Reaction of arylamines with some β,β′-substituted sulfolanes and β-substituted 2- and 3-sulfolenes

The reaction of,gb -substituted sulfolanes and-substituted 2- and 3-sulfolenes with aromatic amines was investigated. 4-Arylamino-2-sulfolenes and 3-arylamino-4-hydroxysulfolanes were obtained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1193–1195, September, 1972.     

Reaction of sulfolanyl sulfonates with some nucleophilic reagents

The corresponding -substituted sulfolane derivatives were isolated in the reaction of 3-sulfolanyl arene(alkane)sulfonates with amines, alcohols, and mercaptans. Depending on the nature of the nucleophile, 3,4-disubstituted sulfolanes and 4- and 3-substituted 2-sulfolenes were obtained with 3,4-sulfolanyl disulfonates and 4-sulfolen-2-yl sulfonates.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 625–630, May, 1974.     

Cluster Chemsitry. 96. Penta- and hexa-nuclear ruthenium cluster complexes derived from reactions of cyclopentadienes with Ru5(μ5-C2PPh2)(μ-PPh2)(CO)13

The reactions between Ru₅( ₅-C₂PPh₂)(gm-PPh₂(CO)₁₃ (1) and cyclopentadienes afforded the hexanuclear clusters Ru₆( ₆-C)( ₃-PPh₂)₂(CO)₁₀(-C₅ R ₅) [R ₅ = H₅ (2), H₄Me (3), Me₅ (4)] which contain an encapsulated carbide and a face-capping ₃-CH group, formed by cleavage of CC and CP bonds of the C₂PPh₂ moiety in1. In the reaction with cyclopentadiene, the unusual ligand C₁₃H₁₂O, formed by combination of C₂, CO and two molecules of C₅H₆ (or one molecule of dicyclopentadien), was characterized in the complex Ru₅( ₄-PPh) ( ₄-C₁₃H₁₂O)(-PPh₂(CO)₁₁(-C₅H₅) (5). In the reaction with pentamethylcyclopentadiene, the vinylidene complex Ru₅( ₃-CCHPh)( ₄-PPh)( ₄-PPh) (-PPh₂)(CO)₉(-C₅Me₅) (6) was also formed.     

Some reactions of the isopropyl radical

The decomposition of ethane sensitized by isopropyl radicals was studied in the temperature range of 496–548°K. The rate of formation of n-butane, isopentane, and 2,3-dimethylbutane were measured. The expression k₁/k₂^½ was found to be where k₁ and k₂ are rate constants of The decomposition of propylene sensitized by isopropyl radicals was studied between 494 and 580°K by determination of the initial rates of formation of the main products. The ratio of k₁₃/k₂^1/2 was evaluated to be where k₁₃ is the rate constant for The isomerization of the isopropyl radical was investigated by studying the decomposition of azoisopropane. The decomposition of the iso-C₃H₇ radical into C₂H₄ and CH₃ was followed by measuring the rate of formation of C₂H₄. On the basis of the experimental data, obtained in the range of 538–666° K, k₁₅/k₂^½ was found: where k₁₅ is the rate constant of      

On the crystal chemistry of three copper(II)-arsenates: Cu3(AsO4)2-III,Na4Cu(AsO4)2, and KCu4(AsO4)3

The three copper(II)-arsenates were synthesized under hydrothermal conditions; their crystal structures were determined by single-crystal X-ray diffraction methods:Cu₃(AsO₄)₂-III:a=5.046(2) Å,b=5.417(2) Å,c=6.354(2) Å, =70.61(2)°, =86.52(2)°, =68.43(2)°,Z=1, space group ,R=0.035 for 1674 reflections with sin / 0.90 Å^–1.Na₄Cu(AsO₄)₂:a=4.882(2) Å,b=5.870(2) Å,c=6.958(3) Å, =98.51(2)°, =90.76(2)°, =105.97(2)°,Z=1, space group ,R=0.028 for 2157 reflections with sin / 0.90 Å^–1.KCu₄(AsO₄)₃:a=12.234(5) Å,b=12.438(5) Å,c=7.307(3) Å, =118.17(2)°,Z=4, space group C2/c,R=0.029 for 1896 reflections with sin / 0.80 Å^–1.Within these three compounds the Cu atoms are square planar [4], tetragonal pyramidal [4+1], and tetragonal bipyramidal [4+2] coordinated by O atoms; an exception is the Cu(2)^[4+1] atom in Cu₃(AsO₄)₂-III: the coordination polyhedron is a representative for the transition from a tetragonal pyramid towards a trigonal bipyramid. In KCu₄(AsO₄)₃ the Cu(1)^[4]O₄ square and the As(1)O₄ tetrahedron share a common O—O edge of 2.428(5) Å, resulting in distortions of both the CuO₄ square and the AsO₄ tetrahedron. The two Na atoms in Na₄Cu(AsO₄)₂ are [6] coordinated, the K atom in KCu₄(AsO₄)₃ is [8] coordinated by O atoms.Die drei Kupfer(II)-Arsenate wurden unter Hydrothermalbedingungen gezüchtet und ihre Kristallstrukturen mittels Einkristall-Röntgenbeugungsmethoden ermittelt:Cu₃(AsO₄)₂-III:a = 5.046(2) Å,b = 5.417(2) Å,c = 6.354(2) Å, = 70.61 (2)°, = 86.52(2)°, = 68.43(2)°,Z = 1, Raumgruppe ,R = 0.035 für 1674 Reflexe mit sin / 0.90 Å^–1.Na₄Cu(AsO₄)₂:a = 4.882(2) Å,b = 5.870(2) Å,c = 6.958(3) Å, = 98.51(2)°, = 90.76(2)°, = 105.97(2)°,Z = 1, Raumgruppe ,R = 0.028 für 2157 Reflexe mit sin / 0.90 Å^–1.KCu₄(AsO₄)₃:a = 12.234(5) Å,b = 12.438(5) Å,c = 7.307(3) Å, = 118.17(2)°,Z = 4, Raumgruppe C2/c,R = 0.029 für 1896 Reflexe mit sin / 0.80 Å^–1.Die Cu-Atome in diesen drei Verbindungen sind durch O-Atome quadratisch planar [4], tetragonal pyramidal [4 + 1] und tetragonal dipyramidal [4 + 2]-koordiniert; eine Ausnahme ist das Cu(2)^{[4 + 1]}-Atom in Cu₃(AsO₄)₂-III: Das Koordinationspolyeder stellt einen Vertreter des Übergangs von einer tetragonalen Pyramide zu einer trigonalen Dipyramide dar. In KCu₄(AsO₄)₃ haben das Cu(1)^[4]O₄-Quadrat und das As(1)O₄-Tetraeder eine gemeinsame O—O-Kante von 2.428(5) Å, was eine Verzerrung der beiden Koordinationsfiguren CuO₄-Quadrat und AsO₄-Tetraeder bedingt. Die zwei Na-Atome in Na₄Cu(AsO₄)₃ sind durch O-Atome [6]-koordiniert, das K-Atom in KCu₄(AsO₄)₃ ist [8]-koordiniert.

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Zur Kristallchemie dreier Kupfer (II)-Arsenate: Cu₃(AsO₄)₂-III, Na₄Cu(AsO₄)₂ und KCu₄(AsO₄)₃

     

Zr 5Ir 2In 4 – A Superstructure of the Lu 5Ni 2In 4 Type

Zr₅Ir₂In₄ was synthesized by reaction of the elements in a glassy carbon crucible in a water-cooled sample chamber of an induction furnace. The sample was characterized by X-ray diffraction on both powder and single crystals. Zr₅Ir₂In₄ crystallizes with a pronounced Lu₅Ni₂In₄ type subcell, space group Pbam, a=1739.5(6), b=766.3(2), c=338.9(2) pm. Weak additional reflections force a doubling of the subcell c axis. The superstructure of Zr₅Ir₂In₄ is of a new type: Pnma, a=1739.5(6), b=677.8(2), c=766.3(2) pm, wR2=0.0529, 1592 F² values, and 60 variable parameters. The group-subgroup scheme for the klassengleiche symmetry reduction is presented. The formation of the superstructure is most likely due to a puckering effect (size of the iridium atoms). The crystal chemistry of Zr₅Ir₂In₄ is briefly discussed.     

Crystal Structures of Two Re(V) Complexes of 3,5-Dimethylpyrazole with Linear and Bent [OReOReO]4+ Fragments

The crystal structures of two new dimer compounds of Re(V) containing an [OReOReO]⁴⁺ fragment have been studied. Re₂O₃Cl₄(3,5-Me₂pzH)₄ (I): space group P2¹/n, Z = 4, a = 10.180(3), b = 18.132(3), c = 16.601(2) , = 94.60(2)°, V = 3054.4(1) ³, d _calc = 2.059 g/cm³, R ₁ = 0.0513, wR₂ = 0.1493 for 4701 I_hkl > 2 _I of 4926 measured reflections; Re₂O₃Cl₂(-3,5-Me₂pz)₂(3,5-Me₂pzH)₂2[(3,5-Me₂pzH₂)Cl] (II): space group P2₁/n, Z = 4, a = 16.904(2), b = 14.573(1), c = 17.401(2) , = 107.23(1)°, V = 4094.2(7) ³, d _calc = 1.848 g/cm³, R ₁ = 0.025, wR₂ = 0.0514 for 6102 I_hkl > 2 _I of 6315 measured reflections (Enraf-Nonius CAD-4 diffractometer, MoK, graphite monochromator). Compound I has a molecular structure, where molecules are dimers Re₂O₃Cl₄(3,5-Me₂pzH)₄ with a bridging O atom. In II, the dominant motif is the ReOCl(3,5-Me₂pzH) fragments bridged by the pyrazole molecules and the O atom.     

Zr<Subscript>5</Subscript>Ir<Subscript>2</Subscript>In<Subscript>4</Subscript> – A Superstructure of the Lu<Subscript>5</Subscript>Ni<Subscript>2</Subscript>In<Subscript>4</Subscript> Type

Summary. Zr₅Ir₂In₄ was synthesized by reaction of the elements in a glassy carbon crucible in a water-cooled sample chamber of an induction furnace. The sample was characterized by X-ray diffraction on both powder and single crystals. Zr₅Ir₂In₄ crystallizes with a pronounced Lu₅Ni₂In₄ type subcell, space group Pbam, a=1739.5(6), b=766.3(2), c=338.9(2) pm. Weak additional reflections force a doubling of the subcell c axis. The superstructure of Zr₅Ir₂In₄ is of a new type: Pnma, a=1739.5(6), b=677.8(2), c=766.3(2) pm, wR2=0.0529, 1592 F² values, and 60 variable parameters. The group-subgroup scheme for the klassengleiche symmetry reduction is presented. The formation of the superstructure is most likely due to a puckering effect (size of the iridium atoms). The crystal chemistry of Zr₅Ir₂In₄ is briefly discussed.     

The collision cross sections for excitation energy transfer in Rb*(5P 3/2) + K(4S 1/2) → Rb(5S 1/2) + K*(4P J ) processes

The collisional excitation transfer for the processes Rb*(5P _3/2)+K(4S _1/2) Rb(5S _1/2)+K*(4P _J ),J=1/2, 3/2, was investigated using two-photon laser excitation technique with a thermionic heat-pipe diode as a detector. The population densities of the K 4P _J levels induced by collisions with excited Rb atoms as well as those produced by direct laser excitation of the potassium atoms were probed through the measurement of the thermionic signals generated due to the ionization of the potassium atoms emerging from the K(4P _J ) K(7S _1/2) excitation channel. The measurements of the thermionic signals in addition to the spectroscopic determination of the potassium number density yield the following values for the excitation transfer cross sections: ₁(Rb 5P _3/2 K 4P _1/2)=8 Ų and ₂(Rb 5P _3/2 K 4P _3/2)=11 Ų. The accuracy of the presented results is 15%. The obtained results are compared to those for the opposite processes K*(4P _J )+Rb(5S _1/2) K(4S _1/2)+Rb*(5P _3/2).     

1D and 2D Systems Derived from Polynuclear [ ML(N 3) 2] n ( M?=?Zn(II) or Cd(II) and L is 2-Picoline- N-oxide or 4-Methylpyrimidine)

Four new polynuclear complexes: [Zn(2picNO)(N₃)₂]_n, [Zn(4Mepym)(N₃)₂]_n, [Cd(2picNO)(N₃)₂]_n, and [Cd(4Mepym)(N₃)₂]_n (2picNO=2-picoline-N-oxide and 4Mepym=4-methylpyrimidine) have been synthesized and characterized by single-crystal X-ray diffraction. The structures of the zinc(II) complexes feature five-coordinate zinc atoms, (-1,1) azido bridges, monodentate organic ligands, and 1D chains. The cadmium(II) azide complexes contain distorted octahedral metal atoms linked by alternate di-(-1,1) and di-(-1,3) azido bridges in cis arrangement and these chains are connected by 2picNO bridges giving a honeycomb 2D framework or by 4Mepym bridges forming extended 2D network structure.     

The designed synthesis and crystallographic characterization of three novel heterotrimetallic linear complexes of [Et4N][(Ph3P)2{M′S2 MS2Fe}Cl2] (M=Mo,M′=Ag;M=W,M′=Cu,Ag)

The complexes [Et₄N][(Ph₃P)₂{MS₂ MS₂Fe}Cl₂] (M=Mo,M=Ag;M=W,M=Cu, Ag) have been obtained by reaction of [Et₄N]₂[S₂ MS₂FeCl₂] (M=Mo, W) with Cu(PPh₃)₃Cl or Ag(PPh₃)₃NO₃ in MeCN/CH₂Cl₂, respectively. Crystal data for [Et₄N][(PPh₃)₂ {AgS₂MoS₂Fe}Cl₂] (I): triclinic, P (No. 2),Z=2,a=13.41(1)Å,b=15.54(1)Å,c=12.30(1)Å, =105.24(6)°, =94.63(7)°, =101.38(6)°, andV=2399(4)ų. The bond lengths of Mo-Fe bond and the Mo-Ag distance are 2.756(2)Å and 3.033(2)Å, respectively. Crystal data for [Et₄N][(PPh₃)₂ {AgS₂WS₂Fe}Cl₂] (II): triclinic, P (No. 2),Z=2,a=13.457(5))Å,b=15.601(6)Å,c=12.338(4)Å, =105.20(3)°, =94.61(4)°, =101.43(4)°, andV=2426(2)ų. The bond length of W-Fe bond and the W-Ag distance are 2.786(2)Å and 3.076(1)Å, respectively. Crystal data for [Et₄N][(PPh₃)₂ {CuS₂WS₂Fe}Cl₂] (III): triclinic, P (No. 2),Z=2,a=13.498(5)Å,b=15.372(4)Å,c=12.340(4)Å, =105.54(2)°, =93.32(3)°, =101.40(3)°, andV=2401(1)ų. The bond lengths of W-Fe bond and the W-Cu bond are 2.800(1)Å and 2.851(1)Å, respectively.     

Single Crystal Growth, Crystal Structure and Thermal Behaviour of Mercury(II) Pyrophosphate Dihydrate

Colourless single crystals of Hg₂P₂O₇(H₂O)₂ up to 0.4 mm in length were grown by a diffusion technique starting from aqueous solutions of Na₄P₂O₇ and Hg(NO₃)₂. The crystal structure is isotypic with that of Ca₂P₂O₇(H₂O)₂ and was determined from a four-circle diffractometer data set (space group , Z=2, a=6.9374(7), b=7.4396(8), c=7.9863(7)Å, =84.685(8), =75.158(8), =72.818(8)°, 2413 structure factors, 132 parameters, R[F ²>2(F ²)]=0.0181, wR(F ² all)= 0.0384). Hg₂P₂O₇(H₂O)₂ is composed of approximately eclipsed P₂O₇ ^4– anions and distorted [HgO₆] octahedra and [HgO₇] pentagonal bipyramids as the main building units. The structure is stabilized by inter-water hydrogen bonding and by hydrogen bonding between terminal pyrophosphate oxygen atoms and the water molecules. The P–O distances to the terminal oxygen atoms range from 1.501(4) to 1.536(3)Å, with an average of 1.522Å; the mean distance of 1.615Å to the bridging O atom is considerably longer with an (O–P–O) bridging angle of 123.44(19)°. Both Hg atoms have two short Hg–O bonds around 2.17Å and additional bonds ranging from 2.381(3) to 2.708(4)Å. Upon heating above 160°C, both crystal water molecules are released simultaneously and anhydrous Hg₂P₂O₇ is formed which is stable up to ca. 660°C. Above this temperature the material decomposes completely.     

A new platinum-osmium alkyne complex from the reaction of Pt2Os4(CO)18 with PhC ≡ CPh: The synthesis,characterization, and crystal structure of Pt2Os4(CO)8 (μ3-PhC2Ph)3(μ4-PhC2Ph)

The new platinum-osmium alkyne cluster complex Pt₂Os₄(CO)₈(₃-PhC₂Ph)₃ ( ₄-PhC₂Ph),2, was obtained from the reaction of Pt₂Os₄(CO)₁₈,1b, with PhC₂Ph and was characterized by IR.¹H NMR and single-crystal X-ray diffraction analyses. The cluster of compound2 consists of an osmium capped Pt₂Os₃ square pyramid. It aLso contains three triply bridging and one quadruply bridging diphenylacetylene ligands. Crystal data for2: space group PI,a = 12.530(2) Å,b = 21.565(4) Å,c = 11.284(2) Å, = 100.31(2), = 111.89(1), = 76.78(2),Z = 2, 3879 reflections,R = 0.032.     

Interaction of Nitromethane with Modified Paramagnetic Defects on a Thermochemically Activated Silica Surface

It was found that the interaction of the modified paramagnetic defects SiO(CH₂) _n H₂ (n = 0.1) with nitromethane on a thermochemically activated silica surface at 300 K results in the formation of the following nitroxyl radicals: SiO(CH₂) _n CH₂ON( )CH₃ and SiO(CH₂) _n CH₂N( )CH₃. It was suggested that these radicals are the products of two different reactions of the modified paramagnetic defects: the first results from a reaction with free nitromethane; the second, from a reaction with nitromethane bound as complexes with diamagnetic surface defects.     

Synthesis and X-ray structural characterization of cobalt(II), copper(II), and silver(I) complexes of triphenylphosphoniopropionate

Four transition-metal carboxylate-like complexes have been synthesized from the reaction of the tertiary phosphine betaine triphenylphosphoniopropionate, Ph₃P⁺(CH₂)₂CO ₂ ^– , with Co(ClO₄)₂· 6H₂O, Cu(ClO₄)₂·6H₂O, Cu(BF₄)₂·xH₂O, and AgClO₄, respectively, and fully characterized by single-crystal X-ray analysis. [CoPh₃P(CH₂)₂CO_{2 4}(H₂O)₂](ClO₄)₂·2H₂O, 1, space groupP¯ l witha=9.195(2),b=13.000(2),c=18.795(3) Å,=102.52(1),=90.12(1),=109.28(2)° andZ=1; [CuPh₃P(CH₂)₂CO_{2 4}][Cu₂ -Ph₃P(CH₂)₂CO₂ -O,O ₄(H₂O)₂] (ClO₄)₆· 4H₂O, 2, space groupP2_l/c witha=14.225(3),b=24.624(6),c=24.297(5) Å,=94.18(1)°, andZ=2; [CuPh₃,P(CH₂)₂CO₂Me₂N(CH₂)₂NMe₂(H₂O)₂](BF₄)₂,3, space groupP2_l/c witha=17.668(2),b=13.454(3),c=15.876(2) Å,=116.45(1)°, andZ=4; [Ag₂Ph₃P(CH₂)₂CO_{2 2}(ClO₄)]₂(ClO₄)₂,4, space groupP¯ l witha=10.925(2),b=13.110(3),c=18.795(3) Å,=82.93(3),=87.45(3),=67.49(3)°, andZ=2. In complex1, the cobalt(II) atom is located in an inversion center and coordinated by four unidentate betaine ligands and a pair oftrans aqua ligands, and strong hydrogen bonds are formed between the aqua ligands and the pendant oxygen atoms of the betaine ligands. In complex2, mononuclear and dinuclear cations coexist in the asymmetric unit. In the mixed-ligand complex3 the betaine ligand acts in the unidentate coordination mode andN,N,N,N-tetramethylethylenediamine (tmen) in the chelate mode. Complex4 contains a discrete centrosymmetric tetranuclear cations in which one pair of betaine ligands act in the bidentate bridging mode and the other in both bidentate and one-atom bridging modes.     

Synthesis and spectroscopic studies of complexes containing the Schiff base 1-acetylferrocene(thio)semicarbazone

Summary [RuCl₂(CO)₂] _n reacts with the Schiff base 1-acetylferrocenethiosemicarbazone, [Fe(-Cp)(-C₅H₄MeC=NN-HCSNH₂)] to give [Fe(-Cp)(-C₅H₄MeC=NN-HCSNH₂)RuCl₂(CO)₂] and with 1-acetylferrocenesemicarbazone [Fe(-Cp)(-C₅H₄MeC=NN-HCSNH₂)] to give [Fe(-Cp)(-C₅H₄MeC=NN-HCSNH₂)RuCl₂-(CO) ₂]. Spectroscopic data indicate that the Schiff bases act as bidentate ligands and coordinate to ruthenium via the hydrazinic N and either the S or O atoms, respectively, giving stable heterobimetallic complexes, which have been characterized by i.r. and ¹H-n.m.r. spectroscopies, and elemental analyses.Part of this work was presented at the First International Conference in Chemistry and its applications in Doha, Qatar, 1993.     

Thermal stability of intermediate sized acetylenic compounds and the heats of formation of propargyl radicals

4-Methylhexyne-1, 5-methylhexyne-1, hexyne-1, and 6-methylheptyne-2 have been decomposed in comparative-rate single-pulse shock-tube experiments. Rate expressions for the initial decomposition reactions at 1100°K and from 2 to 6 atm pressure are In combination with previous results, rate expressions for propargyl C? C bond cleavage are related to that for the alkanes by the expression These results yield a propargyl resonance energy of D(nC₃H₇-H) – D(C₃H₃-H) = 36 ± 2 kJ, in excellent agreement with a previous shock-tube study. They also lead to D(CH₃C≡CCH₂-H) – D(C₃H₃-H) = 0.6 ± 3 kJ, D(sC₄H₉-H) – D(iC₃H₇-H) = 0 ± 3 kJ, D(iC₄H₉-H) – D(nC₃H₇-H) = 2 ± 3 kJ, and D(nC₃H₇-H) – D(iC₃H₇-H) = 13.9 ± 3 kJ (all values are for 300°K). The systematics of the molecular decomposition process are explored.     

Synthesis and X-ray crystal structure of [1,3-bis(η5-cyclopentadienyl)-1,1,3,3-tetramethyldisiloxane]hafnium(IV) dichloride

Summary The tetramethyldisiloxane-bridged hafnocene complex [HfCl₂{-(⁵-C₅H₄)SiMe₂OSiMe₂(²-C₅H₄)}] (1) has been prepared by the reaction of HfCl₄ with the dilithiatedbis(cyclopentadienyl)disiloxane (LiC₅H₄SiMe₂)₂O in a molar ratio of 1:2. The new compound was characterized by spectroscopic and X-ray diffraction methods. The crystals are monoclinic of space groupP2₁/c and isostructural with the corresponding complexes of titanium and zirconium. The unit cell dimensions area=13.51(1) Å,b=8.672(7) Å,c=15.41(1) Å, =97.15(2)°, andZ=4.

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Darstellung und Röntgenkristallstruktur von [1,3-Bis(⁵-cyclopentadienyl)-1,1,3,3-tetramethyldisiloxan]hafnium(IV)dichlorid

Zusammenfassung Der tetramethyldisiloxan-überbrückte Hafnocenkomplex [HfCl₂{-(⁵-C₅H₄)-SiMe₂OSiMe₂(²-C₅H₄)}] (1) wurde durch Umsetzung von HfCl₄ mit dem lithiiertenBis(cyclopentadienyl)disiloxan (LiC₅H₄SiMe₂)₂O im Molverhältnis 1:2 dargestellt. Die neue Verbindung wurde spektroskopisch und röntgenographisch charakterisiert. Sie kristallisiert in der monoklinen RaumgruppeP2₁/c und ist isostrukturell mit den entsprechenden Titan-und Zirkoniumkomplexen. Die Dimensionen der Einheitszelle sinda=13.51(1) Å,b=8.672(7) Å,c=15.41(1) Å, =97.15(2)° undZ=4.

     

The hyperfine structure of electron spin resonance spectrum of tricobalt cluster radical anion CH3CCo3(CO)

CH₃CCo₃(CO)₉ was synthesized from the reaction between chloralose and Co₂(CO)₈. The radical anion was generated by electrochemical reduction, and electron spin resonance spectra in THF were recorded by in situ electrolysis in the sample tube in the ESR cavity at 298 and 110K with the spectral data <g> =2.015, g =2.013, g =2.016; <a> = —35.2G, a₁ = —78.6G and a =—13.5G. The effect on shift of the magnetic resonance field by using the second order perturbation theory was discussed, and the electron spin density on Co atom orbitals 4s, 4p and 3d was calculated, respectively to be 4s: —0.08, 3d: 0.855 and 4p: 0.225.     

Synthesis and structures of cycloalkylidene-bridged biscyclopentadienyl-tetracarbonyldiiron complexes C(CH2) n [( η 5-C5H4)Fe(CO)]2( μ-CO)2(n = 4, 5 and 6)

A series of cycloalkylidene-bridged biscyclopentadienyldiiron complexes, C(CH₂) _n [(⁵-C₅H₄)Fe(CO)]₂(-CO)₂ (n = 4, 5 and 6) have been synthesized by the reacting C(CH₂) _n Cp₂ (Cp = C₅H₅) with Fe(CO)₅ in refluxing xylene. The molecular structures of C(CH₂)₅[(⁵-C₅H₄)Fe(CO)]₂(-CO)₂ (2) and trans-C(CH₂)₄[(⁵-t-BuC₅H₃)Fe(CO)]₂(-CO)₂ (4t) have been determined by X-ray diffraction. The Fe—Fe bond distance [2.466 Å], in (2) is the shortest reported to date for bridged biscyclopentadienyldiiron complexes.