H), in which an unsaturated C 3 S 2 five-membered ring is formed via activation of the propargylic C-H bond. Treatment of 1 with an unsymmetric alkyne, 2-pentyne, gave a mixture of [{Ru(P(OCH 3 ) 3 ) 2 (CH 3 CN) 3 } 2 (µ-SC(CH 3 )dCHCH(CH 3 )S)](CF 3 SO 3 ) 4 ( 7) and [{Ru(P(OCH 3 ) 3 ) 2 (CH 3 CN) 3 } 2 (µ-SC(CH 2 CH 3 )d CHCH 2 S)](CF 3 SO 3 ) 4 ( 8), which corresponds to the activation of secondary and primary propargylic C-H bonds, respectively. The reaction at 0 °C preferably gave 7, whereas 8 was obtained as the major component at 40 °C.

A variety of inter- and intramolecular dehydration was found in the reactions of [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)(mu-S(2))](CF(3)SO(3))(4) (1) with hydroxyl substituted alkenes and alkynes. Treatment of 1 with allyl alcohol gave a C(3)S(2) five-membered ring complex, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCH(2)CH(2)CH(OCH(2)CH=CH(2))S]](CF(3)SO(3))(4) (2), via C-S bond formation after C-H bond activation and intermolecular dehydration. On the other hand, intramolecular dehydration was observed in the reaction of 1 with 3-buten-1-ol giving a C(4)S(2) six-membered ring complex, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2) [mu-SCH(2)CH=CHCH(2)S]](CF(3)SO(3))(4) (3). Complex 1 reacts with 2-propyn-1-ol or 2-butyn-1-ol to give homocoupling products, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCR=CHCH(OCH(2)C triple bond CR)S]](CF(3)SO(3))(4) (4: R = H, 5: R = CH(3)), via intermolecular dehydration. In the reaction with 2-propyn-1-ol, the intermediate complex having a hydroxyl group, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCH=CHCH(OH)S]](CF(3)SO(3))(4) (6), was isolated, which further reacted with 2-propyn-1-ol and 2-butyn-1-ol to give 4 and a cross-coupling product, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCH=CHCH(OCH(2)C triple bond CCH(3))S]](CF(3)SO(3))(4) (7), respectively. The reaction of 1 with diols, (HO)CHRC triple bond CCHR(OH), gave furyl complexes, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SSC=CROCR=CH]](CF(3)SO(3))(3) (8: R = H, 9: R = CH(3)) via intramolecular elimination of a H(2)O molecule and a H(+). Even though (HO)(H(3)C)(2)CC triple bond CC(CH(3))(2)(OH) does not have any propargylic C-H bond, it also reacts with 1 to give [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCH(2)C(=CH(2))C(=C=C(CH(3))(2))]S](CF(3)SO(3))(4) (10). In addition, the reaction of 1 with (CH(3)O)(H(3)C)(2)CC triple bond CC(CH(3))(2)(OCH(3)) gives [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(2)][mu-S=C(C(CH(3))(2)OCH(3))C=CC(CH(3))CH(2)S][Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)]](CF(3)SO(3))(4) (11), in which one molecule of CH(3)OH is eliminated, and the S-S bond is cleaved.

The infrared absorption spectra of thin films of α-alanine formed on pure nickel and “Raney nickel” surfaces, modified with its aqueous solution, were measured by the high-sensitivity reflection method. From the infrared dichroism in the reflection spectra, the molecular orientations in the thin films were derived. In the thin film formed on pure nickel modified at 5 °C, the CO2− group of α-alanine is oriented nearly vertical to the metal surface and the O···O axis is inclined to the surface. On the other hand, when the “Raney nickel” film is modified at 5 °C, the Cα–Co(carboxylate) bond is oriented obliquely to the surface. When the “Raney nickel” film is modified at 100 °C, the Ni-alanine chelate is formed on the surface: the Cα–Co bond and the NH2 group are nearly parallel to the substrate surface, while the O···O axis is vertical to that surface.

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