Preparation of oxopentachlororhenate(VI) and oxotetrachlororhenate(V). The crystal and molecular structure of AsPh4ReOCl4

Abstract

From a suspension of AsPh4ReO 4 or PPh4ReO 4 in various solutions such as ethanol, methanol, acetone, chloroform, water, benzene, formic acid and others, the red compounds containing oxopentachlororhenate(VI) anions were obtained on reaction with gaseous HCI. AsPh4ReOCI 5 and PPh4ReOC15 crystallize in the space group P4/n, with similar axial lengths. From solutions of these complexes in ethanol the yellow complexes AsPhaReOC14 or PPh4ReOCI 4 could be obtained. The crystal structure of AsPh4ReOCI4 has been determined by single-crystal diffractometry. The structure was solved by the heavy-atom technique and refined by the block-diagonal least-squares method to an R = 0.059 for 1134 reflexions. In the squarepyramidal [ReOCI4I-anion the Re and O atoms lie on a fourfold axis, with Re-O and Re-CI 1.63 (3) and 2-344 (4) A respectively. The AsPh~ cation has 4 ($4) crystallographic symmetry, with As-C 1.91 (1) A and two independent C-As-C angles of 107-2 (5) and 110.6 (5) °. [Crystal data for AsPh4ReOCI4: space group P4/n, a = 13.117 (6), c ---7.358 (4) A.]

Re(v) and Re(iii) complexes with sal2phen and triphenylphosphine: rearrangement, oxidation and reduction

“…( n -Bu 4 N)(ReOCl 4 )41 and [ReCl 3 (PPh 3 ) 2 (CH 3 CN)]42 were prepared as reported in the literature. The sal 2 phen ligand was synthesized according to the literature 1…”

In vitro structure–activity relationship of Re-cyclized octreotide analogues

“…Re-cyclization of analogues 9 through 11 was carried out via transchelation reactions of Re(V) from tetrabutylammonium tetrachlorooxorhenium(V) (TBA][ReOCl 4 ]) [17] to reduced linear peptides using modified literature procedures [18, 19]. Analogues 6 – 8 were synthesized by both methods described.…”

A ‘2+2’ complex of trans-[ReO2]+ with isocyanide and triphenylphosphine

“…The crystal structure consists of two independent cations per unit cell with the associated perrhenate anions. [11][12][13][14]. The Re\C bond distances [average of 2.10(2) Å] correspond well with those in other isocyanide monooxorhenium(V) complexes [average of 2.08(2) Å], and suggest that π-back bonding from rhenium(V) to the isonitriles is not extensive [8,9].…”

“…This is the first reported dioxo isocyanide complex of rhenium(V), and it is unusual since it contains the good π-acceptor ligands PPh 3 and CNCy coordinated to the electron-deficient and hard ReO 2 + core. The trans-[ReO 2 ] + core is common for rhenium(V), and it is normally formed when ligands which are only σ-donors or poor π-donors are coordinated to the metal [11][12][13][14]. It would seem that the small cone angle of the isocyanide is essential for the stabilization of counter-ion at 904 cm − 1 .…”