Complexes of rhenium (V) with tridentate ligands having o, n and p donor atoms. The x-ray crystal structures of ReOCl2 [OC6H4-2-CH= N (CH2) 3PPh2] and its … (original) (raw)
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South African journal of chemistry, 2014
Rhenium(V) complexes containing the [ReX(PPh 3 ) 2 ] 4+ (X = Br, I) moiety were studied. The reaction of N-(2-aminophenyl)salicylideneimine (H3pna) with trans-[ReOBr3(PPh3)2] produced the complex salt [Re(pna)Br(PPh3)2]0.5Br.0.5(ReO4) (1), in which the tridentate ligand pna is coordinated via a doubly deprotonated nitrogen (as an imide), an imino nitrogen and a deprotonated phenolate oxygen atom. The reaction of trans-[ReO(OEt)I 2 (PPh 3 ) 2 ] with two equivalents of 2-aminophenol (H3ap) in ethanol led to the isolation of the ‘2+1’ complex salt [Re(Hap)(H 2 ap)I(PPh 3 ) 2 ]I (2) in good yield. TheHapligand is coordinated monodentately via the doubly deprotonated imido nitrogen, and H2ap is chelated bidentately through the neutral amino nitrogen and a deprotonated phenolate oxygen atom. The crystal structures of 1 and 2 were determined by X-ray single crystal diffraction. Spectroscopic results and DFT calculations are also reported. KEYWORDS : Rhenium(V), tridentate imido, ‘2 + 1’ ...
Inorganic Chemistry, 2008
N-[(Dialkylamino)(thiocarbonyl)]benzimidoyl chlorides react with functionalized amines such as 2-aminophenol, 2-methylaminopyridine, and 2-aminobenzoic acid in clean and high-yield procedures with the formation of the novel tridentate N-[(N′′,N′′-dialkylamino)(thiocarbonyl)]-N′-substituted benzamidine ligands H 2 L 1 , HL 2 , and H 2 L 3. By starting from (NBu 4)[MOCl 4 ] (M) Re, Tc) or [ReOCl 3 (PPh 3) 2 ] and H 2 L 1 , a series of oxorhenium(V) and oxotechnetium(V) complexes of the composition [MOCl(L 1)] were synthesized and characterized by spectroscopic methods and X-ray crystallography. The monomeric, five-coordinate compounds are air-stable and bind (L 1) 2tridentate in the equatorial coordination sphere. Dimeric products of the compositions [{ReOCl(L 2)} 2 O] and [ReOCl(L 3)] 2 were isolated during reactions with HL 2 and H 2 L 3. While dimerization in [{ReOCl(L 2)} 2 O] is established via an oxo bridge, the metal atoms in [ReOCl(L 3)] 2 are connected by the carboxylic group of the ligand, and the product represents the first example of a high-oxidation state rhenium complex displaying such a bonding feature.
Rhenium(V)−Salen Complexes: Configurational Control and Ligand Exchange
Inorganic Chemistry, 1998
Reactions of ReO(PPh 3) 2 Cl 3 with tetradentate bis(salicylideneamine) ligands, H 2 salpd (1) and H 2 salbd (2), in different alcohols gave the novel mixed-ligand rhenium complexes ReO(sal)OAlk (OAlk) variety of alkoxy ligands). Configurational studies show that the rhenium complexes ReO(salpd)OAlk (1a-f) display either a symmetrical or a nonsymmetrical configuration, depending on the size of the alcohol and its boiling point. The rhenium complexes ReO(salbd)OAlk (2a-d) are all nonsymmetrical due to the number of carbons that bridge the imine nitrogens. In the case of the symmetrical ReO(salpd)OMe (1a) complex the methoxy ligand can be exchanged for a number of ligands of different types (OAlk, OPh, SAlk, OC(O)Alk). In the newly formed complexes the original configuration was retained except for the ReO(salpd)SAlk (1i,j) complexes which were isolated in the nonsymmetrical configuration. Starting from the nonsymmetrical ReO(salpd)OPr (2c) complex, ligand exchange led to a mixture of the symmetrical and nonsymmetrical complexes, with ratios depending on the reaction time. The crystal structures of ReO(salbd)OPr (2c), and ReO(salpd)OPhOMe (1g) have been determined. ReO(salbd)OPr crystallizes in the triclinic space group P1 h, Z) 2, with a) 10.0344(16) Å, b) 10.647(2) Å, c) 11.481(2) Å, R) 86.551(15)°,) 86.998(14)°, γ) 80.112(15)°, V) 1205.1(4) Å 3 , and final R) 0.0460. Crystals of ReO(salpd)OPhOMe are orthorhombic, space group P2 1 2 1 2 1 , Z) 4, with a) 10.6222-(15) Å, b) 12.442(3) Å, c) 16.354(3) Å, V) 2161.4(7) Å 3 , and final R) 0.0371. Under the influence of traces of water a number of symmetrical complexes react to a "dimeric" structure, consisting of two ReO(salpd) moieties bridged by an oxygen atom with the bridging Re-ORe angle symmetrically imposed at 180°. [ReO-(salpd)] 2 O (3) crystallizes in the monoclinic, space group P2 1 /c, Z) 4, with a) 14.860(2) Å, b) 12.545(2) Å, c) 16.5111(17) Å,) 95.030(10)°, V) 3066.1(7) Å 3 , and final R) 0.0439.
Inorganica Chimica Acta, 2003
The ligand (2-pyridinecarboxaldehyde) benzoylhydrazone (HNN?O) has been reacted with [Rh 2 (m-Cl) 2 (CO) 4 ] in diethyl ether, isolating the carbonyl complex [Rh(k 2 -HNN?)(CO)Cl] (1), where the neutral ligand coordinates the metal through the nitrogen atoms, the amidic oxygen been excluded by the coordination sphere. Repeated attempts aimed to force the ligand to an anionic tridentate coordination, both by prior deprotonation of the free ligand or deprotonation of 1, have resulted in extensive deposition of metallic rhodium. The reaction between HNN?O and [Rh 2 (m-Cl) 2 (CO) 4 ] in basic media and in the presence of PPh 3 , has led to the isolation of the complex [Rh(k 2 -N?O)(PPh 3 )(CO)] ×/1/2CH 2 Cl 2 (2), where the anionic ligand is N?O bidentate. Compound 1 has been reacted with an excess of MeI in CH 2 Cl 2 or THF, isolating [Rh(k 2 -HNN?)(CH 3 CO)ClI] (4) and [Rh(k 2 -HNN?)(CH 3 CO)(THF)ClI] (5), respectively. Although the oxidative addition step is practically instantaneous in both cases, the migratory insertion step results faster in THF, as established by liquid film IR spectroscopy. Compound 2 has been reacted with MeI in THF isolating the complex [Rh(k 2 -N?O)(PPh 3 )(CO)(Me)I] (6), which, however, does not transform into the corresponding acyl complex. The crystal structure of complex 2 ×/1/4CH 2 Cl 2 has been solved. #
Inorganica Chimica Acta, 2002
The reaction of the rhenium(V) nitrido complex [Re(N)Cl 2 (PPh 3 ) 2 ] with the tripodal ligand N(CH 2 CH 2 PPh 2 ) 3 (NP 3 ) in THF gave [Re(N)Cl 2 (h 2 -P,P-NP 3 )] (1) in which NP 3 acts as a tridentate ligand using the nitrogen and two phosphorus donors for coordination. Refluxing 1 in a polar solvent such as ethanol produced [(h 4 -NP 3 )Re(N)Cl]Cl (2) in which NP 3 acts as a tetradentate ligand. Treatment of complex [Re(O)Cl 3 (AsPh 3 ) 2 ] containing the [Re O] 3 + core with NP 3 in THF yielded [ReCl 3 {h 3 -N,P,P-(N{CH 2 CH 2 Ph 2 } 2 {CH 2 CH 2 P(O)Ph 2 })}] (3). Complexes 1 and 3 have been characterized by single-crystal X-ray analyses.
Inorganica Chimica Acta, 2001
The complexes [ReO(SR f) 3 (PPh 3)] and [ReN(SR f) 2 (PPh 3) 2 ] [R f = C 6 F 5 (1) and (6), C 6 F 4-4-H (2) and (7), C 6 H 4-2-F (3) and (8), C 6 H 4-3-F (4) and (9) and C 6 H 4-4-F (5) and (10)] were synthesized in good yields by reacting [ReOCl 3 (PPh 3) 2 ] or [ReNCl 2 (PPh 3) 2 ] and the lead salt of the corresponding fluorobenzenethiol [Pb(SR f) 2 ]. In contrast, when the free thiol HSC 6 F 5 was employed in the presence of NEt 3 as base, the ionic species [ReO(SC 6 F 5) 4 ][NEt 3 •HCl] (11) was isolated. The X-ray crystal structure of 3 was determined.
Polyhedron, 1990
The rhenium(V) complex [Re0(02C6H,&J-has been synthesized by reaction of [ReOCl,(PPh,),] with excess catechol in methanol in the presence of triethylamine under N2. If the reaction is carried out in air the rhenium(VI1) complexes [Re02(0,C,H,R,)2]-(R = H, Bu') can be isolated with a range of cations. Cyclic voltages coupled with convolution analysis showed that the rhenium(VI1) complexes undergo a reversible diffusion-controlled one-electron reduction. The X-ray crystal structure of the rhenium(VII) derivative with R = H revealed a distorted octahedral geometry with cis-0x0 groups. Catechol complexes are well known for most of the transition elements, including iron, molybdenum, osmium, manganese and chromium and a comprehensive review has appeared.' The recent research effort in this area has in part been due to the established wide occurrence of catechol-based metal ion siderophores in biological systems. However, cat-echo1 complexes are also of intrinsic interest from the standpoint-of their redox chemistry. Catecholate? ligands are suspect in Jorgensen's classification and redox reactions may occur either at the metal centre or within the catecholate ligand. We are currently interested in the chemistry of rhenium due to its close analogy with technetium which is used extensively as a radionuclide imaging agent. Recently some six-coordinate cathecholate complexes of rhenium of the type [Re(02C,H4),J2-were *Authors to whom ux-respondence. should be addressed. f We have adopted previously suggested nomenclature in using the term catecholato-complexes as X-ray crystal structural and spectroscopic data are consistent with the dianionic bonding mode.
Synthesis and crystal structure of the first oxofree ‘3+3’ rhenium(V) complex
Inorganic Chemistry Communications, 2008
A new oxofree rhenium(V) complex salt, [Re(L 3 ) 2 ](ReO 4 )(H 2 L 3 = N-(2-aminobenzylidene)benzene-1,2-diamine), has been synthesized and characterized by single crystal X-ray structure determination, IR and NMR spectroscopy. The chelates L 3 are coordinated as dianionic tridentate N,N,N-donor diamidoimines. The rhenium(V) ion is centered in a distorted trigonal prism.