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Reactions of bis[diphenyl-3-(4-methoxyphenylsydnonyl)]phosphine palladium chloride and amines yielded trans-amminedichloropalladium complexes, which were characterized by spectroscopic techniques (compounds 5–9) and X-ray diffraction (compounds 5 and 7). Bond lengths of PC(10), P-(16) decrease more than that of P-(1) after the complex is formed, suggesting that the phenyl rings are able to contribute more electron density to phosphorus for binding with Pd(II) than the sydnone ring. The equilibrium constants and rate constants for the reaction between complex 4 and amines depend not only on the basicity but also on the steric size of amines used.

Dissolution of [CpRu(PPh 3 )(SC 4 H 8 ) 2 ]CF 3 SO 3 in thietane/CH 2 Cl 2 with stirring yields the title compound [CpRu(PPh 3 )(SC 3 H 6 ) 2 ]CF 3 SO 3 ( I ). The single crystal X-ray structure shows a disparity in the puckering of the two thietanes. One thietane ligand is near-planar, with torsion angles of ±1.5(5)° for CSCC and ±1.8(4)° for CCCS; the second thietane ligand of I has torsion angles of ±21.0(4)° for CSCC and ±25.0(3)° for CCCS. Compound I contains both the largest and the smallest torsion angles for any complex reported. Theoretical calculations were carried out for both thietane and for I using the gamess and gaussian 98 packages.

Bifunctional 1,2,3-dithiazoles bridged with azine and phenylenediamine spacers have been prepared, with a view to determining the extent of communication between the two dithiazole rings as a function of the electronic and steric demands of the bridge. The crystal structure of the closed-shell diazine derivative [S(2)NClC(2)=NN=C(2)ClNS(2)] is rigorously planar. Cyclic voltammetry on this compound indicates two reversible one-electron oxidations. The radical cation state has been characterized by EPR spectroscopy and by crystal structure determination of its 1:1 PF(6)(-) salt. The latter reveals little interaction between neighboring radical cations; consistently, the material exhibits a conductivity of sigma10(-5) S cm(-1). Insertion of a phenylene group into the diazine bridge to afford [S(2)NClC(2)=NC(6)H(4)N=C(2)ClNS(2)] leads to significant torsional motion between the phenylene ring and the two end groups, as a result of which the two DTA rings are electronically independent; no radical cation state has been observed for this species. Crystal data for Cl(2)S(4)N(4)C(4): a = 5.1469(15), b = 13.343(2), c = 14.2031(17), orthorhombic, Pbca, Z = 4. Crystal data for Cl(2)S(4)N(4)C(4)PF(6): a = 11.699(4), b = 12.753(5), c = 10.461(4), beta = 112.17(1) degrees, monoclinic, C2/c, Z = 4. Crystal data for C(l2)S(4)N(4)C(10)H(4): a = 3.9477(6), b = 23.790(3), c = 7.3769(9), beta =90.793(12) degrees, monoclinic, P2(1)/c, Z = 2.

Monomeric five-coordinate nickel−cysteine complexes were prepared using anionic tris(3,5-disubstituted pyrazolyl)borates (Tp* - and TpPhMe-) and l-cysteine (ethyl ester and amino acid forms). Tp*NiCysEt crystallizes with a single methanol of solvation in the monoclinic space group P21: a = 7.8145(18), b = 24.201(6), c = 7.9925(14) A; β = 117.991(16)°. [Tp*NiCys-][K+] and TpPhMeNiCysEt show magnetic and electronic characteristics similar to Tp*NiCysEt, so that the trigonal bipyramidal coordination geometry confirmed for Tp*NiCysEt in the solid state likely applies to all three. All three complexes have high spin magnetic ground states at room temperature (μeff = 2.9−3.2 μB, S =1). Their electronic spectra are dominated by sulfur to nickel charge-transfer bands (388−430 nm in chloroform) with energies that correlate to respective thiolate basicities and TpX- donor strengths. The Tp* derivatives undergo a rapid reaction with molecular oxygen. Stoichiometric, infrared, and electronic spectroscopy measurement...

We report the preparation, crystallization, and solid-state characterization of a spiro-biphenalenyl radical. The crystal structure shows that the radical is monomeric in the solid state and withou...

The isolation and characterization of [CpRu(9S3)](O3SCF3), where 9S3 = 1,4,7-trithiacyclononane, is reported. The title compound crystallizes in the orthorhombic space group Pbca: a = 10.2542(18), b = 14.8991(13), c = 22.4832(18) A, and Z = 8. The Ru atom is sandwiched between the π-bound cyclopentadienyl ligand and the 9S3 ligand, bonding to all three of the sulfur atoms in the 9S3. The Ru—S distances are 2.2991(10), 2.2979(11), and 2.3055(10) A. The C—S distances range from 1.819(4) to 1.852(5) A in the trithiacyclononane ring.

The reactions of chlorocyclophosphazenes N3P3Cl6 (1) and N4P4Cl8 (2) and polydichlorophosphazene (3) with cyclohexylamine, cyclopentylamine, and cyclopropylamine have been studied. The major product with 1 is the geminal tetrakis derivative N3P3Cl2(NHR)4, while 2 gives the completely substituted derivative, N4P4(NHR)8. X-ray crystal structure determinations of N3P3Cl2(NHC6H11)4 (1a) and N4P4(NHC3H5)8 (2c) have been carried out. 1a crystallizes in a triclinic space group, P1, with a = 11.2330(13) A, b = 11.4269(16) A, c = 13.4055(12) A, α = 72.211(10)°, β = 72.150(9)°, γ = 81.777(11)°, V = 1557.3(3) A3, and Z = 2. 2c crystallizes in a monclinic space group, P21/n, with a = 12.433(3) A, b = 20.484(4) A, c = 12.645(3) A, β = 92.81(2)°, V = 1557.3(3) A3, and Z = 4. The cycloalkylamino-substituted polyphosphazenes contain a small amount of residual chlorine atoms. These have high glass transition temperatures.

The characterization of the heterocyclic radical 1,2,5-thiadiazolo[3,4-b]-1,3,2-dithiazolo[3,4-b]pyrazin-2-yl (TDP-DTA) is described. The compound is prepared by treatment of 5,6-dithiolo-1,2,5-thiadiazolo[3,4-b]pyrazine with S3N3Cl3 and purified by fractional sublimation in vacuo. The results of cyclic voltammetry and ESR analysis of TDP-DTA and related heterocyclic dithiazolyls indicate that the spin distributions and donor/acceptor properties of these radicals are extremely sensitive to the nature of the 4,5-substituents. The crystal structure of TDP-DTA has been determined at two temperatures. At 293 K, the crystals are triclinic, space group P1, with a = 4.4456(8), b = 8.407(2), c = 9.671(3) A, α = 71.34(2), β = 89.28(2), γ = 87.80(2)°, Z = 2 (for C4N5S3); at 150 K the crystals are triclinic, space group P1, with a = 7.489(7), b = 9.593(4), c = 10.759(6) A, α = 65.77(4), β = 74.10(6), γ = 74.64(6)°, Z = 2 (for C8N10S6). At 293 K the structure consists of ribbons of TDP-DTA radicals packed in a slip...

The condensation of diaminobenzenedithiol with sulfur monochloride leads to the chloride salt of the radical cation of 3,6-dichlorobenzo(1,2-d:4,5-d')bis(1,2,3-dithiazole), dichloro-(BB-123-DTA)(Cl), which can be reduced to neutral dichloro-(BB-123-DTA) with triphenylantimony. A similar condensation with selenium tetrachloride leads, upon reduction, to the corresponding bis(1,2,3-thiaselenazole) dichloro-(BB-123-TSA). The crystal and molecular structures of both compounds have been determined by X-ray diffraction. Both compounds, which are formally antiaromatic 16﷿-systems, exhibit internal bond lengths consistent with a quinoid formulation. The radical cations of both rings have been characterized by ESR spectroscopy; for dichloro-(BB-123-DTA) + g ) 2.0114 and aN ) 0.201 mT, while for dichloro-(BB-123-TSA) + g ) 2.021 and aN ) 0.44 mT. Further oxidation of both rings affords the corresponding dications, both of which have been characterized crystallographically as their AlCl 4 - salts. The structural features of these compounds are consistent with those expected for dithiazolylium (or thiaselenazolylium) derivatives. The structure and redox chemistry of the benzo(1,2-d:4,5-d')bis(1,2,3-dithiazole) framework is discussed in the light of the results of ab initio calculations.

The synthesis of dicyanooligothiophenes NC(C4H2S)nCN (n = 3−6) is reported. For n = 3, 4, and 5 the dinitriles are generated by treatment of the corresponding dibromo compounds with copper(I) cyanide in quinoline. For n = 6 the preparation involves the Ni-catalyzed coupling of 5-bromo-2,2‘:5‘,2‘‘-terthiophene-5‘‘-carbonitrile. The structures of all four dicyano derivatives have been determined by X-ray crystallography. For n = 3, the space group is monoclinic C2/c, with a = 18.363(7), b = 11.8356(9), c = 30.666(4) A, β = 102.15(2)°, V = 6515(3) A3, Z = 20. For n = 4 the space group is triclinic P1, a = 7.3254(9), b = 7.8658(6), c = 8.1813(8) A, α = 64.706(8), β = 76.059(8), γ = 76.692(8)°, V = 409.29(7) A3, Z = 1. For n = 5 the space group is monoclinic C2/c, with a = 13.633(4), b = 11.706(5), c = 37.073(8) A, β = 90.22(2)°, V = 5929(3) A3, Z = 12. For n = 6, the space group is monoclinic P21/a, with a = 13.8962(14), b = 5.9100(16), c = 14.0798(16) A, β = 98.446(4)°, V = 1143.8(4) A3, Z = 2. In all four ...

The title compound [CpRu(PPh3)2(tht)]BF4,1, tht=tetrahydrothiophene, is obtained by the reaction of CpRu(PPh3)2Cl, tht and AgBF4 in CH2Cl2 solution. Yellow crystals of [CpRu(PPh3)2(tht)]BF4 were grown by the slow diffusion of pentane into a CH2Cl2 solution of1 and have been studied by X-ray crystallography: space group is P21/n,a=9.507(2),b=18.336(3),c=22.372(6) A, β=94.28(2)°,V=3889(1) A3,Z=4. The tht ligand binds to the Ru atom through the sulfur atom at a distance of 2.395(2) A. The tht ring is in the puckered configuration.

Electroreduction of 1,3- and 1,4-benzene-bridged bis(diselenadiazolium) salts [1,4-Se][SbF6]2 and [1,4-Se][SbF6]2 in acetonitrile, at a Pt wire and in the presence of iodine affords the 1:1 charge-transfer salts [1,4-Se][I] and [1,3-Se][I]. Crystals of [1,4-Se][I] belong to the monoclinic space group C2/m, with FW = 598.9, a = 10.586(2), b = 16.713(2), c = 3.5006(14) A, β = 104.26(2)°, V = 600.2(3) A3, Z = 2. Crystals of [1,3-Se][I] belong to the orthorhombic space group Ima2, with FW = 598.9, a = 28.489(7), b = 3.543(2), c = 12.283(2) A, V = 1239.8(8) A3, Z = 4. In the presence of an excess of iodine, electrocrystallization of [1,4-Se]2+ affords the mixed iodide/triiodide salt [1,4-Se][I][I3], space group C2/c, FW = 979.59, a = 12.862(3), b = 15.063(2), c = 9.028(3) A, β = 100.62(2)°, V = 1719.1(7) A3, Z = 4. The structures of the two 1:1 compounds consist of perfectly superimposed stacks of molecular units interspersed by columns of disordered iodines. Interstack contacts in both structures are limited,...

The preparation of the bis(1,2,3,5-dithiadiazolyl) radicals [S2N2C]−X−[CN2S2], where X is a heterocyclic bridging group (X = piperazine, thiophene, bithiophene) is described. Crystal structures of ...

Cosublimation of 2,5-furanbis(1,2,3,5-dithiadiazolyl) [F-2,5-S] and iodine affords 1:1 and 2:1 charge-transfer salts, [F-2,5-S][I] and [F-2,5-S]2[I]. Cosublimation of 2,6-pyridinebis(1,2,3,5-dithiadiazolyl) [P-2,6-S] and iodine affords uniquely the 2:1 charge-transfer salt [P-2,6-S]2[I]. Crystals of the latter belong to the space group P21/c, a = 3.434(3), b = 9.8914(9), c = 30.803(4) A, β = 91.52(3)°, V = 1045.9(9) A3, Z = 2. The structure consists of [P-2,6-S] molecules stacked along the x direction. Pairs of stacks are linked head-on through iodine atoms, which themselves form disordered stacks running parallel to x. The internal structural parameters of the two CN2S2 rings within each molecule suggest that one (linked to iodine) is formally uncharged, while the other is partially oxidized. This latter ring is heavily coordinated through S- - -N linkages to neighboring CN2S2 rings and pyridine. Magnetic susceptibility measurements on [P-2,6-S]2[I] indicate that it is diamagnetic below 220 K.

Condensation of oxamidrazone with sulfur dichloride in acetonitrile affords 4,4‘-bis(1,2,3,5-dithiadiazolium) dichloride in moderate yield. Reduction of this salt with triphenylantimony yields the diradical 4,4‘-bis(1,2,3,5-dithiadiazolyl) [S2N2C−CN2S2], which has been isolated and characterized in the solid state as its dimer [S2N2C−CN2S2]2. The diradical is disjoint, and ab initio molecular orbital methods confirm a very small energy gap (

The structure of the [CpRu(PPh3)2(C6H11SH)]BF4·CH2Cl2 complex was determined by X-ray diffraction techniques; triclinic space group $$P\bar 1$$ ,a=12.567(1),b=13.409(1),c=14.733(1) A, α=95.380(7), β=111.041(7), γ=96.454(8)°,V=2278.5(4) A3,Z=2,R=0.056,R w=0.088. The Ru is attached to two triphenylphosphine ligands, a cyclopentadienyl and the S atom of the cyclohexylthiol. The Ru−S distance is 2.389(2) A and the S−H distance is 1.23 A.

The isolation and characterization of the trimethylenesulfide-coordinated complex, [CpRu(PPh3)2(SC3H6)]CF3SO3, is reported. The structure of [CpRu(PPh3)2(SC3H6)]CF3SO3 was determined by X-ray diffraction techniques: monoclinic space group I2/a, a=23.864(10), b=14.233(3), c=24.385(7) A, β=97.10(3)°, Z=8, R=0.046, Rw=0.065. The Ru is attached to two triphenylphosphine ligands, a cyclopentadienyl and the trimethylenesulfide. The Ru-S distance is 2.3459(20) A.

4-CF3—C6H4—CN3S2, 1, forms symmetrical sulfur-bound adducts with norbornene (NBE), norbornadiene (NBD), and 1-heptene (C7H14), which were studied by 1H, 13C, COSY-45, and HETCORR NMR. 1•NBE exists in solution in a single isomeric form which corresponds to that found in the solid state for 4-CH3O—C6H4—CN3S2•NBE by single-crystal X-ray diffraction: orthorhombic, P212121 with Z = 4, a = 10.224(3), b = 10.369(5), c = 14.075(5). R = 0.0475 and Rw = 0.0492 for 634 data. 1•NBD exists in solution in two isomeric forms which are not interchangeable. One of these corresponds to that found in the NBE adduct, i.e. exo addition; the other is the first example of endo addition. Two bis adducts of stoichiometry NBD•21 have been prepared and separated. They are isomers exhibiting exo-exo and exo-endo addition. The structure of the latter was confirmed by X-ray diffraction: orthorhombic, Pcab with Z = 8, a = 7.816(2), b = 17.264(3), c = 36.842(5). R = 0.068 and Rw = 0.106 for 1506 data. 1•C7H14 exists as a mixture of syn and anti isomers. NMR structure parameters derived here have been applied to published data on over 15 thiazene NBE and NBD adducts.

The structure of the [CpRu(PPh[sub 3])[sub 2](t[minus]C[sub 4]H[sub 4]SH)]BF[sub 4] complex was determined by X-ray diffraction techniques; monoclinic space group P2[sub 1]/c, a = 14.662(9), b = 18.515(7), c = 15.368(6) [angstrom], [beta] = 101.88(5)[degrees], V = 4082(6) [angstrom][sup 3], Z = 4, R = 0.049, R[sub w] = 0.057. The Ru is attached to two triphenylphosphine ligands, a cyclopentadienyl and the t-butylmercaptan. The Ru-S distance is 2.396(2)[angstrom] and the S-H distance is 1.289(2)[angstrom].

The reactions of N,N,N[prime]-tris(trimethylsilyl)formamidine with ECl[sub 2] (E = S, Se) afford 1,2,3,5-dithia- and 1,2,3,5-diselenadiazolium chloride, which can be reduced with triphenylantimony to the corresponding dithia- and diselenadiazolyl radicals [HCN[sub 2]E[sub 2]]. The solid state structure of the cofacial dimer [HCN[sub 2]S[sub 2]][sub 2] has been determined by X-ray diffraction; crystals of [HCN[sub 2]S[sub 2]][sub 2] belong to the monoclinic space group P2[sub 1]/n, with a = 6.833(6), b = 16.463(4), c = 19.161(4) A, [beta] = 93.57(4)[degrees], FW = 210.30, Z = 12. The crystal structure consists of stacked dimers, with three dimers in the asymmetric unit. Along the stacking axis the mean intradimer S---S contact is 3.11 A; the mean interdimer contact is 3.76 A. Ab initio calculations with split-valence and larger basis sets have been employed to evaluate the structures and energies of both the gas phase radicals and their dimers. Minor changes in geometry are predicted upon association of the monomers; this relative structural invariance is consistent with low binding energies, the best predictions (including zero point vibrational energy corrections) being ca. 4 kcal/mol (for E = S) and ca. 10 kcal/mol (for E = Se). 30 refs., 6 figs., 9 tabs.

The preparation and solid-state characterization of the 1,3,5-triazine-bridged tris(1,2,3,5-ditliiadiazolyl) complex 4,4',4''-(2,4,6-(1,3,5-triazinetriyl))tris(1,2,3,5-dithiadiazolyl) [N 3 C 3 (CN 2 S 2 ) 3 ] are described. The crystals belong to the monoclinic space group C2/c, with a=20.759(7) A, b=10.525(3) A, c=17.554(3) A, β=140.18(4) o , fw=390.5, Z=8, and V=2456.2(12) A 3 . The crystal structure consists of layers of interlocked dimers. Alternate layers are oriented in an antiparallel fashion, thereby precluding a stacked structure similar to that found in the related 1,3,5-benzene-based triradical. There are two dimerization environments

The reaction of [CpRu(PPh3)2(n-C3H7SH)]BF4 with dithiooxamide (dtoxa) gave two products: {[CpRu(PPh3)2]2(μ-dtoxa)} (BF4)2,1, and [CpRu(PPh3)(dtoxa-H2O)]BF4,2. The structures of both complexes were determined by X-ray diffraction techniques. Compound1 crystallized in the triclinic space groupP¯1,a=12.822(4),b=14.16(1),c=23.631(8) A,α=84.57(4),β=83.64(3), γ=83.57(4)°,Z=2,R=0.069,Rw=0.084. The structure of1 shows two CpRu(PPh3)2+ units bridged through the S atoms of the dtoxa ligand. Ru-S distances are 2.377(6)A for Ru1-S1 and 2.368(6) A for Ru2-S2. Compound2 crystallized in the monoclinic space groupP21/c,a=13.446(3),b=13.461(7),c=31.214(7) A,β=100.78(3)°,Z=8,R=0.054,Rw=0.055. The structure of2 has two molecules in the asymmetric unit. The Ru is chelated to the dtoxa through the S atoms: Ru1-S1, 2.307(4); Ru1-S2, 2.300(4); Ru2-S3, 2.295(4); Ru2-S4, 2.287(4) A. The coordination sphere of the Ru in2 is completed by a cyclopentadienyl ligand and a triphenylphosphine.

The isolation and characterization of two mercaptan complexes of the general formula [CpRu(PPh3)2(RSH)]BF4, where R=benzyl and phenethyl, were undertaken to model the substrate/catalyst interaction of the hydrode-sulfurization (HDS) process. The IR data show a shift in the SH stretching frequency upon coordination. The structure of the [CpRu(PPh3)2(C6H5CH2CH2SH)]BF4 complex was determined by X-ray diffraction techniques: monoclinic space group P21/n, a=15.317(4), b=13.924(9), c=21.815(7) A, β=95.20(2)°, Z=4, R=0.057, Rw=0.073. The Ru is attached to two triphenylphosphine ligands, a cyclopentadienyl and the phenethylmercaptan. The Ru-S distance is 2.369(2) A and the S-H distance is 1.18 A.

The structures of trans-[(MeCN)2(bpy)2Ru](ClO4)2(I) andtrans-[(NH3)2(bpy)2Ru](ClO4)2(II) have been determined by single crystal X-ray diffraction methods. (I) forms monoclinic crystals in the space groupP21/c witha=8.399(2),b=10.406(2),c=15.590(3) A,β=93.78(2)° andZ=2 atT=293 K. The final refinement gaveR=0.040 for 2448 reflections withF 2 >3σ(F 2 ). (II) crystallizes in the triclinic space groupP¯1 witha=1.702(1),b=8.439(2),c=10.525(2) A,α=107.56(2),β=104.63(1), γ=100.89(2)° andZ=1 atT=293 K. Refinement using 1878 reflections withF 2 >3σ(F 2 ) produced a finalR value of 0.036. Both of these structures have the ruthenium atom located on a crystallographic inversion center. The bipyridine ligands in both structures are in the bowed conformation as a means of circumventing the steric problems associated with the trans arrangement of the bipyridine ligands. The Ru-N(monodentate) distance is longer for the ammonia complex (2.106(3) A) than for the acetonitrile complex (2.008(4) A); there are no significant differences in the distances and angles of the two Ru(bpy)2 frameworks.

The preparation and solid-state characterization of the dimers of the cyanophenyl-substituted 1,2,3,5-dithia- and 1,2,3,5-diselenadiazolyl radicals [NCC6H4CN2E2]· (E = S, Se) are described. Crystals of the 4-cyanophenyl derivatives 4 are triclinic, space group P¯1. The radicals dimerize in a cofacial fashion, with mean intradimer E- - -E spacings of 3.104/3.233 Å (E = S/Se). The dimer units form ribbonlike arrays connected by head-to-tail CN- - -E contacts. The ribbons are packed in an antiparallel fashion with no close interdimer E- - -E contacts. The 3-cyanophenyl sulfur derivative 5 crystallizes in two phases. The α-phase, along with the isomorphous selenium compound, belongs to the monoclinic space group P21/n. As in the 4-cyano derivatives, the radicals dimerize cofacially, generating ribbons connected by head-to-tail CN- - -E contacts. The ribbons, however, are layered with CN2E2 rings oriented into stacks parallel to the a axis. In addition to short intradimer E- - -E contacts (mean values = 3.13 (2)/3.27 (4) Å for E = S/Se), there are relatively short interdimer E- - -E contacts (mean values = 4.26 (5)/4.15 (5) Å (E = S/Se) along the stacking axis. The β-phase of the 3-cyanophenyl sulfur compound 5, monoclinic space group P21/n, forms discrete dimers associated in a trans antarafacial fashion, with intradimer S- - -S contacts of 3.121 (1) Å; there are no close interdimer S- - -S contacts. The 2-cyanophenyl selenium derivative 6 crystallizes in the polar space group P21. In this structure also the dimer units are laced together by short CN- - -Se contacts. The dimers form stacks parallel to the b axis, with mean intradimer and interdimer Se- - -Se contacts of 3.312/4.083 Å, respectively. Lattice constants for the six structures are: 4 (E = S), C8H4N3S2, a = 10.466 (3) Å, b = 10.342 (2) Å, c = 9.169 (2) Å, α = 104.97 (2)°, β = 112.97 (2)°, γ = 69.84 (2)°, V = 849.0 (3) Å3, Z = 4; 4 (E = Se), C8H4N3Se2, a = 10.478 (4) Å, b = 10.780 (4) Å, c = 9.432 (4) Å, α = 107.16 (3)°, β = 115.23 (2)°, γ = 68.39 (3)°, V = 883.8 (6) Å3, Z = 4; 5 (E = S, α-phase), C8H4N3S2, a = 7.295 (3) Å, b = 20.488 (2) Å, c = 11.276 (2) Å, β = 95.54 (2)°, V = 1676.0 (7) Å3, Z = 8; 5 (E = Se), C8H4N3Se2, a = 7.364 (8) Å, b = 21.085 (2) Å, c = 11.119 (4) Å, β = 94.91 (5)°, V = 1720 (7) Å3, Z = 8; 5 (E = S, β-phase), C8H4N3S2, a = 8.782 (1) Å, b = 5.638 (1) Å, c = 17.128 (4) Å, β = 102.94 (2)°, V = 826.5 (6) Å3, Z = 4; 6 (E = Se), C8H4N3Se2, a = 7.301 (1) Å, b = 11.883 (2) Å, c = 10.186 (1) Å, β = 101.50 (1)°, V = 866.1 (5) Å3, Z = 4.

The solid-state characterization of a second or β-phase of the 1,3-phenylene-bridged diselenadiazolyl diradical 1,3-[(Se2N2C)C6H4(CN2Se2)] is reported. Crystals of this β-phase are monoclinic, space group P21/n, with a = 9.108 (6), b = 15.233 (13), c = 16.110 (5) Å, β = 103.37 (5)°, Z = 8. The crystal structure consists of chain-like arrays of discrete dimers (4 per unit cell), although one intradimer Se-Se linkage is notably longer (3.411 Å) than the other three (3.125, 3.196, 3.204 Å). The dimer units lie in chains that are linked by a complex three-dimensional array of Se-Se contacts. Variable-temperature single-crystal conductivity measurements on this phase indicate a band gap of 0.77 eV. Consistent with the conductivity measurements, extended Hückel band structure calculations suggest a relatively isotropic electronic structure.

A stable discrete nickel borohydride complex (Tp*NiBH(4) or Tp*NiBD(4)) was prepared using the nitrogen-donor ligand hydrotris(3,5-dimethylpyrazolyl)borate (Tp*-). This complex represents one of the best characterized nickel(II) borohydrides to date. Tp*NiBH(4) and Tp*NiBD(4) are stable toward air, boiling water, and high temperatures (mp230 degrees C dec). X-ray crystallographic measurements for Tp*NiBH(4) showed a six-coordinate geometry for the complex, with the nickel(II) center facially coordinated by three bridging hydrogen atoms from borohydride and a tridentate Tp(-) ligand. For Tp*NiBH(4), the empirical formula is C(15)H(26)B(2)N(6)Ni, a = 13.469(9) A, b = 7.740(1) A, c = 18.851(2) A, beta = 107.605(9) degrees, the space group is monoclinic P2(1)/c, and Z = 4. Infrared measurements confirmed the presence of bridging hydrogen atoms; both nu(B[bond]H)(terminal) and nu(B[bond]H)(bridging) are assignable and shifted relative to nu(B-D) of Tp*NiBD(4) by amounts in agreement with theory. Despite their hydrolytic stability, Tp*NiBH(4) and Tp*NiBD(4) readily reduce halocarbon substrates, leading to the complete series of Tp*NiX complexes (X = Cl, Br, I). These reactions showed a pronounced hydrogen/deuterium rate dependence (k(H)/k(D) approximately 3) and sharp isosbestic points in progressive electronic spectra. Nickel K-edge X-ray absorption spectroscopy (XAS) measurements of a hydride-rich nickel center were obtained for Tp*NiBH(4), Tp*NiBD(4), and Tp*NiCl. X-ray absorption near-edge spectroscopy results confirmed the similar six-coordinate geometries for Tp*NiBH(4) and Tp*NiBD(4). These contrasted with XAS results for the crystallographically characterized pseudotetrahedral Tp*NiCl complex. The stability of Tp*Ni-coordinated borohydride is significant given this ion's accelerated decomposition and hydrolysis in the presence of transition metals and simple metal salts.

The title phosphazene, P 3 N 3 R 4 XX, where R is 3,5-dimethylpyrazole and XX is a spiro-bonded −NHCH 2 CH 2 CH 2 NH− ring, has P−N bonds of 1.554 (5)-1.614 (5) A in the phosphazene ring with exocyclic bonds of 1.609 (5) and 1.635 (5) A to the spiro ring and 1.683 (4)-1.708 (5) A to the pyrazole groups. The N−P−N angle within the phosphazene ring at the unique P atom is 6.9 (3)° smaller than those at the other P atoms. One of the pyrazole-substituted P atoms is displaced by 0.252 (5) A from the best plane of the other five ring atoms, which are coplanar to within 0.087 (6) A. The −PNCCCN− ring conformation is intermediate between a boat and a twist-boat

The title compound [Ru(C 5 H 5 )(C 2 H 5 NS)(C 18 H 15 P) 2 ]BF 4 crystallizes in the space group P2 1 /c. The Ru atom has pseudotetrahedral coordination geometry formed by the cyclopentadienyl centroid, the two PPh 3 ligands and the S atom of the neutral thioacetamide molecule. The Ru-S and C=S distances are 2.3820 (13) and 1.671 (5) A, respectively, and the Ru-S=C angle is 116.3 (2) o . The Ru atom is at a distance of 0.405 (9) A from the plane formed by the atoms of the thioacetamide group

Numerous examples of five coordination of Cu(II) are known and have been reviewed by O'Brien (1984) and Hathaway (1982, 1983). The ability of the bis (1, 10-phenanthroline) copper (II) cation to add an additional ligand to make a five coordinate species is well documented. Structures previously reported for Cu(phen)[sub 2] X cations include complexes in which X is a small molecule or ion such as Cl- (Boys et al., 1981), CN- (Anderson, 1975) and H[sub 2]O (Nakai et al., 1975; Nakai et al., 1978) and, more recently, a large heterocycle such as 3,5-dimethyl-pyridine (Jeter et al., 1988). With a small ligand near trigonal bipyramidal geometry seems to prevail, but, with the large heterocylic ligand the geometry approximately a square pyramid. In this work, we report the structure of a second complex with a large heterocylic ligand, 4-aminopyridine.

[Fe(CO) 4 (SO 2 )(C 5 H 5 ) 2 ]•H 2 O cristallise dans P2 1 /n avec a=10,884, b=12,424, c=12,658 A, β=103,35 o , Z=4; affinement jusqu'a R=0,0355. Les liaisons hydrogene entre l'eau et SO 2 lient les complexes entre eux. L'eau provoque la cristallisation du complexe dans usne conformation trans, en opposition a la forme gauche du materiau anhydre

[Rh(C 13 H 23 ) {(PCC 6 H 5 ) 3 } 2 ]•0,5 C 6 H 6 cristallise dans P1 avec a=12,260, b=13,05, c=15,91 A, α=71,30, β=76,24, γ=67,71 o , τ=2; affinement jusqu'a R=0,043. Les atomes du cycle a 13 chai←nons sont dans une configuration trans. Les distances des 3 atomes de ce cycle lies au metal sont de 2,120; 2,180; 2,231 A, et les angles formes par ces atomes sont de 123,9 et 125,7 o

C 16 H 22 S 2 cristallise dans P2 1 /n avec a=8,851, b=15,398 et c=11,590 A, Z=4; affinement jusqu'a R=0,036. Presence de quatre contacts intramoleculaires entre les atomes H et le cycle phenylene dans le domaine 2,53 a 2,68 A, contribuent au «benzene courbe» typique des paracyclophanes

The Ru atom of the title complex, [Ru(C10H8N2)2-(H2O)2](PF6)2, is located on a crystallographic inversion center; the bipyridine ligands are bowed [dihedral angle between C5N planes is 162.68 (12) degrees] due to the interligand steric interactions of the trans bipyridyl units. The Ru--O distance is 2.116 (2) A and the mean Ru--N distance is 2.074 (2) A.

Sublimation of 1,2,3,5-dithiadiazolyl in vacuo affords a triclinic phase of the dimer [HCN2S2]2. The crystals belong to the space group P¯1, a = 6.816(3), b = 13.940(2), c = 14.403(3) Å, α = 116.830(14), β = 98.64(3), γ = 99.18(3)°, FW = 212.4 (for [HCN2S2]2·[N2]0.08) Z = 6. The crystal structure consists of stacked dimers, with three dimers per asymmetric unit. Pairs of asymmetric units, related by an inversion center, generate a pinwheel motif consisting of six dimers. The columnar structure associated with these pinwheels forms close-packed sets of “molecular tubes”. Cosublimation of the radical in the presence of iodine in the mole ratio (HCN2S2:I = 5:1) yields an iodine-doped hexagonal phase of composition [HCN2S2]6[I]1.1. Crystals of this material belong to the space group P61, a = b = 14.132(16), c = 3.352(5) Å, FW = 128.20, Z = 6. The crystal structure consists of sixfold pinwheels in which the now evenly spaced HCN2S2 rings form a spiral about the 61 axis. The iodine atoms lie within the columnar cavity of the pinwheels in a disordered array wrapped tightly about the sixfold screw axis. The single-crystal conductivity of the doped material is 15 S cm-1 at room temperature. Raman spectroscopic and magnetic susceptibility measurements on the doped material are reported.

The reaction of oxamidrazone with sulfur dichloride affords 4,4'-bis(1,2,3,5-dithiadiazolium) dichloride, which can be reduced with triphenylantimony to the corresponding bis(1,2,3,5-dithiadiazolyl) diradical; the solid state structure and transport properties of the dimer [S2N2CCN2S2]2 are reported.

The 1:1 reaction of the heterocyclic radicals [PhCN2E2]∙ (E = S, Se) and iodine affords the mixed valence salts [PhCN2E2]3[I3], while reaction of PhCN2S2 with an excess of iodine affords the simple salt [PhCN2S2][I3]; the solid-state structures of these complexes have been determined by X-ray crystallography. Crystals of both of the mixed valence compounds belong to the triclinic space group P¯1; for E = S, a = 10.278(4), b = 11.508(2), c = 13.333(4) Å, α = 114.97(2), β = 99.21 (3), γ = 92.65(2)°, FW = 308.15, Z = 6; for E = Se, a = 10.368(6), b = 10.818(8), c = 13.421(8) Å, α = 80.64(5), β = 81.20(5), γ = 75.18(6)°, FW = 401.95, Z = 6. Crystals of the simple salt belong to the monoclinic space group P21/a; a = 7.366(4), b = 11.734(1), c = 15.166(2) Å, β = 95.92(3)°, FW = 1303.99(7), Z = 4. In each of the mixed valence compounds the molecular (asymmetric) unit consists of a trimeric [PhCN2E2]3+ cation and an associated triiodide anion. Within the cations the mean interannular E-E contacts are 3.181/3.377 Å (E = S/Se). The packing patterns of the two compounds show important differences. For E = S the crystal structure does not exhibit stacking of the trimeric molecular building blocks, but for E = Se the trimer units form dovetailed stacks in which consecutive layers are oriented in a trans-antipodal fashion. This arrangement introduces close interannular contacts between the blocks along the stack, as well as close lateral contacts. The asymmetric unit of [PhCN2S2][I3] consists of a single PhCN2S2+ cation and an associated triiodide anion; there are no unusual stacking features. The magnetic and conductivity properties of [PhCN2Se2]3[I3] are reported, and the results discussed in the light of extended Hückel band structure calculations.

The preparation and solid-state characterization of the bifunctional radicals [4,4’-(5-cyanobenzene)-1,3-bis(1,2,3,5-dithiadiazolyl)] and [4,4’-(5-cyanobenzene)-1,3-bis( 1,2,3,5-diselenadiazolyl)] [5-CN-1,3-C6H3(CN2E2)2] (E = S, Se) are described. The crystals of the two title compounds are isomorphous and belong to the monoclinic space group P21/c, with (for E = S) a = 7.00(2), b = 30.050(6), c = 10.713(8) A, β = 104.80(10)°, V = 2179(6) A3, Z = 8 and (for E = Se) a = 7.124(4), b = 30.50(2), c = 10.874(2) A, β = 105.46(3)°, V = 2277(2) A3, Z = 8. The crystal structures consist of stacks of diradicals running parallel to x; radical dimerization up and down the stack generates a zigzag arrangement, as seen in the related 1,3-phenylene structures. Along the stacking axis the mean intradimer E-E contacts are 3.12 (E = S) and 3.23 A (E = Se), while the mean interdimer E- - -E distances are 3.89 (E = S) and 3.91 A (E = Se). Magnetic and conductivity data are presented and discussed in light of extended Huckel band structure calculations.

The two termini of the torsionally strained dithiadiazolyl diradical S2N2C–C6H3Me–MeC6H3–CN2S2 3 possess different solid state structural environments; the bulk magnetic susceptibility of 3 is interpreted in terms of the distinct properties of the two radical centres.

A crystallographic twofold rotation axis passes through the C-C bond joining the imidazole rings of the title compound, C10H10N4O2. The molecule crystallizes in a cis disposition. The planar acetyl group is twisted by 5.0 (3)° with respect to the imidazole ring and the two imidazole rings are tilted by 60.53 (5)° in relation to one another.

The title molecules, C 6 H 4 N 6 O 4 .2C 3 H 7 NO, lie on a center of inversion. One N atom of the ring is hydrogen bonded to the O atom of the dimethylformamide (DMF) solvate molecule [N-H...O = 2.699 (4) A]. The nitro group is tilted by 4.11 (18)° with respect to the imidazole ring.

K[RuCl 4 (C 10 H 8 N 2 )] cristallise dans Pbcn avec a=14,382, b=13,980 et c=7,491 A, Z=4; affinement jusqu'a R=0,051. L'anion [Ru(bpy)Cl 4 ] − est sur un axe cristallographique d'ordre 2. Les cycles organiques des anions voisins se recouvrent avec des espacements entre les plans 3,27 et 3,36 A

Preparation du complexe trans-[Ru(phen) 2 (OH 2 ) 2 ]PF 6 par photolyse du cis en solution aqueuse de HPF 6 . Par substitution thermique de coordinats, formation de trans-[Ru(phen) 2 (CH 3 CN)(OH 2 )](PF 6 ) 2 , trans-[Ru(phen) 2 (CH 3 CN) 2 ](PF 6 ) 2 et trans-[Ru(phen) 2 (py) 2 ](PF 6 ) 2 . Isomerisation des trans en cis. Structure cristalline