D. Grandjean

A Molecular-Based Magnet with a Fully Interlocked Three-Dimensional Structure

A compound has been synthesized with the formula (rad)2Mn2[Cu(opba)]3(DMSO)2.2H2O, where rad+ is 2-(4-N-methylpyridinium)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, opba is orthophenylenebis(oxamato), and DMSO is dimethyl sulfoxide. It consists of two nearly perpendicular graphite-like networks with edge-sharing Mn(II)6Cu(II)6 hexagons. The two networks are fully interlocked with the same topological relationship as that between adjacent rings of a necklace. The compound has three kinds of spin carriers: Mn(II) and Cu(II) ions, antiferromagnetically coupled through oxamato bridges, and rad+ radical cations, bridging the Cu(II) ions through the nitronyl nitroxide groups and forming Cu-rad chains. The temperature dependence of the magnetization reveals that below 22.5 K, the compound behaves as a magnet.

Etude cristallochimique de derives du chrome(0) : I. Structure cristalline et moleculaire du benzoate de methyle chrome dicarbonyle thiocarbonyle

Abstract The crystal and molecular structure of methylbenzoatechromium dicarbonyl thiocarbonyl has been determined by a single-crystal X-ray study. The compound crystallizes with two molecules in a unit cell of symmetry P 1 , with the following parameters: triclinic system, a = 7.108(3), b = 10.340(4), c = 8.523(3) A; α = 89.75(6), β = 95.89(4), γ = 105.50(4)°; V = 601 A 3 ; d m = 1.57 ± 0.05, d c = 1.56. The structure has been refined to R and R ″ values of 0.030 and 0.038 respectively, for 1963 independent reflections. The main feature of the molecule is the C s symmetry of the Cr(CO) 2 CS group with a CrC(S) bond length of 1.792(2) A, shorter than the CrC(O) bond length, mean: 1.849(3) A.

Structural study of iron carbonyl derivatives: IV. Synthesis and crystal and molecular structure of syn-[μ-(SCH3)Fe(CO)2P(CH3)3]2

Summary The preparation of the compound [μ-(SCH 3 )Fe(CO) 2 L] 2 , with L = P(CH 3 ) 3 , is described. Spectroscopic studies show that this compound exists as syn and anti isomers, with respect to the orientation of the SCH 3 groups relative to the metal-metal bond. The crystal and molecular structure of the syn isomer has been determined by a single-crystal X-ray study. The complex crystallizes in the tetragonal space group P 4 1 2 1 2 (or P 4 3 2 1 2) with Z = 8. The intensities were measured on a Nonius CAD-4 automatic diffractometer. The structure has been refined to R and R″ values of 0.058 and 0.050 respectively, for 2156 independent reflections. The molecular structure contains two Fe(CO) 2 P(CH 3 ) 3 moieties (with the phosphine ligands in axial positions) bridged through the sulfur atoms of the syn -SCH 3 groups. The iron-iron bond length is 2.518(1)A. A comparison is made with similar iron carbonyl derivatives without phosphine substituents.

Structure cristalline et moleculaire du tetracarbonylcobaltatopyridine (N-(phenylamino)-α-methylbenzylidenimino-2-C,N) palladate(II), compose a liaison PdCo

Abstract The crystal and molecular structure of a bimetallic complex containing a PdCo bond has been determined by a single-crystal X-ray study. The compound crystallizes in the monoclinic space-group P21/n, with Z = 4. The intensities were measured on a Nonius CAD-4 automatic diffractometer. The structure has been refined to R and R″ values of 0.068 and 0.058 for 2843 independent reflections. The molecule contains a cyclopalladated ring system, with PdC and PdN(1) bond lengths of 1.998(8) and 2.101(5) A, respectively. Furthermore, the palladium atom is bonded to a pyridine ring (PdN(3) 2.159(6) A) and to a Co(CO)4 group, trans to N(1), through a PdCo bond of length 2.604(1) A.

Ferrocenyltrithiocarbonates : II. Synthesis and x-ray structure determination of diiron hexacarbonyl complexes

Abstract Ferrocenyltrithiocarbonates, I, react with Fe2(CO)9 to afford new types of binuclear complexes in which the diiron hexacarbonyl moiety is linked by two bridges resulting from the insertion of an iron atom into the carbon-sulfur single bond. The X-ray structure determination of μ-(thioferrocenylmethylmethane thiomethylene-C1, S2)-1,1,1,2,2,2-hexacarbonyl-μ-methylthioiron (FeFe) has been refined to R = 0.037. Comparison of X-ray and 13C data with those of the starting materials are in agreement with a metallocarbene structure.

Reactivity of cyclopalladated compounds. Part 7. Syntheses of metallobicyclic compounds and their reactions with acetylenes. X-Ray crystal and molecular structures of the compounds [(NMe2CH2C6H4)Pd{C(CF3)C(CF3)(C6H4CH2NMe2)}] and [{(NMe2CH2C6H4)C(CF3)C(CF3)}Pd{C(CF3)C(CF3)(CH2C9H6N)}]

Hexafluorobut-2-yne (hfb) reacted with [M(dmba – H)2](dmba =NN-dimethylbenzylamine, M = Ni or Pd) to give [([graphic omitted]Me2)}] compounds in which one acetylene was formally inserted into one of the M–C bonds, the second metallocycle being unmodified. A cis geometry has been tentatively assigned to the compound where M = Ni, whereas a trans configuration is found for M = Pd. This latter complex isomerizes slowly in solution to give the cis isomeric form which has been studied by single-crystal X-ray diffraction measurements; the complex crystallizes in the monoclinic space group P21/n with a= 11.705(2), b= 11.146(2), c= 16.317(5)A, β= 93.16(2)°, and Z= 4. The two nitrogen atoms are indeed mutually cis to each other, the Pd–N distances being rather long [2.231 (3) and 2.223 (3)A]; the phenyl ring which is a part of the seven-membered palladated ring is now perpendicular to the co-ordination plane of the Pd atom. Reaction of lithiated NN-dimethylnaphthylamine (dmna) or NN-dimethylaminotoluene (dmat) with [PdCl2(SEt2)2] gave the bicyclic compounds [Pd(dmna – H)2] and [Pd(dmat – H)2], the latter in very low yield however. The former compound gave metallic Pd and an organic product by reaction with hfb. Asymmetric bicyclic compounds have been synthesized by reaction of lithiated dmna, dmat, or dmba with the chlorine-bridged dimers [{Pd(dmba – H)Cl}2] or [{Pd(8Me-quin – H)Cl}2](8Me-quin = 8-methylquinoline). Reaction between hfb and the bicyclic compound [Pd(dmba – H)(dmna – H)] afforded a compound in which again only one acetylene has reacted with the Pd–C bond of the palladated dmba moiety; the two Pd–C bonds are trans to each other and it also isomerizes into the corresponding cis species in solution. [Pd(dmba – H)(8Me-quin – H] with hfb gave a product in which the acetylene reacted with both Pd–C bonds affording a bicyclic compound with two seven-membered rings attached to the same palladium. This product exists as a mixture of cis and trans isomers but only the cis species has been isolated in a pure crystalline form. Its stereochemistry has been confirmed by an X-ray diffraction study; the complex crystallizes in the monoclinic space group P21/n with a= 13.948(8), b= 12.338(7), c= 16.868(6)A, β= 107.89(4)°, and Z= 4. The seven-membered ring containing the dmba ligand resembles that described above whereas the new ring containing 8Me-quin – H is mainly described by two planes whose dihedral angle is 112.3°. [Pd(dmba – H)(8Me-quin – H)] also reacts under smooth conditions with MeO2CCCCO2Me to give a mixture of products from which one compound has been isolated in a pure form : it has fixed one acetylene per palladium atom and we suggest on the basis of n.m.r. data that it has reacted with the C–Pd bond of the palladated 8Me-quin moiety.

Etude structurale de ferrocenophanes I. Structure cristalline et moleculaire du (cyclopentylene-1″,3″)-1,1′ ferrocene

Abstract The crystal and molecular structure of 1,1-(1″,3″ -cyclopentylene)ferrocene, prepared by cleavage of ferrocene by AlCl3, has been determined by a single crystal X-ray study. The compound crystallizes with eight molecules in space group Pbca of the orthorhombic system in a cell of dimensions a 15.260(7), b 14.266(5), c 10.337(2) ». The observed and calculated densitie are 1.46 and 1.49 g cm−3. The structure has been solved by direct methods and refined by full matrix-least-squares methods to a final R index of 0.057. The dihedral angle between the best planes through the two planar cyclopentadienyl rings is 11° and is shown to be deduced from the length of the bridge. The cyclopentadienyl rings are eclipsed and the Fe—cyclopentadienyl distances are the same as in ferrocene. The cyclopentylene bridge is distorted and asymmetrical. The conformation is discussed with regard to 1H and 13C NMR results.

Etude structurale de derives du fer carbonyle ☆: II. Structure cristalline et moleculaire d'un complexe du fer carbonyle avec la 2-mercapto-pyridine, C5H4N(CO)6Fe2-μ4-S-Fe2(CO)6SC5H4N

Abstract The crystal and molecular structure of a complex prepared by reaction between Fe 3 (CO) 12 and 2-mercaptopyridine and of formula C 5 H 4 N(CO) 6 Fe 2 -μ 4 -S-Fe 2 (CO) 6 SC 5 H 4 N has been determined by a single-crystal X-ray study. The compound crystallises in the monoclinic space group P 2 1 n , with Z = 4. Data were collected on a NONIUS CAD-4 automatic diffractometer. The structure was solved both by the heavy-atom method and direct methods and refined to R and R ″ values of 0.041 and 0.038 for 2089 independent reflections. The molecule contains four Fe(CO) 3 groups with two ironiron bonds bridged in a different way, and a sulphur atom tetrahedrally coordinated to the four iron atoms.

Synthesis and molecular structure of new families of iridium(III)-Cp★ and rhodium(III)-Cp★ complexes derived from 1,2-dicyanoethene-1, 2-dithiolate 2,2′-biimidazole or 2,2′-bithiazole. Single crystal structures of [(η5-Me5C5)Ir(biimH2)Cl]Cl and [(η5-Me5C5)Rh(dcdt)]

Reaction of [(η5-Me5C5)MCl2]2 (M  Ir or Rh) with 1,2-dicyanoethene-1,2-dithiolate (dcdt2−), 2,2′-biimidazole (biimH2), or 2,2′-bithiazole (bith) affords various d6 complexes in high yield. Pentacoordinate compounds such as [(η5-Me5C5)M(dcdt)] (M  Ir or Rh) and hexacoordinate complexes of the type [(η5-Me5C5)M(biimH2)Cl]Cl, (M  Ir or Rh) or [(η5-Me5C5)Ir(bith)Cl]Cl have been synthesized and characterized. [(η5-Me5C5)Rh (dcdt)] crystallizes in the orthorhombic space group C2221 with unit cell parameters a = 11.972 (3), b = 15.072 (4), c = 16.456 (5) A. Refinement of 859 observed reflections led to the final values of R = 2.31 and Rw = 3.46%. [(η5-Me5C5)Ir(biimH2)Cl]Cl crystallizes in the orthorhombic space group P212121 with unit cell parameters a = 14.610 (4), b = 14.556 (6), c = 8654 (3) A. Refinement of 1630 observed reflections led to a value of R = 186 and Rw = 2.65%. The biimH2-iridium complex exhibits a characteristic three-legged “piano-stool” arrangement and the dcdt-rhodium complex a flattened basket shaped arrangement.

Sulfur-containing carbene-metal compounds: General route from carbon disulfide manganese complexes; X-ray structure of 1,3-dithiol-2-ylidenemanganese(I) derivative

Abstract Chiral carbene-manganese(I) complexes have been synthesized by the cyclo-addition of dimethyl acetylenedicarboxylate to the coordinated CS 2 ligand in Mn(η 2 -CS 2 )(CO)(L)C 5 H 4 R (L = P(OMe) 3 ; PMe 2 Ph; PMe 3 ). Irrespective of the nature of the ligand L, these 1,3-dithiol-2-ylidenemanganese(I) complexes are stable towards isomerisation into heterometallocycles and exhibit low frequency carbonyl absorption bands in the infrared consistent with a strong electron releasing effect of the carbene ligand. The structure of Mn(CS 2 C 2 (CO 2 Me) 2 )(CO)(P(OMe) 3 )(C 5 H 5 ) has been determined by X-ray analysis of a suitable crystal. The molecule shows a carbene carbonmanganese bond C(7)Mn of length 1.876 A and a planar carbene which does not adopt the 1,3-dithiolium aromatic-ring geometry but contains a carboncarbon double bond, C(8)C(9), of length of 1.341 A. The CO 2 Me groups are out of the plane of the carbene ligand and two positions with equal occupancy are found for each oxygen atom O(3) and O(5) belonging to the CO groups.