Ta(NMe(2))(4)[N(SiMe(3))(2)] (1) undergoes the elimination of Me(3)Si-NMe(2) (2), converting the -N(SiMe(3))(2) ligand to the ═NSiMe(3) ligand, to give the imide "Ta(NMe(2))(3)(═NSiMe(3))" (3) observed as its dimer 4. CyN═C═NCy captures 3 to yield guanidinates Ta(NMe(2))(3-n)(═NSiMe(3))[CyNC(NMe(2))NCy](n) [n = 1 (5), 2 (6)]. The kinetic study of α-SiMe(3) abstraction in 1 gives ΔH(‡) = 21.3(1.0) kcal/mol and ΔS(‡) = -17(2) eu.

Reactions of the zirconium amide guanidinates (R2N)2M[(i)PrNC(NR2)N(i)Pr]2 (R = Me, M = Zr, 1; M = Hf, 2; R = Et, M = Zr, 3) with O2 or H2O give products that are consistent with the oxo dimers {M(μ-O)[(i)PrNC(NR2)N(i)Pr]2}2 (R = Me, M = Zr, 4; M = Hf, 5; R = Et, M = Zr, 6) and polymers {M(μ-O)[(i)PrNC(NR2)N(i)Pr]2}n (R = Me, M = Zr, 7; M = Hf, 8; R = Et, M = Zr, 9). Mass spectrometric (MS) analyses of the reactions of water in air with 1 and 2 show formation of the Zr monomer Zr(═O)[(i)PrNC(NMe2)N(i)Pr]2 (10), oxo dimers 4 and 5, and dihydroxyl complexes M(OH)2[(i)PrNC(NMe2)N(i)Pr]2 (M = Zr, 11; Hf, 12). Similar MS analyses of the reaction of diethylamide guanidinate 3 with water in air show the formation of Zr(═O)[(i)PrNC(NEt2)N(i)Pr]2 (13), Zr(OH)2[(i)PrNC(NEt2)N(i)Pr]2 (14), 6, and {(Et2N)Zr[(i)PrNC(NEt2)N(i)Pr]2}(+) (15). Kinetic studies of the reaction between 1 and a continuous flow of 1.0 atm of O2 at 80-105 °C indicate that it follows pseudo-first-order kinetics with ΔH(‡) = 8.7(1.1) kcal/mol, ΔS(‡) = -54(3) eu, ΔG(‡)(358 K) = 28(2) kcal/mol, and a half-life of 213(1) min at 85 °C.

No abstract

In the title compound, [Cu(C2H8N2)2(H2O)2](C7H4NO4)2, the component complex cations and organic anions inter­act by way of N—H⋯O and O—H⋯O hydrogen bonds, leading to a layered structure. The Cu atom has site symmetry .