Rhenium(V) Complexes Containing Mono- and Tridentate Imido Ligands: Crystal Structures, Spectroscopic Results and DFT Optimization (original) (raw)
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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.
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.
Complexes of rhenium(V) with aminoacetophenones and their reactions with some bidentate ligands
Bulletin of The Chemical Society of Ethiopia, 2002
Complexes of rhenium(V) with 2-, 3-and 4-aminoacetophenone (H2aap) have been synthesized. The reaction of trans-ReOCl3(PPh3)2 with 2-H2aap in benzene yielded the imido complex [Re(2-aap)Cl3(PPh3)], in which the oxo oxygen and one of the PPh3 groups were substituted by the dianionic imido nitrogen and the neutral ketonic oxygen, respectively. With 3-and 4-H2aap the imido complexes trans-[Re(aap)Cl3(PPh3)2] were isolated. The monodentate coordination mode of these latter two ligands was authenticated by the X-ray crystal structure of trans-[Re(3aap)Cl3(PPh3)2]; crystals are triclinic, P1, with a = 10.567(5), b = 11.989(6), c = 18.739(8) Å, α = 74.82(4)°, β = 75.27(4)°, γ = 73.15(4)°, U = 2152(2) Å 3 , Z = 2, R = 0.0469. The further reaction of [Re(3-aap)Cl3(PPh3)2] with the bidentate ligands 2-aminophenol and 8-hydroxyquinoline (HL) led to the isolation of complexes of the type [Re(3-aap)Cl2(PPh3)(L)]. However, with 1,2-diaminobenzene (H2dab), the 3-aap imido moiety was displaced by the imido group {N(C6H4)NH2}, to give the complex trans-[Re(dab)Cl3(PPh3)2].
Polyhedron, 2013
The reactions of di-2-pyridyl ketone (dpk), 2-benzoylpyridine (zpy) and 2-hydroxybenzophenone (Hbp) with [Re(CO)5Cl] (A) and trans-[ReOX3(PPh3)2] (B, X = Cl, Br) were studied. The complex fac-[Re(CO)3(dpk·OCH3)] was isolated from the reaction of A with dpk in methanol. The monoanionic tridentate chelate dpk·OCH3 was formed by the nucleophilic attack of methanol at the carbonylic carbon atom of dpk. A similar attack of water on dpk was observed in the compound cis-[ReOBr2(dpk·OH)]·2(dpkH+Br−), which was formed from dpk and [ReOBr3(PPh3)2] in acetone. The reaction of zpy with B in acetonitrile produced the complexes [ReIIIX3(zpy)(PPh3)], but in methanol as solvent the compounds [ReOX2(zpyH)(PPh3)] were isolated, where zpyH coordinates bidentately as the monoanionic ligand [C6H5(HC-O)C5H4N]−. With A as starting material the complex fac-[Re(CO)3(zpy)Cl] was isolated. The complexes cis-[ReOX2(bp)(PPh3)] were the products of the reaction of Hbp with B in acetonitrile; however, in methanol cis-[ReIIIBr2(bp)(PPh3)2] was isolated. All these complexes were characterized by conductance measurements, elemental analyses, UV–Vis, IR and NMR spectroscopy and by single crystal X-ray diffraction. DFT calculations regarding the electronic ground states show single states for all the complexes, except for the rhenium(III) complexes [ReIIIX3(zpy)(PPh3)] and [ReBr2(bp)(PPh3)2], in which the states are triplet. The DFT and experimental results are in agreement in all cases, especially the anisotropy of the Re–N bond length of fac-[Re(CO)3(dpk·OCH3)] and exact O(1)–Re–O(3) angles for [ReOX2(bp)(PPh3)].
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.
Polyhedron, 1997
Under mild conditions [ReX(CO),(THF),] reacts with pyrazolylmethylpyridines to form the complexes fat-[ReX(CO),(BPz)] and fat-[ReX(CO),(BMPz)] (X = Cl, Br, or I; BPz = 2,6-bis(pyrazol-l-ylmethyl)pyridine ; BMPz = 2,6-bis(3,5-dimethylpyrazol-1-ylmethyl)pyridine) that involve BPz and BMPz acting as non-fluxional bidentate chelate ligands. Under more severe reaction conditions fuc-[ReX(CO),(BPz)] is converted to@-[Re(CO),(BPz)]X (X = Cl, Br, or I). Trimethylplatinum(IV)iodide reacts with BPz to form fuc-[PtMe,(BPz)]I. The crystal structure offac-[ReI(CO)3(BMPz)] confirms the bidentate chelate bonding of BMPz with a N-Re-N angle of 85.8".
Inorganic Chemistry, 2002
The quadruply bonded dirhenium(III) complex (n-Bu 4 N) 2 Re 2 Cl 8 reacts with tridentate ligands that contain essentially planar P,O,P donor sets to afford the complexes Re 2 Cl 6 (η 3-L 1) (3) (L 1) bis[2-(diphenylphosphino)phenyl]ether) and (n-Bu 4 N)[Re 2 Cl 7 (η 1-L 2)] (4) (L 2) 4,6-bis(diphenylphosphino)dibenzofuran). Spectroscopic and electrochemical data support the unsymmetrical structure Cl 4 ReReCl 2 (η 3-L 1) in the case of 3, while 4 contains monodentate P-bound L 2 ; both complexes contain Re&Re bonds. The synthon cis-Re 2 (µ-O 2 CCH 3) 2 Cl 4 (H 2 O) 2 reacts with ligands L 1 , L 2 , 2,6-bis(diphenylphosphinomethyl)pyridine (L 3), bis[2-(diphenylphosphino)ethyl]amine (L 4), and N,N-bis[2-(diphenylphosphino)ethyl]trimethylacetamide (L 5) to give the paramagnetic complexes Re 2 (µ-O 2 CCH 3)Cl 4 (η 3-L n) (5−9) with Re 3.5 Re bonds. The lability of the µ-acetato ligands in 5−9 has been demonstrated by the reactions of compounds 5 (n) 1) and 7 (n) 3) with 4-Ph 2 PC 6 H 4 CO 2 H, 2-Ph 2 PC 6 H 4 CO 2 H, and quinoline-4-carboxylic acid to give complexes 10−12 (from 5) and 13−15 (from 7), respectively. These products contain uncoordinated donor atoms that can be used to produce mixed-metal assemblies. Compounds 5 and 7 also react with terephthalic acid (1,4-C 6 H 4 (CO 2 H) to give [Re 2 Cl 4 (η 3-L 1)] 2 (µ-O 2 CC 6 H 4 CO 2) (16) and [Re 2 Cl 4 (η 3-L 3)] 2 (µ-O 2 CC 6 H 4 CO 2) (17) in which electronic coupling between the paramagnetic sets of dirhenium units is very weak. Single-crystal X-ray structure determinations have been carried out on complexes 5−8, 11, 12, and 14−16.