New SO(2) Iron-Containing Cluster Compounds [PPN](2)[Fe(3)(CO)(9)(&mgr;(3),eta(2)-SO(2))], [PPN](2)[Fe(3)(CO)(8)(&mgr;-SO(2))&mgr;(3)-S], [PPN](2)[Fe(3)(CO)(8)(&mgr;-SO(2))(&mgr;(3)-CCO)], and [PPN](2)[Fe(2)(CO)(6)(&mgr;-SO(2))(2)] from Heterometal Precursors.

Sulfur dioxide reacts with [PPN](2)[MFe(3)(CO)(14)] (M = Cr, Mo, W) (PPN = bistriphenylphosphonium iminium) to produce [PPN](2)[Fe(3)(CO)(9)(&mgr;(3),eta(2)-SO(2))] (I) and [PPN](2)[Fe(3)(CO)(8)(&mgr;-SO(2))&mgr;(3)-S] (II), which were characterized by infrared spectroscopy, (13)C NMR, and X-ray crystallography. Further reaction of I with sulfur dioxide results in the formation of II in 48% yield. Reaction of SO(2) with [PPN](2)[Fe(4)(CO)(13)] yields [PPN](2)[Fe(2)(CO)(6)(&mgr;-SO(2))(2)] (III) which was characterized by infrared spectroscopy, (13)C NMR, mass spectrometry, and X-ray crystallography.

Substitution and Redox Chemistry of [Bu(4)N](2)[Ta(6)Cl(12)(OSO(2)CF(3))(6)].

Two sequential electrochemical reductions occur for the cluster anion [Ta(6)Cl(12)(OSO(2)CF(3))(6)](2)(-) at 0.89 and 0.29 V vs Ag/AgCl, with the generation [Ta(6)Cl(12)(OSO(2)CF(3))(6)](3)(-) and [Ta(6)Cl(12)(OSO(2)CF(3))(6)](4)(-).

Reactions of Triosmium Carbonyl Clusters with Thionylaniline. Crystal Structures of Os(3)(CO)(9)(&mgr;(3)-NPh)(&mgr;(3)-S), Os(3)(CO)(9)(&mgr;(3)-eta(2)-(PhN)(2)SO)(&mgr;(3)-S), and Os(3)(CO)(8)(NCMe)(&mgr;(3)-NPh)(&mgr;(3)-S).

Reaction of Os(3)(CO)(12) with thionylaniline (PhN=S=O) in refluxing methylcyclohexane produces Os(3)(CO)(9)(&mgr;(3)-NPh)(&mgr;(3)-S) (1) in good yield. When Os(3)(CO)(10)(NCMe)(2) is treated with PhN=S=O at room temperature, compound 1 and Os(3)(CO)(9)(&mgr;(3)-eta(2)-(PhN)(2)SO)(&mgr;(3)-S) (2) result. Compound 1 reacts with trimethylamine oxide in the presence of acetonitrile to give Os(3)(CO)(8)(NCMe)(&mgr;(3)-NPh)(&mgr;(3)-S) (3).

Preparation and substitution chemistry of [Bu4N]2[W6Cl8(p-OSO2C6H4CH3)6]. A useful precursor for pseudohalide, acetate, and organometallic complexes containing the [W6Cl8](4+) core.

The tosylate (p-toluenesulfonate) cluster [Bu4N]2[W6Cl8(p-OSO2C6H4CH3)6] (1) has been prepared and characterized by IR and NMR spectroscopy, elemental analysis, and an X-ray crystal structure. This cluster complex is shown to be a useful starting material for the preparation of pseudohalide clusters, [Bu4N]2[W6Cl8(NCQ)6] (Q = O (2), S (3), and Se (4)), in high yields. Cluster 1 also serves as a precursor to the new cluster compounds: [Bu4N]2[W6Cl8(O2CCH3)6] (5), [Bu4N]2[W6Cl8((mu-NC)Mn(CO)2(C5H5))6] (6), [W6Cl8((mu-NC)Ru(PPh3)2(C5H5))6][ p-OSO2C6H4CH3]4 (7), and [W6Cl8((mu-NC)Os(PPh3)2(C5H5))6][ p-OSO2C6H4CH3]4 (8).

Synthesis and characterization of a polycarbon organometallic cluster, [PPN]2[Fe6(CO)18C4].

The polycarbon metal cluster [Fe6(CO)18C4]2- is formed by the reaction of CF3SO3SO2CF3 with [Fe3(CO)9(CCO)]2-. Apparently, the SO2CF3 moiety abstracts an oxygen from the ketenylidene (CCO) ligand and C-C coupling occurs to form the C4 ligand. A single-crystal X-ray structure determination reveals that the pattern of C-C bond lengths of the C4 ligand in [Fe6(CO)18C4]2- mimic those in free butadiene.

Synthesis, characterization, and substitution chemistry of [Bu4N]2[W6Cl8(OSO2CF3)6]. A versatile precursor for axially substituted clusters containing the (W6Cl8)4+ core.

The new cluster [Bu4N]2[W6Cl8(OSO2CF3)6] (1) has been prepared and structurally characterized. This material is an effective precursor for the generation of cluster ions with the general formula [W6C18L6]n (L = Cl-, Br-, I-, NCS-, NCO-, NCSe-, and O=PPh3; n = 2- or 4+). The last three clusters are new.

Stoichiometric characteristics and resonance Raman spectra of azidosemimethemerythrin.

With extra precautions to remove dissolved oxygen, reduction of aquomethemerythrin with dithionite occurs with a stoichiometry very close to 1.0. The aquosemimethemerythrin so produced combines with N3- ion almost on a 1:1 basis per monomer.

Raman and infrared spectroscopy of the oxo-bridged iron(III) complex, [Cl3Fe-O-FeCl3]-2 as a spectroscopic model for the oxo bridge in hemerythrin and ribonucleotide reductase.

Vibrational spectroscopic data were collected on the salt [C5H6N]2[Cl3FeOFeCl3] . C5H5N, which has previously been structurally characterized by X-ray crystallography. The modes associated with the oxo bridge were identified by experiments on the 18O-containing species.

Multiple conformations at functional site of hemerythrin: Evidence from resonance Raman spectra.

Resonance Raman spectra were obtained for monomeric oxymyohemerythrin and for the azide, thiocyanate, cyanate, cyanide, and fluoride adducts of metmyohemerythrin. The internal ligand vibrations in these complexes appear at essentially the same frequencies as those in the corresponding complexes of octameric hemerythrin. Likewise the Fe-O frequencies in H(2) (16)O do not depend on quaternary structure of the protein.

Structure-sensitive resonance Raman bands of capped tetraphenylporphyrinatoiron complexes.

Resonance Raman spectra have been determined for the capped tetraphenylporphyrinatoiron complexes and their base adducts. The five-coordinate mono-base complexes of these porphyrin complexes display Raman spectra that are nearly identical to those previously determined for five-coordinate iron(II) tetraphenylporphyrin complexes in the marker regions around 1540, 1345, and 370 cm(-1). A similar correspondence is found between Raman bands of iron(II) complexes of the capped complexes and those of tetraphenylporphyrin.

Laser Raman spectroscopy of lipid-protein systems. Differences in the effect of intrinsic and extrinsic proteins on the phosphatidylcholine Raman spectrum.

Laser Raman spectroscopy is used to examine the interactions of intrinsic and extrinsic proteins with the lipid layer structure. The interactions of cytochrome c and cytochrome c oxidase with lipids have been well established by others using a variety of techniques. Cytochrome c is thought to act as an extrinsic membrane protein while cytochrome c oxidase is thought to act as an intrinsic membrane protein.

Raman spectroscopic detection and examination of the interaction of amino acids, polypeptides and proteins with the phophatidylcholine lamellar structure.

Raman spectral peaks in the vicinity of 1100 and 2900 cm-1 for phosphatidylcholine were found to be sensitive to interactions with amino acids, polypeptides and plasma proteins. The amino acids L-luecine, L-isoleucine, L-tryptophan, L-arginine HCl, L-histidine HCl, L-threonine and L-aspartic acid decreased the dipalmitoyl phosphatidylcholine Raman intensity ratio I1064/I1089 indicating an increase in the gauche hydrocarbon chain character of the lipid. The increase in the lipid approx.

Effect of ions on phospholipid layer structure as indicated by Raman spectroscopy.

Various anions and cations are found to induce changes in the layered structure of phosphatidylcholine-water systems as indicated by Raman Spectroscopy. From the ratio of Raman intensities, I1064/I1089, it is inferred that dipositive ions decrease the proportion of gauche character in the hydrocarbon chains, with the relative influence being: Ba2+ less than Mg2+ less than Ca2+ similar to Cd2+. Unipositive ions (Li+, K+ and Na+) produce no observed changes in the Raman spectrum of the lecithin dispersion.

Resonance Raman studies of hemerythrin-ligand complexes.

Resonance Raman spectroscopy has been used as a probe of the structure of ligands at the active site of hemerythrin. Molecularly revealing insights have been obtained with oxyhemerythrin and with metazidohemerythrin. This spectroscopic technique has also facilitated a comparison of oxygen carrier within erythrocytes with that in solution.

Resonance raman spectra of manganese (III) tetraphenylporphin halides.

Unique resonance Raman spectra were obtained when manganese(III) tetraphenylporphin halides in noncoordinating solvents were illuminated by laser frequencies around 500 nm. Of particular interest is the observation of a feature that is sensitive to the nature of the axial ligand. This feature disappears when the coordinating solvent pyridine is employed, and it, therefore, appears to be diagnostic of the manganese coordination number.

Resonance Raman studies of the electronic state of oxygen in hemerythrin.

Excitation of oxyhemerythrin with radiation within the envelope of its strong oxygen --> iron chargetransfer band generates two Raman frequencies, at 844 cm(-1) and 500 cm(-1). These are assigned to O-O and Fe-O stretching modes. Confirmation of these assignments is provided by the observed shifts in frequency when (16)O(2) is substituted by (18)O(2) as ligand.