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The new N,N,O heteroscorpionate ligand 3,3-bis(1-vinylimidazol-2-yl)propionic acid (Hbvip) (5) was synthesised in five steps starting from 1-vinylimidazole. This ligand is closely related to 3,3-bis(1-methylimidazol-2-yl)propionic acid (Hbmip), but contains two vinyl linker groups which can be used for radical-induced polymerisation reactions. The κ3-N,N,O coordination behaviour of 5 was proven by the synthesis of the tricarbonyl complexes [Re(bvip)(CO)3] (6), [Mn(bvip)(CO)3] (7) and [Cu(bvip)2] (8). To obtain good yields of 6, it was synthesised in water instead of THF. The ligand as well as all three complexes were characterised by X-ray crystallography. Copolymerisation of 5 with pure methyl methacrylate (MMA) or a combination of MMA and ethylene glycol dimethacrylate (EGDMA) led to the solid phases P1 and P2. Polymer-bound rhenium and manganese tricarbonyl complexes could be obtained by the reaction of deprotonated P1 with [MBr(CO)5] (M = Re, Mn) and also by copolymerisation of 6 and 7 with MMA. In both cases, the facial tripodal binding behaviour was evidenced by IR spectra of the polymers. Furthermore, the content of metal incorporated in the polymers was determined by elemental analysis, AAS or ICP-OES measurements. Reaction of the deprotonated solid phase P1 with copper(II) chloride led to a blue solid-phase (P1-Cu). The UV–Vis absorption maximum of P1-Cu is found at 615 nm, which is almost identical to that found for 8. Thereby, it seems likely that P1 is flexible enough to form bisligand complexes with copper(II). This means that the copper centres act as a kind of crosslinking agents. In contrast, the heterogeneous reaction of P2 with copper(II) chloride yielded a lime green solid phase (P2-Cu). The bathochromic shift of the absorption maximum by 102 nm suggests one-sided bound copper centres.

The chelating ligand t ris-[2-(3-aryl- im idazol-2-ylidene) e thyl]ami n e (TIMEN R , R = aryl = 2,6-xylyl (xyl), mesityl (mes)) has provided access to reactive transition metal complexes. Here, two new tripodal N-heterocyclic carbene ligands of the TIMEN R system (R = aryl = tolyl (tol), 3,5-xylyl (3,5xyl)), featuring sterically less demanding aryl substituents were synthesized. With these ligands, Fe(II) precursor complexes could be obtained, namely [(TIMEN tol )Fe](BF 4 ) 2 ( 3 ) and [(TIMEN 3,5xyl )Fe(CH 3 CN)](PF 6 ) 2 ( 7 ), which showed unexpected reactivity upon reduction. Treatment of the compounds with sodium amalgam yield the tris- and bis-metallated products, [(TIMEN tol∗∗∗ )Fe] ( 4 ) and [(TIMEN 3,5xyl∗∗ )Fe] ( 8 ), respectively. While the Fe(III) complex 4 is relatively inert towards oxygen, the Fe(II) complex 8 is prone to oxidation. This oxidation of 8 can readily be observed in chlorinated solvents, producing the Fe(III) complex [(TIMEN 3,5xyl∗∗ )Fe](PF 6 ) ( 9 ). All new ligand imidazolium precursors and metal complexes were characterized by single crystal X-ray structure determination.

Saponification of the bis(carbamic acid ester) 1,3-C6H4(CMe2NHCO2Me)2 (1), made by the addition of methanol to commercial 1,3-C6H4(CMe2NCO)2, yielded the meta-phenylene-based bis(tertiary carbinamine) 1,3-C6H4(CMe2NH2)2 (2). Dinuclear [{(η4-1,5-C8H12)RhCl}2{μ-1,3-C6H4(CMe2NH2)2}] (3) resulted from the action of 2 on [{(η4-1,5-C8H12)Rh(μ-Cl)}2] in toluene. Combination of 2 with PdCl2 or K2[PdCl4] gave the dipalladium macrocycle trans,trans-[{μ-1,3-C6H4(CMe2NH2)2}2(PdCl2)2] (4) along with cyclometalated [{2,6-C6H3(CMe2NH2)2-κN,κC1,κN′}PdCl] (5). Substitution of PEt3 for the labile chlorido ligand of 5 afforded [{2,6-C6H3(CMe2NH2)2-κN,κC1, κN′}Pd(PEt3)]Cl (6). The crystal structures of the following compounds were determined: bis(carbamic acid ester) 1, ligand 2 as its bis(trifluoroacetate) salt [1,3-C6H4(CMe2NH3)2](O2CCF3)2, 2 · (HAcf)2, complexes 3 and 6, as well as 1,3-C6H4(CMe2OH)2 (the diol analogue of 2).

The reaction of dioxygen with the copper(I) complex of the tridentate ligand 1,1,4,7,7-pentamethyldiethylenetriamine (Me5dien) has been investigated using low-temperature stopped-flow techniques. The formation of a bis(μ-oxo)copper(III) complex as a reactive intermediate could be detected spectroscopically at low temperatures and a quantitative kinetic analysis was performed for this system. Crystal structures of the copper(II) complexes [(Me-bpa)Cu(Cl)2] (1), [{(Me-bpa)Cu(Cl)(ClO4)}2] (2), [{(MeL)Cu(Cl)(ClO4)}2] (3), and [(MeL)Cu(NCS)2] (4) (Me-bpa = N-methyl-[bis(2-pyridyl)methyl]amine; MeL = N-methyl-[(2-pyridyl)ethyl(2-pyridyl)methyl]amine) are reported.

In quest of complexes having [MN 3 S 2 ] cores in the monomeric form and trans -thiolate donor atoms, the new pentadentate thiolate amine py t Bu N 2 H 2 S 2 –H 2 [ = py t Bu N 2 H 2 S 2 2 - = 2 , 6 -bis ( 2 -mercapto- 3 , 5 -di- tert -butylphenylaminomethyl ) pyridine ( 2 - ) ] has been synthesized.The template condensation reaction of bis(2-mercapto-3,5-di- tert -butylaniline)zinc (II)[Zn( t Bu 2 ma) 2 ] and pyridine-2,6-dicarbaldehyde in methanol at 40 °C leads to the formation of imine zinc complex [Zn(py t Bu N 2 S 2 )] ( 7 ), which is very unstable and decomposes to give thiazole 5 . However, if the template condensation is followed by in situ reduction with an excess of NaBH 4 , the stable saturated amine complex [Zn(py t Bu N 2 H 2 S 2 )] ( 8 ) is formed. Demetallation of zinc complex 8 under acidic conditions leads to the formation of the desired dithiolate py t Bu N 2 H 2 S 2 –H 2 ligand ( 9 ).

The new pyridine-based N∩N∩N tridentate ligand 2,6-C5H3N(CMe2NH2)2 (1) was synthesized by the treatment of 2,6-pyridinedicarbonitrile with an excess of the organocerium reagent in situ generated from CeCl3 and methyllithium in THF. The reaction of 1 with [RuCl2(PPh3)3] in THF at ambient conditions afforded (OC-6-23)-[RuCl{2,6-C5H3N(CMe2NH2)2}(PPh3)2]Cl (2). The corresponding dimethyl sulfoxide complex [RuCl{2,6-C5H3N(CMe2NH2)2}{S(O)Me2}2]Cl (3) was isolated as a mixture of the (OC-6-23) and (OC-6-32) stereoisomers 3a and 3b from the reaction between 1 and (OC-6-22)-[RuCl2{S(O)Me2}3(OSMe2)] in toluene at 80 °C. A prolonged interaction in toluene at reflux temperature gave isomerically pure 3a. The metal trichloride hydrates MCl3 · xH2O (M = Ru, Rh, Ir; x ≅ 2–4) produced mer-[RuCl3{2,6-C5H3N(CMe2NH2)2}] (M = Ru: 4; Rh: 5; Ir: 6), when combined with 1 in refluxing ethanol. The crystal structures of the following compounds were determined: ligand 1 and complexes 2–5 as addition compounds 2 · CH2Cl2, 3a · C7H8, 4 · EtOH and 5 · 2 1 2 DMF .

In quest of ruthenium complexes having [RuN3S2] cores, a non-flexible configuration, trans-thiolate donors and exchangeable coligand L, [Ru(L)(pyN2H2S2)] complexes have been synthesized [ pyN 2 H 2 S 2 2 - = 2 , 6 - bis ( 2 - mercaptophenylaminomethyl ) pyridine ( 2 - ) ] . Treatment of [RuCl2(CH3CN)4] with pyN 2 H 2 S 2 2 - gave [Ru(py)(pyN2H2S2)] (1). The pyridine coligand in 1 proved to be labile and could be substituted by either CO or DMSO under normal conditions to give [Ru(CO)(pyN2H2S2)] (2) and [Ru(DMSO)(pyN2H2S2)] (3), respectively. Alternatively, 2 could be obtained directly from [RuCl2(CH3CN)4] and pyN 2 H 2 S 2 2 - in the presence of CO, whereas the reaction in the absence of CO gave the dinuclear [Ru(pyN2H2S2)]2 (8). Treatment of either 2 or 3 with NOBF4 afforded [RuIII(CO)(pyN2H2S2)]BF4 ([4]BF4) and [Ru(NO)(pyN2H2S2)]BF4 ([5]BF4), respectively. Treatment of [5]BF4 with either NEt4N3 or N2H4 afforded the amide [Ru(NO)(pyN2HS2)] (6) and the hydrazine [Ru(N2H4)(pyN2H2S2)] (7), respectively. Treatment of the dinuclear 8 with either one or two equivalents of NOBF4 afforded the mixed-valence diruthenium (II,III) [RuIIIRuII(pyN2H2S2)2]BF4 ([9]BF4) and the diruthenium (III) [RuIIIRuIII(pyN2H2S2)2](BF4) 2 {[10](BF4)2}, respectively. The diruthenium (III) complex [10](BF4)2 is diamagnetic, which can be ascribed to spin–spin pairing between the two RuIII atoms. A preliminary structure determination of [10](BF4)2 supports this observation, indicating a single bond between the two RuIII atoms. Novel diruthenium complex of this type could be synthesized more generally by treatment of [RuCl3(MeSPh)3] with pyN 2 H 2 S 2 2 - . All complexes were characterized by spectroscopic methods and elemental analysis. The cations [9]+ and [10]2+ were characterized by X-ray structure analysis.

Subsequent addition of 1,2-benzenedithiol (S 2 –H 2 ) and n BuLi to a solution of [Ru(NO)Cl 3 · x MeOH] in THF afforded exclusively the monomeric species NBu 4 [Ru II (NO)(S 2 ) 2 ] ( 1 ). Formation of dimeric (NBu 4 ) 2 [Ru II (NO)(S 2 ) 2 ] 2 ( 2 ) has been confirmed when the deprotonated ligand S 2 –Li 2 was added to [Ru(NO)Cl 3 · x MeOH] and allowed to stir for 30 h. The monomer 1 undergoes aerial oxidation to give (NBu 4 ) 2 [Ru IV (S 2 ) 3 ] ( 3 ). The reaction between RuCl 3 · x H 2 O and S 2 –H 2 in the presence of NaOMe, afforded the dinulear Ru III species (NMe 4 ) 2 [Ru III (S 2 ) 2 ] 2 ( 4 ). A modified method for the preparation of 1 is being employed to synthesize the osmium analogue NBu 4 [Os(NO)(S 2 ) 2 ] ( 5 ) effectively. The solid state structures of 1 , 2 and 3 were determined by X-ray crystal structure analysis. A comparison of relevant bond distance data suggests that 1,2-benzenedithiolate acts as an “innocent” ligand.

Metal-sulfur complex fragments, to which small molecules like N2, N2H2, N2H4, NH3, or CO can bind, are desirable model compounds concerning enzymatic N2 fixation. This paper reports on the effects of the phosphane co-ligand on formation and reactivity of [Ru(L)(PR3)(`N2Me2S2')] [`N2Me2S2'2−=1,2-ethanediamine-N,N′-dimethyl-N,N′-bis(2-benzenethiolate)(2−)] complexes with nitrogenase relevant ligands, especially N2, N2H4, NH3, and CO. Treatment of [Ru(NCCH3)4Cl2] with Li2`N2Me2S2', excessive LiOMe, bulky PPh3 or PCy3, respectively, led to the formation of two series of [Ru(L)(PR3)(`N2Me2S2')] complexes [for R=Ph: 1b, 1c (L=NCCH3), 6b (L=N2H4), 7b (L=N2), 8b1–3 (L=CO), 9b (L=NH3); for R=Cy: 1a (L=NCCH3), 6a (L=N2H4), 7a (L=N2), 8a (L=CO), 9a (L=NH3)]. While the use of PPh3 (θ=145°) yielded cis,trans and cis,cis isomers of [Ru(NCCH3)(PPh3)(`N2Me2S2')] (1b, 1c), no isomer formation was observed with the bulkier phosphane PCy3 (θ=170°). Sterically less demanding phosphanes (θ=118–132°) afforded bisphosphane complexes [Ru(PR3)2(`N2Me2S2')] [2d (R=Me), 2e (R=Et), 2f (R=nPr), and 2g (R=nBu)], which were practically inert and could only be converted in two cases and under drastic reaction conditions into the CO complexes [Ru(CO)(PR3)(`N2Me2S2')] [4e (R=Et), 4f (R=nPr)]. The chelating bidentate phosphane dppe (bisdiphenylphosphanoethane) yielded exclusively the mononuclear complex [Ru(dppe)(`N2Me2S2')] (3).

The preparation of optically pure ((R)-3-phenylbutanol)Ru(II) complexes is described. Depending on the reaction conditions and the co-ligands, the chiral alcohol side chain may dangle free at the periphery of the η6-co-ordinated arene ligand or be co-ordinated to the metal to result in a η6:η1-chelate ligand system. A key molecule is the dimeric complex [(η6-(R)-3-phenylbutanol)RuCl2]2 (2) with dangling side chains. It is accessible in good yield either by oxidation and COD ligand exchange of the Ru(0) species [(COD)(η6-(R)-3-phenylbutanol)Ru] (1) (COD=1,5-cyclooctadiene) or by complexation and dehydrogenation of (R)-3-cyclohexa-(1,4-dien-1-yl)-butanol (5). 5 is thus accessible in good yield in two steps from a commercially available starting material. Dimer 2 can be split into mononuclear complexes by heating alcohol solutions to afford tethered [(η6:η1-(R)-3-phenylbutanol)RuCl2] (6), or by reaction with an additional ligand L (L=PR3, P(OR)3, pyridine) to furnish [(η6-(R)-3-phenylbutanol)(L)RuCl2] (7a–f). If 7a–d are reacted with silver salts, the side chain is strapped through chloride elimination to form the diastereomeric salts [(η6:η1-(R)-3-phenylbutanol)(L)RuCl]+X− (8X) (X=BF4, PF6). The absolute molecular structures of the complexes have been determined in the solid state. Especially the side chains exhibit interesting conformational features. The CD spectra of 2, 6, and 7a are reported.

Binding N2 to the metal sulfur cofactors of nitrogenase is considered the first step of biological N2 fixation. In quest of low-molecular weight complexes modeling this step [μ-N2{Ru(PiPr3)(N2Me2S2)}2] (3) was synthesized and completely characterized. Complex 3 was obtained from [Ru(N2)(PiPr3)(N2Me2S2)] (1) that dissociates N2 under reduced partial pressure of N2. Complex 1, in turn, forms from [Ru(CH3CN)(PiPr3)(N2Me2S2)] (2) and N2 at standard conditions (20 °C, 1 bar) such that the formation of 3 corresponds with a binding of molecular nitrogen to metal thiolate complex fragments under mild conditions, not requiring abiologically strong reductants. Complex 3 forms as racemate of (R,R)-3 and (S,S)-3 enantiomers which spontaneously separate upon crystallization and could both be characterized by X-ray crystallography. Complex 3 exhibits short bonds trans to the N2 ligand, a ν(N2) frequency (2042 cm−1) low in comparison with that of 1 (2113 cm−1) and a non-linear [RuNNRu] entity. The thiolate donors of 3 represent Broensted-basic sites for reversible protonations so that 3 becomes a complex suited for investigations aiming at the reduction of N2 by nitrogenase-like coupled [2H+/2e−] transfer steps.

The molecular structure of K[Fe(Hedta)(Cl)]·H2O (1, edta=ethylenediaminetetraacetate) has been determined: Triclinic, P 1 (No. 1), Z=1, a=6.735(1), b=7.245(1), c=8.815(2) A, α=72.87(2), β=85.00(2), γ=76.30(2)°, V=399.3(2) A3, R1=0.0355, wR2=0.0968. Compound 1 is the third spontaneously resolved edta-complex containing an uncoordinated, protonated acetate arm. The Δ λE enantiomorph has been refined during the structure determination. The reasons for this exceptional behavior are discussed in the framework of related transition metal complex structures with monoprotonated edta as a ligand. Important forces behind the formation of optically pure crystals are: the strong FeCl bond and the presence of potassium as a counter ion. Trials to prepare the six-coordinate derivative of 1 by simple deprotonation of the detached acetate arm did not result in the formation of K2[Fe(edta)(Cl)] but the seven-coordinate salt K[Fe(edta)(H2O)]·1.5H2O (2) was obtained with the following crystallographic parameters: Monoclinic P2/c (No. 13), Z=4, a=15.287(4), b=7.697(2), c=14.380(3) A, β=104.98(2)° V=1634.5(7) A3, R1=0.0338, wR2=0.0821.

New diazene complexes of the type [μ-N2H2{Fe(PR3)(‘tpS4’)}2] (R=Pr (1), Bu (2)) have been synthesized from FeCl2·4H2O, PR3, ‘tpS4’ 2− in THF–MeOH solution and N2H2 generated in situ by hydrolysis of K2N2(CO2)2 with acetic acid. The deuterated complexes [μ-N2D2{Fe(PR3)(‘tpS4’)}2] (R=Pr (3), Bu (4)) were obtained by using D2O, CH3OD and CH3CO2D. The complexes 1–4 each form as a mixture of two diastereomers. Fractional crystallization of 1 from either toluene or CH2Cl2 afforded single crystals of 1a·2toluene and 1b·4CH2Cl2 that were characterized by X-ray structure determination and permitted to establish unambiguously the hydrogen bridge diastereoisomerism of 1a and 1b. Complexes 1a and 1b differ from each other mainly with respect to the orientation of NH⋯S(thiolate) bridges, but are nearly identical otherwise. The reactivity of 1–4 was investigated with respect to H+/D+ exchange, reversible oxidation and PR3 exchange reactions. The PPr3 ligands of 1 can be exchanged reversibly for PBu3 to give 2 under retention of the [FeNHNHFe] cores. The PR3 exchange is rationalized by dissociation of the PR3 ligands yielding intermediates with five-coordinate iron centers. Such intermediates also account for the isomerization of 1a and 1b and related diazene complexes, for which a mechanism is proposed.

The reaction of ‘buS2’2−=3,5-ditertiarybutyl-1,2-benzenedithiolate(2−) with Ni(ac)2·4H2O and subsequently AsPh4Cl, yielded (AsPh4)2[Ni(‘buS2’)2] (1). Complex 1 is extremely air sensitive and oxidized rapidly to give (AsPh4)[Ni(‘buS2’)2] (2). The anion of 2 could be further oxidized by iodine to give neutral [Ni(‘buS2’)2] (3). Complexes 1, 2 and 3 contain nickel in the formal oxidation states +2, +3 and +4, and could be completely characterized by X-ray structure determination and spectroscopic methods. The results indicate that the oxidation of 1→2→3 concerns electrons residing in molecular orbitals having [NiS4] character. No evidence could be obtained for an involvement of the benzene rings or an electron delocalization beyond the [NiS4] core. This conclusion corresponds with the reactivity of 3 versus 2 and 1 towards protons and CO. While 3 is inert to the attack of H+ and CO, 2 and 1 exhibit rapid reactions to give ‘buS2’H2 and either nickel–chloro complexes or Ni(CO)4.

A zinc complex with the tripodal ligand bis[2-(2-pyridyl)ethyl]-(2-pyridyl)methylamine (pmap) reacts with carbon dioxide to form a new dinuclear carbonate bridged zinc complex, [μ-CO3{Zn(pmap)}2](ClO4)2. This complex was structurally characterized and shows a binding mode for carbonate, which so far has not been observed for zinc carbonate complexes.

The pentaamine methylcobalt(III) compound [Co(pyN4)(CH3)](NO3)2 (pyN4=2,6-bis(1′,3′-diamino-2′-methyl-prop-2′-yl)pyridine) has been synthesised from [Co(NH3)5(CH3)](NO3)2 and pyN4 by ligand exchange, and characterised by IR, 1H, 13C and 59Co NMR spectroscopy as well as elemental analysis. The structure of the complex has been determined using the dithionate salt [Co(pyN4)(CH3)]S2O6. The coordination geometry at cobalt is close to octahedral, the tetrapodal pentadentate amine ligand providing a C2-symmetrical coordination cap for the metal centre. One axial position is occupied by the pyridine nitrogen atom, while the four equivalent primary amino groups take the equatorial positions. The other axial position, trans to the pyridine ring, is occupied by the methyl group. The Co–Npy bond length of 2.018(2) A is significantly elongated compared with other cobalt(III) complexes of the pyN4 ligand, demonstrating the strong trans influence of the CH3 ligand. The Co–C bond length (1.975(4) A) is virtually identical to the value found in the related complex [Co(NH3)5(CH3)](S2O6).

The suspension of LiN(PPh 2 ) 2 ( 1 ) in CH 2 Cl 2 that is acting in the case under discussion not only as a solvent but also as an alkylating agent, results in the formation of [Ph 2 MePNPMePh 2 ]Cl ( 2 ). The metathesis of 2 with NaBPh 4 in acetone yields the title compound [Ph 2 MePNPMePh 2 ]BPh 4 ( 3 ). The crystal structure of 3 has been determined by X-ray crystal analysis.

The [FeNHNHFe] chromophore of [μ-N2H2{Fe(PPr3)(‘S4’)}2] (1) [D. Sellmann, H. Friedrich, F. Knoch, M. Moll, Z. Naturforsch., Teil B 48 (1994) 76] is retained in phosphine and H + D + exchange reactions. 1 exchanges the PPr3 ligand for PBu3 to give the analogous [μ-N2H2{Fe(PBu3)(‘S4’)}2] (2). Treatment of 1 with CO, however, leads to cleavage of the chromophore and the formation of [Fe(CO)(PPr3)(‘S4’)] (3) as major product and of [Fe(CO)2(‘S4’)] and [Fe(CO)(‘S4’)]2 as by-products. The substitution reactions are suggested to be initiated by a primary reversible dissociation of one PPr3 ligand in 1. Complex 1 exchanges the diazene NH protons for D+ from D2O or CD3OD via a base-catalyzed mechanism that involves the reversible formation of the [μ-N2H{Fe(PPr3)(‘S4’)}2]− anion. Cyclic voltammetry showed that 1 in CH2Cl2 solution can be oxidized in four consecutive steps, three of which are quasi-reversible. The redox waves are influenced by temperature changes and the presence of MeOH or NaOMe, indicating that the redox steps involve also reversible deprotonations of 1 and its oxidation products. Chemical oxidation of 1 by O2, BuOOH or I2 resulted in nitrogen-free products. Oxidation of 1 by two equivalents of [Cp2Fe]PF6 gave [μ-N2H2{Fe(PPr3)(‘S4’)}2](PF6)2 (9). 9 is extremely unstable and decomposes above temperatures of −20°C with release of N2. The properties of 9 are compatible with the μ-N2 complex [μ-N2{Fe(PPr3)(‘S4’)2] that has been twofold protonated by HPF6. 2H- and 15N-labeled isotopomers of 1 have been synthesized and completely characterized. The molecular structures of [Fe[CO](PPr3)(‘S4’)] (3), [Fe(CO)(PPh3)(‘S4’)] (5) and [Fe(PPr3)2(‘S4’)] (11) have been elucidated by X-ray structure determination.

Rhodium hydride complexes [Rh(H)(L)(•buS4•)] (LPMe3 (2a); PCy3 (3a); THT (4); NH3 (5); •buS4•2 = 1,2-bis(2-mercapto-3,5-di-t-butylphenylthio)ethane(2−)) and [Rh(H)(L)(•S4•)] (LPMe3 (2b); PCy3 (3b); •S4•2 = 1,2-bis(2-mercapto-phenyl-thio)ethane(2−)) have been obtained by CO substitution reactions from [Rh(H)(CO)(•RS4•)] (R=1bu (1a); RH (1b)) and monodentate two electron donors. In the absence of appropriate donors. [Rh(•buS4•)]2 (15) and [Rh(H)(•S4•)]2 (19) formed. CO substitution in [Rh(Cl)(CO)(•buS4•)] (6) by various monodentate two-electron donors yielded the chloro complexes [Rh(Cl)(L)(•buS4•)] (L=1buSH (7); THT (8); SEt2 (9); PCy3 (10); PMe3 (11a): NH3 (13)). [Rh(PMe3)2(•buS4•)]Cl (12a) and [Rh(NH3)-(CONH2)(•buS4•)] (14) were by products in the reaction with LPMe3 and NH3. The chloro complexes 11a, 11b and [Rh(Cl)(PPh3)(•S4•)] (18) were obtained from the hydride complexes 2a, 2b and [Rh(H)(PPh3)(•S4•)] (17), respectively, when dissolved in chlorinated hydrocarbons. Reaction of complex 1b with hydrochloric acid or gaseous HCl yielded [Rh2(H)(Cl)(•S4•)2] (20) that was cleaved into complex 2b and [Rh(PMe3)2(•S4•)]Cl (12b) upon addition of PMe3. Complexes 3a, 17 and 18 crystallize in the monoclinic space group P2 1 c , Z=4 , with a=14.720(3), b=15.37(2), c=27.719(6) A and β=90.98(2)° for 3a·4CH2Cl2, with a=15.922(3), b=17.681(4), c=16.510(5) A and β=115.17(2)° for 17·3THF, and with a= 10.712(3), b=20.19(1), c=20.228(5) A and β=97.87(2)° for 18·3CHCl3. Complex 11b·1/3THF crystallizes in the rhombohedral space group R 3 , Z=18 , with a=b=25.464(4) and c=17.69(2) A . The rhodium centers of all complexes are surrounded pseudo-octahedrally by four S, one P and the H or Cl atom. The distances and the PCy3 conformation in 3a·4CH2Cl2 indicate H…H interactions between cyclohexyl CH atoms and the hydrido ligand. Complex 15·4.5acetone crystallizes in the monoclinic space group C2 c , Z=4 , with a=19.817(9), b=21.134(9), c=21.51(1) A and β=114.74(5)°. Both Rh centers of 15·4.5acetone are surrounded by five S atoms and the neighboring Rh atom to give a distorted octahedron. One of the S(thiolate) donors of each •buS4•2 ligand bridges both Rh centers.

Ru(II) and Ru(III) azido complexes were synthesized as potential precursors for dinitrogen complexes with sulfur-dominated coordination spheres. NEt4[Ru(N3)(PCy3)(‘S4’)] (1) was obtained from the reaction of [Ru(DMSO)(PCy3)(‘S4’)] with NEt4N3 ( ‘ S 4 ’ 2− = 1,2- bis (2- mercaptophenylthio ) ethane (2−) ). The oxidation of [Ru(DMSO)(PR3)(‘S4’)] with I2 yielded [Ru(I)(PR3)(‘S4’)] ( R = Cy 2 a , i Pr 2 b ). The iodo ligand in 2a and 2b could be exchanged for azide and chloride yielding [Ru(N3)(PR3)(‘S4’)] ( R = Cy 3 a , i Pr 3 b ) and [Ru(Cl)(PCy3)(‘S4’)] (4). The azido ligand of 1 could not be transformed into a N2 ligand, and the reaction of 3a with HBF4 yielded the nitrido complex [μ-NRu(PCy3)(‘S4’))2](PF6) ([5]PF6) via a labile intermediate exhibiting an IR band at 2070 cm−1 at −40°C. The molecular structures of 2a, 4 and [5]+ as the BPh4staggered− salt were determined by X-ray structure analysis. Crystal data of (a) 2a·C7H8: triclinic space group P 1 ; a = 1087.4(1), b = 1089.5(1), c = 1988.8(1) pm; α = 74.13(1), β = 78.66(1), γ = 61.22(1)°; Z = 2; (b) 4·CH2Cl2: triclinic space group P 1 ; a = 1088.7(5), b = 1065.6(3), c = 1778.4(6) pm; α = 80.66(2), β = 72.10(4), γ = 67.52(3)°; Z = 2; (c) [5]BPh4·3THF: orthorhombic space group Pna21; a = 1972.9(6), b = 2606.3(6), c = 1831.1(12) pm; Z = 4. The metal centers of all three complexes show pseudo-octahedral coordination and exhibit no anomalies in distances and angles. The two Ru centers in [5](BPh4)·3THF are linked via a bent nitrido bridge.

The reaction of Na2PtCl6 with glycine in water yields cis-[PtCl2(gly)2] (1). [Na(18-cr-6)]2[PtCl6]·3H2O reacts with glycine and D-(+)-alanine in water to give [Na(18-cr-6)(H2O)2][PtCl4(gly)]·(18-cr-6) (2) and [Na(18-cr-6)][PtCl4(ala)] (3), respectively. Cis-[PtCl4(glyH)2]·2(18-cr-6) (4) and cis-[PtCl4(alaH)2]·(18-cr-6) (5), respectively, are formed when the reaction mixture is irradiated with light from a halogen lamp. All complexes were characterized by microanalysis as well as by NMR, IR and Raman spectroscopy revealing that in complexes 1–3 the glycinato and alaninato ligands act as N,O-chelate ligands whereas in complexes 4 and 5 the amino acids act as N-donor ligands. The molecular structure of 1 (orthorhombic, Pbca, a=10.163(2), b=11.028(2), c=16.310(4) A, Z=8, R1=0.0413, wR2=0.0953) exhibits a distorted octahedral coordinated Pt atom with a cis-PtCl2 unit and two N,O-coordinated glycinato ligands (OC-6-32). The complex is stabilized by intramolecular hydrogen bonds between the amino group and the C–O group as well as the chloro ligand. The crystal structure of 2 (orthorhombic, Pnma, a=23.262(9), b=11.149(4), c=15.834(5) A, Z=4, R1=0.067, wR2=0.1644) shows a [PtCl4(gly)]− unit and an [Na(18-cr-6)(H2O)2]+ unit linked via hydrogen bridges with a further crown ether molecule.