Loreto Ballester

Structural, magnetic, electrical and optical characterization of systems built from [M([9]aneN3)2]2+ (M=CuII or NiII) and TCNQ or TCNQF4

Three different supramolecular architectures corresponding to [M([9]aneN 3 ) 2 ](TCNQ) 2 , (M=Ni II 1 or Cu II 2, [9]aneN 3 =1,4,7-triazacyclononane, TCNQ=7,7,8,8-tetracyanoquinodimethane), [Cu([9]aneN 3 ) 2 ](TCNQ) 3 3 and [Cu([9]aneN 3 ) 2 ](TCNQF 4 ) 2 , 4 (TCNQF 4 =2,3,5,6-tetrafluoro-7,7,8,8,-tetracyanoquinodimethane), have been prepared and crystallographically characterized: 1, triclinic, P1, a=8.6488(9), b=8.919(3), c=11.316(2) A, α=82.06(2), β=74.331(10), γ=85.71(2)°, Z=1; 2, triclinic, P1, a=8.6806(11), b=8.915(5), c=11.348(2) A, α=82.03(3), β=74.109(14), γ=84.95(2)°, Z=1; 3, triclinic, P1, a=8.350(2), b=9.884(4), c=14.369(4) A, α=74.10(2), β=89.01(2), γ=69.11(2)°, Z=1; 4, triclinic, P1, a=15.476(5), b=16.146(4), c=16.441(4) A, α=77.15(2), β=78.04(3), γ=85.43(3)°, Z=2. Compounds 1 and 2 are formed by dimeric (TCNQ) 2 2– units and 4 by three different dimeric (TCNQF 4 ) 2 2– units. Compound 3 is formed by isolated [Cu([9]aneN 3 ) 2 ] 2+ groups and trimeric (TCNQ) 3 2– units. The electrical, optical and magnetic properties of the four new compounds have been interpreted on the basis of their supramolecular architectures.

Mono- and dinitrosyl complexes of molybdenum: crystal structure of molybdenum dinitrosyl bis(2-picolinate)

Abstract The reaction of the [Mo(NO)2]2+ moiety with the (X,Y)-donor ligands (X,Y = dithiocarbamates, xanthates, 2-picolinate, o-aminophenoxide, o-aminothiophenoxide or dithizone) leads fundamentally to formation of complexes of type Mo(NO)2(X,Y)2. Sometimes secondary products are also formed, as for example the mononitrosyl heptacoordinated complex Mo(NO)(2-pic)3 (5) (2-pic = 2-picolinate). In the reaction with dithizone a complex of composition Mo(NO)2(HDtz)2(H2Dtz) was isolated. The Mo(NO)2(R2dtc)2 (R2dtc = N,N-dialkyldithiocarbamates) complexes decompose in CHCl3 or by reaction with CO in CH2Cl2 to give the mononitrosyl derivatives Mo(NO)(R2dtc)3. The reaction of complex 6 with PPh3 yields Mo(2-pic)3·H2O. The crystal structure of Mo(NO)2(2-pic)2 has been determined. The crystals are orthorhombic, space group Pbca with a = 12.502(3), b = 15.15(4), c = 15.296(6) A, U = 2897(8) A3, z = 8, Dc = 1.84 g cm−3 μ(Mo-Kα) = 9.23 cm−1, F(000) = 1584. The Mo atom presents a distorted octahedral coordination. The atomic parameters have been refined by least-squares analysis of 1845 observed reflexions to R = 0.025.

Five-coordinate nickel(II) xanthate derivatives with triphos. Crystal structure of tris(O-cyclohexyldithiocarbonato)nickelate(II) of bis(2-diphenylphosphinoethyl)phenylphosphine-O-cyclohexyldithiocarbonatonickel(II)

Abstract Five-coordinate complexes, [Ni(S 2 COR)(TRIPHOS)]X (R = cyclo-C 6 H 11 , X = Cl, PF 6 , [Ni(S 2 COC 6 H 11 ) 3 ]; R = Et, X = PF 6 , [Ni(S 2 COEt) 3 ]), have been obtained by the reaction of O-alkyldithiocarbonato complexes, [Ni(S 2 COR) 2 ], with bis(2-diphenylphosphinoethyl)phenylphosphine (TRIPHOS). The structure of [Ni(S 2 COC 6 H 11 ) (TRIPHOS)][Ni(S 2 COC 6 H 11 ) 3 ] was determined by X-ray crystallography. The compound contains a five-coordinate cation and a hexa-coordinate anion. The geometry about the nickel atom in the [Ni(S 2 COC 6 H 11 )(TRIPHOS)] + is distorted trigonal bipyramidal with the axial positions occupied by one sulfur atom of the bidentate O-cyclohexyldithiocarbonate and the central phosphorus atom of the TRIPHOS. In the [Ni(S 2 COC 6 H 11 ) 3 ] − anion, the nickel atom is bonded to six sulfur atoms of three O-cyclohexyldithiocarbonate ligands. Formation of the dithiocarbonato complexes in the reactions of [Ni(S 2 COEt) 2 ] with TRIPHOS has also been observed.

Supramolecular architecture and magnetic properties of copper(II) and nickel(II) porphyrinogen-TCNQ electron-transfer salts.

The compounds [Cu(Tz)-(MeOH)2](TCNQ)2 (1), [Ni(Tz)-(MeOH)2](TCNQ)2 (2), [Cu(Tz)2]-(TCNQ)7 (3) and [Ni(Tz)2](TCNQ)7 (4) (Tz = 2,7,12,17-tetramethyl-1,6,11,16-tetraazaporphyrinogen) were obtained by metathesis reaction of [M(Tz)](ClO4)2 with LiTCNQ and Et3NH(TCNQ)2, respectively. They were characterized by a combination of spectroscopic and physical methods. Compound 1 crystallizes in the monoclinic space group P2(1)/n with a = 8.310(2), b = 25.180(4), c = 20.727(4) A, beta = 93.58(2) degrees; Z = 4. Compound 3 crystallizes in the triclinic space group P1 with a = 11.244(1), b = 16.700(1), c = 17.321(1) A, a = 113.47(1), beta = 108.52(1), gamma = 96.12(1) degrees; Z = 2. The asymmetric unit of the compound 1 is formed by cationic [Cu(Tz)(MeOH)2]2+ and by two crystallographically non equivalent TCNQ.- anions; these anions form dimeric units by overlap of the pi clouds. The dimers form hydrogen bonds with the metal-lomacrocyclic cation through the methanol ligands. According to this structure the compound is paramagnetic and behaves as an insulator in the temperature range studied. The paramagnetism arises only from the metal-complex moieties. Compound 3 shows an unprecedented structure due to the steric requirements of the macrocycle that favors the stacking of the TCNQ groups. The structure consists of infinite stacks of TCNQ units separated by the metal-macrocyclic units; there are seven TCNQ molecules per formula unit, one of which is formally mono-anionic, while the other six bear one half of an electron per molecule. The copper is six-coordinate in a very distorted octahedral environment. The Tz ligand is located in the equatorial plane and the apical nitrogens of the nitrile groups of two TCNQ molecules complete the coordination around the copper. The compound is a semiconductor and its magnetic behavior can be explained by the sum of the Curie contribution of the metal complex and the contribution arising from the magnetic-exchange interactions of the spins located on the TCNQ units. The latter is found to be typical of one-dimensional antiferromagnetic distorted chains of S = 1/2 spins and can be fitted according to a one-dimensional Heisenberg antiferromagnetic model.

Magnetic and optical characterization of one-dimensional isostructural σ-bonded tetracyanoquinodimethanido complexes of nickel(II) and copper(II)

The complex [CuL(tcnq)2][L = 3,10-bis(2-hydroxyethyl-1,3,5,8,10,12-hexaazacyclotetradecane); tcnq = 7,7,8,8-tetracyanoquinodimethane] has been prepared and crystallographically characterized. Its structure consists of linear chains of alternating copper–macrocycle and tetracyanoquinodimethanide dimers σ bonded to the copper atoms through a nitrile group. The compound is an insulator. The magnetic properties of both the copper and corresponding nickel compounds are the sums of the contributions arising from the transition-metal ion in octahedral symmetry and of (tcnq)22– dimers. The magnetic data were fitted by a model which accounts for contributions from independent Curie spins for the cation and a thermally activated triplet state for the dimerized anions. No magnetic interactions between the metal ion and tcnqs have been observed, even at low temperatures.

Reactivity of ruthenium complexes with uninegative (X,S)-donor ligands (X=S,P). II: Phosphine substitution in [Ru(S,S)2(PR3)2] derivatives, crystal structure of trans-bis(O-ethyldithiocarbonate)bis(dimethylphenylphosphine)-ruthenium(II)

Abstract The complexes [Ru(S,S)2(PPh3)2] [S,S  EtCOCS2−, (CH2)4NCS2−] react with a variety of tertiary phosphines with the substitution of triphenylphosphine and the formation of [Ru(S,S)2(PR3)2]. The reaction occurs with the formation ofthe cis isomer, except for the complex with PMe2Ph that gives rise to the trans isomer as the crystal structure shows. The effect of the different phosphines on the ruthenium complex is analysed in terms of the spectroscopic and electrochemical properties of the isolated compounds. The cyclic voltammetric studies of the cis complexes show that isomerization to the trans isomer occurs on oxidation. This isomerization is not observed in the trans-[Ru(S,S)2(PMe2Ph)2] complexes that give rise to stable trans-ruthenium(II)/ruthenium(III) couples. In a similar way the diphosphine complexes afford a quasi-reversible cis-ruthenium(II)/ruthenium(III) process.

Carbonyl complexes of molybdenum and tungsten with sulfur donors: IV. Pyridine replacement reactions of Mo(S,S)(π-allyl)-(CO)2(py) complexes ((S,S) = xanthate and dithiocarbamate)☆

Abstract The reactions of Mo(S,S)(π-allyl)(CO) 2 (py) [(S,S) = methylxanthate, N -ethyldithiocarbamate and N,N -diethyldithiocarbamate] with various N- and P-donor mono- bi-dentate ligands has given four types of mono- and bi-nuclear complexes: Mo(S,S)(π-allyl)(CO) 2 (L) [(S,S_ = Mexant, EtHdtc, Et 2 dtc; L = PPh 3 ], Mo(S,S)(π-allyl)(CO) 2 (LL) [(S,S) = Mexant, (LL) = bipy, phen, DDH, GBCHI; (S,S) = EtHdtc, (LL) = bipy, phen, GBCHI; (S,S) = Et 2 dtc, (LL) = phen¦, [Mo(S,S)(π-allyl)(CO) 2 ] 2 (μ-LL) [(S,S) = Mexant, EtHdtc, Et 2 dtc; (LL) = 4,4′-DTBP, dppe], and [Mo(S,S)(π-allyl)(LL)] 2 (μ-CO) 2 [(S,S) = EtHdtc, Et 2 dtc; LL = dppe]. In some cases the pyridine replacement is accompanied by a change in the coordination mode of the 1,1,-dithiolate ligand.

Electrochemical synthesis and studies on the reactivity of heterocylic-thionato derivatives of nickel(II) with nitrogen donor bases

Abstract The [Ni(S,N)2] complexes (S,N = 1,3-thiazolidine-2-thionato, tzdt, 1,3-thiazoline-2-thionato, tzt, and 2-mercaptobenzothiazolato, mbt) have been obtained in good yield by direct electrochemical oxidation of nickel in the presence of the corresponding ligand. The [Ni(tzdt)2] and [Ni(mbt)2] derivatives react with nitrogen donor bases to give the adducts [Ni(S,N)2(L)2] (L = substituted pyridines and primary amines) and [Ni(S,N)2L] (L = bpy, phen, dmp) also obtained by direct electrochemical synthesis. A crystal structure analysis shows that in [Ni(mbt)2(dmp)] the hexacoordinated environment of the nickel atom is formed by two bidentate mbt ligands and one dmp ligand.

N-bonded TCNQ in stacked dimeric systems. Synthesis and crystal structure of [Ru(PPh3)2(TCNQ)]2(TCNQ = 7,7,8,8-tetracyanoquinodimethane)

The reaction of [Ru(CO)2(PPh3)2(thf)2](BF4)2(thf = tetrahydrofuran) with PPh3 in CH2Cl2 and LiTCNQ in methanol leads to the formation of [Ru(PPh3)2(TCNQ)]; the crystal structure of this compound shows a tetrahedral environment of the ruthenium atom with the TCNQ molecule coordinated via N.

MONOMERIC AND DIMERIC RUTHENIUM-TCNQ COMPLEXES CONTAINING PHOSPHINE LIGANDS (TCNQ=7,7,8,8-TETRACYANOQUINODIMETHANE)

Abstract Treatment of [Ru(CO)2(PPh3)2(THF)2](BF4)2 with LiTCNQ (TCNQ = 7,7,8,8-tetracyanoquinodimethane) in dichloromethane at reflux resulted in the formation of [Ru(CO)2(PPh3)2(TCNQ)]BF4 (1). The synthesis of the carbonylhydride compound [RuH(CO)(PPh3)2(TCNQ)]2 (2) was carried out by reaction of RuHCl(CO)(PPh3)3 and TCNQ or from [RuH(CO)(PPh3)2(CH3CN)2]PF6 and LiTCNQ. The preparation of compounds with diphosphines [Ru(dppe)2(TCNQ)]2TCNQ(ClO4) (3) and [Ru(dppm)3 TCNQ]ClO4 (4) is also described. In all cases substitution reactions of labile ligands occurred with formation of compounds with σ-coordinated TCNQ. From IR, UV-vis, 1H and 31P NMR spectroscopy and FAB mass spectrometric determinations, monomeric and dimeric compounds are proposed.