Maki Sato

Preparation and properties of molybdenum- and tungsten-dinitrogen complexes 7 [1]. The molecular structure of MoCl(N2COPh) (Ph2PCH2CH2PPh2)2.

Abstract The structure of the complex MoCl(N2COPh)(Ph2PCH2CH2PPh2)2 has been determined from three-dimensional X-ray counter data collected on a single crystal. The material crystallizes in space group P21/n of the monoclinic system with four formula units of the complex in a cell of dimensions a = 21.17(1) A, b = 19.97(1) A, c = 12.56(2) A, β = 100.57(3)°, V = 5220.6(52) A3. The structure has been refined by blockdiagonal least-squares techniques to a final R index 0.0715 based on 7386 reflections above background. The complex has, an octahedral geometry with benzoyldiazenido and chloride ligands in a trans position and the benzoyldiazenido ligand is not chelating through the carbonyl oxygen. The bond orders of NN, NC, and CO are estimated to be 1.85, 1.3, and 1.85, respectively, which indicate the mesomeric spread of a high electron density from the metal to the benzoyldiazenido ligand. However, this spread does not extend so far to the phenyl group.

Transfection of cultured fish cells RBCF-1 with exogenous oncogene and their resistance to malignant transformation

1. Plasmids bearing the G418-resistant gene neo were transfected into cultured fish cells RBCF-1 by electroporation at an efficiency comparable to that in NIH3T3 cells. 2. Transfection of plasmids bearing both neo and activated human c-Ha-ras into NIH3T3 and RBCF-1 cells resulted in the malignant transformation of the former but not of the latter cells.

Reactions of Hydrazido(2-) Complexes Derived from Molybdenum and Tungsten Dinitrogen Complexes

Since the discovery of the first dinitrogen complex of molybdenum, trans-[Mo(N2)2(dpe)2] (dpe = Ph2PCH2CH2PPh2)1, many dinitrogen complexes of molybdenum and tungsten have been prepared and their chemical properties have been extensively studied for possible relevance to nitrogen fixation as well as to open a new chemistry of dinitrogen.2 Until now, many hydrazido(2-) complexes have been isolated as an intermediate stage in the reduction of dinitrogen. The hydrazido(2−) complexes, [MF(NNH2)(dpe)2][BF4] (M = Mo or W), are readily obtained by the reaction of trans- [M[N2)2(dpe)2] with fluoroboric acid.3,4 On the other hand, treatment of [M(N2)2(PMe2 Ph)4] (M = Mo or W) with aqueous HX (X = Cl, Br, or I) in methanol affords a series of the hydrazido(2-) complexes [MX2(NNH2)(PMe2Ph)3] in good yields. The X-ray structure of the former hydrazido(2−) complex (M = Mo) shows that the Mo-N-N linkage is essentially linear. The N-N bond distance indicates a bond order greater than unity while the Mo-N bond distance is consistent with considerable multiple bonding between the metal and nitrogen.4 This result is interpreted in terms of a combination of two resonance structures (i) and (ii).