High-spin manganese(II) complexes of an amido/bis(phosphine) PNP ligand.
Syntheses of several Mn complexes supported by a monoanionic amido/bis(phosphino) PNP ligand (PNP = [2-P(CHMe(2))(2)-4-MeC(6)H(3)](2)N) from anhydrous MnCl(2) are reported. Treatment of (PNP)Li (2) with MnCl(2) in tetrahydrofuran (THF) led to isolation of either (PNP)Mn(mu-Cl)(2)Li(THF)(2) (5) or (PNP)MnCl (6), depending on the workup. Reaction of 6 with 2 equiv of MeLi resulted in isolation of (PNP)Mn(mu-Me)(2)Li(THF)(2) (7) that is structurally similar to 5. Reduction of 6 in the presence of pyridine produced material analytically consistent with (PNP)Mn(py)(3) (8), whereas reduction in the presence of 2,2'-bipyridine gave fully characterized (PNP)Mn(bipy) (9). Compounds 5 and 7 display magnetic moments indicative of high-spin Mn(II) (S = 5/2). The magnetic moment of 9 (S = 2) was interpreted as an antiferromagnetic combination of a high-spin Mn(II) center and a singly reduced bipyridine ligand. Addition of a single CO ligand to 9 generated diamagnetic, low-spin (PNP)Mn(bipy)(CO) (10). Solid-state structures of 5, 7, 9, and 10 were determined by X-ray diffraction methods and used in conjunction with density functional theory studies to analyze the electronic nature of the (PNP)Mn complexes under study.
Bacciu
Deborha
D
Department of Chemistry, Brandeis University, MS 015, 415 South Street, Waltham, Massachusetts 02454, USA.
Chen
Chun-Hsing
CH
Surawatanawong
Panida
P
Foxman
Bruce M
BM
Ozerov
Oleg V
OV