Synthesis, Crystal Structure, DFT, and Anticancer Activity of Some Imine-Type Compounds via Routine Schiff Base Reaction: An Example of Unexpected Cyclization to Oxazine Derivative.

The synthesis, characterization, and anticancer properties of three imine-type compounds 1-3 and an unexpected oxazine derivative 4 are presented. The reaction of p-dimethylaminobenzaldehyde or m-nitrobenzaldehyde with hydroxylamine hydrochloride afforded the corresponding oximes 1-2 in good yields. Additionally, the treatment of benzil with 4-aminoantipyrine or o-aminophenol was investigated. Routinely, the Schiff base (4E)-4-(2-oxo-1,2-diphenylethylideneamino)-1,2-dihydro-1,5-dimethyl-2-phenylpyrazol-3-one 3 was obtained in the case of 4-aminoantipyrine. Unexpectedly, the reaction of benzil with o-aminophenol proceeded with cyclization to produce the 2,3-diphenyl-2H-benzo[b][1,4]oxazin-2-ol 4. The structures of compounds 3 and 4 were unambiguously determined by single crystal X-ray diffraction. Hirshfeld analysis of molecular packing revealed the importance of the O…H (11.1%), N…H (3.4%), C…H (29.4%), and C…C (1.6) interactions in the crystal stability of 3. In the case of 4, the O…H (8.8%), N…H (5.7%), and C…H (30.3%) interactions are the most important. DFT calculations predicted that both compounds have a polar nature, and 3 (3.4489 Debye) has higher polarity than 4 (2.1554 Debye). Different reactivity descriptors were calculated for both systems based on the HOMO and LUMO energies. The NMR chemical shifts were calculated and were found well correlated with the experimental data. HepG2 growth was suppressed by the four compounds more than MCF-7. The IC50 values of 1 against HepG2 and MCF-7 cell lines were the lowest, and it is considered the most promising candidate as an anticancer agent.

A New Pt(II) Complex with Anionic s-Triazine Based NNO-Donor Ligand: Synthesis, X-ray Structure, Hirshfeld Analysis and DFT Studies.

The reaction of PtCl2 with s-triazine-type ligand (HTriaz) (1:1) in acetone under heating afforded a new [Pt(Triaz)Cl] complex. Single-crystal X-ray diffraction analysis showed that the ligand (HTriaz) is an NNO tridentate chelate via two N-atoms from the s-triazine and hydrazone moieties and one oxygen from the deprotonated phenolic OH. The coordination environment of the Pt(II) is completed by one Cl-1 ion trans to the Pt-N(hydrazone). Hirshfeld surface analysis showed that the most dominant interactions are the H···H, H···C and O···H intermolecular contacts. These interactions contributed by 60.9, 11.2 and 8.3% from the whole fingerprint area, respectively. Other minor contributions from the Cl···H, C···N, N···H and C···C contacts were also detected. Among these interactions, the most significant contacts are the O···H, H···C and H···H interactions. The amounts of the electron transfer from the ligand groups to Pt(II) metal center were predicted using NBO calculations. Additionally, the electronic spectra were assigned based on the TD-DFT calculations.

Alkoxy-1,3,5-triazapentadien(e/ato) copper(II) complexes: template formation and applications for the preparation of pyrimidines and as catalysts for oxidation of alcohols to carbonyl products.

Template combination of copper acetate (Cu(AcO)(2)⋅H(2)O) with sodium dicyanamide (NaN(C≡N)(2), 2 equiv) or cyanoguanidine (N≡CNHC(=NH)NH(2), 2 equiv) and an alcohol ROH (used also as solvent) leads to the neutral copper(II)-(2,4-alkoxy-1,3,5-triazapentadienato) complexes [Cu{NH=C(OR)NC(OR)=NH}(2)] (R = Me (1), Et (2), nPr (3), iPr (4), CH(2)CH(2)OCH(3) (5)) or cationic copper(II)-(2-alkoxy-4-amino-1,3,5-triazapentadiene) complexes [Cu{NH=C(OR)NHC(NH(2))=NH}(2)](AcO)(2) (R = Me (6), Et (7), nPr (8), nBu (9), CH(2)CH(2)OCH(3) (10)), respectively. Several intermediates of this reaction were isolated and a pathway was proposed. The deprotonation of 6-10 with NaOH allows their transformation to the corresponding neutral triazapentadienates [Cu{NH=C(OR)NC(NH(2))=NH}(2)] 11-15. Reaction of 11, 12 or 15 with acetyl acetone (MeC(=O)CH(2)C(=O)Me) leads to liberation of the corresponding pyrimidines NC(Me)CHC(Me)NCNHC(=NH)OR, whereas the same treatment of the cationic complexes 6, 7 or 10 allows the corresponding metal-free triazapentadiene salts {NH(2)C(OR)=NC(NH(2))=NH(2)}(OAc) to be isolated. The alkoxy-1,3,5-triazapentadiene/ato copper(II) complexes have been applied as efficient catalysts for the TEMPO radical-mediated mild aerobic oxidation of alcohols to the corresponding aldehydes (molar yields of aldehydes of up to 100 % with >99 % selectivity) and for the solvent-free microwave-assisted synthesis of ketones from secondary alcohols with tert-butylhydroperoxide as oxidant (yields of up to 97 %, turnover numbers of up to 485 and turnover frequencies of up to 1170 h(-1)).

Pt(II)-mediated imine-nitrile coupling leading to symmetrical (1,3,5,7,9-pentaazanona-1,3,6,8-tetraenato)Pt(II) complexes containing the incorporated 1,3-diiminoisoindoline moiety.

Treatment of trans-[PtCl(2)(NCR)(2)] (1; R = Et (1a), Ph (1b)) with 1,3-diiminoisoindoline (2) gives access to the corresponding symmetrical (1,3,5,7,9-pentaazanona-1,3,6,8-tetraenato)Pt(II) complexes [PtCl{NH═C(R)N═C(C(6)H(4))NC═NC(R)═NH}] (3). The reactions of 1 with one equivalent of 1,1,3,3-tetramethylguanidine (4), 1,3-diphenylguanidine (6), or acetone oxime (8) leads to the formation of mixed asymmetrical Pt(II) complexes trans-[PtCl(2){NH═C(R)N═C(NMe(2))(2)}(NCR)] (5), [PtCl{NH═C(R)NC(NHPh)═NPh}(NCR)] (7), or trans-[PtCl(2){NH═C(Ph)ON═CMe(2)}(NCPh)] (9), respectively, as a result of nucleophilic addition to one of the nitrile ligands in 1. Treatment of 5, 7, and 9 with one equivalent of 2 leads to complexes 3. The complexes were characterized by IR, (1)H, (13)C{(1)H}, and (195)Pt NMR (for 3) spectroscopies, ESI(+)-MS, elemental analyses, and X-ray diffraction (for 3). Complex 3a has an asymmetric unit with five independent Pt molecules of the same chemical composition and two molecules of water, resulting in a total of 40 molecules of the complex and sixteen guest water molecules per unit cell. Theoretical calculations revealed that the most plausible mechanism of formation of complexes 3 includes stepwise nucleophilic addition of 2 to one of the nitrile ligands in 1, a first cyclization upon formation of the Pt-N bond and elimination of HCl, and a second nucleophilic addition/cyclization.

Pt(II)-promoted [2 + 3] cycloaddition of azide to cyanopyridines: convenient tool toward heterometallic structures.

The [2 + 3] cycloaddition reactions (which are greatly accelerated by microwave irradiation) of the di(azido)platinum(II) compounds cis-[Pt(N(3))(2)(PPh(3))(2)] (1) with cyanopyridines NCR (2) (R = 4-, 3-, and 2-NC(5)H(4)) give the corresponding bis(pyridyltetrazolato) complexes trans-[Pt(N(4)CR)(2)(PPh(3))(2)] (3) [R = 4-NC(5)H(4) (3a), 3-NC(5)H(4) (3b), and 2-NC(5)H(4) (3c)]. Compound 3c has been characterized as the N(1)N(2)-bonded isomer in the solid state by X-ray crystallography and represents the first bis(tetrazolato) complex of this kind. Complexes 3a and 3b have been used as metallaligands to generate heteronuclear coordination polymers in the presence of copper nitrate. A one-dimensional supramolecular architecture was obtained as the exclusive product, {trans-[Pt(2)(N(4)CR)(4)(PPh(3))(4)Cu](n)(NO(3))(2n).nH(2)O (4.nH(2)O) (R = 4-NC(5)H(4)), when 3a was employed, whereas with 3b the heteronuclear square complex trans-[Pt(N(4)CR)(2)(PPh(3))(2)Cu(NO(3))(2)(H(2)O)](2) (5) (R = 3-NC(5)H(4)), composed of Pt/Cu ions, was obtained. All the isolated complexes were characterized by IR, elemental, and (for 3b, 3c, 4, and 5) X-ray structural analyses. Complexes 3 were additionally characterized by (1)H, (13)C, and (31)P {(1)H} NMR spectroscopies.

Crystal structures of (E)-1-naphthaldehyde oxime and (E)-phenanthrene-9-carbaldehyde oxime.

The aldoximes C11H9NO (I) and C15H11NO (II), synthesized in ca 90% yield, by treatment of 1-naphthaldehyde or phenanthrene-9-carbaldehyde, respectively, with hydroxyl-amine hydro-chloride and sodium carbonate, have been characterized by IR, 1H, 13C and DEPT-135 NMR spectroscopies, and also by single-crystal X-ray diffraction analysis. The mol-ecules of (I) and (II) are conformationally similar, with the aldoxime substituent groups lying outside the planes of the naphthalene or phenanthrene rings, forming dihedral angles with them of 23.9 (4) and 27.9 (6)°, respectively. The crystal structures of both (I) and (II) are similar with a single inter-molecular O-H⋯N hydrogen-bonding inter-action, giving rise to the formation of one-dimensional polymeric chains extending along the 21 (b) screw axes in each.

Crystal structure of trans-di-chloridobis-[N-(5,5-di-methyl-4,5-di-hydro-3H-pyrrol-2-yl-κN)acetamide]palladium(II) dihydrate.

The title complex, [PdCl2(C8H14N2O)2]·2H2O, was obtained by N-O bond cleavage of the oxa-diazo-line rings of the trans-[di-chlorido-bis-(2,5,5-trimethyl-5,6,7,7a-tetra-hydro-pyrrolo-[1,2-b][1,2,4]oxa-diazole-N1)]palladium(II) complex. The palladium(II) atom exhibits an almost square-planar coordination provided by two trans-arranged chloride anions and a nitro-gen atom from each of the two neutral organic ligands. In the crystal, N-H⋯O, O-H⋯O and O-H⋯Cl hydrogen bonds link complex mol-ecules into double layers parallel to the bc plane.

Synthesis, molecular structure, spectroscopic properties and stability of (Z)-N-methyl-C-2,4,6-trimethylphenylnitrone.

New N-methyl-C-2,4,6-trimethylphenylnitrone 1 has been synthesized starting from N-methylhydroxylamine and mesitaldehyde. The product was fully characterized using different spectroscopic techniques; FTIR, NMR, UV-Vis, high resolution mass spectrometry and X-ray diffraction. The relative stability and percent of population of its two possible isomers (E and Z) were calculated using the B3LYP/6-311++G(d,p) method in gas phase and in solution. In agreement with the X-ray results, it was found that Z-isomer is the most stable one in both gas phase and solution. The molecular geometry, vibrational frequencies, gauge-including atomic orbital (GIAO), and chemical shift values were also calculated using the same level of theory. The TD-DFT results of the studied nitrone predicted a π-π(∗) transition band at 285.1nm (fosc=0.3543) in the gas phase. The rest of the spectral bands undergo either hyperchromic or hypsochromic shifts in the presence of solvent. Polarizability and HOMO-LUMO gap values were used to predict the nonlinear optical properties (NLO) of the studied compound. NBO analysis has been used to determine the most accurate Lewis structure of the studied molecule.

Unprecedented intermolecular transamidation reaction of N-carbamoylmethyl-N'-tosylguanidines.

[reaction: see text] N-Carbamoylmethyl-N'-tosyl guanidine 2 reacts easily with primary alkylamines to afford substituted carboxamides 3. The reaction proceeds via a five-membered-ring intermediate 5, which could be isolated, and features a rare example of an intermolecular transamidation reaction under mild conditions.

Synthesis and evaluation of 2-tosylamino and 2-tosyliminopyrimidine derivatives as inhibitors of some leukocyte functions.

We have studied the potential anti-inflammatory effects of 20 2-tosylamino and 2-tosyliminopyrimidine new derivatives in human neutrophils. We have evaluated their interference with some leukocyte functions and 5-lipoxygenase activity. All the compounds reduced neutrophil degranulation process at concentrations in the microM range. Besides, compounds with a phenolic substitution inhibited leukotriene B(4) biosynthesis in neutrophils and decreased the cell-free 5-lipoxygenase activity. This study demonstrates that 2-tosylamino and 2-tosyliminopyrimidine derivatives can reduce the activation of neutrophil cells which may have relevance for the modulation of the inflammatory response.

Self-assembled dicopper(II) diethanolaminate cores for mild aerobic and peroxidative oxidation of alcohols.

The new dicopper(ii) complexes [Cu(2)(µ-Hmdea)(2)(NCS)(2)] (1) and [Cu(2)(µ-Hedea)(2)(N(3))(2)]·(H(2)O)(0.25) (2) with the {Cu(2)(µ-O)(2)} diethanolaminate cores have been easily generated by aqueous medium self-assembly reactions of copper(ii) nitrate with N-methyl- or N-ethyldiethanolamine (H(2)mdea or H(2)edea, respectively), in the presence of sodium thiocyanate (for 1) or sodium azide (for 2) as ancillary ligands sources. They have been isolated as air-stable crystalline solids and fully characterized by IR and UV-vis spectroscopies, ESI-MS(+), elemental and single-crystal X-ray diffraction analyses. The latter complex also features a fourfold linkage of neighbouring dimeric units via strong intermolecular O-HO hydrogen bonds, giving rise to the formation of tetracopper aggregates. The catalytic activity of compounds 1 and 2 has been studied for the mild (50-80 °C) and selective oxidations of alcohols, namely for (i) the aerobic aqueous medium oxidation of benzyl alcohols to benzaldehydes, mediated by TEMPO radical, and for (ii) the solvent-free oxidation of secondary alcohols to ketones by t-BuOOH under microwave (MW) irradiation. Complex 2 shows the highest efficiency in both oxidation systems, resulting in up to 99% molar yields (based on the alcohol substrate) of products. In addition, remarkably high values of TON (1020) and TOF (4080 h(-1)) have been achieved in the MW-assisted peroxidative oxidation of 1-phenylethanol to acetophenone (model reaction). Attractive green features of these catalytic systems include the operation in aqueous or solvent-free reaction medium, under mild conditions and with high yields and selectivities, using Cu catalyst precursors that are readily available by self-assembly in water of simple chemicals.

Solvent-free microwave-assisted peroxidative oxidation of secondary alcohols to the corresponding ketones catalyzed by copper(ii) 2,4-alkoxy-1,3,5-triazapentadienato complexes.

A facile, efficient and selective solvent-free synthesis of ketones from secondary alcohols with tert-butylhydroperoxide (TBHP) as the oxidant under microwave irradiation is achieved, where the copper(ii) 2,4-alkoxy-1,3,5-triazapentadienato complexes are efficient catalysts providing high yields (up to 100%), TONs (up to 890) and TOFs (up to 1780 h(-1)).

Single-pot template transformations of cyanopyridines on a Pd(II) centre: syntheses of ketoimine and 2,4-dipyridyl-1,3,5-triazapentadiene palladium(II) complexes and their catalytic activity for microwave-assisted Suzuki-Miyaura and Heck reactions.

[2 + 3] cycloaddition of the pyrrolin N-oxide (-)O[upper bond 1 start](+)N[double bond, length as m-dash]CHCH(2)CH(2)C[upper bond 1 end]Me(2) with 2-cyanopyridine NC(5)H(4)(2-CN) in the presence of PdCl(2) at room temperature in acetone gives the ketoimine palladium(II) complex cis-[PdCl(2){N(=[upper bond 1 start]CCH(2)CH(2)C(Me)(2)N[upper bond 1 end]H)C(=O)C(5)H(4)N}] containing the (E)-N-(5,5-dimethylpyrrolidin-2-ylidene)picolinamide ligand, in good yield (85%). The reaction of with 3-cyanopyridine NC(5)H(4)(3-CN) or 4-cyanopyridine NC(5)H(4)(4-CN) under the same experimental conditions gives the simple adducts of cyanopyridines trans-[PdCl(2){NC(5)H(4)(3-CN)}(2)] or trans-[PdCl(2){NC(5)H(4)(4-CN)}(2)] , respectively. When the cyanopyridines NC(5)H(3)R(1)R(2) (R(1) = 2-CN, R(2) = H ; R(1) = 3-CN, R(2) = H ; R(1) = 4-CN, R(2) = H ; R(1) = 4-CN, R(2) = 2-Cl ; R(1) = 3-CN, R(2) = 5-Me ) are heated at 100 degrees C for 12 h with 2-butanone oxime (used as a reagent and solvent) in the presence of PdCl(2), the 2,4-dipyridyl-1,3,5-triazapentadienate (or bis-imidoylamidinate) palladium(II) complexes [Pd{HN[double bond, length as m-dash]C(NC(5)H(3)R(2))NC(NC(5)H(3)R(2))[double bond, length as m-dash]NH}(2)] (2-NC(5)H(3), R(2) = H ; 3-NC(5)H(3), R(2) = H ; 4-NC(5)H(3), R(2) = H ; 4-NC(5)H(3), R(2) = 2-Cl ; 3-NC(5)H(3), R(2) = 5-Me ) are synthesized by one-pot template transformations followed by deprotonation by a base (n-PrNH(2)). The compounds were characterized by IR, (1)H and (13)C NMR spectroscopies, FAB(+)-MS, elemental analyses and, in the cases of , , and , also by X-ray diffraction analyses. The catalytic activity of complexes and was studied under microwave irradiation for C-C coupling reactions, in the solid phase on a silica gel support, and it was found that complex is the most active one with the maximum TON of 2.0.10(5) and TOF of 1.3.10(4) min(-1) for Suzuki-Miyaura, and TON of 800 and TOF of 27 min(-1) for Heck reactions.

Pd(II)-promoted [2 + 3] cycloaddition of pyrroline N-oxide to organonitriles. Application of (Delta(4)-1,2,4-oxadiazoline)-Pd(II) complexes in the Suzuki-Miyaura reaction.

[2 + 3] Cycloaddition reactions of the organonitriles RCN 1 (R = Me (1a), Et (1b), p-IC(6)H(4) (1c), p-BrC(6)H(4) (1d), p-ClC(6)H(4) (), p-FC(6)H(4) (1e)) with the pyrroline N-oxide (-)O(+)[upper bond 1 start]N[double bond, length as m-dash]CHCH(2)CH(2)C[upper bond 1 end]Me(2) in the presence of PdCl(2) proceed at room temperature for 12 h and allow the isolation of the corresponding palladium(ii) complexes trans-[PdCl(2){[upper bond 1 start]N[double bond, length as m-dash]C(R)O[lower bond 1 start]NC[upper bond 1 end](H)CH(2)CH(2)C[lower bond 1 end]Me(2)}(2)] 3a-3f containing fused bicyclic Delta(4)-1,2,4-oxadiazoline ligands, in good to excellent yields (75-90%). Treatment of trans-[PdCl(2)(EtCN)(2)] with the nitrone in acetone or propionitrile at room temperature affords, in good yield, (R = Et), confirming that complexes 3 are formed via nitrile activation by coordination. These reactions proceed with high diastereoselectivity and afford mixtures of enantiomers, due to the rigid conformation (E) of the cyclic nitrone 2. The oxadiazolines [upper bond 1 start]N[double bond, length as m-dash]C(R)O[lower bond 1 start]NC[upper bond 1 end](H)CH(2)CH(2)C[lower bond 1 end]Me(2) (R = Et (4b), p-FC(6)H(4) (4f)) are liberated upon reaction of complexes 3b,3f with a diphosphine (dppe). During the liberation of , the complex trans-[PdCl(2){[upper bond 1 start]N[double bond, length as m-dash]C(NHCOC(6)H(4)F-4)CH(2)CH(2)C[upper bond 1 end]Me(2)}(2)] was formed in a minor amount upon N-O bond cleavage of the oxadiazoline ring to give a pyrrolylbenzamide species coordinated by the N-atom of the pyrrolyl moiety. The compounds were characterized by IR, (1)H and (13)C NMR spectroscopies, ESI-MS, elemental analyses and, in the cases of 3b, 3d and 5, also by X-ray diffraction analyses. Complexes 3b and 3f show a high catalytic activity towards the microwave-assisted Suzuki-Miyaura cross-coupling reaction in aqueous medium, achieving a TON value of 2.7 x 10(5) and a TOF value of 1.1 x 10(6) h(-1).

Metal-free and PdII-promoted [2+3] cycloadditions of a cyclic nitrone to phthalonitriles: syntheses of oxadiazolines as well as phthalamide-PdII and dihydropyrrolyl-iminoisoindolinone-PdII complexes with high catalytic activity in Suzuki-Miyaura cross-coupling reactions.

The previously unknown reactions between phthalonitriles, 1,2-(CN)2(C6)R1R2R3R4 1 (1 a, R1=R2=R3=R4=H; 1 b, R1=R2=R4=H, R3=CH3; 1 c, R1=R4=H, R2=R3=Cl; 1 d, R1=R2=R3=R4=Cl; 1 e, R1=R2=R3=R4=F), and a cyclic nitrone, -O+N==CHCH2CH2CMe2 2, proceed under heating in a sealed tube to give phthalimides 3, 2-oxadiazolyl-benzonitriles 4 or ortho-bis(oxadiazolyl)tetrafluorobenzene 4 e'. In the presence of palladium(II) chloride, phthalonitriles 1 react with 2 at room temperature, to give bis(pyrrolidin-2-ylidene)phthalamide PdII complexes 5 via metal-promoted rupture of the N--O bond of the oxadiazoline ring. The ketoimine ligands thus generated can be liberated from the metal by displacement with a diphosphine. Although the first [2+3] cycloaddition of 2 to 1 can occur in the absence of the metal to give the mono-cycloadducts 4, the second [2+3] coupling at the still-unreacted cyano group requires its activation by coordination to PdII, affording complexes 6 containing two ligated oxadiazolyl-benzonitriles. These ligands undergo either i) further cycloaddition with 2 to afford ultimately (upon rearrangement) the bis(pyrrolidinylidene)phthalamide complexes 5 or ii) N--O bond cleavage in the oxadiazoline ring with intramolecular attack of the imine nitrogen on the cyano carbon and bridging to a second PdII center to afford dimeric palladium(II) complexes 7, with chloride bridges, that bear a dihydropyrrolyl-iminoisoindolinone, a new type of ligand.The compounds were characterized by IR, 1H, and 13C NMR spectroscopy, ESI MS or FAB+ MS, elemental analyses and, in the case of 4 c, 5 a, 5 c, and 7 c, also by X-ray diffraction analysis. Complexes 5 a and 7 c show high catalytic activity for the Suzuki-Miyaura cross-coupling reaction of bromobenzene and phenylboronic acid and give biphenyl in high yields with turnover frequencies (TOFs) of up to 9.0x10(5) h(-1).

Stereospecific synthesis of polysubstituted E-olefins by reaction of acyclic nitrones with free and platinum(II) coordinated organonitriles.

Free nitriles NCCH2R (1a R = CO2Me, 1b R = SO2Ph, and 1c R = COPh) with an acidic alpha-methylene react with acyclic nitrones -O+N(Me)=C(H)R' (2a R' = 4-MeC6H4 and 2b R' = 2,4,6-Me3C6H2), in refluxing CH2Cl2, to afford stereoselectively the E-olefins (NC)(R)C=C(H)R' (3a-3c and 3a'-3c'), whereas, when coordinated at the platinum(II) trans-[PtCl2(NCCH2R)2] complexes (4a R = CO2Me and 4b R = Cl), they undergo cycloaddition to give the (oxadiazoline)-PtII complexes trans-[PtCl2{N=C(CH2R)ON(Me)C(H)R'}2] (R = CO2Me, Cl and R' = 4-MeC6H4, 2,4,6-Me3C6H2) (5a-5d). Upon heating in CH2Cl2, 5a affords the corresponding alkene 3a. The reactions are greatly accelerated when carried out under focused microwave irradiation, particularly in the solid phase (SiO2), without solvent, a substantial increase of the yields being also observed. The compounds were characterized by IR and 1H, 13C, and 195Pt NMR spectroscopies, FAB+-MS, elemental analyses and, in the cases of the alkene (NC)(CO2Me)C=C(H)(4-MeC6H4) 3a and of the oxadiazoline complex trans-[PtCl2{N=C(CH2Cl)ON(Me)C(H)(4-C6H4Me)}2] 5c, also by X-ray diffraction analyses.

Mixed unsymmetric oxadiazoline and/or imine platinum(II) complexes.

Iminoacylation of acetone oxime Me(2)C[double bond, length as m-dash]NOH upon reaction with trans-[PtCl(2)(NCCH(2)CO(2)Me)(2)] and [2 + 3] cycloaddition of acyclic nitrone (-)O(+)N(Me) = C(H)(C(6)H(4)Me-4) to a nitrile ligand in lead to the formation of mono-imine trans-[PtCl(2)(imine-a)(NCCH(2)CO(2)Me)] [imine-a = NH[double bond, length as m-dash]C(CH(2)CO(2)Me)ON = CMe(2)] and mono-oxadiazoline trans-[PtCl(2)(oxadiazoline-a)(NCCH(2)CO(2)Me)] [oxadiazoline-a = [upper bond 1 start]N[double bond, length as m-dash]C(CH(2)CO(2)Me)ON(Me)C[upper bond 1 end](H)(C(6)H(4)Me-4)] unsymmetric mixed ligand complexes, respectively, as the main products. Reactions of or with acetone oxime , cyclic nitrone (-)O(+)N = CHCH(2)CH(2)C[upper bond 1 end]Me(2) or N,N-diethylhydroxylamine give access, in moderate to good yields, to the unsymmetric mixed ligand oxadiazoline and/or imine complexes trans-[PtCl(2)(oxadiazoline-a)(imine-a)] , trans-[PtCl(2)(oxadiazoline-a)(oxadiazoline-b)] [oxadiazoline-b = [upper bond 1 start]N[double bond, length as m-dash]C(CH(2)CO(2)Me)O[lower bond 1 start]NC[upper bond 1 end](H)CH(2)CH(2)C[lower bond 1 end]Me(2)], trans-[PtCl(2)(imine-a)(imine-b)] [imine-b = NH = C(CH(2)CO(2)Me)ONEt(2)] or trans-[PtCl(2)(imine-a)(oxadiazoline-b)] . The cis mono-imine mixed ligand complex cis-[PtCl(2)(imine-a)(NCCH(2)CO(2)Me)] is the major product from the reaction of cis-[PtCl(2)(NCCH(2)CO(2)Me)(2)] with the oxime , while the di-imine compound cis-[PtCl(2)(imine-a)(2)] is a minor product. Reaction of cis-[PtCl(2)(imine-a)(NCCH(2)CO(2)Me)] with N,N-diethylhydroxylamine or the cyclic nitrone affords, in good yields, the unsymmetric mixed ligand complexes cis-[PtCl(2)(imine-a)(imine-b)] or cis-[PtCl(2)(imine-a)(oxadiazoline-b)] , respectively. All these complexes were characterized by elemental analyses, IR and (1)H, (13)C and (195)Pt NMR spectroscopies, and FAB(+)-MS. The X-ray structural analysis of trans-[PtCl(2){NH=C(CH(2)CO(2)Me)ON=CMe(2)}(NCCH(2)CO(2)Me)] is also reported.

Microwave synthesis of mono- and bis-tetrazolato complexes via 1,3-dipolar cycloaddition of organonitriles with platinum(II)-bound azides.

[2 + 3] Cycloaddition reactions of the diazidoplatinum(II) complexes cis-[Pt(N3)2(PPh3)2] 1 and cis-[Pt(N3)2(2,2'-bipy)] 4 with organonitriles NCR 2 give the bis(tetrazolato) complexes trans-[Pt(N4CR)2(PPh3)2] 3 [R = Me (3a), Et (3b), Pr (3c), Ph (3d), 4-ClC6H4 (3e)] and cis-[Pt(N4CR)2(2,2'-bipy)] 5 [R = Me (5a), Et (5b), Pr (5c), Ph (5d)]. The reaction of cis-[Pt(N3)2(PPh3)2] I with propionitrile also affords, apart from 3b, the unexpected mixed cyano-tetrazolato complex trans-[Pt(CN)(5-ethyltetrazolato)(PPh3)2] 3b' which is derived from the reaction of the bis(tetrazolato) 3b with propionitrile, with concomitant formation of 5-ethyl-1H-tetrazole, via a suggested unusual oxidative addition of the nitrile to PtII. All these reactions are greatly accelerated by microwave irradiation and this method also shows a higher selectivity in the case of the reaction of propionitrile with 1, leading only to the formation of 3b. All the complexes obtained were characterized by IR, 1H, 13C and 31P[1H] (for complexes 3) NMR spectroscopies, FAB-MS and elemental analyses. Complexes 3b', 3d, 3e and 5d were also characterized by X-ray structural analyses.

Direct synthesis of (imine)platinum(II) complexes by iminoacylation of ketoximes with activated organonitrile ligands.

The metal-mediated iminoacylation of ketoximes R1R2C=NOH (1a R1 = R2 = Me; 1b R1 = Me, R2 = Et; 1c R1R2 = C4H8; 1d R1R2 = C5H10) upon treatment with the platinum(II) complex trans-[PtCl2(NCCH2CO2Me)2] 2a with an organonitrile bearing an acceptor group proceeds under mild conditions in dry CH2Cl2 to give the trans-[PtCl2{NH=C(CH2CO2Me)ON=CR1R2}2] 3a-d isomers in moderate yield. The reaction of those ketoximes with trans-[PtCl2(NCCH2Cl)2] 2b under the same experimental conditions gives a 1 : 1 mixture of the isomers trans/cis-[PtCl2{NH=C(CH2Cl)ON=CR1R2}2] 3e-h and 4e-h in moderate to good yield. These reactions are greatly accelerated by microwave irradiation to give, with higher yields (ca. 75%), the same products which were characterized by IR and 1H, 13C and 195Pt NMR spectroscopies, FAB-MS, elemental analysis for the stable trans isomers, and X-ray diffraction analysis (3f). The diiminoester ligand in 3a was liberated upon reaction of the complex with a diphosphine.