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A dimolybdenum derivative of decamethylpentasilacycloheptyne (1) was synthesized by direct reaction of the heptyne with Mo2(CO)4(η5-C5H5)2. 1 crystallized in the space group P 1 , a=9.386(2), b=9.866(3), c=20.178(4) A, α=92.17(2), β=97.17(2), γ=115.71(2)°. The acetylenic bond is lengthened from 1.213 A in the free ligand to 1.359(4) A and all the Si–Si bond lengths in 1 are significantly lengthened upon complexation. This is due to relaxation of the ring strain as evidenced by the Si–C–C bond angles in 1 of 132.7 and 140.9° compared to 159.2 and 162.6° in the uncomplexed ring. 29Si-NMR data exhibit significant downfield chemical shifts upon complexation for the Si atoms adjacent to the triple bond, with moderate upfield shifts for the other Si atoms. The related cycloheptyne·Mo2(CO)4(η5-C5H5)2 (2) was synthesized by the reaction of cyclohepteno-1,2,3-selenadiazole with Mo2(CO)4(η5-C5H5)2. 2 crystallized in the space group C21/c, a=30.396(10), b=8.9093(3), c=16.156(4) A, β=115.39(2)°. The acetylenic bond in 2 is 1.345 A, compared with a calculated value (ab initio 3-21 G*) of 1.190 A for the free cycloheptyne.

A transition metal-substituted silylacetylene [( η 5 -C 5 H 5 )Fe(CO) 2 SiMe 2 C] 2 , [FpMe 2 SiC] 2 ( I ) was synthesized and characterized spectroscopically and structurally. I crystallized in the monoclinic space group P 2 1 n , a = 13.011(3) A b = 12.912(3) A , c = 13.175(5) A , β = 94.95(2) . The acetylene linkage is reactive toward Co 2 (CO) 8 to form I . Co 2 (CO) 6 ( II ) which was also characterized spectroscopically and by single crystal X-ray diffraction. II crystallized in the orthorhombic space group Pbca, a = 17.64(2) A , b = 14.225(10) A , c = 24.49(2) A .

Treatment of ferrocenecarboxaldehyde with base at 0°C, lithium diisopropylamide (LDA) or n-butyllithium, followed by the addition of trimethylsilylcyanide, produced 1-(diisopropylamino)cyanomethylferrocene, FcCH(N{iPr}2(CN) (II) or 1-trimethyl-siloxy-n-pentylferrocene, FcCH(nBu)OSiMe3 (IIIa). The reaction of naphthaldehyde, NpCHO, with LDA/Me3SiCN led to formation of 1-(diisopropylamino)cyanomethylnaphthalene, NpCH{N(iPr)2}(CN) suggesting a general new synthesis for cyanoamines. The reaction of ferrocenecarboxaldehyde with Me3SiCN led to the expected silylether FcCH(CN)OSiMe3 (I). An alternative synthesis of ferrocenylmethylsilylethers, FcCH2OSiR3 (IV), involved the reaction of 1-ferrocenylmethanol with R3SiCl in the presence of pyridine. The basicity of the new silylethers III and IV is reported.

The first organotin(IV), aluminium(III)-μ-oxoisoprovides of the type [R3SnOA](OiPr)2] (R = Me or Ph) have been made by heating of trimethyl- or triphenyl-tin acetate with aluminium isopropoxide. The reactions of these μ-oxoisopropoxides with benzoylacetone in 1:1 and 1:2 molar ratios yielded the compounds of the type [R3SnOAl(OiPr)(bzac)] and [R3SnOAl(bzac)2] (where R = Me or Ph and bzac = deprotonated benzoylacetone), respectively.

The synthesis and structure of the unknown trimethylgermyltriphenylsilane (I, Ph 3 SiGeMe 3 ) is reported. The molecular geometry is compared to that of the isomeric Me 3 SiGePh 3 (II) and the related Ph 3 SiSiMe 3 (III) and (η 5 -C 5 H 5 )Fe(CO) 2 SiMe 2 GePh 3 (IV). The SiGe bond of I is significantly longer than that for II. We suggest that this is due to expansion of Ge bonding orbitals by the relatively electron-donating methyl groups in conjunction with the contraction of the corresponding orbitals of Si due to the electron-withdrawing phenyl groups. The overall result is a better orbital overlap between the Si and Ge atoms for II.

Trimethyl- and tri ethyllead derivatives (η 5 -C 5 H 5 )M(CO) 3 PbR 3 (M  Cr, Mo, and W) have been synthesized. The trimethyllead derivatives are photochemically, and to a lesser extent, thermally unstable with respect to methyl transfer reactions that yield the corresponding (η 5 -C 5 H 5 )M(CO) 3 CH 3 complex. The related triethyllead complexes behave in a distinctly different fashion exhibiting rearrangements to [(η 5 -C 5 H 5 )M(CO) 3 ] 3 PbEt 2 (M  W, Mo). The reactions of the Cr, Mo, and W complexes with SO 2 yielded the corresponding alkyl sulphinato complexes as did the reaction of the related Fe complex [(η 5 -C 5 H 5 )Fe(CO) 2 PbEt 3 ].

The complex t-Bu(η 5 -C 5 H 5 )FE(CO) 2 has been treated with triphenylphosphine in refluxing THF to produce t-BuCO(η 5 -C 5 H 5 )Fe(CO)(PPh 3 ). The large steric bulk of the t-butyl group suggests that this reaction should be faster than the reaction involving the methyl group, and a kinetic investigation illustrates this to be the case. The same steric bulk predicts that the reaction with SO 2 should be slow, and indeed we have been unable to effect the related SO 2 insertion reaction. Attempts to prepare the corresponding t-Bu(η 5 -C 5 H 5 )W(CO) 3 led to formation of the related isobutyl complex.

The first phenylmagnesium carboxylates, C6H5MgOOCR·THF, have been made by reaction of phenylmagnesium bromide with the sodium salt of carboxylic acids [RCOONa {where R = CH3, ClCH2, Cl2CH, Cl3C, CH3CH2, (CH3)2CH, C6H5CH2 and CH3(CH2)3CH2}]. All these derivatives are white or pale yellow solids, soluble in polar solvents. The carboxylates have been characterized by elemental analysis, conductance measurements, and spectral studies (1H NMR and IR). The IR data suggest that carboxylate group acts as a bridging bidentate ligand.

Reactions of various π-cyclopentadienyl and carbonyl halides with silver perfluorocarboxylates in dichloromethane solution yield new organometallic transition metal perfluorocarboxylates by metathetical reactions. The following types of compounds have been prepared: (a) red-orange, RfCO2Fe(CO)2C5H5; (b) red-brown RfCO2Mo(CO)3C5H5; (c) yellow RfCO2Mn(CO)5; (d) white RfCO2Re(CO)5; (e) yellow-orange [C5H5Mo(NO)(CO2Rf)2]2; (f) yellow RfCO2Fe(CO)3(π-C3H5); (g) red-brown RfCO2Co(CO)(C3F7)(C5H5); (h) red-orange (C5H5)2Ti(CO2Rf)2; (i) white (C5H5)2Zr(CO2Rf)2. In most cases the trifluoroacetates (Rf = CF3), pentafluoropropionates (Rf = C2F5), and heptafluorobutyrates (Rf = n-C3F7) were prepared. In these compounds the perfluorocarboxylate groups appear to be bonded to the transition metal thru the oxygen atom. They exhibit a characteristic v(CO) frequency in the range 1680-1730 cm-1 arising from the carbonyl group of the perfluorocarboxylate ligand. The force constants k1, k2, and ki calculated from the v(CO) frequencies in the RfCO2M(CO)5 (M = Mn or Re) compounds by the Cotton-Kraihanzel procedure were found to be similar to those in the metal carbonyl halides M(CO)5X (M = Mn or Re) indicating similar bonding properties of the perfluorocarboxylate and halide ligands.

Ultraviolet irradiation of the perfluoroalkyliron derivatives RfFe(CO)2C5H5 [Rf=C2F5 and (CF3)2CF] with the saturated chelating ditertiary phosphine (C6H5)2PCH2CH2P(C6H5)2(Pf-Pf) results in stepwise substitution of the carbonyl groups giving first the monodentate monometallic derivatives RfFe(CO)(Pf-Pf)(C5H5) and then the carbonyl-free bidentate monometallic derivatives RfFe(Pf-Pf)(C5H5). By contrast, UV irradiation of the same perfluoroalkyliron derivatives with the unsaturated chelating ditertiary phosphine cis-(C6H5)2PCH=CHP(C6H5)2 (cPf=Pf) proceeds directly to the carbonyl-free bidentate monometallic derivatives RfFe(cPf=Pf)(C5H5) without formation of an isolable monodentate monometallic derivative. UV irradiation of the RfFe(CO)2C5H5 derivatives with triphenylphosphine gives the substitution products RfFe(CO)[P(C6H5)3](C5H5) (Rf=CF3, CF3CO, C2F5, and (CF3)2CF); IR and NMR spectral data on the compound of this type with the relatively bulky (CF3)2CF group suggest the presence of conformational isomers arising from hindered rotation about the iron-perfluoroalkyl bond. Similar UV irradiation of the molybdenum derivative CF3Mo(CO)3C5H5 with the appropriate tertiary phosphines gives the substitution products CF3Mo(CO)2[P(C6H5)3](C5H5) and CF3Mo(CO)(Pf-Pf)(C5H5). An improved preparation of the RfFe(CO)2C5H5 [Rf=C2F5F and (CF3)2CF] derivatives from the corresponding perfluoroalkyliron tetracarbonyl iodides RfFe(CO)4I and thallium(I) cyclopentadienide is described.