Synthesis and Crystallographic Characterization of New Manganese(I) Complexes of Donor-Functionalized Indenes

Treatment of 1-PiPr2-2-NMe2-indene (2[H]) with BrMn(CO)5 provided κ2-P,N-(2-NMe2-3-PiPr2-indene)Mn(CO)3Br (4) in 73% yield. Addition of either AgBF4 or AgSO3CF3 to 4 yielded
the corresponding inner-sphere tetrafluoroborate (5a) and triflate (5b) complexes in 62%
and 65% yield, respectively. Deprotonation of 4, 5a, or 5b produced an intractable mixture
of products. The cationic complex [κ2-P,N-(2-NMe2-3-PiPr2-indene)Mn(CO)4]+BF4- (6) was
prepared in 30% yield by treating BrMn(CO)5 with AgBF4, followed by the addition of 2[H].
The benzocymantrene η5-[2]Mn(CO)3 was prepared in 56% yield via reduction of η5-(2-NMe2-3-P(S)iPr2-indenyl)Mn(CO)3 with Cl3SiSiCl3. Compound 2[Li] reacts with BrMn(CO)5 to give
a complex product mixture, from which 4 and [κ2-P,N-(2-NMe2-3-PiPr2-indene)Mn(CO)4]+[Mn2(CO)8(μ-PiPr2)]- (7) were isolated. 2-Dimethylaminoindene (1[H]) was silylated to give
1-SiMe3-2-NMe2-indene (8[H]) in 93% yield. Treatment of 8[Li] with ClPiPr2, followed by
the addition of BrMn(CO)5, afforded κ2-P,N-(1-SiMe3-2-NMe2-3-PiPr2-indene)Mn(CO)3Br (10)
in 27% yield. Alternatively, addition of 8[Li] to BrMn(CO)5 followed by the addition of
ClPiPr2 generated a mixture of products, from which the substituted 1,1‘-biindene rac-(2-NMe2-3-SiMe3-C9H5)2 (rac-12) was isolated. Treatment of 1[Li] with BrMn(CO)5 provided
η5-(2-NMe2-indenyl)Mn(CO)3 (11) in 41% yield. Single-crystal X-ray diffraction data for
4·0.5C7H8, 5a·0.5C7H8, 5b, 6, η5-[2]Mn(CO)3, 7·0.5C7H8, 10, 11, and rac-12 are reported.