Varied Reactions of [M(L)]₃ with HgCl₂, FeBr₂, CeCl₃, AgOTf; Ligand Transfer, Nucleophilic Attack with Recombination and/or Fragmentation [M = Li or Na; L = N(SiMe₃){C(H)N}₃SiMe₃]

The crystalline compounds [Hg{N(R)C(H)NR}2] (1), [Fe(L)2]2 (2), [Ce(L)2Cl]2 (3), [(AlMe2)3{(N(R)C(H)NC(H)N)2C(H)NC(H)NR}] (4), and [Ag8Na{(N(R)C(H)N)2(C(H)N)4R}3] (5) were obtained from [Li(L)]3 (A) (for 1) or [Na(L)]3 (B) and HgCl2, FeBr2, CeCl3, Al(Cl)Me2, and AgOTf, respectively [L = N(R){C(H)N}3R; R = SiMe3]. Compounds 1, 2, 3, and 5 were prepared in tetrahydrofuran (THF) at 20 °C; for 4, it was C6H14 at −78 °C. NMR data for 1 showed only a single SiMe3 environment for 1, implicating a fast exchange process. Single crystal X-ray data showed dinuclear structures for 2 and 3. Each ligand [L]− in crystalline 2 was bound to each of the two Fe atoms in a κ1- or κ2-fashion, respectively, with one NSiMe3 group of the former unattached; this was consistent with VT 1H NMR spectral data indicative of fast exchange (at 313 K) between axial κ1- and equatorial κ2-N,N′-coordination to Fe. The magnetic moment for 2 in C6H6 was appropriate for high-spin octahedral Fe(II). The ligands [L]− in crystalline 3 are arranged in a helical fashion. The NMR spectra of 4 in C6D5CD3 showed that there is an equilibrium between two asymmetric structures; minor co-products were 4′, assigned as a symmetrical isomer of 4, and N(R)C(H)NR2. The anion of 5 is proposed to be identical to that of 4′. Routes to the ligands of 1, 4, 4′, and 5 are suggested; the key feature is that the ligand [L]−, unless tethered in an appropriate metal-containing matrix (as in A, B, 2, or 3), is labile because of SiMe3 mobility, fragmentation, and/or recombination.