5-Mercaptotetrazolyl-derived metallaboratranes.

The reactions of 1-tert butyl-5-thiotetrazole (HtttBu) with Na[BH4] provides Na[H2B(tttBu)2] (Na[1]) or Na[HB(tttBu)3] (Na[2]) in refluxing THF or xylene, respectively. Treating [RuCl(Ph)(CO)(PPh3)2] with Na[2] affords the triply-buttressed ruthenaboratrane [Ru(CO)(PPh3){κ4-B,S,S',S''-B(tttBu)3}] (5) whilst Na[1] with [IrCl(CO)(PPh3)2] or [RuCl(Ph)(CO)(PPh3)2] provides rare examples of doubly-buttressed metallaboratranes [IrH(CO)(PPh3){κ3-B,S,S'-BH(tttBu)2}] (7) and [Ru(CO)(PPh3)2{κ3-B,S,S'-BH(tttBu)2}] (12), the latter via the isolable thiotetrazoylborate complex [Ru(Ph)(CO)(PPh3){κ3-H,S,S'-H2B(tttBu)2}] (11).

Linear Optical, Quadratic and Cubic Nonlinear Optical, Electrochemical, and Theoretical Studies of "Rigid-Rod" Bis-Alkynyl Ruthenium Complexes.

The syntheses of oligo(p-phenylene ethynylene)s (OPEs) end-functionalized by a nitro acceptor group and with a ligated ruthenium unit at varying locations in the OPE chain, namely, trans-[Ru{(C≡C-1,4-C H ) NO }(C≡CR)(dppe) ] (dppe=1,2-bis(diphenylphosphino)ethane; n=1, R=1,4-C H C≡C-1,4-C H C≡CPh, 1,4-C H NEt ; n=2, R=Ph, 1,4-C H C≡CPh, 1,4-C H C≡C-1,4-C H C≡CPh, 1,4-C H NO , 1,4-C H NEt ; n=3, R=Ph, 1,4-C H C≡CPh), are reported. Their electrochemical properties were assessed by cyclic voltammetry, their linear optical properties and quadratic and cubic nonlinear optical properties were assayed by UV/Vis/NIR spectroscopy, hyper-Rayleigh scattering studies employing nanosecond pulses at 1064 nm, and broad spectral range Z-scan studies employing femtosecond pulses, respectively, and their linear optical properties and vibrational spectroscopic behavior in the formally Ru state was examined by UV/Vis/NIR and IR spectroelectrochemistry, respectively. The potentials of the metal-localized oxidation processes are sensitive to alkynyl-ligand modification, but this effect is attenuated on π-bridge lengthening.

Stellar Multi-Photon Absorption Materials: Beyond the Telecommunication Wavelength Band.

Very large molecular two- and three-photon absorption cross-sections are achieved by appending ligated bis(diphosphine)ruthenium units to oligo(p-phenyleneethynylene) (OPE)-based "stars" with arms up to 7 phenyleneethynylene (PE) units in length. Extremely large three- and four-photon absorption cross-sections, through the telecommunications wavelengths range and beyond, are obtained for these complexes upon optimizing OPE length and the ruthenium-coordinated peripheral ligand. Multi-photon absorption (MPA) cross-sections are optimized with stars possessing arms 2 PE units in length.

Phosphine, isocyanide, and alkyne reactivity at pentanuclear molybdenum/tungsten-iridium clusters.

The trigonal bipyramidal clusters M2Ir3(μ-CO)3(CO)6(η(5)-C5H5)2(η(5)-C5Me4R) (M = Mo, R = Me 1a, R = H; M = W, R = Me, H) reacted with isocyanides to give ligand substitution products M2Ir3(μ-CO)3(CO)5(CNR′)(η(5)-C5H5)2(η(5)-C5Me4R) (M = Mo, R = Me, R′ = C6H3Me2-2,6 3a; M = Mo, R = Me, R′ = (t)Bu 3b), in which core geometry and metal atom locations are maintained, whereas reactions with PPh3 afforded M2Ir3(μ-CO)4(CO)4(PPh3)(η(5)-C5H5)2(η(5)-C5Me4R) (M = Mo, R = Me 4a, H 4c; M = W, R = Me 4b, H), with retention of core geometry but with effective site-exchange of the precursors’ apical Mo/W with an equatorial Ir. Similar treatment of trigonal bipyramidal MIr4(μ-CO)3(CO)7(η(5)-C5H5)(η(5)-C5Me5) (M = Mo 2a, W 2b) with PPh3 afforded the mono-substitution products MIr4(μ-CO)3(CO)6(PPh3)(η(5)-C5H5)(η(5)-C5Me5) (M = Mo 5a; M = W 5b), and further reaction of the molybdenum example 5a with excess PPh3 afforded the bis-substituted cluster MoIr4(μ3-CO)2(μ-CO)2(CO)4(PPh3)2(η(5)-C5H5)(η(5)-C5Me5) (6). Reaction of 1a with diphenylacetylene proceeded with alkyne coordination and C≡C cleavage, affording Mo2Ir3(μ4–η(2)-PhC2Ph)(μ3-CPh)2(CO)4(η(5)-C5H5)2(η(5)-C5Me5) (7a) together with an isomer.

Syntheses of pentanuclear group 6 iridium clusters by core expansion of tetranuclear clusters with Ir(CO)2(η5-C5Me4R) (R = H, Me).

Metal cluster core expansion at tetrahedral group 6-group 9 mixed-metal clusters MIr3(μ-CO)3(CO)8(η(5)-L) (M = W, Mo, L = C5H5; M = Mo, L = C5Me5) with the iridium capping reagents Ir(CO)2(η(5)-L') (L' = C5Me5, C5Me4H) in refluxing toluene afforded the trigonal-bipyramidal clusters MIr4(μ-CO)3(CO)7(η(5)-C5H5)(η(5)-L') (M = Mo, L' = C5Me5, 1a; M = W, L' = C5Me5, 1b; M = Mo, L' = C5Me4H, 1c; M = W, L' = C5Me4H, 1d) and MoIr4(μ3-H)(μ-CO)2(μ-η(1):η(5)-CH2C5Me4)(CO)7(η(5)-C5Me5) (2). Related reactions with M2Ir2(μ-CO)3(CO)7(η(5)-L)2 (M = W, Mo, L = C5H5; M = Mo, L = C5Me5) afforded M2Ir3(μ-CO)3(CO)6(η(5)-C5H5)2(η(5)-L') (M = Mo, L' = C5Me5, 3a; M = W, L' = C5Me5, 3b; M = Mo, L' = C5Me4H, 3c; M = W, L' = C5Me4H, 3d), W2Ir3(μ-CO)4(CO)5(η(5)-C5H5)2(η(5)-C5Me4H) (4), and Mo2Ir3(μ-CO)3(CO)6(η(5)-C5Me5)3 (5). Single-crystal X-ray diffraction studies of 1a-1d, 2, 3a-3d, and 4 confirmed their molecular structures, including the μ-η(1):η(5)-CH2C5Me4 ligand at hydrido cluster 2, derived from a C-H bond activation of one of the methyl groups.

Syntheses and spectroscopic, structural, electrochemical, spectroelectrochemical, and theoretical studies of osmium(II) mono- and bis-alkynyl complexes.

The syntheses of trans-[Os(C≡C-4-C(6)H(4)X)Cl(dppe)(2)] [X = Br (3), I (4)], trans-[Os(C≡C-4-C(6)H(4)X)(NH(3))(dppe)(2)](PF(6)) [X = H (5(PF(6))), I (6(PF(6)))], and trans-[Os(C≡C-4-C(6)H(4)X)(C≡C-4-C(6)H(4)Y)(dppe)(2)] [X = Y = H (7), X = I, Y = C≡CSiPr(i)(3) (8)] are reported, together with improved syntheses of cis-[OsCl(2)(dppe)(2)] (cis-1), trans-[Os(C≡CPh)Cl(dppe)(2)] (2), and trans-[Ru(C≡C-4-C(6)H(4)I)(NH(3))(dppe)(2)](PF(6)) (9(PF(6))) (the last-mentioned direct from trans-[Ru(C≡C-4-C(6)H(4)I)Cl(dppe)(2)]), and single-crystal X-ray structural studies of 2-4, 5(PF(6)), 6(PF(6)), and 7. Ammine complexes 5(PF(6))/6(PF(6)) are shown to afford a facile route to both symmetrical (7) and unsymmetrical (8) osmium bis(alkynyl) complexes. A combination of cyclic voltammetry, UV-vis-NIR spectroelectrochemistry, and time-dependent density functional theory (TD-DFT) has permitted identification and assignment of the intense transitions in both the resting state and the oxidized forms of these complexes.

Length-dependent convergence and saturation behavior of electrochemical, linear optical, quadratic nonlinear optical, and cubic nonlinear optical properties of dipolar alkynylruthenium complexes with oligo(phenyleneethynylene) bridges.

The syntheses of trans-[Ru{4,4'-C[triple bond]CC(6)H(2)[2,5-(OEt)(2)]C[triple bond]CC(6)H(4)NO(2)}Cl(dppm)(2)] (19), trans-[Ru{4,4',4''-C[triple bond]CC(6)H(4)C[triple bond]CC(6)H(2)[2,5-(OEt)(2)]C[triple bond]CC(6)H(4)NO(2)}Cl(dppm)(2)] (20), trans-[Ru{4,4',4'',4'''-C[triple bond]CC(6)H(4)C[triple bond]CC(6)H(2)[2,5-(OEt)(2)]C[triple bond]CC(6)H(2)[2,5-(OEt)(2)]C[triple bond]CC(6)H(4)NO(2)}Cl(dppe)(2)] (21), trans-[Ru{4,4',4'',4'''-C[triple bond]CC(6)H(4)C[triple bond]CC(6)H(2)[2,5-(OEt)(2)]C[triple bond]CC(6)H(2)[2,5-(OEt)(2)]C[triple bond]CC(6)H(4)NO(2)}Cl(dppm)(2)] (22), trans-[Ru{4,4',4'',4'''-C[triple bond]CC(6)H(4)C[triple bond]CC(6)H(4)C[triple bond]CC(6)H(2)[2,5-(OEt)(2)]C[triple bond]CC(6)H(4)NO(2)}Cl(dppm)(2)] (23), and trans-[Ru{4,4',4'',4''',4''''-C[triple bond]CC(6)H(4)C[triple bond]CC(6)H(4)C[triple bond]CC(6)H(2)[2,5-(OEt)(2)]C[triple bond]CC(6)H(2)[2,5-(OEt)(2)]C[triple bond]CC(6)H(4)NO(2)}Cl(dppm)(2)] (24) are reported, together with those of precursor alkynes, complexes with the donor-pi-bridge-acceptor formulation that affords efficient quadratic and cubic NLO compounds; the identity of 19 was confirmed by a structural study. The electrochemical properties of 19-24 and related complexes with shorter pi-bridge ligands were assessed by cyclic voltammetry, and the linear optical, quadratic nonlinear optical, and cubic nonlinear optical properties were assayed by UV-vis-NIR spectroscopy, hyper-Rayleigh scattering studies at 1064 and 1300 nm, and broad spectral range femtosecond Z-scan studies, respectively. The Ru(II/III) oxidation potentials and wavelengths of the optical absorption maxima decrease on pi-bridge lengthening, until the tri(phenyleneethynylene) complex is reached, further chain lengthening leaving these parameters invariant; theoretical studies employing time-dependent density functional theory have shed light on this behavior.