors.affiliation: Institute of Inorganic Chemistry, Faculty of Chemistry and Mineralogy, Leipzig University, Johannisallee 29, 04103 Leipzig, Germany. hey@uni-leipzig.de.
authors.forename: E
authors.identifier: http://orcid.org/0000-0003-4267-0603
authors.initials: E
authors.lastname: Hey-Hawkins
authors.affiliation: Chemistry Department, University of Cambridge, Lensfield Road, CB2 1EW, Cambridge, UK. dsw1000@cam.ac.uk.
authors.forename: D S
authors.initials: DS
authors.lastname: Wright