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Adult, female specimens of Pinnotheres maculatus accumulated radioactivity when in bay and calico scallops fed Nitzchia closterium labeled with 14C and in blue mussels fed labeled Thalassiosira pse...

Variable temperature 13C NMR spectra of dienetricarbonylruthenium and olefintetracarbonylruthenium type complexes are reported. It is shown that the molecules are fluxional and that the rearrangement in (ethyl acrylate)tetracarbonylruthenium is consistent with a coupled olefin rotation—Berry pseudorotation type mechanism.

1. All stages of Pinnotheres maculatus were more abundant near the inlets of Bogue Sound, North Carolina.2. Distribution and abundance of adult crabs did not conform to distribution of scallops, since scallops were numerous throughout the sound.3. It is possible that crab distribution is controlled by a physical or chemical gradient such as salinity.

The carbon-13 NMR spectra of six carbenoid complexes of the type (OC) 5 Cr-(CXX′) have been recorded. The carbenoid carbon atoms are all markedly deshielded (chemical shifts vs. TMS in the range −271 to −360). With only one minor inversion of uncertain significance, the chemical shifts correlate well with the expected ability of the X and X′ groups to engage in dative π bonding to the carbenoid carbon atom. The longitudinal relaxation times for both carbenoid and carbonyl carbon atoms in (OC) 5 Cr[C(CH 3 )(OC 2 H 5 )] are 1 – 2 sec. The chemical shift difference for carbonyl carbon atoms cis and trans to the carbenoid ligand is essentially invariant in the six compounds.

The carbon-13 nuclear magnetic resonance spectrum of (h5-C5H5)(CO)2Fe (h1-C5H5) has been recorded over the temperature range + 52 to −88°. The results add further support to the view that the rearrangement pathway for the h1-C5H5 ring is a sequence of 1,2 shifts. Assignment of resonances was made by comparison with the chemical shifts of the allyl group in (h5-C5H5)(CO)2FeCH2CHCH2, the spectrum of which was also recorded, as well as by consideration of relative intensities and the multiplets due to proton splitting. The Arrhenius activation parameters, which are considered to be more accurate than those previously derived from PMR spectra, were evaluated as: Ea = 10.7 ± 0.5 kcal/mol and log A = 126. ± 0.5.

Arsenic trifluoride and iron pentacarbonyl react at 120 °C to give dark violet crystals of As2[Fe(CO)3]3 with orthorhombic symmetry, space group Bmmb, cell dimensions a0= 10·82(2), b0= 10·96(2), and c0= 13·29(2)A, and Z= 4.The structure was solved from photographic data by three-dimensional Patterson and Fourier methods and refined by least squares methods to R 0·107 for 630 independent reflections. The structure is disordered with one molecule randomly distributed in two orientations which are related by a crystallographic two-fold rotation axis. The idealized molecular symmetry is 3/m(C3h). The molecule is characterized by an equilateral triangle of iron atoms, mean Fe–Fe 2·62(1)A. The two arsenic atoms lie above and below the iron triangle, and are related by a mirror plane containing the iron atoms. Both arsenic atoms are bonded equally to the iron triangle, mean As–Fe 2·35 A. Other mean bond lengths: Fe–C 1·80, C–O 1·12 A.