Imides of 2-Trifluoroacetylphenol and other Trifluoracetic acid Esters: Novel Reactions with Phosphorus(III) Derivates

Abstract

The imido derivates of 2-trifluoroacetylphenol, 1 (R¹=H, Me, iPr) react with the isocyanatophosphites (R²O)₂PNCO, 2 (R²[dbnd]Et, R²-R²[dbnd]CMe₂-CMe₂) to yield the bicyclic compounds 3, wheras in case of 1 (R¹[dbnd](CH₂)₂NMe2) the λ³σ³P compounds 4 are found. The phosphorus(III) chlorides R3PC12 (R³[dbnd]Ph, OEt) and 1 (R¹[dbnd]H, Me) give rise to furnish the tricyclic phosphoranes 5. However with 1 (R¹[dbnd]iPr) phosphite 6 is obtained, which adds hexafluoracetone to give the 1,3,2λ⁵σ⁵-dioxaphospholane 7. 2-(Trifluoracetoxy)pyridine 8. reacts with Tris(trimethylsily1)phosphite to yield the bis(phosph0nate) 10. Some molecular structures are discussed on the basis of x-ray diffraction results.     

Synthesis,spectral characterization,and evaluation of antimicrobial activity of O,O′-alkanediyl S-(N-phthalimidomethyl) dithiophosphates and zinc bis(O,O′-alkanediyl) dithiophosphates

The synthesis of novel dithiophosphate derivatives has been achieved. Two O,O′-alkanediyl S-(N-phthalimidomethyl) dithiophosphates and two Zinc bis(O,O′-alkanediyl) dithiophosphates are synthesized by an easy and facile chemical synthetic route. Zinc bis[O,O′-(2-methylpentane-2,4-diyl) dithiophosphate] L¹, Zinc bis[O,O′-(2-ethylhexane-1,3-diyl) dithiophosphate] L², O,O′-(2-methylpentane-2,4-diyl) S-(N-phthalimidomethyl) dithiophosphate L³ and O,O′-(2-ethylhexane-1,3-diyl) S-(N-phthalimidomethyl) dithiophosphate L⁴ are synthesized from the respective ammonium salts. Compounds L¹, L², L³, and L⁴ are characterized by (CHN) elemental analysis, ESI mass, FT-IR, ¹H, ¹³C, and ³¹P NMR techniques. The crystal structure of ammonium O,O′-(2-methylpentane-2,4-diyl) dithiophosphate is discussed. L¹, L², L³, and L⁴ were evaluated for antimicrobial activity. It was found that the phthalimide derivatives L³ and L⁴ showed much better antifungal potential against some species of fungus. The Zinc dithiophosphates L¹ and L² showed good antibacterial activity against Bacillus cereus and Escherichia coli.     

New Look into the Synthesis of Polyhalogenoarylphosphanes

The present study shows new aspects of the synthesis of polyhalogenoarylphosphanes. The sterically hindered anions Ph(R)P-Y^? (1a–c, Y = O, lone pair; R = Ph, Bu^t) have been used to show the complexity of the reaction between phosphorus nucleophiles and hexahalogenobenzenes or 9-bromofluorene (E3). The Ph(Bu^t)P-O^? (1a) anion reacts with hexachlorobenzene (E1), hexafluorobenzene (E2), or E3 to give Ph(R)P(O)X (4a–c, X = F, Cl, Br) with the release of the corresponding carbanion as a nucleofuge, followed by side reactions. In contrast, the lithium phosphides Ph(R)PLi (1b,c) react with hexahalogenobenzenes to give the corresponding diphosphanes 5a,b as the main product and traces of P-arylated products, i.e., Ph(R)P-C₆X₅ (10a,b, X = Cl, F). Unexpectedly, Ph(Bu^t)PLi (1b) reacts with an excess of 9-bromofluorene to give only halogenophosphane Ph(Bu^t)P-X.     

Group 3 and lanthanide triflate-complexes with [N,N,O]-donor ligands: synthesis,characterization, and cytotoxic activity

Group 3 and rare-earth triflate-complexes M(OTf)₂(bdmpza) {M?=?Sc (1^Sc ), Y (1^Y ), La (1^La ), Sm (1^Sm ), Eu (1^Eu ) OTf?=?SO₃CF₃} bearing the heteroscorpionate ligand bdmpza {bdmpza?=?bis(3,5-dimethyl-pyrazol-1-yl)acetate} have been synthesized and characterized, together with the yttrium and europium complexes M(OTf)(bdmpza)₂ {M?=?Y (2^Y ), Eu (2^Eu )}. The photoluminescent behavior of 2^Eu has been investigated. The coordination mode of the [N,N,O]-donor in these complexes has been elucidated by DFT calculations. The cytotoxic effect of selected complexes and of the free ligand toward HeLa cells has been evaluated.     

Synthesis and structure of the platinum complexes [Bu4N]+[PtBr5(DMSO)]?, [Ph4P]+[PtBr5(DMSO)]?, and [Ph3(n-Am)P]+[PtBr5(DMSO)]?

The complexes [Bu₄N]₂⁺[PtBr₆]²⁻ (I), [Ph₄P]₂⁺[PtBr₆]²⁻ (II), and [Ph₃(n-Am)P]₂⁺ (III) are synthesized by the reactions of tetrabutylammonium bromide, tetraphenylphosphonium bromide, and triphenyl(n-amyl)-tetraphenylphosphonium bromide, respectively, with potassium hexabromoplatinate (mole ratio 2: 1). After recrystallization from dimethyl sulfoxide, complexes I, II, and III transform into [Bu₄N]⁺[PtBr₅(DMSO)]⁻ (IV), [Ph₄P]⁺[PtBr₅(DMSO)]⁻ (V), and [Ph₃(n-Am)P]⁺[PtBr₅(DMSO)]⁻ (VI). According to the X-ray diffraction data, the cations of complexes IV–VI have a slightly distorted tetrahedral structure. The N-C and P-C bond lengths are 1.492(7)–1.533(6) and 1.782(10)–1.805(10) ?, respectively. The platinum atoms in the mononuclear anions are hexacoordinated. The dimethyl sulfoxide ligands are coordinated with the Pt atom through the sulfur atom (Pt-S 2.3280(18)–2.3389(11) ?). The Pt-Br bond lengths are 2.4330(6)–2.4724(6) ?.     

Two 1-D and 2-D cobalt(II) complexes: synthesis,crystal structures,spectroscopic and electrochemical properties

Two new cobalt(II) complexes, [Co(L³)₂]·CH₃OH·CH₃COCH₃ (1) (HL³ = 1-(2-{[(E)-3,5-dichloro-2-hydroxybenzylidene]amino}phenyl)ethanone oxime) and Co(L⁴)₂ (2) (HL⁴ = 1-(2-{[(E)-3,5-dibromo-2-hydroxybenzylidene]amino}phenyl)ethanone oxime), have been synthesized via complexation of Co(II) acetate tetrahydrate with HL¹ and HL². HL¹, HL², and their corresponding Co(II) complexes were characterized by IR, ¹H NMR spectra, as well as by elemental analysis and UV–Vis spectroscopy, respectively. The crystal structures of the complexes have been determined by single-crystal X-ray diffraction. 1 and 2 display that extensive hydrogen bonds and C–X···π bonding interactions construct the 1-D infinite chain [Co(L³)₂]·CH₃OH·CH₃COCH₃ and Co(L⁴)₂ into 2-D supramolecular frameworks. The electrochemical properties of two Co(II) complexes were also investigated by cyclic voltammetry.     

Complexes of Co(II) and Zn(II) with N-(Thio)phosphorylthioureas AdNHC(S)NHP(O)(OiPr)2 and MeNHC(S)NHP(S)(OiPr)2

The reaction of the potassium salt of the N-(thio)phosphorylated thioureas AdNHC(S)NHP(O)(OiPr)₂ (HL^I , Ad = Adamantyl) and MeNHC(S)NHP(S)(OiPr)₂ (HL^II ) with Co(II) and Zn(II) in aqueous EtOH leads to [ML^I,II ₂] chelate complexes. They were investigated by UV-vis, ¹H and ³¹P NMR spectroscopy, and microanalysis. The molecular structures of [ML^I ₂] were elucidated by single crystal X-ray diffraction analysis. The metal centers in both complexes are found to be in a distorted-tetrahedral O₂S₂ environment formed by the C=S sulfur atoms and the P=O oxygen atoms of two deprotonated L^I ligands. The photoluminescence properties of [ZnL^II ₂] are also reported.     

Complexes of N-(thio)phosphorylthioureas AdNHC(S)NHP(X)(OiPr)2 (X?=?O, S) with cobalt(II), zinc(II), and cadmium(II). Crystal structure of Co[AdNHC(S)NP(S)(OiPr)2]2

Reaction of the potassium salts of N-(thio)phosphorylated thioureas of common formula AdNHC(S)N(H)P(X)(OiPr)₂ (Ad = adamantyl; X = O, HL ^I ; X = S, HL ^II ) with Co(II), Zn(II), and Cd(II) cations in aqueous EtOH leads to M(L ^I,II -X, S) ₂ chelate complexes. The Cd(II) complex Cd(L ^I ) ₂ could not be isolated under analogous conditions because of its hydrolytic lability. The structure of the resulting compounds was studied by means of spectroscopy and microanalysis; in addition, the molecular structure of the complex Co(L ^II ) ₂ was elucidated by single crystal X-ray diffraction analysis. The cobalt atom is in a tetrahedral S₄ environment formed by the C=S and P=S sulfur atoms of two deprotonated ligands L ^II . The magnetic properties of Co(L ^I,II ) ₂ were investigated and the photoluminescent properties of the complexes are also reported.     

Generation and characterization of ionic and neutral [HS-P-OH]<Superscript>+/·</Superscript> and S=P(OH)<Stack><Subscript>2</Subscript><Superscript>+/·</Superscript></Stack> in the Gas Phase by Tandem Mass Spectrometry and Computational Chemistry

Dissociative electron ionization of diethyl dithiophosphate (I) and O,O′-diethyl methylphosphonothioate (II) generates moderately abundant m/z 81 ions of composition [P, O, S, H₂]⁺. From tandem mass spectrometry experiments and theoretical calculations at the B3LYP/6-31G(d,p), G2, and G2 (MP2) levels it is concluded that the majority of the ions have the structure of HS-P-OH⁺ (1a ⁺) and it is separated by high-energy barriers from its isomers P(= S)OH₂⁺ (1b ⁺), P(= O)SH₂⁺ (1c ⁺), HP(= S)OH⁺ (1d ⁺), and HP(= O)SH⁺ (1e ⁺). Low-energy (metastable) ions 1a ⁺ dissociate via losses of H₂O and H₂S to yield m/z 63 (PS⁺) and m/z 47 (PO⁺) product ions, respectively. These reactions involve isomerization of 1a ⁺ into the stable isomers 1b ⁺ and 1c ⁺. Neutralization-reionization experiments confirm the theoretical prediction that radical 1a ^· is a stable species in the gas-phase. Variable-time NR experiments indicated that only a small fraction of metastable 1a ^· radicals dissociate in the 0.4–4.6 μs time window, while most dissociations occurred on a shorter time scale. RRKM calculations were performed to investigate unimolecular dissociation kinetics of 1a ^· which were found to be in agreement with the fragmentation observed in the NR spectrum. The 70-eV electron ionization of (I) and diethyl chlorothiophosphate (III) yields m/z 97 ions, predominantly of the structure S = P(OH)₂⁺ (2a ⁺). This conclusion follows from tandem mass spectrometry experiments and theoretical calculations. The calculations predict that (2a ⁺) is separated by high-energy barriers from its isomers O = P(SH)OH⁺ (2b ⁺), S = P(= O)OH₂⁺ (2c ⁺), and O = P(= O)SH₂⁺ (2d ⁺). Neutralization-reionization experiments confirmed that 2a ^· radical is a kinetically stable species on the time scale of up to 5 μs, which is in agreement with ab initio calculations. However, owing to a mismatch of Franck-Condon factors a large fraction of 2a ^· dissociates by loss of SH^· yielding O=P-OH.     

Synthesis,crystal structure,redox behavior and DNA-binding properties of a series of copper(II) complexes with two new carboxamide derivatives

Four mononuclear copper(II) complexes of two new carboxamide derivatives formulated as [Cu(L¹)₂](ClO₄)₂ (1a), [Cu(L¹)₂](NO₃)₂ (1b), [Cu(L²)₂(H₂O)₂](ClO₄)₂ (2a), and [Cu(L²)₂(H₂O)](NO₃)₂ (2b) have been isolated in pure form from the reaction of L¹ and L² [where L¹ = N-(furan-2-ylmethyl)-2-pyridinecarboxamide and L² = N-(thiophen-2-ylmethyl)-2-pyridinecarboxamide] with copper(II) salts of perchlorate and nitrate. All the complexes were characterized by physicochemical and spectroscopic tools along with single-crystal X-ray diffraction studies. The structural analyses showed that 1 is monomeric of square planar geometry with copper(II) chelated by two L¹ ligands. Complex 2 differs in coordination geometry, being octahedral and distorted square pyramidal. Two L² ligands occupy the equatorial positions of the octahedral 2a and the basal sites of the pyramidal 2b, with water molecules that complete the coordination sphere in each case. Electrochemical studies using cyclic voltammetry showed a reversible redox behavior of the copper(II) in 1 and 2. The electronic spectroscopic behavior and the trend of one electron equivalent redox potential corresponding to a Cu^II/Cu^I couple have also been confirmed by density functional theory calculations. The spectroscopic and viscosity measurement study in tris–HCl buffer suggested an intercalative interaction of 1a and 2 with calf thymus DNA likely due to the stacking between the non-coordinated furan and thiophene chromophore with the base pairs of DNA.     

Binary and ternary oxorhenium(V) complexes: synthesis,characterization, and crystal structure

A series of anionic five-coordinate binary oxorhenium(V) complexes with dithiolato ligands, Bu₄N[ReO(L¹)₂] (1a), Bu₄N[ReO(L²)₂] (1b), and Bu₄N[ReO(L³)₂] (1c), and a series of neutral octahedral ternary oxorhenium(V) complexes of mixed dithiolato and bipyridine ligands, [ReO(L¹)(bpy)Cl] (2a), [ReO(L²)(bpy)Cl] (2b), and [ReO(L³)(bpy)Cl] (2c) (where L¹H₂ = ethane-1,2-dithiol, L²H₂ = propane-1,3-dithiol, L³H₂ = toluene-3,4-dithiol, and bpy = 2,2′-bipyridine), were isolated and characterized by physicochemical and spectroscopic methods. The solid state structure of 1c was established by X-ray crystallography. All the mononuclear oxorhenium(V) complexes are diamagnetic. The redox behavior of all the complexes has been studied voltammetrically.     

Copper(II) bis(hexafluoroacetylacetonate) complexes with 2-(2-methyltetrazolyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole 1-oxides

An efficient procedure was developed for the synthesis of alkyltetrazolyl-substituted nitronyl nitroxides (L ¹ and L ²). These compounds were used to prepare the first alkyltetrazolyl-substituted imino nitroxides (L ³ and L ⁴). The molecular structures of L ³ and L ⁴ were confirmed by X-ray diffraction. Investigation of the products prepared by the reaction of copper(II) bis(hexafluoroacetylacetonate), Cu(hfac)₂, with nitroxides made it possible to divide ligands L ¹—L ⁴ into two groups. The reactions of spin-labeled tetrazoles L ¹—L ³ with Cu(hfac)₂ afford the heterospin complexes Cu(hfac)₂L₂, whereas L ⁴ serves as a bidentate ligand in the Cu(hfac)₂ L ⁴ complex. In the solid Cu(hfac)₂L₂ complexes, antiferromagnetic exchange interactions between the unpaired electrons of the nitroxide fragments of the adjacent molecules prevail, due to which μ_eff decreases with decreasing temperature, and the spins of nitroxides are completely compensated at 5–10 K. The Cu(hfac)₂ L ⁴ complex displays strong intramolecular ferromagnetic coupling, due to which μ_eff at room temperature is close to 2.9 μ_B. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 64–70, January, 2006.     

Synthesis,characterization, and structures of copper(I) complexes with N,N′-bis[1-(4-chlorophenyl)ethylidene]ethane-1,2-diamine and N,N′-bis[1-(4-nitrophenyl)ethylidene]ethane-1,2-diamine

Two ligands, N,N′-bis[1-(4-chlorophenyl)ethylidene]ethane-1,2-diamine (L¹ ) and N,N′-bis- [1-(4-nitrophenyl)ethylidene]ethane-1,2-diamine (L² ) and their corresponding copper(I) complexes, [Cu(L ¹)₂]ClO₄ (1) and [Cu(L ²)₂]ClO₄ (2), have been synthesized and characterized by CHN analyses, ¹H-NMR, IR, and UV–Vis spectroscopy. The crystal structures of L¹ and [Cu(L ¹)₂]ClO₄ (1) were determined from single crystal X-ray diffraction. L¹ lies across a crystallographic inversion center and the C=N is approximately coplanar with the benzene ring and adopts E configuration. The coordination polyhedron about copper(I) in 1 is best described as a distorted tetrahedron. Quasireversible redox behavior is observed for the complexes.     

Unexpected results of the reactions of manganese and vanadium β-diketiminate halide complexes with Na[HBEt3]

The reaction of [(^Menacnac^Dipp)Mn(μ-Cl)]₂(2) (^Menacnac^Dipp = HC(C(Me)NDipp)₂; Dipp = 2,6-Prⁱ₂C₆H₃) with sodium triethylborohydride in a toluene—THF mixture afforded the complex [(^Menacnac^Dipp)Mn(μ-H)₂BEt₂(THF)] (3). The reaction of 2 with Na[HBEt₃] in toluene under THF-free conditions gave a mixture of products. The set and the ratio of these products in the resulting crystalline mixture were established by quantitative powder X-ray diffraction analysis: [(^Menacnac^Dipp)Mn(μ-H)]₂(1), [(^Menacnac^Dipp)?Mn(μ-H)₂BEt₂] (4), and unreacted compound 2 in the ratio of 15:4:1 and traces of an unknown crystalline phase. The reaction of [(^Menacnac^Dipp)VCl₂] (5) with Na[HBEt₃] yielded the compound [(^Menacnac^Dipp)V(μ-H)(μ,κ^1:1?C:C′?C₂H₄)BEt₂] (6) containing the unusual ligand [HBEt₂(CH₂CH₂)]^2?. The vanadium analog of compound 3, [(^Menacnac^Dipp)V(μ-H)₂BEt₂(THF)] (7), was isolated in one experiment. Besides. a small amount of the complex [(^Menacnac^Dipp)V(μ-H)BEt₃(THF)] (8) was detected in the mixture of crystalline products. The structures of compounds 3, 4, 6, 7, and 8 were determined by single-crystal X-ray diffraction.

     

Structure and properties of an oxalato-bridged dinickel(II) complex with a tetraazamacrocycle bearing an aminomethyl pendant arm, 5-aminomethyl-5R(S),12R(S)-dimethyl-1,4,8,11-tetraazacyclotetradecane

The oxalato-bridged dinickel(II) complex with the title ligand, [Ni₂(L ^a H)₂(μ-ox)](ClO₄)₂·2H₂O (1), was prepared and its structure was determined by X-ray crystallography, as well as that of the monomeric nickel(II) complex, [Ni(L ^a H)ox]ClO₄·3H₂O (2). In Complexes 1 and 2, the ligand, L ^a , is folded along the N(4)–Ni(1)–N(11) axis. The antiferromagnetic coupling between the two nickel(II) centers in 1 was revealed and the coupling constant, J?=??17.4?cm^?1, and g?=?2.11 were estimated. It was found that the oxalato-bridged dimer 1 was readily converted to the mononuclear cis-nickel(II) complex [NiL ^a (OH₂)](ClO₄)₂ (3a), in basic aqueous solution. In [NiL ^a (CH₃CN)]I₂ (3b), which was derived from 3a, the aminomethyl pendant arm is coordinated to the Ni(II) ion and L ^a is folded along the N(1)–Ni(1)–N(8) axis.     

SYNTHESE DU FOSTEDIL (4-(2-BENZOTHIAZOLYL) BENZYLPHOSPHONATE DE DIETHYLE) A PARTIR D'IMIDATES N-ACYLES

Fostedil (diethyl 4-(benzothiazol-2-yl) benzylphosphonate) 7 has been synthesized efficiently by treatment of 2-(4-bromomethylphenyl) benzothiazole 6 with triethylphosphite. The latter (6) has been prepared by bromation of benzothiazole 3c. N-acylimidates 1(a–d) react with 2-aminobenzenethiol 2 to lead to the corresponding benzothiazoles 3(a–d) after elimination of primary amide 5. The structure of these products have been unequivocally confirmed by means of IR, ¹H, ¹³C, and ³¹P NMR spectroscopy and mass spectra.     

Kinetics and mechanism of formation of isomeric 1-methyl- and 2-methyl-5-vinyltetrazoles

The alkylation of 5-(β-dimethylaminoethyl)tetrazole (1) with dimethyl sulfate afforded 5-(β-dimethylaminoethyl)-1-methyltetrazole (2) and 5-(β-dimethylaminoethyl)-2-methyltetrazole (3). The exhaustive alkylation of compounds 2 and 3 at the terminal dimethylamino group gave 1-methyl-(4) and 2-methyl-5-(β-trimethylammonioethyl)tetrazole (5) methyl sulfates. The proton elimination from the α-methylene (with respect to the tetrazole cycle) groups of the quaternary ammonium cations of salts 4 and 5 by the action of a base leads to the corresponding zwitterions 4 ^± and 5 ^±, which in the rate-determining step undergo the cleavage of the nitrogen—carbon bond with the formation of 1-methyl-5-vinyl- (6) and 2-methyl-5-vinyltetrazole (7). The true constant of the transformation of zwitterion 4 ^± into tetrazole 6 is 21 times higher than that for the transformation of zwitterion 5 ^± into tetrazole 7.     

Organotellurium Ligands & Their Metal Complexes: Recent Developments

Abstract

The ligand chemistry of telluroethers, halotellurium ligands, and polytellurides has received good attention in the last decade. Tellurium-containing species have been used to design clusters. In the recent past the ligation of di and tri-telluroethers (including bis(4-methoxyphenyltelluro)methane) has been studied. Hybrid organotellurium ligands, N-[2-(4-methoxyphenyltelluro)propyl]phthalimid (L ¹ ), 2-(4-ethoxyphenyltelluromethyl)-tetrahydro-2H-pyran (L ² ), 2-(2-{4-ethoxyphenyl} telluroethyl)-1,3-dioxane (L ³ ), N-{2-(4-methoxyphenyltelluro)ethyl}morpholine (L ⁴ ), N-{2-(4-methoxyphenyltelluro)ethyl}-pyrrolidine (L ⁵ ), bis{2-(pyrrolidine-N-yl)ethyl}telluride (L ⁶ ), 1-(4-methoxyphenyltelluro)-2-[3-(6-methyl-2-pyridyl) propoxy]ethane (L ⁷ ), and 2-[2-(4-methoxyphenyltelluro)ethyl]thiophene (L ⁸ ) have been designed recently and studied for their complexation reactions. The (Te, N) and (N, Te, N) ligands, L ⁵ and L ⁶ , coordinate with Hg(II) through Te and N both, but the bonding with N is some what weak. The morpholine nitrogen of L ⁴ does not coordinate with Pd(II) or Pt(II) along with Te. The L ⁷ behaving as a (Te, N) ligand has formed 20-membered metallomacrocycle ring with Pt(II). Tellurated Schiff bases 4-MeOC₆H₄TeCH₂CH₂N═C(CH₃)C₆H₄-2-OH (L ⁹ ) and 2-HO-C₆H₄-(CH₃)C═NCH₂CH₂TeCH₂CH₂N═C(CH₃)C₆H₄-2-OH (L ¹⁰ ) and their reduction products 4-MeOC₆H₄TeCH₂CH₂NHCH(CH₃)C₆H₄-2-OH (L ¹¹ ) and 2-HO-C₆H₄-(CH₃)CHNHCH₂CH₂TeCH₂CH₂NHCH(CH₃)C₆H₄-2-OH (L ¹² ) respectively have been synthesized and studied for ligation behaviour. The L ⁹ on reaction with the [Ru(p-cymene)Cl₂]₂ results in [Ru(p-cymene)(4-MeOC₆H₄TeCH₂CH₂NH₂)Cl]Cl · H₂O whereas in the reaction of L ¹⁰ with [Ru(p-cymene) Cl₂]₂, p-cymene ligand is lost resulting in [RuCl(L ¹⁰ -H)]. The recent developments, particularly designing of L ¹ to L ¹² and their ligand chemistry, are reviewed in the present paper.     

Zinc(II) and mercury(II) complexes with Schiff bases: syntheses,spectral, and structural characterization

Schiff bases o-vanilidene-1-aminobenzene (HL¹) and o-vanilidene-2-methyl-1-aminobenzene (HL²) lead to the formation of mono- and bis-[(Cl)Zn(L¹)] (1), [(Cl)Zn(L²)] (2), [(Cl)Hg(L¹)] (3), [(Cl)Hg(L²)] (4), [Zn(L¹)₂] (5), [Zn(L²)₂] (6), [Hg(L¹)₂] (7), and [Hg(L²)₂] (8) complexes by reactions of zinc(II) and mercury(II) chlorides in different mole ratio(s). Complexes 1–8 have been characterized by elemental analyses (Zn, Hg, C, H, Cl, and N), melting point and spectral (IR, ¹H-NMR), PXRD, molar conductivity measurement, and TGA. Conductivity measurements suggest non-electrolytes. Structural compositions have been assigned by mass spectral studies. Four-coordinate geometry may be assigned to these complexes tentatively. Structural study reveals that in 1–4 two metal centers are held together by two bridged (μ₂-Cl) chlorides, whereas 5–8 contain two bidentate Schiff-base ligands around one metal-producing monomers.     

13C, 15N and 113Cd NMR and Molecular Orbital Studies of Novel Bile Acid N-(2-aminoethyl)amides and Their Cd2+-complexes

Lithocholic acid N-(2-aminoethyl)amide (1) and deoxycholic acid N-(2-aminoethyl)amide(2) have been prepared and characterized by¹H, ¹³C and ¹⁵N NMR. The accurate molecular masses of 1 and 2 have been determined by ESI MS. The formation of the Cd²⁺-complexes (1+Cd and 2+Cd) in CD₃OD solution have been detected by ¹H,¹³C, ¹⁵N and ¹¹³Cd NMR. The ¹³C NMR chemical shift assignments of 1 and 2 and their Cd²⁺-complexes are based on DEPT-135 and z-GS ¹H,¹³C HMQC experiments as well as comparison with the assignments of the related structures. The ¹⁵N NMR chemical shiftassignments of the ligands and theirCd²⁺-complexes are based on z-GS¹H,¹⁵N HMBC experiments. ¹³C NMR chemical shift differences between 1and its 1:1 Cd²⁺-complex based on ab initiocalculations at Hartree-Fock SCI-PCM level using3-21G(d) basis set are in agreement with theexperimental shift changes observed onCd²⁺-complexation.