Synthesis and Structure of Group 4 Iminophosphonamide Complexes

Abstract

The syntheses of a variety of iminophosphonamide (PN2) ligands (2a−f), the corresponding hydrochloride salts (1a−c), and a number of bis(PN2) dichloride complexes of group 4 (3a−e) and their corresponding dialkyls (5a−e) are described. A novel monosubstituted PN2 “ate” complex 4 was prepared from ligand 2f and Zr(NMe2)4 on treatment with excess Me2NH·HCl. Piano-stool PN2 zirconium dichloride complexes 6a−h were accessible on treatment of CpZr(NMe2)3 (Cp = C5H5, Cp*) with PN2 ligands 2a−e, followed by metathesis with excess Me3SiCl or Me2NH·HCl (6a−g) or at low T with ethereal HCl (6h). Dialkyl derivatives 8a−h could be prepared from 6a−h or directly from ligands 2 and CpMMe3 (Cp = C5H5, Cp*; M = Ti or Zr). The intermediate Cp(PN2)Zr(NMe2)2, precursor to 6h, rearranged to the novel terminal difluoride complexes 7a,b at room temperature. A variety of complexes 3 and 6 or their corresponding alkyl derivatives have been characterized by X-ray crystallography. In addition, the novel “ate” complex 4 and difluoride complexes 7a,b have been structurally characterized in this manner. The structures of 7a,b in the solid state reveal strong, intramolecular coordination of the NMe2 group to the metal center, resulting in eight-coordinate complexes. One of these complexes is fluxional in solution, suggesting rapid exchange of bound versus free NMe2 groups coupled with the formation of coordination stereoisomers.

Influence of N‐Substitution on the Oxidation of 2‐Pyridylmethylamines with Bis(trimethylsilyl)amides of Iron(III) – Synthesis of Heteroleptic Iron(II) 2‐Pyridylmethylamides

“…Comparable bis(benzylamido)diphenylphosphonium anions show similar P-N bond lengths between 160 and 163 pm and act as bidentate ligands at titanium and zirconium. [38] The deviation of the angles at P1 in 3 from tetrahedral geometry is smaller than Ϯ4°. The N-P-N values between 95 and 98°f or the group 4 complexes with bis(benzylamido)diphenylphosphonium ligands are much smaller.…”

The half-sandwich 18- and 16-electron arene ruthenium iminophosphonamide complexes

“…Among transition metal complexes with κ 2 -N,N-heteroallylic ligands, the iminophosphonamides bearing a coordinated R 2 P(NR′) 2 − anion (NPN) are studied fragmentarily; there have been less than a hundred of molecular structures of NPN complexes established to date, that is in sharp contrast to more than a thousand of transition metal amidinate structures, according to the Cambridge Structural Database (CSD). The IV group metals, [1][2][3][4][5][6] chromium, 7-10 nickel [11][12][13][14][15] and copper [16][17][18][19][20][21][22] iminophosphonamides are the most studied, which is due to their catalytic application in cyclopropanation, 16,21,23 olefin oligomerization [7][8][9] and polymerization. 2,6,12,15,24,25 A few platinum metal group iminophosphonamides have been reported for palladium 24 and ruthenium 26 before 2009, when we started systematic studies of these complexes.…”

Thermal Decomposition In Situ Monitoring System of the Gas Phase Cyclopentadienyl Tris(dimethylamino) Zirconium (CpZr(NMe2)3) Based on FT-IR and QMS for Atomic Layer Deposition

“…2 TGA result with chemical structure and FT-IR spectrum from 100 to 250°C of CpZr(NMe 2 ) 3 . a Chemical structure, FT-IR spectrum, b full range of 3000~700 cm −1 , c range of 3000~2750 cm −1 , and d range of 1300~700 cm −1 expected main decomposition products are summarized in Table 1 [32][33][34]. And, the mechanisms of expected main decomposition products are as follows:…”