Chlorodifluoroacetyl cyanide, ClF2CC(O)CN: synthesis, structure, and spectroscopic characterization

The novel molecule difluorochloroacetyl cyanide, ClF(2)CC(O)CN, has been characterized by IR (gas phase, Ar matrix), Raman (liquid), (19)F and (13)C NMR, and photoelectron (PES) spectroscopies; photoionization mass spectrometry (PIMS); and gas electron diffraction (GED). The conformational properties of ClF(2)CC(O)CN have been studied by joint application of vibrational spectroscopy, GED, and quantum chemical calculations. The existence of two conformers is detected in the gas and liquid phases, in which the C-Cl bond adopts gauche and syn orientations with respect to the C═O group. The computed enthalpy difference is in harmony with the experimental results of the gauche being more stable than the syn conformer by ΔH° = 1.3 kcal mol(-1) (MP2/cc-pVTZ). The valence electronic properties and the possible ionization and dissociation processes of the title compound are studied using the PES and PIMS. The experimental first vertical ionization energy of 12.0 eV corresponds to the ejection of an electron of the oxygen lone pairs. Taking into account the properties and broad applications of acyl cyanides, ClF(2)CC(O)CN is a promising new precursor in preparative chemistry.     

TCNE dimer dianion coordination complexes, [Mn(TPA)(TCNE)]2[micro2-(TCNE)2] and [Mn(TPA)(micro4-C4(CN)8)0.5].ClO4, TPA=tris(2-pyridylmethyl)amine: synthesis, structure and magnetic properties

The structures and magnetic properties of two products that result from the reactions of [Mn(TPA)(CH3CN)2](ClO4)2, TPA=tris(2-pyridylmethyl)amine and potassium tetracyanoethylenide, KTCNE, are reported. [Mn(TPA)(TCNE)]2[mu2-(TCNE)2] (1) and [Mn(TPA)(micro4-C4(CN)8)0.5].ClO4 (2) are obtained by using two different ratios of the initial reactants. Each was intended to possess two or more cis-TCNE radical anions (TCNE*/-) as ligands. 1 is a dinuclear species that crystallizes in the triclinic system in the space group P, with a=10.4432(17), b=12.2726(16), and c=13.708(2) A; alpha=88.505(12), beta=75.560(14), and gamma=87.077(12) degrees; V=1698.9(4) A3; and Z=1 and features two metal centers each with three nearly orthogonal TCNE*/- ligands. However, the three TCNE*/- ligands are all dimerized via the formation of four-center, two-electron bonds: two bridge the two Mn(II) centers, and a third TCNE*/- ligand forms an intermolecular bond to another equivalent TCNE*/-. 2 crystallizes in the tetragonal system in the space group P42212, with a=17.170(3), b=17.170(3), and c=17.1837(6) A; V=5065.9(13) A3; and Z=8. It consists of a ribbon-like coordination polymer containing the previously observed but still relatively rare octacyanobutyl dianion. The [C4(CN)8]2- anion is derived from the dimerization of two TCNE radical anions via the formation of a new sigma bond, and each anion bridges four Mn(II) centers. Both 1 and 2 display magnetic behavior consistent with only weak antiferromagnetic coupling between the high-spin d5 Mn(II) in which the TCNE*/- are rendered diamagnetic through dimerization.     

Experimental and theoretical electron density distribution and magnetic properties of the butterfly-like complex [Fe(4)O(2)(O(2)CCMe(3))(8)(NC(5)H(4)Me)(2)].2CH(3)CN

The structure and electron density distribution (EDD) of the carboxylate-bridge iron complex [Fe(III)(4)(micro(3)-O)(2)(O(2)CCMe(3))(8)(NC(5)H(4)Me)(2)].2CH(3)CN, 1, has been determined from synchrotron X-ray diffraction data (R(int) = 0.025) collected with the crystal cooled to 16(5) K. At this temperature complex 1 crystallized in the triclinic space group P with cell parameters a = 12.6926(7) A, b = 12.9134(8) A, c = 13.4732(8) A, alpha = 115.372(2) degrees, beta = 107.702(3) degrees, and gamma = 102.731(2) degrees. The theoretical EDD determined from a density functional theory (DFT) single point calculation of an entire molecule of 1 at the experimental geometry has been analyzed and compared to the experimental EDD. The latter is expressed in the framework of a multipolar model with parameters determined by least-squares refinement (R(w)(F(2)) = 0.024) based on the X-ray diffraction data. The central micro(3)-oxygen atom in 1 is significantly out of the plane spanned by the three Fe atoms coordinated to this oxygen. Comparison of measures for the bonding geometry around the iron atoms in 1 with the corresponding values for the iron atoms in relevant trinuclear complexes suggests that there are significant differences in the Fe-(micro(3)-O) bonds in the two cases. Analyses of both the experimental and theoretical EDDs reveal very significant differences between the two Fe-(micro(3)-O) bonds in 1, with one bond being much more directed and stronger than the other bond. A topological analysis of the EDDs using the atoms in molecules approach also reveals very distinct differences between the properties of the two Fe(III) atoms. A clear exponential relationship is found between the Laplacian of the experimental density at the bond critical points in the Fe-ligand bonds and their bond lengths. M?ssbauer spectroscopy of 1 shows two easily separable doublets corresponding to the two different iron sites. Magnetic susceptibility measurements between 4.2 and 300 K indicate antiferromagnetically coupled Fe(III) atoms constituting an S = 0 ground state.     

The first dinitrile frameworks of the rare earth elements: infinity(3)[LnCl3(1,4-Ph(CN)2)] and infinity(3)[Ln2Cl6(1,4-Ph(CN)2)], Ln = Sm, Gd, Tb, Y; access to novel metal-organic frameworks by solvent free synthesis in molten 1,4-benzodinitrile

The three-dimensional frameworks infinity(3)[LnCl3(1,4-Ph(CN)2)] of the lanthanides Ln = Sm (1), Gd (2), Tb (3), and infinity(3)[Ln2Cl6(1,4-Ph(CN)2)] for the group 3 metal Y (4) were obtained as single crystalline materials by the reaction of the anhydrous chlorides of the referring rare earth elements with a melt of 1,4-benzodinitrile. No additional solvents were used for the reactions. The dinitrile ligand is strongly coordinating and substitutes parts of the chlorine coordination. The Ln halide structures are reduced to two-dimensional networks, whereas coordination of both nitrile functions to the metal ions renders bridging in the third direction accessible. This enables formation of new metal organic framework (MOF) structure types with the large 1,4-benzodinitrile spacers interlinking infinity (2)[LnCl3] planes. In comparison to 1,4-Ph(CN)2 the mono functional benzonitrile ligand does not constitute framework structures, which is underlined by comparison with a reaction of yttrium chloride with PhCN resulting in the molecular complex [Y2Cl6(PhCN)6] (5) with end-on coordination PhCN ligands. The coordination spheres of the rare earth ions consist of double capped (infinity(3)[LnCl3(1,4-Ph(CN)2)] (1-3)) as well as single capped trigonal prisms (infinity(3)[Ln2Cl6(1,4-Ph(CN)2)] (4)) of chloride ions and N[triple bond]C groups while 5 displays edge sharing pentagonal bipyramids as coordination polyhedra. Sm (1), Gd (2), and Tb (3) exhibit isotypic framework structures with intercrossing dinitrile ligands. The group 3 metal Y (4) gives a framework with a coplanar arrangement of ligands and a lower ligand content. The largest cavities within the MOF structures of 1-4 have diameters of 3.9-8.0 A. All compounds were identified by single crystal X-ray analysis. Mid IR, Far IR, and Raman spectroscopy, microanalyses and simultaneous Differential Thermal Analysis-Thermogravimetry (DTA/TG) were also carried out to characterize the products. Crystal data for infinity(3)[LnCl3(1,4-Ph(CN)2)] (1-3): Pnma, T = 170(2) K; Sm (1): a = 7.172(1) A, b = 22.209(3) A, c = 6.375(1) A, V = 1015.4(3) A(3), R1 for F(o) > 4sigma(F(o)) = 0.032, wR2 = 0.079. Gd (2): a = 7.116(1) A, b = 22.147(4) A, c = 6.345(1) A, V = 1000.0(3) A(3), R1 for F(o) > 4sigma(F(o)) = 0.033, wR2 = 0.085. Tb (3): a = 7.090(2) A, b = 22.140(4) A, c = 6.325(2) A, V = 992.8(3) A(3), R1 for F(o) > 4sigma(F(o)) = 0.025, wR2 = 0.061. Crystal data for infinity (3)[Y2Cl6(1,4-Ph(CN)2)] (4): P1, T = 170(2) K; a = 6.653(2) A, b = 6.799(2) A, c = 9.484(2) A, V = 397.9(2) A(3), R1 for F(o) > 4sigma(F(o)) = 0.027, wR2 = 0.069. Crystal data for [Y2Cl6(PhCN)6] (5): P2(1)/c, T = 170(2) K; a = 9.767 (2) A, b = 12.304(3) A, c = 19.110(4) A, V = 2294.8(8) A(3), R1 for F(o) > 4sigma(F(o)) = 0.041, wR2 = 0.092.     

Experimental and theoretical studies of carbodiphosphorane-CX2 adducts with unusual bonding situations: preparation, crystal structures, and bonding analyses of S2CC(PPh3)2, O2CC(PPh3)2, and [(CO)4MS2CC(PPh3)2] (M = Cr, Mo, W)

We report about the first X-ray structure analyses of the CS2 and CO2 adducts with carbodiphosphorane C(PPh3)2 and the synthesis and X-ray structure analysis of group 6 carbonyl complexes with compound S2CC(PPh3)2 as a ligand [(CO)4MS2CC(PPh3)2] (M = Cr, Mo, W). The nature of the carbon-carbon bonding in X2CC(PPh3)2 and in the model compounds X2CC(PH3)2 and the metal-ligand bonding in [(CO)4MoS2CC(PH3)2] have been analyzed with charge and energy decomposition methods using DFT calculations. Carbodiphosphoranes C(PR3)2 are double electron pair donors having sigma- and pi-carbon lone-pair orbitals as the two highest occupied MOs.     

N,N'-diisopropyl-N'-bis(trimethylsilyl)guanidinate ligand as a supporting coordination environment in yttrium chemistry. Synthesis, structure, and properties of complexes [(Me(3)Si)(2)NC(Ni-Pr)(2)]YCl(2)(THF)(2), [(Me(3)Si)(2)NC(Ni-Pr)(2)]Y(CH(2)SiMe(3))(2)(THF)(2), and [(Me(3)Si)(2)NC(Ni-Pr)(2)]Y[(mu-H)(mu-Et)(2)BEt](2)(THF)

The reaction of anhydrous YCl3 with an equimolar amount of lithium N,N'-diisopropyl-N' '-bis(trimethylsilyl)guanidinate, Li[(Me3Si)2NC(Ni-Pr)2], in tetrahydrofuran (THF) afforded the monomeric monoguanidinate dichloro complex {(Me3Si)2NC(Ni-Pr)2}YCl2(THF)2 (1). Alkylation of complex 1 with 2 equiv of LiCH2SiMe3 in hexane at 0 degrees C yielded the monomeric salt-free dialkyl complex {(Me3Si)2NC(Ni-Pr)2}Y(CH2SiMe3)2(THF)2 (2). The bis(triethylborohydride) complex [(Me3Si)2NC(Ni-Pr)2]Y[(mu-H)(mu-Et)2BEt]2(THF) (5) was prepared by the reaction of complex 1 with 2 equiv of LiBEt3H in a toluene-THF mixture at 0 degrees C. The complexes 1, 2, and 5 were structurally characterized. Complex 2 as well as the systems 2-Ph3B, 2-Ph3B-MAO, and 1-MAO (MAO = methylaluminoxanes) in toluene were inactive in ethylene polymerization, while the product obtained in situ from the reaction of complex 2 with a 2-fold molar excess of PhSiH3 in toluene polymerized ethylene with moderate activity.     

Reactions of (E)-1,2-di(3-guaiazulenyl)ethylene and 2-(3-guaiazulenyl)-1,1-bis(4-methoxyphenyl)ethylene with tetracyanoethylene (TCNE) in benzene: comparative studies on the products and their spectroscopic properties

Reactions of the title ethylene derivatives, (E)-1,2-di(3-guaiazulenyl)ethylene (1) and 2-(3-guaiazulenyl)-1,1-bis(4-methoxyphenyl)ethylene (2), with a 2 M amount of TCNE in benzene at 25 °C for 24 h under argon give new cycloaddition compounds, 1,1,2,2,11,11,12,12-octacyano-3-(3-guaiazulenyl)-8-isopropyl-5,10-dimethyl-1,2,3,6,9,10a-hexahydro-6,9-ethanobenz[a]azulene (3) from 1 and 1,1,2,2,11,11,12,12-octacyano-8-isopropyl-3,3-bis(4-methoxyphenyl)-5,10-dimethyl-1,2,3,6,9,10a-hexahydro-6,9-ethanobenz[a]-azulene (4) from 2, respectively, in 66 and 87% isolated yields. Comparative studies on the above reactions as well as the spectroscopic properties of the unique products 3 and 4, possessing interesting molecular structures, are reported and, further, a plausible reaction pathway for the formation of these products is described.     

Synthesis, characterization, and hydrolysis of aluminum(III) compounds bearing the C6F5-substituted beta-diketiminate HC[(CMe)(NC6F5)]2 (L) ligand

A series of Al(III) compounds containing the C6F5-substituted beta-diketiminate ligands LAlMeCl (2), LAlMe2 (3), LAlMeI (4), and LAlBr2 (5) (L = HC[(CMe)(NC6F5)]2) were synthesized and characterized. The hydrolysis of 2 and 4 in the presence of 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene as the hydrogen halide acceptor both lead to (LAlMe)2(mu-O) (6), a methylalumoxane derivative, which is the first hydrolysis product with the general formula of (RAlMe)(n)O. A comparison of the hydrolysis products of 2 and 4 with that of L'AlMeCl (L' = HC[(CMe)(NAr)]2, Ar = 2,6-iPr2C6H3) shows that with the C6F5-substituted beta-diketiminate ligand, it was not possible to generate LAlMe(OH). This is obviously due to the stronger Br?nsted acidity of the proton and the smaller size of the C6F5 group in this compound compared to that of the corresponding 2,6-iPr2C6H3 derivative.     

A novel class of aryldiazene complexes: [(PPh3)2 (CO)IrCl(HNNC6H4R-p)(CCPh)] (BF4) (R = NO2, CN,COCH3)

In the reaction with phenylacetylene leading to [(PPh₃)₂(CO)IrCl (HNNC₆H₄R-p)(CCPh)] (BF₄) (R  NO₂, CN, COCH₃), the vacant coordination site in [(PPh₃)₂ (CO)IrCl(N₂C₆H₄ R-p)] (BF₄) plays a key role in the activation of the acetylenic CH bond. ca]To whom correspondence should be addressed.     

The [Ag{Se2C2(CN)2}(Se6)]3−, [Sb{Se2C2(CN)2}2]3−, and [As(Se)3(CH2CN)]2− Anions: Facile Formation of the Maleonitrilediselenolate (mns) Ligand, [Se2C2(CN)2]2−

An unusual route to the maleonitrilediselenolate (mns) ligand has been discovered with the isolation of compounds that contain this ligand bound to silver (structure shown on the right) or antimony. The formation of the [As(Se)₃(CH₂CN)]²⁻ anion along with possible pathways to the mns ligands is discussed.     

Synthese,Schwingungsspektren und Kristallstrukturen der Nitratoargentate (Ph4P)[Ag(NO3)2(CH3CN)]·CH3CN und (Ph4P)[Ag2(NO3)3]

Synthesis, Vibrational Spectra, and Crystal Structures of the Nitrato Argentates (Ph₄P)[Ag(NO₃)₂(CH₃CN)]·CH₃CN and (Ph₄P)[Ag₂(NO₃)₃] Tetraphenylphosphonium bromide reacts in acetonitril suspension with excess silver nitrate to give (Ph₄P)[Ag(NO₃)₂(CH₃CN)]·CH₃CN ( 1 ), whereas (Ph₄P)[Ag₂(NO₃)₃] ( 2 ) is obtained in a long‐time reaction from (Ph₄P)Br and excess AgNO₃ in dichloromethane suspension. Both complexes were characterized by vibrational spectroscopy (IR, Raman) and by single crystal structure determinations. 1 : Space group P2₁/c, Z = 4, lattice dimensions at 193 K: a = 1781.5(3), b = 724.8(1), c = 2224.2(3) pm, β = 96.83(1)°, R₁ = 0.0348. 1 contains isolated complex units [Ag(NO₃)₂(CH₃CN)]^?, in which the silver atom is coordinated by the chelating nitrate groups and by the nitrogen atom of the solvated CH₃CN molecule with a short Ag—N distance of 220.7(4) pm. 2 : Space group I2, Z = 4, lattice dimensions at 193 K: a = 1753.4(4), b = 701.7(1), c = 2105.5(4) pm, R₁ = 0.072. In the polymeric anions [Ag₂(NO₃)₃]^? each silver atom is coordinated in a chelating manner by one nitrate group and by two oxygen atoms of two bridging nitrate ions. In addition, each silver atom forms a weak π‐bonding contact with a phenyl group of the (Ph₄P)⁺ ions with shortest Ag···C separations of 266 and 299 pm, respectively, indicating a (4+1) coordination of silver atoms.     

[Na(DB18C6)(CH3CN)]2W6O19·(CH3CN)2的合成、晶体结构及谱学表征

A super-molecular complex, [Na(DB18C6)(CH₃CN)]₂W₆O₁₉·(CH₃CN)₂, was obtained by solvothermal reaction and characterized by IR , ¹H NMR, gumbc spectrum single crystal and X-ray diffraction. The compou- nd crystallizes in monoclinic space group P2₁/c with a=1.185 22(4) nm, b=2.091 51(8) nm, c=1.487 19(5) nm, β=117.467(2)° and Z=2. The complex contains four basic units: Na⁺, CH₃CN, DB18C6 and W₆O₁₉^2-. Sodium ions located in the cavity of dibenzo-18-crown-6 with 6 Na-O bonds and the crown ether-sodium ion complex is supported on the terminal oxygen atoms of the typical Lindqvist isopolyanion W₆O₁₉^2- via the coordinative interactions. W₆O₁₉^2- located between two DB18C6 and led to the formation of the “hamburger” structure. Two isolated CH₃CN are included in the complex. The whole title crystal is stabilized by van der waals force. CCDC: 292369.     

Synthesis and characterization of the silver maleonitrilediselenolates and silver maleonitriledithiolates [K([2.2.2]-cryptand)]4[Ag4(Se2C2(CN)2)4], [Na([2.2.2]-cryptand)]4[Ag4(S2C2(CN)2)4].0.33MeCN, [NBu4]4[Ag4(S2C2(CN)2)4], [K([2.2.2]-cryptand)]3[Ag(Se2C2(CN)2)2].2MeCN, and [Na([2.2.2]-cryptand)]3[Ag(S2C2(CN)2)2

Reaction of AgBF(4), KNH(2), K(2)Se, Se, and [2.2.2]-cryptand in acetonitrile yields [K([2.2.2]-cryptand)](4)[Ag(4)(Se(2)C(2)(CN)(2))(4)] (1). In the unit cell of 1 there are four [K([2.2.2]-cryptand)](+) units and a tetrahedral Ag(4) anionic core coordinated in mu(1)-Se, mu(2)-Se fashion by each of four mns ligands (mns = maleonitrilediselenolate, [Se(2)C(2)(CN)(2)](2)(-)). Reaction of AgNO(3), Na(2)(mnt) (mnt = maleonitriledithiolate, [S(2)C(2)(CN)(2)](2)(-)), and [2.2.2]-cryptand in acetonitrile yields [Na([2.2.2]-cryptand)](4)[Ag(4)(mnt)(4)].0.33MeCN (2). The Ag(4) anion of 2 is analogous to that in 1. Reaction of AgNO(3), Na(2)(mnt), and [NBu(4)]Br in acetonitrile yields [NBu(4)](4)[Ag(4)(mnt)(4)] (3). The anion of 3 also comprises an Ag(4) core coordinated by four mnt ligands, but the Ag(4) core is diamond-shaped rather than tetrahedral. Reaction of [K([2.2.2]-cryptand)](3)[Ag(mns)(Se(6))] with KNH(2) and [2.2.2]-cryptand in acetonitrile yields [K([2.2.2]-cryptand)](3)[Ag(mns)(2)].2MeCN (4). The anion of 4 comprises an Ag center coordinated by two mns ligands in a tetrahedral arrangement. Reaction of AgNO(3), 2 equiv of Na(2)(mnt), and [2.2.2]-cryptand in acetonitrile yields [Na([2.2.2]-cryptand)](3)[Ag(mnt)(2)] (5). The anion of 5 is analogous to that of 4. Electronic absorption and infrared spectra of each complex show behavior characteristic of metal-maleonitriledichalcogenates. Crystal data (153 K): 1, P2/n, Z = 2, a = 18.362(2) A, b = 16.500(1) A, c = 19.673(2) A, beta = 94.67(1) degrees, V = 5941(1) A(3); 2, P4, Z = 4, a= 27.039(4) A, c = 15.358(3) A, V = 11229(3) A(3); 3, P2(1)/c, Z = 6, a = 15.689(3) A, b = 51.924(11) A, c = 17.393(4) A, beta = 93.51(1) degrees, V = 14142(5) A(3); 4, P2(1)/c, Z = 4, a = 13.997(1) A, b = 21.866(2) A, c = 28.281(2) A, beta = 97.72(1) degrees, V = 8578(1) A(3); 5, P2/n, Z = 2, a = 11.547(2) A, b = 11.766(2) A, c = 27.774(6) A, beta = 91.85(3) degrees, V = 3772(1) A(3).     

Synthesis,crystal and spectroscopic characterization of [RuHCl(CO)(PPh3)2(pyrazine)]

The reaction of [RuHCl(CO)(PPh₃)₃] with pyrazine has been examined and a ruthenium(II) complex – [RuHCl(CO)(PPh₃)₂(C₄H₄N₂)] -- has been obtained. The compound has been studied by IR, UV–Vis spectroscopy, and X-ray crystallography. The molecular orbital diagram of the complex has been calculated with density functional theory (DFT). The spin-allowed singlet--singlet electronic transitions of the complex have been calculated with the time-dependent DFT method, and the UV–Vis spectrum of the compound has been discussed on this basis.     

A theoretical study on structural, spectroscopic and energetic properties of acetamide clusters [CH3CONH2] (n=1-15)

Insights into the formation of hydrogen bonded clusters are of outstanding importance and quantum chemical calculations play a pivotal role in achieving this understanding. Structure and energetic comparison of linear, circular and standard forms of (acetamide)(n) clusters (n = 1-15) at the B3LYP/D95** level of theory including empirical dispersion correction reveals significant cooperativity of hydrogen bonding and size dependent structural preference. A substantial amount of impact of BSSE is observed in these calculations as the cluster size increases irrespective of the kind of arrangement. The interaction energy per monomer increases from dimer to 15mer by 90% in the case of the circular arrangement, by 76% in the case of the linear arrangement and by 34% in the case of the standard arrangement respectively. The cooperativity in hydrogen bonding is also manifested by a regular decrease in average OH and C-N bond distances, while average C=O and N-H bond lengths increase with increasing cluster size. Atoms-In-Molecules (AIM) analysis is used to characterize the nature of hydrogen bonding between the acetamide molecules in the cluster on the basis of electron density (ρ) values obtained at the bond critical point. An analysis of N-H bond stretching frequencies as a function of the cluster size shows a marked red shift as the cluster size increases from 1 to 15.     

Crystal structures and magnetic properties of new cyano-bridged two-dimensional grid-like bimetallic assemblies [Ni(tn)2]2[Cr(CN)5((NO)]OH*H2O and [NI(tn)2]2[Co(CN)6]NO3*2H2O (tn=1,3-propanediamine)

Two bimetallic assemblies, [Ni(tn)(2)](2)[Cr(CN)(5)(NO)]OH.H(2)O (1) and [Ni(tn)(2)](2)[Co(CN)(6)]NO(3).2H(2)O (2) (tn = 1,3-diaminopropane), have been prepared and structurally and magnetically characterized. Crystal data for 1 (2): space group P1 (P1), a = 8.698(3) (8.937(2)) A, b = 10.001(2) (9.863(1)) A, c = 10.158(2) (10.064(1)) A, alpha = 87.40(2) (86.064(10)) degrees, beta = 65.10(2) (65.489(10)) degrees, gamma = 81.63(2) (81.572(12)) degrees and Z = 1 (1). Both structures consist of two-dimensional grid-like polycations containing Ni-N triple bond C-M linkages (M = Cr or Co) and counteranions (OH, NO(3)). Magnetic studies of 1 showed that the complex displays a metamagnetic behavior originating from intralayer ferromagnetic and interlayer antiferromagnetic interactions. Long-range antiferromagnetic ordering was observed at T(N) = 3.3 K. Complex 2 exhibits intramolecular ferromagnetic interactions through the diamagnetic N triple bond C-Co-N triple bond C bridges, owing to superexchange involving the empty d(sigma) orbital of the diamagnetic Co(III) ion.     

Reactions of (1R,2S)-1,2-di(2-furyl)-1,2-di(3-guaiazulenyl)ethane and (1R,2S)-1,2-di(3-guaiazulenyl)-1,2-di(2-thienyl)ethane with tetracyanoethylene (TCNE) in benzene: comparative studies on the products and their spectroscopic properties

Reactions of the title meso forms, (1R,2S)-1,2-di(2-furyl)-1,2-di(3-guaiazulenyl)ethane (1) and (1R,2S)-1,2-di(3-guaiazulenyl)-1,2-di(2-thienyl)ethane (2), with a two molar amount of TCNE in benzene at 25 °C for 5 h (for 1) and 48 h (for 2) under oxygen give new compounds, 2,2,3,3-tetracyano-4-(2-furyl)-8-isopropyl-6-methyl-1,4-dihydrocyclohepta[c,d]azulene (3) and 2,2,3,3-tetracyano-8-isopropyl-6-methyl-4-(2-thienyl)-1,4-dihydrocyclohepta[c,d]azulene (4), respectively, in 74 and 21% isolated yields. Comparative studies on the above reactions as well as the spectroscopic properties of the unique products 3 and 4, possessing interesting molecular structures, are reported and, further, a plausible reaction pathway for the formation of these products is described.