Synthesis of mono- and bis-tetrazolato complexes of Ni(II), Pt(II) and Cu(II) via 1,3-dipolar cycloadditions of 2-cyanopyridines with metal ligated azides in N,N,O-aminoiminophenolato complexes.

Reactions of the aminoiminophenols 2-((2-(dimethylamino)ethylimino)methyl)phenol (HL(1)) or 2-{(3-(dimethylamino)propylimino)methyl}phenol (HL(2)) with nickel(II) chloride, K(2)[PtCl(4)] or copper(II) acetate in alcoholic solution, in the absence or in the presence of sodium azide, afford the corresponding new mononuclear complexes [M(L(1))(X)(H(2)O)(n)] [M = Ni, X = Cl(-), n = 2 (); M = Ni, X = N(3)(-), n = 0 (); M = Pt, X = Cl(-) () or N(3)(-) (), n = 0] or the known dinuclear compound [Cu(L(2))(N(3))](2) (). Complexes , and react with 2-cyanopyridine leading to the [2 + 3] cycloaddition products with 5-(2-pyridyl)tetrazolato [PTZ = N(4)C(2-NC(5)H(4))] ligands [Ni(L(1))(PTZ)](2) (), [Pt(L(1))(PTZ)] () and [Cu(PTZ)(2)(H(2)O)(2)] . The obtained complexes were characterized by IR, (1)H and (13)C (for , and ) NMR spectroscopies, elemental analyses and single crystal X-ray diffraction analyses (for , , , , and ).

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.

New water-soluble azido- and derived tetrazolato-platinum(II) complexes with PTA. Easy metal-mediated synthesis and isolation of 5-substituted tetrazoles.

The water-soluble four- and five-coordinate diazido-platinum(II) complexes cis-[Pt(N3)2(PTA)2] (1) (PTA = 1,3,5-triaza-7-phosphaadamantane), cis-[Pt(N3)2(Me-PTA)2]I2 (2) (Me-PTA = N-methyl-1,3,5-triaza-7-phosphaadamantane cation) and [Pt(N3)2(PTA)3] (3) were obtained by reactions of cis-[Pt(N3)2(PPh3)2] with PTA or [Me-PTA]I in dichloromethane. [2 + 3] cycloadditions of with organonitriles NCR gave the bis(tetrazolato) complexes trans-[Pt(N4CR)2(PTA)2] (R = Ph (4), 4-ClC6H4 (5) or 3-NC5H4 (6)), the reactions being greatly accelerated by microwave irradiation. 5-R-1H-Tetrazoles N4CR (R = Ph, 4-ClC6H4 and 3-NC5H4) were easily liberated from the tetrazolato complexes and isolated in high yields, in a single-pot process, upon reaction with aqueous diluted HCl, with concomitant formation of the water soluble cis-[Pt(Cl)2(PTA-H)2] complex 7.

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.

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.

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.

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.

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.

Unprecedented single-pot synthesis of nitrile-derived ketoimino platinum(II) complexes by ring opening of Delta4-1,2,4-oxadiazolines.

[PtCl2(RCN)2] (1a R=CH2CO2Me, 1b R=CH2Cl) prepared upon EtCN replacement at [PtCl2(EtCN)2] by the appropriate organonitrile, react with a cyclic nitrone -O-+N=CHCH2CH2C(Me)2, under mild conditions, to give, in an unprecedented single-pot synthesis involving spontaneous N-O bond cleavage, the ketoimino complexes trans-[PtCl2[RC(=O)N=CN(H)C(Me)2-CH2CH2]2 (2a, 2b) with two (pyrrolidin-2-ylidene)amino ligands. The analogous 2c (R=Et) and 2d (R=Ph) are formed by treatment with H2, in the absence of any added catalyst, of the Delta4-1,2,4-oxadiazoline complexes trans-[PtCl2[N=C(R)ONC(Me)2CH2CH2CH]2] (3a R=Et, 3b R=Ph) derived from the [2 + 3]-cycloaddition of the cyclic nitrone with the appropriate organonitrile complex of type 1. The compounds were characterized by elemental analyses, IR, 1H, (13C and 195Pt NMR spectroscopies, FAB mass spectrometry and X-ray structure analyses for 2a and 2d.