Rhenium(V)-nitrido complexes with different nitrogen donor bidentate ligands

Abstract

Rhenium(V)-nitridocyano complexes with 2,2′bipyridine (bipy), 1,10-phenanthroline (phen) and 2,9-dimethyl-1,10-phenanthroline (Me₂phen) are isolated for the first time and characterized by IR and X-ray crystallography as (AsPh₄)[ReN(CN)₃(2,2′bipy)]·2H₂O·0.5bipy, 2{(AsPh₄)[ReN(CN)₃(phen)]·0.5H₂O·0.54EtOH·0.46MeOH and (PPh₄)[ReN(CN)₃(Me₂phen]·H₂O·Me₂phen. The rhenium anions in all three structures have a distorted octahedral geometry with the Re(V) atom coordinated by a terminal nitrido ligand, three carbon atoms of the cyanide ligands and bidentate ligands that are bonded bidentally via two pyridine nitrogen atoms. The bidentate ligands coordinate to the Re(V) metal centre via two nitrogen atoms and form five-membered chelate rings with bite angles of 71.37(9)°, 72.7(2)° and 70.7(3)° for the bipy, phen and Me₂phen complexes, respectively. Principal dimensions are: bipy: Re≡N = 1.651(3), Re–N(11) = 2.144(1), Re–N(12) = 2.374(2), Re–C(1) = 2.025(4), Re–C(2) = 2.142(4) and Re–C(3) 2.080(3) Å; phen: Re≡N = 1.674(5), Re–N(11) = 2.164(5) Å, Re–N(12) = 2.374(5) Å, Re–C(1) = 2.112(6), Re–C(2) = 2.082(6) and Re–C(3) 2.102(6) Å; Me₂phen: Re≡N = 1.634(9), Re–N(11) = 2.190(7) Å, Re–N(22) = 2.454(8), Re–C(1) = 2.074(9) Å, Re–C(2) = 2.095(10) Å and Re–C(3) 2.094(10) Å. One of the major differences between the complexes of phen and Me₂phen is that the latter exhibits a fluxional behaviour, while the phenanthroline plane in the phen complex is almost coplanar with the coordination plane. This pronounced distortion in the Me₂phen complex is illustrated by the dihedral angle of 117°(2) between the plane of the chelating moiety and that of the square-planar coordination plane.