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The reaction of the benzothiazole derivatives N -phenyl- N -(2-benzothiazole)thiourea (Hpbt), 1-(1,3-benzothiazol-2-yl)-3-benzoylthiourea (Hbbt), methylbenzothiazol-2-ylidenecarbamodithioate (Hmby) and N -(benzothiazol-2-yl)- S , S ′-dimethyldithiocarboimine (Hbdc) with [Re(CO) 5 Cl] led to the isolation of the neutral complexes of the type [Re(HL)(L)(CO) 3 ] (HL = Hpbt ( 1 ), Hmby ( 3 )) and [ReCl(HL)(CO) 3 ] (HL = Hbbt ( 2 ), Hbdc ( 4 )). In these complexes the ligands L act as monoanionic bidentate N,S-donor chelates, and HL is coordinated in a monodentate manner via the neutral sulfur atom only. The formation of 1 and 3 is due to the ease of thione-thiol tautomerization of the ligands Hpbt and Hmby. The crystal structures of the complexes were determined by X-ray single crystal diffraction. In addition, infra-red, 1 H NMR and electronic properties are also reported. [ABSTRACT FROM AUTHOR]

The reaction of trans -[ReOCl 3 (PPh 3 ) 2 ] with 1-(1,3-benzothiazol-2-yl)-3-benzoylthiourea (Hbbt) in methanol led to the isolation of the complex [ReOCl 2 (cbt)(PPh 3 )] ( 1 ). It contains the monoanionic bidentate chelate N -((benzothiazol-2-ylamino)methylene)benzamide (cbt). The new ligand cbt is coordinated via a neutral ketonic oxygen and an anionic imino-acyl carbon atom, and was formed by the abstraction of the thionyl sulfur of Hbbt by a triphenylphosphine of the starting complex, with S = PPh 3 also been formed as by-product. Compound 1 was characterized by elemental analysis, FTIR, proton NMR and single crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

The rhenium(V) complexes [ReCl 3 ( t -BuNC)(L)(PPh 3 )] ( 1 – 3 ) were isolated by the reaction of trans -[Re III Cl 3 ( t -BuNC)(PPh 3 ) 2 ] ( t -BuNC = tert -butyl isocyanide) with the ligands H 2 L (H 2 L = aniline ( 1 ), o -phenylenediamine ( 2 ), anthranilic acid ( 3 )). In all these complexes the dianionic ligands L are coordinated monodentately as the imide. However, unexpectedly, with 2-aminophenol the complexes [Re V Cl 2 ( t -BuNC)(L)(PPh 3 ) 2 ](ReO 4 ) ( 4 ) and the novel [Re III Cl 2 ( t -BuNC)(ibq)(PPh 3 ) 2 ] ( 5 ) (ibq − = 2-iminobenzoquinonate, the two-electron oxidized form of HL − ) were identified as the products. These complexes were characterized by single crystal X-ray crystallography, 1 H NMR spectrometry, IR and electronic spectroscopy, and cyclic voltammetry. To complement the experimental data, density functional theory (DFT) and time-dependent DFT methods were used to have a deeper understanding into the molecular parameters and infrared and electronic spectra of these complexes. [ABSTRACT FROM AUTHOR]

The reaction of 5-amino-orotic acid (H 2 aor) with trans -[ReOBr 3 (PPh 3 ) 2 ] in 2-propanol produced the complex [Re V (apd)Br(aor)(PPh 3 ) 2 ] ( 1 , apd 2 − = 5-imidopyrimidine-2,4-dione). The ligand apd 2 − was formed by the decarboxylation of H 2 aor, and it is coordinated via the dinegative imido nitrogen only. The Schiff base derivative of H 2 aor, salicylimine-orotic acid {5-(2-hydroxy-benzylideneamino)-1,2,3,6-tetrahydro-2,6-dioxopyrimidine-4-carboxylic acid; H 2 sor}, was also decarboxylated in the reaction with trans -[ReOI 2 (OEt)(PPh 3 ) 2 ] in ethanol to form [Re III (cor)I(PPh 3 ) 2 ]I ( 2 , Hcor = 5-(2-hydroxybenzylideneamino)-pyrimidine-2,4(1H,3H)-dione). Decarboxylation of H 2 sor was not observed in its reaction with trans -[ReOCl 3 (PPh 3 ) 2 ], which led to the isolation of [ReOCl(sor)(PPh 3 )] ( 3 ), in which sor 2 − is coordinated as a tridentate ligand as expected. Spectroscopic results and the X-ray crystal structures of compounds 1 – 3 are also presented. [ABSTRACT FROM AUTHOR]

The heating of cis -[ReO 2 I(PPh 3 ) 2 ] at reflux in benzene in air led to the isolation of the rhenium(VI) complex [ReO 2 I 2 (PPh 3 ) 2 ] ( 1 ). The compound is centrosymmetric around the octahedrally coordinated rhenium center, and the Re O bond length of 1.797(2) Å is longer than in typical trans -dioxorhenium(V) complexes. The asymmetric Re O stretching frequency occurs at 744 cm − 1 . Density functional theory has been used for the calculation of the vibrational spectrum density which confirms the experimental asymmetric Re O stretching frequency. DFT calculation within the polarizable continuum model shows that complex 1 is more stable in CH 2 Cl 2 than in the gas phase. EPR spectroscopy confirms a single d electron in 1 . The crystal structure was determined by X-ray single crystal diffraction. In addition, infra-red, redox and electronic properties are also reported. [ABSTRACT FROM AUTHOR]

The reaction of the rhenium(V) complex cis-[ReO2I(PPh3)2] with 2-aminothiophenol (H2atp), benzene-1,2-dithiol (H2tdt) and 2-hydroxybenzenethiol (H2otp) led to the formation of the rhenium(III) complexes [Re(Hatp)(ibsq)2]·OPPh3, [Re(sbsq)3]·OPPh3 and [Re(obsq)3]·OPPh3 (ibsq=2-iminothiobenzosemiquinonate, sbsq=1,2-dithiobenzosemiquinonate, obsq=2-hydroxothiobenzosemiquinonate) respectively. These paramagnetic complexes were characterized by single crystal X-ray crystallography, 1H NMR spectrometry, IR and electronic spectroscopy, and cyclic voltammetry. To complement the experimental data, density functional theory (DFT) and time-dependent DFT were successfully used to investigate the structural, molecular, infrared and electronic spectra of these three complexes. [ABSTRACT FROM AUTHOR]

Abstract: The reactions of [Re(CO)5Br] with the potentially bidentate ligands N,N-dialkylbenzoylthiourea (HL1) and its N,N-diphenyl derivative (HL2) were studied. In the complex fac-[Re(CO)3(HL1)2Br] (1) the two neutral HL1 ligands are coordinated in a monodentate manner via the thiourea sulfur atom. Coordination of the monoanionic chelate L2 occurs through the neutral benzoyl oxygen atom and the anionic sulfur atom, which also acts as a bridge to the second metal centre, in the dimeric complex [Re2(CO)6(L2)2] (2). The crystal structures of 1 and 2 were determined by X-ray single crystal diffraction. UV–vis absorption spectra of the complexes show the intraligand and MLCT transitions. [Copyright &y& Elsevier]

Abstract: The reactions of 2-hydroxybenzhydrazide (salicylhydrazide; Hshz) with trans-[ReOX3L2] (X=Cl (a), Br (b); L=PPh3] in acetonitrile and acetone were studied. With a in acetonitrile, the rhenium(III) complex [ReCl2(shz)(NCCH3)L2] (1), with shz coordinated as a monodentate diazenide, was isolated. However, with b in acetonitrile, the oxorhenium(V) dimer (μ-shd) [ReOBr(OPPh3)]2 (2) was formed. The bridging ligand shd4− was formed by the condensation of two shz ligands, with the elimination of hydrazine. In acetone, the reaction of Hshz with a produced [ReOCl2(sha)L] (3), in which the bidentate Schiff base ligand sha− was formed by the condensation of shz with acetone. The spectral and X-ray crystallographic characterization of complexes 1–3 are reported. [Copyright &y& Elsevier]

Abstract: The reactions of bis(benzothiazol-2-ylethyl)sulfide (bts) and its benzimidazole analogue (btn), both with a N2S-donor atom set, with [Re(CO)5Br] and cis-[ReO2I(PPh3)2] were studied. The X-ray crystal structure of fac-[Re(CO)3(bts)Br] shows that bts acts as a bidentate NS-donor ligand, with a free uncoordinated benzothiazole group. With rhenium(V) the dimer (μ-O)2[Re2O2(btn)2]I2 was isolated, in which btn acts as a tridentate N2S chelate to each metal centre. Each oxo-bridge is unsymmetrical, with unequal Re-O distances. [Copyright &y& Elsevier]

Abstract: A series of rhenium(I) tricarbonyl complexes, containing bidentate derivatives of aniline, was synthesized and structurally characterized. With 1,2-diaminobenzene (Hpda) the ‘2+1’ complex salt fac-[Re(CO)3(Hpda)2]Br was isolated. The neutral complex [Re(CO)3(Hapa)Br] was formed with 2-aminodiphenylamine (Hapa) as ligand. 2-Aminophenol (Hopa) also produced the neutral ‘2+1’ complex [Re(CO)3(opa)2(Hopa)], but with 2-mercaptophenol (Hspo) the bridged dimer [Re2(CO)7(spo)2] was found. In the complex [Re(CO)3(Htpn)Br] (Htpn=N′-{(2-methylthio)benzylidene}benzene-1,2-diamine) the potentially tridentate ligand Htpn is coordinated via the methylthio sulfur and imino nitrogen atoms only, with a free amino group. [Copyright &y& Elsevier]

The reaction of [ReCl 3 (MeCN)(PPh 3 ) 2 ] with 2-mercapto-orotic acid (H 2 moa) in ethanol led to the isolation of the multiply-bridged dimer ( μ -Cl)( μ -O)( μ -moa) 2 [Re III Re IV (PPh 3 )] 2 ( 1 ). The compound has a Re Re bond distance of 2.5425(7) Å with a formal bond order of 2.5. The dianionic bridging ligands moa 2 − coordinate bidentately via a neutral pyrimidine nitrogen and carboxylate oxygen to one Re ion, and monodentately through a thiolate sulfur to the second metal ion. Complex 1 was characterized by FTIR, electronic spectroscopy, cyclic voltammetry, microanalysis and single crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

Abstract: The oxo-bridged dinuclear rhenium(V) complex [(μ-O){ReOCl(amp)}2] (1) was prepared by the reaction of trans-[ReOCl3(PPh3)2] and 6-amino-3-methyl-1-phenyl-4-azahept-2-ene-1-one (Hamp) in acetone. The characterization of 1 by elemental analysis, infrared and 1H NMR spectroscopy and X-ray crystallography shows that amp is coordinated as a monoanionic NNO-donor chelate as an amino-amido ketone. However, the reaction of the similar ligand 7-amino-4,7-dimethyl-5-aza-3-octen-2-one (Hada) with [Re(CO)5Br] produced fac-[Re(CO)3Br(Hada)], with Hada coordinated as a neutral bidentate N,N-donor amino-imino-ketone. [Copyright &y& Elsevier]

The cationic complex [ReO(ahp)2(PPh3]+ was isolated as the chloride salt from the reaction of trans- [ReOCl3(PPh3)] and 2-amino-3-hydroxypyridine (Hahp) in ethanol. Coordination of the chelates only occurs through the amino nitrogen and the phenolate oxygen of ahp-. The X-ray crystal structure shows a distorted octahedral geometry, in which a phenolate oxygen coordinated trans to the oxo group and the rhenium atom is displaced by 0.2520(1) Å out of the mean equatorial plane towards the oxo oxygen. [ABSTRACT FROM AUTHOR]

The complex [ReO(Hamb)(H2amb)(PPh3)](1) was prepared by the reaction of csi-[ReO2I(PPh3)2] with two equivalents of 2-amino-3-methylbenzoic acid (H3amb) in toluene under reflux conditions. Crystallographic data show that 1 contains the coordinated amidobenzoate chelate (Hamb) and symmetrically chelating carboxylate ion (H2amb) in a pseudo-octahedral geometry. [ABSTRACT FROM AUTHOR]

The reaction of a twofold molar excess of 2-aminothiophenol (H2L) with trans-[ReOCl3(PPh3)2] in benzene led to the isolation of the oxo-free rhenium(V) complex [ReCl(PPh3)L2] (1), IR, ¹H NMR and X-ray crystallographic results indicate that the ligands L coordinate in a dianionic form to the metal and that the complex has the unusual skew-trapezoidal bipyramidal geometry. The ligands L have an average bite angle of 78,8(1)°, with average Re-N and Re-S bond lengths equal to 1,978(5) and 2,297(1) A, respectively. [ABSTRACT FROM AUTHOR]

The complex [ReOI 2 (ame)(PPh 3 )] (Hame=2-(2-aminophenyl)ethanol) was prepared from trans -[ReOI 2 (OEt) (PPh 3 ) 2 ] and Hame in benzene. It contains an unusually long Re=O bond (1.717(5) Å) and a large trans O=Re-O (ethanolate) bond angle of 171.4(2)°. [ABSTRACT FROM AUTHOR]

The complex [ReOCl 2 (OEt)(dpa)] was prepared by reaction of trans -[ReOCl 3 (PPh 3 ) 2 ] with a twofold molar excess of 2,2′-dipyridylamine (dpa) in ethanol under an inert atmosphere. Its X-ray crystal structure shows that the N , N -chelated dpa ligand is coordinated in the equatorial plane cis to the oxo and ethoxo groups, which are in trans positions relative to each other. The two pyridine rings of dpa are folded around the bridging nitrogen atom away from the oxo oxygen atom. [ABSTRACT FROM AUTHOR]

The complex [Re(ddcat) 3 ] (H 2 ddcat = 3,5-di- tert -butylcatechol) was prepared by the reaction of either cis -[Re V O 2 I(PPh 3 ) 2 ] or ( n -Bu 4 N)[Re V OCl 4 ] with H 2 ddcat in toluene in air. X-ray structure determination of the product unequivocally illustrates that the bidentate chelates are in the catecholato rather than the semiquinone form and that the metal has a formal oxidation state of +VI. [ABSTRACT FROM AUTHOR]

The reaction of cis-[ReO2I(PPh3)2] with 3-methyl-2-aminophenol (H2map) in ethanol led to the formation of trans-[Re(map)(Hmap)I(PPh3)2]I. The X-ray crystal structure shows that the ligand map is coordinated monodentately through the doubly deprotonated amino nitrogen and is therefore present as an imide. The chelate Hmap is coordinated via the neutral amino nitrogen and the singly deprotonated phenolate oxygen, which is coordinated trans to the imido nitrogen. In benzene equimolar quantities of cis-[ReO2I(PPh3)2] and 4-methyl-2-aminophenol (H2amp) produced the five-coordinate cis-[ReO2(Hamp)(PPh3)]. A twofold molar excess of 2-aminophenol (H2ap) yielded the six-coordinate [ReO(Hap)(ap)(PPh3)]. The chelate ap is coordinated through the deprotonated phenolate oxygen and the singly deprotonated amino nitrogen (amide). [Copyright &y& Elsevier]

The reaction of a twofold molar excess of 2-amino-3-methylbenzoic acid (H 3 amb) with cis -[ReO 2 I(PPh 3 ) 2 ] in ethanol led to the isolation and characterization of the six-coordinate [Re(amb)(OEt)I(PPh 3 ) 2 ] ( 1 ). The X-ray crystal structure of 1 illustrates that the trianionic ligand amb acts as a bidentate chelate via the doubly deprotonated amino nitrogen, which is present in 1 as an imide, and the deprotonated acetoxy oxygen. The Re=N bond length is 1.751(3) Å, and the Re=N-C angle [143.6(3)°] deviates considerably from linearity. [ABSTRACT FROM AUTHOR]

Cationic distorted octahedral complexes [ReOCl(OEt)(L)(PPh 3 )]X {L = 2-(1-ethylaminomethyl)-1-methylimidazole (eami), 2-(1-methylaminomethyl)-1-methylimidazole (mami), 2-(1-ethylthiomethyl)-1-methylimidazole (etmi); X=ReO 4 , PF 6 } were prepared by reaction of trans -[ReOCl 3 (PPh 3 ) 2 ] with a twofold molar excess of L in ethanol under anaerobic conditions. X-ray structure determinations of [ReOCl(OEt)(eami)(PPh 3 )](ReO 4 ) ( 1a ) and its etmi equivalent ( 3a ) were performed. In 1a coordination of the chloride occurs trans to the imidazole nitrogen. However, in 3a the chloride is coordinated trans to the ethereal sulfur donor of etmi. [ABSTRACT FROM AUTHOR]

The reactivity of oxorhenium(V) precursors with the potentially N , N -donor ligand 2,2′-dipyridylamine (dpa) has been investigated. Reaction of a two-fold molar excess of dpa with trans -[ReO(OEt)Cl 2 (PPh 3 ) 2 ] in ethanol led to the isolation of [ReOCl 2 (OEt)(dpa)] ( 1 ). Spectroscopic measurements indicate that dpa is coordinated as a bidentate in the equatorial plane cis to the oxo group, with the ethoxide in the trans position. Treatment of trans -[ReOCl 3 (PPh 3 ) 2 ] with a tenfold molar excess of dpa in ethanol at reflux yielded the trans -dioxo complex [ReO 2 (dpa) 2 ]Cl ( 2 ), but with a twofold molar excess (μ-O)[{ReOCl 2 (dpa)} 2 ] ( 3a ) was isolated. The latter reaction with ( n -Bu 4 N)[ReOCl 4 ] as starting material in ethanol at room temperature led to a dark green product, also with the formulation (μ-O)[{ReOCl 2 (dpa)} 2 ] ( 3b ). These compounds were characterised by common spectroscopic techniques, and the crystal structures of 2 ·3H 2 O, 3a and 3b ·2DMSO were determined. The structure of 3b presents a nearly linear O=Re-O-Re=O group, with the two [ReOCl 2 (dpa)] halves of the dimer rotated by 180.0° about the Re-O-Re fragment away from an eclipsed conformation. In 3a , the two halves are only rotated by 61.4°. [ABSTRACT FROM AUTHOR]

The reaction of trans -[ReOBr 3 (PPh 3 ) 2 ] with 5-amino-orotic acid (H 2 aoa) in ethanol led to the isolation of the triply-bridged dimer [Re IV 2 (μ-O)(μ-Br)(μ-aoa)Br(OEt) 2 (PPh 3 ) 2 ] ( 1 ). The compound has a Re Re bond distance of 2.5526(4) Å. The dianionic bridging ligand aoa coordinates bidentately via an amido nitrogen and carboxylate oxygen to one Re ion, and monodentately through a neutral carbonylic oxygen to the second metal ion. Density functional theory (DFT) calculation shows that the presence of the rhenium atoms leads to a noncollinear spin phase arrangement for the bridging atoms. [ABSTRACT FROM AUTHOR]

[Display omitted] • Five novel rhenium(I) complexes were synthesized. • All complexes were characterized fully by 1H NMR, FTIR, UV–Vis and X-ray diffraction. • A rare four-membered Re 2 Cl 2 bridging ring was observed. • The ligands all coordinated in a monodentate fashion. The reactivity of the rhenium(I) precursor fac -[Re(CO) 5 Cl] with various benzo-fused ligands were studied. 2-Aminobenzothiazole (abt), mercaptobenzimidazole (mbi), N -(1,3-benzothiazol-2-yl)-2-chloroacetamide (bct), ethyl-(1 H -benzimidazol-2-yl-sulfanyl)acetate (bsa) and (dibenzothiazol-2-yl)tetraazathiapentalene (dbt) were chosen as the ligands of interest, where all ligands coordinated in a monodentate mode. The novel complexes isolated were fully characterized, with abt, mbi and dbt (L) resulting in rhenium complexes of the type fac -[ReCl(L) 2 (CO) 3 ]. However, the ligands bct and bsa produced [ReCl(bct)(CO) 3 (NCMe)] and the bridged species (µ-Cl) 2 [Re(bsa)(CO) 3 ] respectively. [ABSTRACT FROM AUTHOR]

Abstract: The products of the reactions of [Re(CO)5Cl] with 1-(benzothiazol-2-ylidene)-3-methylthiourea (Hmbt) and bis{1,2-(benzothiazol-2-ylidene)}thiourea (Hdbt) were studied. The X-ray crystal structure of (μ-mbt)2[Re(CO)3]2 shows that bridging between the two metal centres occurs via the two thiolic sulfur atoms of the two mbt ligands. One mbt ligand is also coordinated via a benzothiazole nitrogen atom to a rhenium(I) atom, with the second mbt ligand attached to the metal via a thiourea imino nitrogen. In the complex (μ-dbt)2[Re(CO)3]2, each dbt ligand bridges two metal centres in a ‘2+1’ manner, with each rhenium atom in a N2SC3 donor atom set. [Copyright &y& Elsevier]

The reaction of pyrazole-benzothiazole hybrids towards [Re(CO) 5 Cl], trans -[ReOCl 3 (PPh 3) 2 ] and cis -[ReO 2 I(PPh 3) 2 ] were studied. The structures of the rhenium(I) and rhenium(V) complexes were determined by X-ray diffraction methods and confirmed spectroscopically. The reaction of the pyrazole-benzothiazole hybrids 2-(3,5-dimethylpyrazol-1-yl)benzothiazole (dmp) and 2-(2-benzothiazolyl)-4,5,6,7-tetrahydro-2 H -indazol-3-ol (Hbth) with [Re(CO) 5 Cl] resulted in the formation of neutral complexes with the general formula [ReCl(CO) 3 (HL)] (HL = dmp (1), Hbth (2)). 1-(Benzo[ d ]thiazol-2-yl)-4-methyl-1 H -pyrrol-2-ol (Hbtm) gave the trimeric species [Re(btm)(CO) 3 ] 3 (3) by reaction with [Re(CO) 5 Cl]. Reaction with [ReVOCl 3 (PPh 3) 2 ] led to the isolation of the oxo-bridged dimeric compound (µ-O)[ReOCl 2 (dmp)] 2 (4) and [ReOCl(bth)(bth 1)] (5) [bth 1 = 2-(benzo[ d ]thiazol-2-yl)-1,2,4,5,6,7-hexahydro-3 H -indazol-3-one] by reaction with dmp and Hbth, respectively. The reactivity of Hbtm with trans -[ReOCl 3 (PPh 3) 2 ] in ethanol gave [ReOCl(btm)(btm 1)] (6) [btm 1 = 2-(benzo[ d ]thiazol-2-yl)-5-methyl-1,2-dihydro-3 H -pyrazol-3-one], whereas [ReOCl(btm 1)(btz)] (7) [btz = 1-(benzo[ d ]thiazol-2-yl)-4-(1-iminoethyl)-3-methyl-1 H -pyrazol-5ol] formed in acetonitrile using the same reactants. The rhenium(V) complexes [ReO(OMe)(btm)(btm 1)] (8) and [ReO(OEt) 0.96 (I) 0.04 (btm)(btm 1)] (9) were isolated upon reacting Hbtm with cis -[ReO 2 I(PPh 3) 2 ] in methanol and ethanol, respectively. The structures of complexes 1 – 9 were determined by X-ray diffraction methods and confirmed spectroscopically. [ABSTRACT FROM AUTHOR]

Reports on the metal-promoted nucleophilic addition of water to coordinated 2,3-bis(2-pyridyl)benzoquinoxaline (BBQ) in rhenium (V) complexes. Reaction of BBQ with ReOCl4-; Synthesis of ReOCl2(BBQ;OH); Formation of a planar seven-membered ring between rhenium and BBQ; Coordination of BBQ with metal ions.

The reaction of trans -[ReOBr 3 (PPh 3 ) 2 ] with 6-hydroxypicolinic acid (H 2 hpa) in ethanol led to the isolation of the Re IV Re IV dimer ( μ -O)( μ -hpa) 2 [Re 2 Br(OEt)(PPh 3 ) 2 ] ( 1 ). Each hpa 2− anion acts as a bridging ligand with the coordination of a neutral pyridol oxygen to one rhenium ion, and the coordination of a carboxylate oxygen and a pyridinate nitrogen to the other rhenium ion. By using [ReOCl 3 (PPh 3 ) 2 ] as precursor in ethanol, two products were isolated, i.e. (μ-Cl)(μ-O)(μ-hpa)[Re IV 2 Cl 2 (OEt)(PPh 3 ) 2 ] ( 2 ) and [Re III Cl 2 (Hhpa)(PPh 3 ) 2 ] ( 3 ). The complexes cis -[ReOX 2 (Hhpa)(PPh 3 )] (X = Br ( 4 ); Cl ( 5 )) were the only products formed by the reaction of [ReOX 3 (PPh 3 ) 2 ] with H 2 hpa in acetonitrile. The bromide equivalent of 3 , i.e. [Re III Br 2 (Hhpa)(PPh 3 ) 2 ] ( 6 ), was obtained from the reaction of [ReOBr 3 (PPh 3 ) 2 ] with H 2 hpa in 2-propanol. Coordination of Hhpa − in 3 – 6 occurs through the carboxylate oxygen and neutral pyridyl nitrogen. In addition to the X-ray crystal structures, infra-red, 1 H NMR, electrochemical and electronic properties are also reported. [ABSTRACT FROM AUTHOR]

The ligand-bridged dimers [Re(CO) 3 (μ-H 2 salet)] 2 ( 1 ) and [{Re(CO) 3 } 2 (μ-salpd)] ( 2 ) are formed by the reactions of [Re(CO) 5 Cl] with the potentially heptadentate Schiff base 2,2′,2″-tris(salicylideneimino)triethylamine (H 3 salet) and the hexadentate N 1 -(3-(2-hydroxybenzylidene-amino)propylamino)ethyl)-benzylidenepropane-1,3-diamine (H 2 salpd) respectively. In 1 , the two H 2 salet ligands bridge two fac -[Re(CO) 3 ] + moieties. Mono-dentate coordination is by a neutral phenone oxygen atom, generated by the conversion of one salicylideneimine entity to an iminium zwitter-ion. In 2 each fac -[Re(CO) 3 ] + core resides in a ‘3 + 0’ environment. In both complexes π–π interaction between the phenolate rings contribute to the stability. The crystal structures of 1 and 2 were determined by X-ray single crystal diffraction. Spectroscopic results are also reported. [ABSTRACT FROM AUTHOR]

The reaction of orotic acid (H 2 or) with trans -[ReOBr 3 (PPh 3 ) 2 ] in ethanol produced the triply-bridged dimer ( μ -Br)( μ -O)( μ -or)[Re IV 2 Br(OEt) 2 (PPh 3 ) 2 ] ( 1 ). In 2-propanol as solvent the product ( μ -Br)( μ -O)( μ -or)[Re IV 2 Br 2 (OPr i )(PPh 3 ) 2 ] ( 2 ) was isolated. In order to eliminate the oxo group as a bridging ligand, the imido-coordinated [Re V {=NC 6 H 4 (2-NH 2 )}Br 3 (PPh 3 ) 2 ] was reacted with H 2 or to give the monomer [Re{NC 6 H 4 (NH 2 )}Br(or)(PPh 3 ) 2 ] ( 3 ) as product. To remove PPh 3 as possible ligand, the reaction of [ReO 2 (py) 4 ]Cl with H 2 or produced [ReO(OEt)(or)(py) 2 ] ( 4 ). H 2 or was also reacted with [Re(CO) 5 Cl], yielding the product (Ph 4 P)[Re(CO) 3 (H 2 O)(or)] ( 5 ). The crystal structures of 1 – 5 were determined by X-ray single crystal diffraction. In addition, infra-red, 1 H NMR, electrochemical and electronic properties are also reported. [ABSTRACT FROM AUTHOR]

Abstract: The reactions of the potentially tridentate Schiff bases 2-[(2-hydroxyphenyl)iminomethyl]phenol (H2ono) and 2-(2-aminobenzylideneimino)phenol (H3onn) with trans-[ReOBr3(PPh3)2] were studied, and the complexes [ReIIIBr(PPh3)2(ono)] (1) and [ReVBr(PPh3)2(onn)]Br (2) were isolated. In 1 ono acts as a dianionic tridentate ligand, and in 2 onn is coordinated as a tridentate trianionic imido-imino-phenolate. The complex [ReI(CO)3(ons)(Hno)] was isolated from the reaction of [Re(CO)5Br] with 2-[(2-methylthio)benzylideneimino]phenol (Hons; Hno=2-aminophenol), with ons coordinated as a bidentate chelate with a free SCH3 group. These complexes were characterized by X-ray crystallography, NMR and IR spectroscopy. [Copyright &y& Elsevier]

Abstract: The solvent-free reaction of ferrocenecarboxaldehyde and diaminoalkanes under solvent-free conditions gave bisferrocenylimines (L) in excellent yields. Cationic rhodium(I) complexes with the formulation [Rh(COD)(L)]ClO4 were prepared by the reaction of [Rh(COD)Cl]2 with the bisferrocenylimines in the presence of silver perchlorate. The compounds were characterised by NMR, IR, MS and elemental analysis. The X-ray crystal structures of two rhodium(I) complexes are also reported. [Copyright &y& Elsevier]

Abstract: The seven-coordinate rhenium(III) complex cation [ReIII(dhp)(PPh3)2]+ was isolated as the iodide salt from the reaction of cis-[RevO2I(PPh3)2] with 2,6-bis(2-hydroxyphenyliminomethyl)pyridine (H2dhp) in ethanol. In the complex fac-[Re(CO)3(H2dhp)Br], prepared from [Re(CO)5Br] and H2dhp in toluene, the H2dhp ligand acts as a neutral bidentate N,N-donor chelate. The complexes were characterized by elemental analysis, infrared and 1H NMR spectroscopy and X-ray crystallography. [Copyright &y& Elsevier]

The reaction of dithizone (H 2 dtz) with [Re(CO) 5 Cl] led to the complex fac- [Re(CO) 3 (Hdtz)(dttz)] (1). The ligand 1,2-diphenyltetrazolethione-5 zwitterion (dttz) was formed from the cyclisation of dithizone ligand, and both N,S-donor Hdtz− anion and S-donor dttz zwitterion coordinate to the fac -[Re(CO) 3 + giving fac- [Re(CO) 3 (Hdtz)(dttz)] (1). • Cyclisation of dithizone in 2,3-diphenyl-5-thione-tetrazolium zwitterion. • Coordination of dithizone to the fac -[Re(CO) 3 + core as a bidentate N,S-donor ligand. • Coordination of 2,3-diphenyl-5-thione-tetrazolium zwitterion to the fac -[Re(CO) 3 + core as a monodentate S-donor ligand. • The conversion a bidentate N,S-donor ligand to monodentate S-donor ligand. The reaction of dithizone (H 2 dtz) with an organometallic rhenium(I) precursor; [Re(CO) 5 Cl] in ethanol led to the isolation of the octahedral organometallic fac -[Re(CO) 3 + core complex fac -[Re(CO) 3 (Hdtz)(dttz)] (1). The chelating ligand 1,2-diphenyltetrazolethione-5 zwitterion (dttz) in 1 was formed from the double deprotonation and cyclisation of dithizone in ethanol. The cyclisation of H 2 dtz to dttz zwitterion is a good example of the conversion of N,S-donor dithizone to S-donor ligand. Both dithizone anion Hdtz− and neutral zwitterion dttz coordinated to the fac -[Re(CO) 3 + core in which Hdtz− is coordinated as bidentate chelate via thiolate sulfur and azoic nitrogen atoms while dttz coordinated as monodentate ligand via thione sulfur atom. In addition to the synthesis, infra-red, 1H NMR, electronic properties and X-ray crystal structure of the complex 1 are reported. [ABSTRACT FROM AUTHOR]

Rhenium(I) complexes with benzimidazolidines, imidazolidines and their derivatives are reported. This study highlights the unusual synthetic route that led to a series of the unexpected ring-containing benzimidazolidines and imidazolidines, obtained from the reaction of ketone and diamino-containing compounds. The reaction of the bridging pyridyl; 2,2′-dipyridylketone (dpk) with 1,2-diaminobenzene and 1,2-diaminoethane in methanol led to the isolation of 2,3-dihydro-2,2-di(pyridin-2-yl)-1 H -benzo[ d ]imidazole (H 2 dpb) and 2-(2-(pyridine-2-yl)imidazolidin-2-yl)pyridine (H 2 pip) respectively. The compounds fac -[Re(CO) 3 (H 2 dmb)Cl] (1) and fac -[Re(CO) 3 (H 2 pip)]Cl.H 2 O (2) were isolated in good yield by reacting [Re(CO) 5 Cl] with 2,3-dihydro-2,2-di(pyridin-2-yl)-1 H -benzo[ d ]imidazole (H 2 dpb) and 2-(2-(pyridine-2-yl)imidazolidin-2-yl)pyridine (H 2 pip) in toluene respectively. A surprising aspect of fac -[Re(CO) 3 (H 2 dmb)Cl] (1) is the benzimidazolidine ring opening in H 2 dpb, which resulted in the formation of the neutrally coordinated Schiff-base ligand, N 1-(di(pyridine-2-yl)methylene)benzene-1,2-diamine (H 2 dmb), which acts as a bidentate N,N-donor chelate. On other hand, the H 2 pip ligand did not undergo any modification. Therefore, it acted as a tridentate N 3 ,O-donor ligand towards the cationic cluster compound with a fac -[Re(CO) 3 ]+ core. The crystal structure of H 2 dpb, 1 and 2 were determined by X-ray single crystal diffraction, in addition to IR, 1H NMR and electronic analysis. Image 1 • Tridentate. • Structures. • Benzimidazolidine. • Rhenium(I). [ABSTRACT FROM AUTHOR]

The reaction of di-2-pyridyketone-2-aminobenzoylhydrazone (Hdpa) and N′((pyridin-2-yl)methylene)benzohydrazide (Hhpmb) with [ReCO 5 Cl] and [ReCO 5 Br] led to the complexes [Re(CO) 3 Cl(Hdpa)] (1) and [Re(CO) 3 Br(Hhpmb)] (2) respectively. The reaction of 2-hydroxy-N′-((thiophen-3-yl)methylene)benzohydrazide (H 2 htmb) with trans- [ReOCl 3 (PPh 3) 2 ] gave the complex cis -[ReOCl 2 (Hhtmb)(PPh 3)] (3). The complexes cis -[ReOBr 2 (Hhpb)(PPh 3)] (4) and (μ-O)[ReO(pbz) 2 ] 2 (5) were isolated from the reaction of trans -[ReOBr 3 (PPh 3) 2 ] with salicylhydrazide (Hshz) and trans- [ReO 2 (py) 4 ]Cl with benzohydrazide (Hbhz) respectively. The coordination mode of aroylhydrazones-based ligands to the fac -[ReCO) 3 ]+, [ReO]3+ and [Re 2 O 3 ]4+ cores is reported. The reaction of di-2-pyridylketone-2-aminobenzoylhydrazone (Hdpa) with [ReCO 5 Cl] in ethanol led to the complex [Re(CO) 3 Cl(Hdpa)] (1). Similar reaction using N′((pyridin-2-yl)methylene)benzohydrazide (Hhpmb) and [ReCO 5 Br] led to the complex [Re(CO) 3 Br(Hhpmb)] (2). The reaction of 2-hydroxy-N′-((thiophen-3-yl)methylene)benzohydrazide (H 2 htmb) with trans- [ReOCl 3 (PPh 3) 2 ] in acetonitrile gave the complex cis -[ReOCl 2 (Hhtmb)(PPh 3)] (3). The complexes cis -[ReOBr 2 (Hhpb)(PPh 3)] (4) and (μ-O)[ReO(pbz) 2 ] 2 (5) were isolated from the reaction of [ReOBr 3 (PPh 3) 2 ] with salicylhydrazide (Hshz) and trans- [ReO 2 (py) 4 ]Cl with benzohydrazide (Hbhz) in acetone respectively. The chelating ligands 2-hydroxy-N′-(propan-2-ylidene)benzohydrazide (H 2 hpb) and N′-(propan-2-ylidene)benzohydrazide (Hpbz) were formed from the condensation of acetone with Hshz and Hbhz respectively upon the reaction of [ReOBr 3 (PPh 3) 2 ] with Hshz in acetone and [ReO 2 (py) 4 ]Cl with Hbhz in acetone respectively. In addition to the X-ray crystal structures, conductivity, infra-red, 1H NMR and electronic properties are reported. [ABSTRACT FROM AUTHOR]

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)]. [ABSTRACT FROM AUTHOR]