Template synthesis of a macrocycle with a mixed NHC/phosphine donor set

Abstract

Reaction of cis-[ReCl(NHC)(CO) 4] cis-[ 1] (NHC = NH,NH-substituted saturated cyclic diaminocarbene) with diphosphine (2-F–C 6H 4) 2P–CH 2CH 2–P(C 6H 4-2-F) 2 2 yields complex fac-[Re(NHC)( 2)(CO) 3]Cl fac-[ 3]Cl. Deprotonation of the NH,NH-NHC ligand in fac-[ 3]Cl with KO tBu leads to an intramolecular nucleophilic aromatic substitution of one fluorine atom from each –P(C 6H 4-2-F) group by the NHC ring nitrogen atoms with formation of complex fac-[ 4]Cl bearing a facially coordinated [11]ane-P 2C NHC ligand. Reaction of cis-[MnBr(NHC)(CO) 4] cis-[ 5] (NHC = NH,NH-substituted saturated cyclic diaminocarbene) with diphosphine 2 yields complex [MnBr(NHC)( 2)(CO) 2] [ 6] without substitution of the bromo ligand and with the phosphine donors from the bidentate diphosphine occupying one cis and one trans position to the NHC donor.