Shao Meicheng

Organonickel chemistry: I. The crystal and molecular structures of Ph3PNi(Ph)(Ph2PCHCOPh) and cis-Ni(Ph2PCHCOPh)2·0.5C7H8

Reaction of Ni(Cod)2, Ph3P and Ph3PCHCOPh in toluene affords Ph3PNi(Ph)(Ph2PCHCOPh) (I), but with Ph3As instead of Ph3P, it affords cis-Ni(Ph2PCHCOPh)2·0.5tol (II). The crystal and m studied by X-ray diffraction. The crystals of I, are monoclinic, space group Cc, with a 13.549(7), b 13.775(3), c 19.763(6) A, β 102.34(3)°, V 3603(2) A3, Z = 4. The final R factor is 0.070 for 1392 observed reflections. The crystals of II are monoclinic, space group C2/c, with a 27.425(7), b 11.113(2), c 24.534(7) A, β 108.27(2)°, V 7100(3) A3, Z = 8. The final R factor is 0.083 for 1409 observed reflections. The coordinations of the nickel atoms in both structures are square planar, and the bond lengths and bond angles in the PCCONi five-membered ring indicate a delocalized system.

Synthesis and crystal structure of isomerized butadiene(dicarbonyl)(ethoxyarylcarbene)iron complexes

Reaction of π-butadienetricarbonyliron(I) with aryllithium ArLi (Ar = phenyl, substituted phenyl, 1-naphthyl and 2-thienyl) in ether at low temperature, followed by the alkylation of the acylmetallate obtained with triethyloxonium tretrafluoroborate [(C2H5)3OBF4] in water solution at 0°C 10 orange-red crystalline complexes with the composition C4H6(CO)2FeC(OC2H5)Ar. On the basis of elemental analyses, IR, 1H NMR and mass spectra, as well as single crystal X-ray structure determination, it is corroborated that these new compounds were isomers of butadienyldicarbonyl(ethoxyarylcarbene)iron complexes with two types of structure. A possible reaction mechanism is tentatively proposed and discussed in this paper.

Studies on olefin-coordinating transition metal-carbene complexes ☆: VII. Studies on the synthesis, spectra and structure of cycloheptatriene(dicarbonyl)[ethoxy(aryl)carbene]-molybdenum and -chromium, and bicycloheptadiene(tricarbonyl)-[ethoxy(aryl)carbene]molybdenum complexes

Abstract Reaction of cycloheptatriene(tricarbonyl)-molybdenum (I) and -chromium (II), and bicycloheptadiene(tetracarbonyl)molybdenum (III) with aryllithium, ArLi (Ar = C 6 H 5 , p -, o -, m -CH 3 C 6 H 4 , p -CH 3 OC 6 H 4 , p -CF 3 -C 6 H 4 ), in ether at low temperature, and subsequent alkylation of the acylmetallate formed with Et 3 OBF 4 in aqueous solution at 0°C, gave 10 crystalline complexes with the compositions C 7 H 8 (CO) 2 MoC(OC 2 H 5 )Ar (IV–VII), C 7 H 8 (CO) 2 CrC(OC 2 H 5 )C 6 H 4 CF 3 - p (VIII) and C 7 H 8 (CO) 3 MoC(OC 2 H 5 )Ar (IX–XIII) formulated as cycloheptatriene(dicarbonyl)[ethoxy(aryl)carbene]-molybdenum and -chromium, and bicycloheptadiene (tricarbonyl)[ethoxy(aryl)carbene]molybdenum complexes, respectively. When C 6 H 5 Li or p -, o -CH 3 C 6 H 4 Li was allowed to react with II under the same conditions, deprotonation at the saturated carbon atom of the cycloheptatriene ligand occurred. After treatment with CH 3 I, the 7- exo -(methylcycloheptatriene)tricarbonylchromium was obtained. The products IV–XIII were identified by elemental analyses, IR, 1 H NMR and mass spectra, and finally confirmed by the single crystal X-ray structure determinations of VI and VII.

A molecular ferromagnet with Tc = 3.3 K and an S = 92 high spin ground state in trinuclear oxo-centred mixed-valence carboxylates

The trinuclear oxo-centred cluster [Mn3O(PriCOO)6(Im)3]·3PriCOOH (1·3PriCOOH), where Pri = isopropyl and Im = imidazole, with the S = 92 high spin ground state, orders ferromagnetically at Tc = 3.3 K; below this critical temperature it exhibits a hysteresis loop characteristic of a hard ferromagnetic with large coercive field.

CRYSTAL AND MOLECULAR STRUCTURES OF TWO ISOMERS OF DIETHYL 2, 3-DICYANO-2, 3-DIPHENYLSUCCINATE

Diethyl 2, 3-dicyano-2, 3-diphenylsuccinate was prepared through the oxidative coupling of ethyl α-cyanophenylacetate with Cu~(++)-TMEDA-O_2 system. The product gave, upon chromatography, two crystalline compounds 1 and 2. The single crystals of 1 and 2 were identified by X-ray crystallographic analysis to be meso-and racemie-diethyl 2,3-dicyano-2,3-diphenylsuccinate respectively. It is noteworthy that in the molecules of 1 and 2 there is a remarkable lengthening effect of the bond length for the central C—C bond, i. e. 1: 1.585; 2: 1.62. It is also observed that there is steric hindrance between the substituent groups attached to the two carbon atoms of the central C—C bond respectively. These data provide the structural basis for the facile dissociation into radicals and the action of polymerization initiator of the title compound. CNDO/2 calculation of charge density and Wiberg bond order for compound 1 yields the results, which are consistent with the crystallographic data.