Uncommon Anionic Dioxorhenium(V) and Neutral Monooxorhenium(V) Mixed-Ligand Complexes Containing Heterofunctionalized Phosphine Ligands:  Syntheses and Structural Characterization

Abstract

The potentially bidentate hybrid ligand (o-hydroxyphenyl)diphenylphosphine, abbreviated POH, reacted via ligand-exchange with pentavalent rhenium precursors to give a series of six-coordinate mono- and dioxo complexes. Accurate control of the metal:ligand stoichiometric ratio allowed for the isolation of the mono-substituted [ReOCl3(PO)]- (1) and [ReOCl2(PO)(PPh3)] (2) derivatives. 1 was found to be the key intermediate for the syntheses of three more types of bis-substituted compounds: anionic dioxo [ReO2(PO)2][A] (A = NBu4 (3), AsPh4 (4)), neutral monooxo [ReOX(PO)2] (X = Cl (5), Br (6), I (7)), and neutral monooxo mixed-ligand [ReOX(PO)(PNH)] [PNH = (o-amidophenyl)diphenylphosphine; X = Cl (8), Br (9), I (10)] complexes. In the mono-substituted complexes, the P,O-donors of the bidentate ligand spanned an equatorial (P) and the apical position (O) trans to the ReO linkage in a distorted octahedral arrangement. In all of the bis-substituted monooxo compounds, the second chelate ligated on the equatorial plane almost orthogonally positioned with respect to the first one, the two phosphorus donors showing a mutual cis-(P,P) orientation. Dioxo complexes retained the cis-(P,P) configuration with the bidentate ligands symmetrically coordinated on the equatorial plane normal to the trans-ReO2 core. All the complexes were characterized by various physical techniques, including IR, MS, and 1H/31P{1H} NMR. The X-ray structure of a representative compound for each category, namely [ReOCl3(PO)][NBu4] (1), [ReO2(PO)2][AsPh4] (4), [ReOCl(PO)2] (5), and [ReOCl(PO)(PNH)] (8), were determined. Crystals of 1 were monoclinic, P21/n, a = 10.840(3) Å, b = 22.167(6) Å, c = 15.210(4) Å, β = 95.91(2)°, and Z = 4; those of 4 were triclinic, P1̄, a = 12.679(7) Å, b = 13.082(7) Å, c = 19.649(8) Å, α = 82.64(4)°, β = 81.16(4)°, γ = 62.27(3)°, and Z = 2; those of 5 were orthorhombic, a = 10.225(4) Å, b = 14.208(6) Å, c = 21.771(9) Å, P212121, and Z = 4; and those of 8 were orthorhombic, a = 10.199(2) Å, b = 14.147(4) Å, c = 21.772(6) Å, P212121, and Z = 4. The four structures were solved by the Patterson method and refined by full-matrix least-squares procedures to R = 0.050, 0.063, 0.043, and 0.039 for 1, 4, 5 and 8, respectively. Both solution state (31P{1H} NMR) and solid state (X-ray) demonstrated a cis-(P,P) arrangement for each bis-substituted complex, with the Re atom at the center of a highly distorted octahedron. Detailed analyses of the IR spectra of this series of Re(V) compounds in the region 900−580 cm-1 allowed us the possibility to distinguish between symmetrical and asymmetrical bis-substituted complexes.

Mononuclear and heterodinuclear transition metal complexes of functionalized phosphines

“…The Pd-P(1) and Pd-P(2) bond distances are 2.241(1) and 2.251(1) Å , respectively. The P(1)-Pd-O(1) angle of 84.88(6)°is also comparable with the same in analogous five-membered metallacycles [10]. The chloride ion in the phosphonium salt is held by five intermolecular hydrogen bonding interactions of which two are the O-H. .…”

“…The 31 P NMR spectrum of the Table 1 Crystallographic data for complexes 8,9,10,16 (3) 18.468 (3) 11.2638 (6) 11.372(2) b 11.3395 (5) 16.6920 (8) 13.295 (2) 13.4451 (7) 11.829(2) c 15.6674 (8) 19.1080 (9) 18.867 (3) (17) involves the cleavage of a C-O (ether linkage) bond of the ligand, which forms the phenolate ion, presumably with the elimination of methoxymethylchloride as observed in the case of ruthenium complexes 10 and 11. Similar reaction of Pd(COD)Cl 2 with analogous ligand, PPh 2 C 6 H 4 OCH 3 affords the simple chelate complex, PdCl 2 (PPh 2 C 6 H 4 OCH 3 -o) 2 [2,9].…”

Heterobinuclear and Heterotrinuclear complexes of Oxorhenium(V) with Cu(II), Ni(II), Fe(III), UO2(VI) and Th(IV) in the solid state

“…Re¼O with values previously cited in the literature for similar oxorhenium(V) complexes [26][27][28][29][30][31][32].…”

Synthesis and Characterization of Some New Oxorhenium(V) Complexes with Annulene Derivatives and Their Biological Activities

“…[18,20,22,23,31,32] A new band is observed at 362 cm 21 due to n(Re -Cl). The IR spectrum of the heated product showed a band of n(Re5 5O) at 976 cm 21 , which indicates that the heated product is still a mononuclear complex.…”