Abstract:A family of thio‐alkyne complexes [Tp′Mo(CO)(L)(BnSC2S)] {Bn = benzyl, Tp′ = hydrotris(3,5‐dimethylpyrazolyl)borate, L = carbonyl (2), 2,6‐dimethylphenyl isocyanide (7), tert‐butyl isocyanide (8), 4‐(dimethylamino)pyridine (9)} was prepared by reductive removal of a benzyl group in the corresponding bis(benzylthio)acetylene complexes [Tp′Mo(CO)(L)(BnSC2SBn)](PF6) (1‐PF6, 4‐PF6, 5‐PF6 and 6‐PF6). All complexes were characterized by IR, 1H, 13C spectroscopy and cyclic voltammetry. X‐ray diffraction studies of 5‐… Show more
“…However, at low temperatures we encountered serious solubility problems. We have recently shown that weaker π-acidic ligands like isocyanides in the alkyne complex distinctively lower the rotational barrier of the alkyne . Consistently, a single alkyne carbon resonance was observed in the room-temperature 13 C NMR spectrum of 6a and 6b .…”
Section: Resultsmentioning
confidence: 57%
“…The C1−S1 and C2−S2 bond distances of 1.668(8) and 1.670(7) Å are equal within the margin of error. The difference in the Mo−C1 and Mo−C2 bond distances (2.056(8) vs 2.108(7) Å) reflects contributions of resonance structure B (see Scheme ), but it is smaller compared with the differences found in the neutral complexes 2a / 2b / 2c . , The bend-back angles of 143.8° (C1−C2−S2) and 138.3° (C2−C1−S1), respectively, give rise to an intramolecular S1−S2 distance of 3.899 Å, which is far too large for a chelate coordination. 1 Molecular structure of the anion 3c - ; hydrogen atoms are omitted; 50% ellipsoid probability. 2 Synthesis of Metalla-Acetylendithiolato Complexes 2 Molecular structure of 4b ; hydrogen atoms are omitted; 50% ellipsoid probability.…”
Section: Resultsmentioning
confidence: 98%
“…Synthesis and Characterization of the Metalla-Acetylenedithiolate Ligands. According to the preparative procedure outlined in Scheme , stoichiometric one-electron reduction of [Tp‘(CO)(L)M(η 2 -BnSC 2 SBn)](PF 6 ) (Tp‘ = hydrotris(3,5-dimethylpyrazolyl)borate, Bn = benzyl, M = W, L = CO ( 1a ), M = Mo, L = 2,6-Me 2 C 6 H 3 NC ( 1b ), M = Mo, L = t -BuNC ( 1c )) led to the neutral complexes [Tp‘(CO)(L)M(η 2 -BnSC 2 S)] (M = W, L = CO ( 2a ), M = Mo, L = 2,6-Me 2 C 6 H 3 NC ( 2b ), M = Mo, L = t -BuNC ( 2c )), which were isolated in 50−70% yield by chromatography and subsequent crystallization. , Reaction of analytically pure 2a / 2b / 2c with 1 equiv of C 8 K in THF at −78 °C resulted in intensely colored solutions. Upon warming to ambient temperature, the solutions turned red-brown, and the potassium salts K[Tp‘(CO)(L)W(η 2 -C 2 S 2 )] (M = W, L = CO (K- 3a ), M = Mo, L = 2,6-Me 2 C 6 H 3 NC (K- 3b ), M = Mo, L = t -BuNC (K- 3c )) were precipitated.…”
Section: Resultsmentioning
confidence: 99%
“…All solvents were dried and saturated with argon by standard methods and freshly distilled prior to use. [Tp‘W(CO) 2 (BnSC 2 S)] ( 2a ), [Tp‘Mo(CO)(2,6-Me 2 C 6 H 3 NC)(BnSC 2 S)] ( 2b ), and [Tp‘Mo(CO)(Me 3 CNC)(BnSC 2 S)] ( 2c ) were prepared according to published procedures. , [(C 5 H 5 )Ru(CH 3 CN) 2 (PPh 3 )](PF 6 ), [(C 5 H 5 )Ru(CH 3 CN) 2 (2,6-Me 2 C 6 H 3 NC)](PF 6 ), and [Ni(CH 3 CN) 6 ](BF 4 ) were obtained by literature methods. NMR spectra were recorded on Bruker AC 200 and Bruker Avance 400 NMR spectrometers.…”
The generation of polynuclear complexes with one, two, or four acetylenedithiolate bridging units via the isolation of eta2-alkyne complexes of acetylenedithiolate K[Tp'M(CO)(L)(C2S2)] (Tp'=hydrotris(3,5-dimethylpyrazolyl)borate, M=W, L=CO (K-3a), M=Mo, L=CNC6H3Me2 (K-3b)) is reported. The strong electronic cooperation of Ru and W in the heterobimetallic complexes [(eta5-C5H5)(PPh3)Ru(3a)] (4a) and [(eta5-C5H5)(Me2C6H3NC)Ru(3a)] (4b) has been elucidated by correlation of the NMR, IR, UV-vis, and EPR-spectroscopic properties of the redox couples 4a/4a+ and 4b/4b+ with results from density functional calculations. Treatment of M(II) (M=Ni, Pd, Pt) with K-3a and K-3b afforded the homoleptic bis complexes [M(3a)2] (M=Ni (5a), Pd (5b), Pt (5c)), and [M(3b)2] (M=Pd (6a) and Pt (6b)), in which the metalla-acetylendithiolates exclusively serve as S,S'-chelate ligands. The vibrational and electronic spectra as well as the cyclic voltammetry behavior of all the complexes are compared. The structural analogy of 5a/5b/5c and 6a/6b with dithiolene complexes is only partly reflected in the electronic structures. The very intense visible absorptions involve essential d orbital contributions of the central metal, while the redox activity is primarily attributed to the alkyne complex moiety. Accordingly, stoichiometric reduction of 5a/5b/5c yields paramagnetic complex anions with electron-rich alkyne complex moieties being indistinguishable in the IR time scale. K-3a forms with Cu(I) the octanuclear cluster [Cu(3a)]4 (7) exhibiting a Cu4(S2C2)4W4 core. The nonchelating bridging mode of the metalla-acetylenedithiolate 3a- in 7 is recognized by a high-field shift of the alkyne carbon atoms in the 13C NMR spectrum. X-ray diffraction studies of K[Tp'(CO)(Me3CNC)Mo(eta2-C2S2)] (K-3c), 4b, 6a, 6b, and 7 are included. Comparison of the molecular structures of K-3c and 7 on the one hand with 4b and 6a/6b on the other reveals that the small bend-back angles in the latter are a direct consequence of the chelate ring formation.
“…However, at low temperatures we encountered serious solubility problems. We have recently shown that weaker π-acidic ligands like isocyanides in the alkyne complex distinctively lower the rotational barrier of the alkyne . Consistently, a single alkyne carbon resonance was observed in the room-temperature 13 C NMR spectrum of 6a and 6b .…”
Section: Resultsmentioning
confidence: 57%
“…The C1−S1 and C2−S2 bond distances of 1.668(8) and 1.670(7) Å are equal within the margin of error. The difference in the Mo−C1 and Mo−C2 bond distances (2.056(8) vs 2.108(7) Å) reflects contributions of resonance structure B (see Scheme ), but it is smaller compared with the differences found in the neutral complexes 2a / 2b / 2c . , The bend-back angles of 143.8° (C1−C2−S2) and 138.3° (C2−C1−S1), respectively, give rise to an intramolecular S1−S2 distance of 3.899 Å, which is far too large for a chelate coordination. 1 Molecular structure of the anion 3c - ; hydrogen atoms are omitted; 50% ellipsoid probability. 2 Synthesis of Metalla-Acetylendithiolato Complexes 2 Molecular structure of 4b ; hydrogen atoms are omitted; 50% ellipsoid probability.…”
Section: Resultsmentioning
confidence: 98%
“…Synthesis and Characterization of the Metalla-Acetylenedithiolate Ligands. According to the preparative procedure outlined in Scheme , stoichiometric one-electron reduction of [Tp‘(CO)(L)M(η 2 -BnSC 2 SBn)](PF 6 ) (Tp‘ = hydrotris(3,5-dimethylpyrazolyl)borate, Bn = benzyl, M = W, L = CO ( 1a ), M = Mo, L = 2,6-Me 2 C 6 H 3 NC ( 1b ), M = Mo, L = t -BuNC ( 1c )) led to the neutral complexes [Tp‘(CO)(L)M(η 2 -BnSC 2 S)] (M = W, L = CO ( 2a ), M = Mo, L = 2,6-Me 2 C 6 H 3 NC ( 2b ), M = Mo, L = t -BuNC ( 2c )), which were isolated in 50−70% yield by chromatography and subsequent crystallization. , Reaction of analytically pure 2a / 2b / 2c with 1 equiv of C 8 K in THF at −78 °C resulted in intensely colored solutions. Upon warming to ambient temperature, the solutions turned red-brown, and the potassium salts K[Tp‘(CO)(L)W(η 2 -C 2 S 2 )] (M = W, L = CO (K- 3a ), M = Mo, L = 2,6-Me 2 C 6 H 3 NC (K- 3b ), M = Mo, L = t -BuNC (K- 3c )) were precipitated.…”
Section: Resultsmentioning
confidence: 99%
“…All solvents were dried and saturated with argon by standard methods and freshly distilled prior to use. [Tp‘W(CO) 2 (BnSC 2 S)] ( 2a ), [Tp‘Mo(CO)(2,6-Me 2 C 6 H 3 NC)(BnSC 2 S)] ( 2b ), and [Tp‘Mo(CO)(Me 3 CNC)(BnSC 2 S)] ( 2c ) were prepared according to published procedures. , [(C 5 H 5 )Ru(CH 3 CN) 2 (PPh 3 )](PF 6 ), [(C 5 H 5 )Ru(CH 3 CN) 2 (2,6-Me 2 C 6 H 3 NC)](PF 6 ), and [Ni(CH 3 CN) 6 ](BF 4 ) were obtained by literature methods. NMR spectra were recorded on Bruker AC 200 and Bruker Avance 400 NMR spectrometers.…”
The generation of polynuclear complexes with one, two, or four acetylenedithiolate bridging units via the isolation of eta2-alkyne complexes of acetylenedithiolate K[Tp'M(CO)(L)(C2S2)] (Tp'=hydrotris(3,5-dimethylpyrazolyl)borate, M=W, L=CO (K-3a), M=Mo, L=CNC6H3Me2 (K-3b)) is reported. The strong electronic cooperation of Ru and W in the heterobimetallic complexes [(eta5-C5H5)(PPh3)Ru(3a)] (4a) and [(eta5-C5H5)(Me2C6H3NC)Ru(3a)] (4b) has been elucidated by correlation of the NMR, IR, UV-vis, and EPR-spectroscopic properties of the redox couples 4a/4a+ and 4b/4b+ with results from density functional calculations. Treatment of M(II) (M=Ni, Pd, Pt) with K-3a and K-3b afforded the homoleptic bis complexes [M(3a)2] (M=Ni (5a), Pd (5b), Pt (5c)), and [M(3b)2] (M=Pd (6a) and Pt (6b)), in which the metalla-acetylendithiolates exclusively serve as S,S'-chelate ligands. The vibrational and electronic spectra as well as the cyclic voltammetry behavior of all the complexes are compared. The structural analogy of 5a/5b/5c and 6a/6b with dithiolene complexes is only partly reflected in the electronic structures. The very intense visible absorptions involve essential d orbital contributions of the central metal, while the redox activity is primarily attributed to the alkyne complex moiety. Accordingly, stoichiometric reduction of 5a/5b/5c yields paramagnetic complex anions with electron-rich alkyne complex moieties being indistinguishable in the IR time scale. K-3a forms with Cu(I) the octanuclear cluster [Cu(3a)]4 (7) exhibiting a Cu4(S2C2)4W4 core. The nonchelating bridging mode of the metalla-acetylenedithiolate 3a- in 7 is recognized by a high-field shift of the alkyne carbon atoms in the 13C NMR spectrum. X-ray diffraction studies of K[Tp'(CO)(Me3CNC)Mo(eta2-C2S2)] (K-3c), 4b, 6a, 6b, and 7 are included. Comparison of the molecular structures of K-3c and 7 on the one hand with 4b and 6a/6b on the other reveals that the small bend-back angles in the latter are a direct consequence of the chelate ring formation.
“…In 2011 a double η 2 ‐S, C coordination mode ( B ) was reported, disclosed in a dinuclear Co complex of ethenedithione (S=C=C=S) 5. The alternative η 2 ‐C, C′ mode ( C ) is regularly observed in well‐understood intermediate products on the path to acdt 2– complexes,6 while first examples were originally described by Hill 7. The third type, an end‐on η 1 ‐S motif ( D ) was reported by Behrens , whose studies involve the coordination behavior of certain stable and therefore sterically encumbered thioketenes 8…”
The oxo tungsten(IV) alkyne complexes [Tp′W(O)(I)(η2‐C2Ph2)] (1), [Tp′W(O)(I){η2‐C2(SC2H4SiMe3)2}] (2), and [Tp′W(O)(I){η2‐C2(SBn)2}] (3) [Tp′ = hydridotris(3, 5‐dimethylpyrazolyl)borate, Bn = benzyl] were synthesized from [Tp′W(O)(CO)(I)]. All three compounds were fully characterized including structure determination by X‐ray diffraction analysis. Further elucidation of these reactions led to the isolation of several by‐products including an unexpected tungsten(IV) thioketene complex [Tp′W(O)(I){η2‐S = C=C(H)(SBn)}] (4), which is formed by removal of one Bn group from the alkyne, and dinuclear [Tp′W(O)(I)]2(μ‐O) (6). Both complexes were also fully characterized. X‐ray diffraction analysis reveals an η2‐S, C side‐on binding mode for 4 and a planar O–W–O–W–O moiety for 6. In addition, by changing the solvent from THF to dichloromethane formation of the chiral dihalogen complex [Tp′W(O)(Cl)(I)] (5) was proven.
The η 2 -alkyne complex [(η 5 -C 5 H 5 )Re(1)Br 2 ], 2, (1 = BnSC 2 SBn) reacts with an excess of the dithioalkyne 1 to give the addition product [(η 5 -C 5 H 5 )ReBr 2 {η 3 -(BnS) 2 C 2 C(SBn)-C(SBn)}], 3, displaying a ReC 3 ring with an exocyclic double bond. The molecular structures of the complexes 2 and 3 were determined by single-crystal X-ray diffraction. The nonplanarity of the ReC 3 ring and the largely equal C-C bond lengths within the ring reveal 3 to be a resonance hybrid of an allenylcarbene complex and a folded rhenacyclobutene system. DFT calculations show that complex type 3 is
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