First transition-metal complexes of SP(NHBut)3

Simple entry into N-tert-butyl-iminophosphonamide rare-earth metal alkyl and chlorido complexes

New series of rare-earth metal dialkyls [(NPN^tBu)Ln(CH₂SiMe₃)₂(THF)_n] (Ln = Sc,n= 0 (2), Ln = Y,n= 1 (3)) and monoalkyls [(NPN^tBu)₂Ln(CH₂SiMe₃)] (Ln = Y (4), Nd (6), Sm (7)), [(NPN^tBu)₂Sc(THF)CH₃] (5) are achieved by protolysis of highly basic ligand Ph₂P(N-tBu)(NH-tBu) = (NPN^tBu)H (1). Further alkyl abstraction, alkyl/Cl exchange reactions and X-ray structure analyses of thus obtained new complexes are presented.

Facile formation of stable tris(imido)phosphate trianions as their tri- and hexanuclear Pd(II) complexes in protic solvents

Employing Pd(OAc)2, a facile deprotonation route to access the highly basic tris(alkylimido)phosphate trianions, [(RN)3PO](3-) (R = (t)Bu, (c)Hex, or (i)Pr), analogous to the orthophosphate (PO4(3-)) ion in polar and in protic solvents has been achieved. Trinuclear and prismatic Pd(II) clusters of these imido trianions having the formula {Pd3[(NR)3PO](OAc)3}n (n = 1 or 2) or as mixed-bridged clusters of the type {Pd3[(N(i)Pr)3PO](OAc)2(OR')}2 (R' = Me or H) were isolated exclusively in all these reactions in which the trianionic species acts as a tripodal chelating ligand to the trinuclear Pd3 unit. Reactivity studies aiming at the Pd(II) atoms in these clusters with nucleophilic reagents, such as primary amines (R″NH2), have led to a new trimeric cluster with the formula {Pd3[(NR)3PO](OAc)3(R″NH2)3} in which the tripodal coordination of the Pd-Nimido moieties remained unaffected, exemplifying the robustness of the Pd3 unit in all these clusters. We have also shown the catalytic activity of these Pd(II) complexes in Mizoroki-Heck type coupling reactions in the presence of Cu(OAc)2.

Synthesis, structure, and paramagnetism of manganese(II) iminophosphate complexes

The coordination chemistry of the bidentate bis(imino)bis(amino)phosphate ligands [Me(3)SiN═P{NR}{N(H)R}(2)](-), where R = n-propyl is [L(1)H(2)](-), R = cyclohexyl is [L(2)H(2)](-), and R = tert-butyl is [L(3)H(2)](-), with manganese(II), is described. The bis(imino)bis(amino)phosphate-manganese(II) complexes [(η(5)-Cp)Mn(μ-L(1)H(2))](2) (1), [Mn(L(2)H(2))(2)]·THF (2·THF), and [(η(5)-Cp)Mn(L(3)H(2))] (3) were synthesized by monodeprotonation of the respective pro-ligands by manganocene, Cp(2)Mn. The molecular structures of 1-3 reveal that the steric demands of the ligand N-substituents play a dominant role in determining the aggregation state and overall composition of the manganese(II) complexes. The coordination geometries of the Mn(II) centers are six-coordinate pseudotetrahedral in 1, four-coordinate distorted tetrahedral in 2, and five-coordinate in 3, resulting in formal valence electron counts of 17, 13, and 15, respectively. EPR studies of 1-3 at Q-band reveal high-spin manganese(II) (S = 5/2) in each case. In the EPR spectrum of 1, no evidence of intramolecular magnetic exchange was found. The relative magnitudes of the axial zero-field splitting parameter, D, in 2 and 3 are consistent with the symmetry of the manganese environment, which are D(2d) in 2 and C(2v) in 3.