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Fig. 1. Molecular structure of complex 2 in the crystal (50% probability thermal ellipsoids). The carbonyl groups are represented schematically and the given bond lengths are averages for the respective equivalent bonds. Space group P2,/c, u = 1402.3(6), b= 1 l21.8(4), c= 1954.2(5) pm, 8=92.83 (3)", p,,,,,=2.89,~,,,=2.87 (k0.05) g.cm-', Z = 4 ; 4392 reflections (I> ISo(l)), 215 parameters (measurement: Syntex P3, solution: She1 XTL), R , =0.084. The trinuclear complex Re3(CO),,COOH with the structural element 1 H ,O-Re 0-Re Re-C\has recently been isolated[41. As in this compound, the ReCO, moiety in 2 is planar. The entire six-membered ring is also almost planar. The CO distances of the CO, group correspond to those in the carboxylate anion, and the Re-C bond is almost a o single bond; hence, 2 can best be considered as a metal carboxylate. A carbene structure ,0-Re 0-Re Re=C has little weighting. In the Re(CO), and Re(CO), moieties a shortening of the Re-C bond and a lengthening of the CO bond via the trans-sited donor atoms of the C 0 2 group can clearly be recognized.2 is of interest since it represents a novel type of coordination of carbon dioxide in C 0 2 complexes[5'. For the CS2 ligand, for which numerous types of coordination are known@], covalent bridging of three metal atoms has, to the best of our knowledge, not been observed to date.The bond between a carbonylrhenium group and oxygen donors is apparently very stable, and we were able to obtain the very stable complexes (OC),ReOCHO, (OC),Re(02CC02)Re(CO),, (OCh Re(C,OdWCO),, (OC),ReONO, (OC),ReN02 (mixture of isomers) and (OC),ReON02 by allowing (OC)$eFBF, to react with formate, oxalate, squarate, nitrite, and nitrate, respectively.(1981) 81. Previously, an analogous complex (OC)5ReFAsF5 has been re-

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The mass spectra of some phosphorus-and arsenic-substituted biphenyl systems show doubly charged parent ions of higher abundance than the singly charged molecular ions.

The antibiotic vulgamycin was isolated from a new strain of Streptomyces. Vulgamycin shows herbicidal activity when applied post‐emergence. It controls dicotyledonous weeds and grasses such as Setaria sp. at dosages between 125 and 500 g ha−1. Crops such as cotton, barley and maize tolerate vulgamycin very well. Biochemical mode‐of‐action studies indicate some effect of vulgamycin on an isoleucine‐dependent step within the cell cycle, so‐called GI‐arrest.