Radical Arylation Reactions of 4, 6, 8-Trimethylazulene

The synthesis of 1- and 2-aryl-substituted (aryl = Ph, 4-NO₂? C₆H₄, and 4-MeO? C₆H₄) 4, 6, 8-trimethylazulenes ( 4 and 3 , respectively) in moderate yields by direct arylation of 4, 6, 8-trimethylazulene ( 8 ) with the corresponding arylhydrazines 13 in the presence of Cu^IIions in pyridine (see Scheme 4) as well as with 4-MeO? C₆H₄Pb(OAc)₃ ( 16 ) in CF₃COOH (see Scheme 5) is described. With 13 , also small amounts of 1, 2- and 1, 3-diarylated azulenes (see 14 and 15 , respectively, in Scheme 4) are formed. The 4-methoxyphenylation of 8 with 16 yielded also the 1, 1′-biazulene 17 in minor amounts (see Scheme 5). 4, 6, 8-Trimethyl-2-phenylazulene ( 3a ) was also obtained as the sole product in moderate yields by the reaction of sodium phenylclopentadienide ( 1a ) with 2, 4, 6-trimethylpyrylium tetrafluoroborate ( 2 ) in THF (Scheme 1). The attempted phenylation of 8 as well as of azulene ( 9 ) itself with N-nitroso-N-phenylacetamide ( 10 ) led only to the formation of the corresponding 1-(phenylazo)-substituted azulenes 12 and 11 , respectively (Scheme 3).     

Darstellung und Eigenschaften neuer kationischer Dienyl-isonitril-dicarbonyl-Komplexe des Eisens und Rutheniums

Preparation and Properties of New Cationic Dienyl-isonitrile-dicarbonyl Complexes of Iron and Ruthenium The hydride abstraction from the η⁴-diene isonitrile metal dicarbonyls M(η⁴-dien)(CNR)(CO)₂ (M = Fe, Ru; dien = C₆H₈ cyclohexadiene-1.3; C₇H₁₀ cycloheptadiene-1.3; R = Me, Et) with [Ph₃C]BF₄ lead to the η⁵-dienyl isonitrile dicarbonyl metal cations [M(η⁵-dienyl)(CNR)(CO)₂]⁺ [dienyl = cyclohexa-2.4-dien-1-yl (C₆H₇), cyclohepta-2.4-dien-1-yl (C₇H₉)]. [Fe(η⁵? C₈H₉)(CNMe)(CO)₂]⁺ (C₈H₉ = bicyclo[5.1.0]octa-3.5-dien-2-yl) is formed by protonation of Fe(η⁴? C₈H₈)(CNMe)(CO)₂ (C₈H₈ = COT) under valency isomerization. The two cations [Fe(η⁵? C₇H₉)(CNMe)(CO)₂]⁺ and [Fe(η⁵? C₈H₉)(CNMe)(CO)₂]⁺ can be deprotonated with NEt₃ to the neutral cycloheptatriene respectively COT complexes Fe(η⁴? C₇H₈)(CNMe)(CO)₂ and Fe(η⁴? C₈H₈)(CNMe)(CO)₂. The temperature dependent ¹³C-NMR spectra of [Fe(η⁵? C₇H₉)(CNMe)(CO)₂]⁺ and [Ru(η⁵? C₆H₇)(CNMe)(CO)₂]⁺ show the fluctional behaviour of these cations in solution. At low temperatures one CO group occupies the apical position of a square pyramid whereas the isonitrile ligand, the other CO group and the dienyl part are in the basal positions. The ΔG values of the CP exchange points out a higher activation energy as in the corresponding η⁴-diene metal complexes.     

A ferrocenyl‐substituted pseudo­titanocene complex

The title compound, (η⁵‐cyclo­penta­dienyl)[(1,2,3,4,5‐η)‐4‐ferro­cenyl‐1,2,5,6‐tetrakis­(tri­methyl­silyl)­cyclo­hexa‐2,4‐dien‐1‐yl]­titanium(II), [TiFe(C₅H₅)₂(C₂₃H₄₂Si₄)] or [Ti{η⁵‐C₆H₂{Fe­(η⁵‐C₅H₄)(η⁵‐C₅H₅)}{Si(CH₃)₃}₄}(η⁵‐C₅H₅)], possesses two directly linked metallocene units that subtend an angle of 52.9 (1)° (defined by the least‐squares planes of the directly connected π‐ligands) associated with the steric requirements of the bulky tri­methyl­silyl substituents. The cyclo­hexa­dienyl ligand adopts an envelope conformation; the perpendicular distance of its η⁵‐plane to the Ti atom is 1.512 (1) Å.     

Aminomethyl Transfer (Mannich) Reactions Between an O-Triethylsilylated Hemiaminal and Anilines,RnC6H5−nNH2 Leading to New Diamines,Triamines, Imines,or 1,3,5-Triazines Dependent upon Substituent R

The reactions of the Mannich reagent Et₃SiOCH₂NMe₂ ( 1 ) with a variety of anilines (mono-substituted RC₆H₄NH₂, R=H, 4-CN, 4-NO₂, 4-Ph, 4-Me, 4-MeO, 4-Me₂N; di-substituted R₂C₆H₃NH₂, R₂=3,5-(CH₃)₂, 3,5-(CF₃)₂; tri-substituted R₃C₆H₂NH₂, R₃=3,5-Me₂-4-Br and a “super bulky” aniline (Ar*NH₂) [Ar*=2,6-bis(diphenylmethyl)-4-tert-butylphenyl]) led to the formation of a range of products dependent upon the substituent. With electron-withdrawing substituents, previously unknown diamines, RC₆H₄NH(CH₂NMe₂) [R=CN ( 2 a ), NO₂ ( 2 b )] and R₂C₆H₃NH(CH₂NMe₂) [R₂=3,5-(CF₃)₂ ( 2 c) ] were formed. Further reaction of 2 a , b , c with 1 yielded the corresponding triamines RC₆H₄N(CH₂NMe₂)₂ (R=CN ( 3 a ), NO₂ ( 3 b ) and R₂C₆H₃N(CH₂NMe₂)₂, R₂=3,5-(CF₃)₂ ( 3 c ). The new polyamines were characterized by NMR spectroscopy, and for 2 a , 2 c _, and 3 c , by single crystal XRD. In the case of electron-donating groups, R=4-OMe, 4-NMe₂, 4-Me, 3,5-Me₂, 3,5-Me₂-4-Br, and for R=4-Ph, the reactions with 1 immediately led to the formation of the related 1,3,5-triazines, R=4-MeO ( 5 a ), 4-Me₂N ( 5 b ), 4-Me ( 5 c ), 3,5-Me₂ ( 5 d ), 3,5-Me₂-4-Br ( 5 e ), 4-Ph ( 5 f ), 4-Cl ( 5 g ). The “super bulky” aniline rapidly produced a single product, namely the corresponding imine Ar*N=CH₂ ( 4 ) which was also characterized by single crystal XRD. Imine 4 is both thermally and oxidatively stable. All reactions are very fast, thus based upon the presence of Si we are tempted to denote the reactions of 1 as examples of “Silick” chemistry.     

Correlation of the reactivity of coordinated π-hydrocarbons with electronic parameters : I. Indo calculations on the cation [(C6H7)Fe(CO)3]+

INDO calculations on the cation [(C₆H₇)Fe(CO)₃]⁺ suggest that there is a correlation between the bond index (or free valence) values at each dienyl carbon and the site of nucleophilic addition.     

(η5‐Cyclo­penta­dienyl)(p‐fluoro­phenoxo)(nitro­syl)(tri­methyl­silyl­methyl)­molybdenum(II)

The title complex, [Mo(C₅H₅)(C₆H₄FO)(C₄H₁₁Si)(NO)], is formed by reacting CpMo(NO)(CH₂SiMe₃)₂, where Cp is cyclo­penta­dienyl, with one equivalent of p‐FC₆H₄OH. The complex exhibits the expected piano‐stool molecular structure, with a linear nitro­syl ligand [Mo—N—O 168.2 (2)°] having Mo—N and N—O distances of 1.764 (2) and 1.207 (3) Å, respectively. The phenoxo Mo—O distance of 1.945 (2) Å is suggestive of some multiple‐bond character.     

Direktsynthese von orthometallierten Ketonen des Typs RCO (o-C6H4)Mn(CO)4−nLn (R = Alkyl- und Arylrest,n = 0, 1, 2, L = Ligand)

Direct Synthesis of Orthometallated Ketones of the Type RCO(o-C₆H₄)Mn(CO)_4?nL_n (R = Alkyl and Aryl Groups, n = 0, 1, 2, L = Ligand) The starting materials of the type RMn(CO)_5?nL_n und (C₆H₅)₂ Hg react to the products of the type RCO(o-C₆H₄)Mn(CO)_4?nL_n[n = 0, R = Ch₃, C₂H₅, C₃H₇, C₆H₅,CH₂; R = C₆H₅, n = 1, L = E(C₆H₅)₃, E = P, As, Sb; R = C₆H₅, n = 2, L = P(OR′)₃, R′ = C₆H₅, CH₃, C₂H₅, C₃H₇]. Steps of their complex reaction pathway are proposed. These orthometallated substances have been characterized by means of ¹H-n.m.r., i.r. and u.v. spectroscopic measurements. The determination of the molecular structure of the two compounds RCO(o-C₆H₄)Mn(CO)₃L [R = C₂H₅, L = CO; R = C₆H₅, L = As(C₆H₅)₃] show that both contain a planar heterocyclic five-membered ring of the type .     

The dimeric mixed‐ligand titana­carborane sandwich [1‐(Cp)‐1‐Ti‐2‐(Me)‐3‐(SiMe3)‐2,3‐C2B4H4]2

The title dimer, bis­[1‐cyclo­penta­dienyl‐2‐methyl‐1‐titana‐3‐tri­methylsilyl‐2,3‐dicarba‐closo‐hexaborane(6)], [Ti(C₅H₅)(C₆­H₁₆­B₄Si)]₂, reveals that the centrosymmetric mol­ecule consists of two bent‐sandwich titanacarboranes bridged by the B—H—Ti bonds. The average bond distances are Ti—B 2.445 (3), Ti—C(cage) 2.334 (2) and Ti—C(Cp) 2.376 (3) Å, and the corresponding bond angles are Cp—Ti—Cp 163.2 (1) and Cp—Ti—Cb (Cb = C₂B₃ face) 139.9 (1)°; the Ti—H separations are 2.10 (2) and 2.19 (2) Å.     

(Cycloheptatrienyl)hydridotungsten Complexes

Carbonyl(cycloheptatrienyl)iodo(phosphorus donor)tungstens ([WI(C₇H₇)(CO)L]; L = P(OMe)₃, 1a ; L = P[O(i-Pr)]₃, 1b ; L = PPh₃, 1c ) were prepared from dicarbonyl(cycloheptatrienyl)iodotungsten ([WI(C₇H₇)(CO)₂)] via a carbonyl-substitution process. Similarly, bromocarbonyl(phosphorus donor)(1,2,4,6-tetramethylcycloheptatrienyl)tungstens ([WBr(Me₄C₇H₃)(CO)L]; L = P(OMe)₃, 6a ; L = P[O(i-Pr)]₃, 6b ; L = PPh₃, 6c ) were obtained from the reaction of bromodicarbonyl(1,2,4,6)-tetramethylcycloheptatrienyl)tungsten ([WBr(Me₄C₇H₃)(CO)₂]; 4 ) with L. The reduction of 1a - c , 4 , and 6a , b with sodiumdihydridobis(2-methoxyethoxy)aluminium in toluene led to stable hydrido complexes [WH(R₄C₇H₃)(CO)L] (R = H, L = P(OMe)₃, 2a ; R = H, L = P[O(i-Pr)]₃, 2b ; R = H, L = PPh₃, 2c ; R = Me, L = P(OMe)₃, 7a ; R = Me, L = P[O(i-Pr)]₃, 7b ; R = Me, L = CO, 7d ). Complexes 2a and 7b were characterized by X-ray structure analyses.     

Spezielle Organoschwefel- und -selenverbindungen einiger Übergangsmetalle

Aluminum phenylselenolate and 1-naphthylselenolat react with TiCl₄, ZrCl₄, NbCl₅, TaCl₅, WCl₆ and CrCl₃ · 3THF giving compounds of types M(SeR)₄ (M = Ti, Zr, W; R = C₆H₅, C₁₀H₇) and M(SeR)₃ (M = Nb, Ta, Cr; R = C₆H₅, C₁₀H₇). By reaction of nickel(II), cobalt(II) and cobalt(III) acetylacetonates with thiophenol, selenophenol and 1-selenonaphthol polymeric compounds of composition Ni(XR)₂, Co(XR)_n (X = S, Se; R = C₆H₅, C₁₀H₇; n = 2 or 3) and Co(SC₆H₅)₂ · C₆H₅SH are obtained. [(n-C₄H₉)₃P]₂NiCl₂ and selenophenol in the presence of triethylamine give the monomeric compound [(n-C₄H₉)₃P]₂Ni(SeC₆H₅)₂.     

Further study of estertin trichlorides,Cl3SnCH2CH2CO2R. Lewis acidity towards acetonitrile. Crystal structure of Cl3SnCH2CH2CO2Pr-i

Crystals of Cl₃SnCH₂CH₂CO₂Pri-i are orthorhombic, space group P2₁2₁2₁ with a 9.638(6), b 10.004(7) and c 12.848(8) Å. The tin atom is five-coordinate with two chlorines and carbon equatorial and the remaining chlorine and the carbonyl oxygen axial, in a distorted trigonal-bipyramidal arrangement: (SnCl)_ax 2.389(3), average (SnCl)_eq 2.320(2), SnC 2.142(9), SnO 2.337(5) Å. Apart from the equatorial chlorine and the terminal carbons in the isopropyl group, all non-hydrogen atoms are essentially coplanar. The molecule approaches C_2v symmetry although not constrained to do so by the crystallographic space group.In MeCN solution, the compounds Cl₃SnCH₂CH₂CO₂R (I, R = Me, Pr-i, C₆H₄X (X = p-MeO, H, p-Cl, o-MeO or C₆H₃Cl₂-2,4) form as equilibrium mixtures of 1/1 and 2/1 MeCN/I complexes; the chelate ring is broken in the 2/1 complexes. Equilibrium constants indicate that the strength of the intramolecular SnO coordination in I increases with the electron releasing ability of the R group.     

Reaktionen der Cycloheptatrienylkomplexe [η7-C7H7W(CO)3]BF4 und η7-C7H7Mo(CO)2 Br mit Neutralliganden und die elektrochemische Reduktion des Wolframkomplexes

Reactions of the Cycloheptatrienyl Complexes [η⁷-C₇H₇W(CO)₃]BF₄ and η⁷-C₇H₇Mo(CO)₂Br with Neutral Ligands and the Electrochemical Reduction of the Wolfram Complex Compounds of the type [η⁷-C₇H₇M(CO)₂L][BF₄] (L = P(C₆H₅)₃, As(C₆H₅)₃, Sb(C₆H₅)₃ for M = W and L = N₂H₄ for M = Mo) were synthesized and characterisized. The iodide η⁷-C₇H₇W(CO)₂I reacts with the diphosphine ((C₆H₅)₂PCH₂)₂ to give the trihapto complex η³-C₇H₇ W(CO)₂I((C₆H₅)₂PCH₂)₂. In the case of η⁷-C₇H₇Mo(CO)₂ Br reaction with hydrazine leads to the substitution product [η⁷-C₇H₇ Mo(CO)₂N₂H₄]^⊕, which can be stabilized by large anions. The binuclear complex [C₇H₇W(CO)₃]₂ has been synthesized electrochemically.     

Addition des O'Donnell Reagenzes [Ph2C=NCHCO2Me]– an π-koordinierte,ungesättigte Kohlenwasserstoffe in [(C6H7)Fe(CO)3]+, [(C7H9)Fe(CO)3]+, [(C7H7)M(CO)3]+ (M = Cr,Mo) und [(C2H4)Re(CO)5]+. α-Aminosäuren mit metallorganischen Seitenketten

Metal Complexes of Biologically Important Ligands. CXVII [1] Addition of the O'Donnell Reagent [Ph₂C=NCHCO₂Me]^– to Coordinated, Unsaturated Hydrocarbons of [(C₆H₇)Fe(CO)₃]⁺, [C₇H₉Fe(CO)₃]⁺, [(C₇H₇)M(CO)₃]⁺ (M = Cr, Mo), and [(C₂H₄)Re(CO)₅]⁺. α-Amino Acids with Organometallic Side Chains The addition of [Ph₂C=NCHCO₂Me]^– to [(C₆H₇)Fe(CO)₃]⁺, [(C₇H₉)Fe(CO)₃]⁺, [(C₇H₇)M(CO)₃]⁺ (M = Cr, Mo) and [(C₂H₄)Re(CO)₅]⁺ gives derivatives of α-amino acids with organometallic side chains. The structure of [(η⁴-C₆H₇)CH(N=CPh₂)CO₂Me]Fe(CO)₃ was determined by X-ray diffraction. From the adduct of [Ph₂C=NCHCO₂Me]^– and [(C₇H₇)Mo(CO)₃]⁺ the Schiff base of a new unnatural α-amino acid, Ph₂C=NCH(C₇H₇)CO₂Me, was obtained.     

Dithiocarbamate Complexes of Nickel(II) with 1,1′-Bis(Diphenylphosphino) Ferrocene

Ni(II) complexes of composition [Ni(bzⁱprdtc)(dppf)]X, [Ni(but₂dtc)(dppf)]X and [Ni(Rdtc)(dppf)]X [bz = C₇H₇; ⁱpr = C₃H₇; but = C₄H₉; R = pld = C₄H₈; tz = C₃H₆S; hmi = C₆H₁₂; dtc = S₂CN; dppf = 1,1'-bis(diphenylphosphino)ferrocene C₃₄H₂₈P₂Fe; X = ClO₄, I, Br, NCS] were synthesized and characterized X-ray structural analysis of [Ni(hmidtc)(dppf)]ClO₄ confirmed coordination number four for nickel in a distorted, square-planar, NiS₂P₂ arrangement     

New Dinuclear Ru2(CO)4 Sawhorse‐Type Complexes Containing Bridging Carboxylato Ligands

The thermal reaction of Ru₃(CO)₁₂ with ethacrynic acid, 4‐[bis(2‐chlorethyl)amino]benzenebutanoic acid (chlorambucil), or 4‐phenylbutyric acid in refluxing solvents, followed by addition of two‐electron donor ligands (L), gives the diruthenium complexes Ru₂(CO)₄(O₂CR)₂L₂ ( 1 : R = CH₂O‐C₆H₂Cl₂‐COC(CH₂)C₂H₅, L = C₅H₅N; 2 : R = CH₂O‐C₆H₂Cl₂‐COC(CH₂)C₂H₅, L = PPh₃; 3 : R = C₃H₆‐C₆H₄‐N(C₂H₄‐Cl)₂, L = C₅H₅N; 4 : R = C₃H₆‐C₆H₄‐N(C₂H₄‐Cl)₂, L = PPh₃; 5 : R = C₃H₆‐C₆H₅, L = C₅H₅N; 6 : R = C₃H₆‐C₆H₅, L = PPh₃). The single‐crystal structure analyses of 2 , 3 , 5 and 6 reveal a dinuclear Ru₂(CO)₄ sawhorse structure, the diruthenium backbone being bridged by the carboxylato ligands, while the two L ligands occupy the axial positions of the diruthenium unit.     

Ferrocene compounds. XXXVIII. Di­methyl ferrocene‐1,1′‐di­carboxyl­ate

In the title compound, [Fe(C₇H₇O₂)₂], the cyclo­penta­dienyl rings and the two attached methoxy­carbonyl groups, in an anti arrangement, form an extended π‐conjugated system. The Fe—C distances range from 2.035 (3) to 2.061 (3) Å and the average value of the C—C bond lengths in the two cyclo­penta­dienyl rings is 1.419 (5) Å. The rings are almost parallel to one another [1.0 (2)°] and are mutually twisted from an eclipsed conformation by only 1.8 (3)° (average value). The methoxy­carbonyl groups are twisted out of the plane of the cyclo­penta­dienyl rings by 6.5 (4) and 15.7 (4)°, respectively. The mol­ecules are joined into dimers by intermolecular C—H⃛O hydrogen bonds that form ten‐membered rings. The same types of hydrogen bonds form eight‐membered rings and infinite chains along the b axis.     

Azido­[1,1′‐bis­(di­phenyl­phosphino)­ferrocene](penta­methyl­cyclo­penta­dienyl)­rhodium(III) hexa­fluoro­phosphate

In the title compound, azido‐2κN‐bis­[μ‐(1η⁵:2κP)‐di­phenyl­phosphino­cyclo­penta­dienyl][2(η⁵)‐penta­methyl­cyclo­penta­di­enyl]­iron(III)­rhodium(III) hexa­fluoro­phosphate, [{Rh(C₁₀H₁₅)(N₃)}{Fe(μ‐C₁₇H₁₄P)₂}]PF₆ or [FeRh(C₁₀H₁₅)(μ‐C₁₇H₁₄P)₂(N₃)]PF₆, the coordination sphere of Rh^III can be described as pseudo‐tetrahedral, composed of two P atoms from a 1,1′‐bis­(di­phenyl­phosphino)­ferrocene (dppf) ligand, an azido N atom and the centroid of the ring of a C₅Me₅ (Cp*) ligand. The two cyclo­penta­dienyl rings in the dppf moiety adopt an eclipsed conformation. The Rh⋯Fe distance is 4.340 (2) Å.     

Acid-catalyzed polycondensation of bisdiazoalkanes

Dimerization reactions of diphenyldiazomethane have been applied to the polycondensation of six bisdiazobenzyl arylenes, namely 1,4- and 1,3-bis(α-diazobenzyl)-benzenes C₆H₅CN₂? (C₆H₄)? CN₂C₆H₅; 1,4- and 1,3-bis(α-diazo-p-methoxybenzyl)-benzenes, p,p′-MeO? C₆H₄? CN₂? (C₆H₄)? CN₂C₆H₄? OMe; 4,4′-bis(α-diazobenzyl)-diphenylmethane, C₆H₅CN₂? (C₆H₄CH₂C₆H₄)? CN₂C₆H₅; and 4,4′-bis(α-diazobenyl)-diphenyl ether, C₆H₅CN₂? (C₆H₄? O? C₆H₄)CN₂C₆H₅. Depending on the nature of the catalysts, polyene-arylenes (? C(Ar)?C(Ar)? C₆H₄)_n, and polyazine-arylenes, (? C(Ar)?N? N? C(Ar)? C₆H₄? )_n, can be obtained selectively by acid-catalyzed decomposition of these bisdiazoalkanes at room temperature. With perchloric acid and with arylsulfonic acids in strong polar media, polyene-arylenes are formed. On the other hand, boron trifluoride and arylsulfonic acids in solvents of low dielectric constant afford polyazine-arylenes. Less selective is the thermal decomposition at 75°C in toluene solution; it gives a polymer containing about 90% azine and 10% olefinic groups. All these polymers are soluble in common solvents. Their molecular weight vary from 3 200 to 5 000, i.e., X?_n from 12 to 20. The polyene-arylenes are very stable and decompose only around 500°C; the polyazine-arylenes are less stable and decompose around 370°C by losing nitrogen.     

Homoatomic Rings,Chains and Macromolecules of Main Group Elements : edited by A.L. Rheingold. Elsevier Scientific Publishing Co., Amsterdam - Oxford - New York, 1977, xvi + 616 pages,Dfl. 195.00; U.S. $79.95.

Nucleophilic substitution is correlated with the frontier electron density parameter, the partial valence-inactive population (P^LUMO_A) for two series of polyene-M(CO)₃ complexes, AM(CO)₃ (A = C₆H₆Cr, C₅H₅Mn, C₄H₄Fe, C₃H₅Co and C₂H₄Ni) and [BFe(CO)₃]⁺ (B = C₅H₅, C₆H₇ and C₇H₉). In both series nucleophilic substitution by an S_N2 process is shown as probably occurring by initial attack at the metal atom.     

Five-Membered Ruthenacycles: Ligand-Assisted Alkyne Insertion into 1,3-N,S-Chelated Ruthenium Borate Species

Building upon previous work, the chemistry of [(η⁶-p-cymene)Ru{P(OMe)₂OR}Cl₂], (R=H or Me) has been extended with [H₂B(mbz)₂]⁻ (mbz=2-mercaptobenzothiazolyl) using different Ru precursors and borate ligands. As a result, a series of 1,3-N,S-chelated ruthenium borate complexes, for example, [(κ²-N,S-L)PR₃Ru{κ³-H,S,S’−H₂B(L)₂}], ( 2 a – d and 2 a’ – d’ ; R=Ph, Cy, OMe or OPh and L=C₅H₄NS or C₇H₄NS₂) and [Ru{κ³-H,S,S’-H₂B(L)₂}₂], ( 3 : L=C₅H₄NS, 3’ : L=C₇H₄NS₂) were isolated upon treatment of [(η⁶-p-cymene)RuCl₂PR₃], 1 a – d (R=Ph, Cy, OMe or OPh) with [H₂B(mp)₂]⁻ or [H₂B(mbz)₂]⁻ ligands (mp=2-mercaptopyridyl). All the Ru borate complexes, 2 a – d and 2 a’ – d’ are stabilized by phosphine/phosphite and hemilabile N,S-chelating ligands. Treatment of these Ru borate species, 2 a’ – c’ with various terminal alkynes yielded two different types of five-membered ruthenacycle species, namely [PR₃{C₇H₄S₂-(E)-N-C=CH(R ’ )}Ru{κ³-H,S,S ’ −H₂B(L)₂}], ( 4 – 4’ ; R=Ph and R ’ =CO₂Me or C₆H₄NO₂; L=C₇H₄NS₂) and [PR₃{C₇H₄NS-(E)-S-C=CH(R ’ )}Ru{κ³-H,S,S ’ −H₂B(L)₂}], ( 5 – 5’ , 6 and 7 ; R=Ph, Cy or OMe and R ’ =CO₂Me or C₆H₄NO₂; L=C₇H₄NS₂). All these five-membered ruthenacycle species contain an exocyclic C=C moiety, presumably formed by the insertion of a terminal alkyne into the Ru−N and Ru−S bonds. The new species have been characterized spectroscopically and the structures were further confirmed by single-crystal X-ray diffraction analysis. Theoretical studies and chemical-bonding analyses established that charge transfer occurs from phosphorus to ruthenium center following the trend PCy₃<PPh₃<P(OPh)₃<P(OMe)₃.