Syntheses and Spectroscopic and Structural Characterization of Silver(I) Complexes Containing Tertiary Phosphines and Hydrotris(pyrazol-1-yl)-, Hydrotris(4-bromopyrazol-1-yl)-, Hydrotris(3,5-dimethypyrazol-1-yl)-, and Hydrotris(3-methyl-2-thioxo-1-imidazolyl)borates

Abstract

(Trialkyl- and (triarylphosphine)silver(I) derivatives containing anionic tris(1H-pyrazol-1-yl)borates were prepared from AgX (X = CF3SO3 or NO3), PR3 (R = phenyl, benzyl, cyclohexyl, 2,4,6-trimethylphenyl, or o-, m-, and p-tolyl) or PMePh2, and M[HB(pz)3] [M = K or Na; pzH = pyrazole in general; in detail, pyrazole (PzH), 3,5-dimethylpyrazole (3,5-Me2PzH), or 4-bromopyrazole (4-BrPzH)] and characterized through analytical and spectral (IR; 1H, 13C, and 31P NMR) measurements. These air stable, light-sensitive complexes are not electrolytes in CH2Cl2 and acetone. In these solvents they decompose even with strict exclusion of oxygen and light. The solid-state structures show that the silver atom adopts a distorted tetrahedral geometry. Crystal data with Mo Kα (λ = 0.710 70 Å) at 293 K: [HB(Pz)3]Ag(PPh3), C54H50Ag2B2N12P2, a = 15.082(2) Å, b = 19.728(2) Å, c = 9.432(1) Å, α = 94.8(1)°, β = 107.4(1)°, γ = 87.8(1)°, triclinic, P1̄, Z = 2; [HB(Pz)3]Ag[P(o-tolyl)3], C30H31AgBN6P, a = 14.461(2) Å, b = 14.461(2) Å, c = 30.473(2) Å, α = 90°, β = 90°, γ = 120°, trigonal, R3̄, Z = 6; [HB(Pz)3]AgP(Bz)3, C30H31AgBN6P, a = 12.183(2) Å, b = 18.596(2) Å, c = 13.804(2) Å, β = 100.8(1)°, monoclinic, P21/n, Z = 4; [HB(3,5-Me2Pz)3]Ag[P(p-tolyl)3], C36H41AgBN6P, a = 34.839(3) Å, b = 10.375(2) Å, c = 10.203(2) Å, β = 90.8(1)°, monoclinic, P21/n, Z = 4. Crystal data with Cu Kα (λ = 1.5418 Å): [HB(4-BrPz)3]AgPPh3, C27H22AgBBr3N6P2, a = 10.306(2) Å, b = 11.425(2) Å, c = 13.571(2) Å, α = 90.3(1)°, β = 107.0(1)°, γ = 91.4(1)°, triclinic, P1̄, Z = 2. The anionic soft S3-donor hydrotris(3-methyl-2-thioxo-1-imidazolyl)borate (Tm) was synthesized as its potassium salt from the corresponding imidazole and KBH4 in high yield. The potassium complex KTm was used as ligand transfer agent in the preparation of the silver(I) derivatives [(Tm)Ag] n and (Tm)Ag(PPh3). The S-donor 1-methylimidazolyl-2-thione (Hmimt) reacts with [HB(3,5-Me2Pz)3]Ag(PPh3), yielding the derivative [HB(3,5-Me2Pz)3](Hmimt)AgPPh3 in which the [HB(3,5-Me2Pz)3]- acts likely as bidentate N2-donor.

Mixed Alkyl‐Perfluoroalkyl Silver Scorpionates: Synthesis, X‐ray Structures and Stabilizing Substituent Effects

“…The calculated 1 J P-¹º⁷AG and ¹ J P-¹º⁹AG values (in 5 for example, 648 and 748 Hz, respectively), are higher than the ones encountered for typical Ag I complexes, but are not uncommon for silver scorpionates . The ⁵ J P‐F coupling was 7–8 Hz.…”

“…In the 1 H spectra, the diagnostic resonances of the boron‐bonded hydrogen appear, as expected,, as a quadrupolar broadend signal stretched over ca. 1 ppm and centered around 5 ppm, confirming the 1 H interaction with the 11 B quadrupole ( I = 3/2) . The 19 F resonances of the CF 3 and C 2 F 5 groups were consistently found at almost same values in all compounds, namely ca.…”

“…Coordination of toluene and phosphine ligands produced minimal shifts (<1 ppm), suggesting that the perfluoroalkyl spin system is not sensitive to electronic changes at the metal site. The 31 P NMR spectroscopic data matched previously reported observations, on signal multiplicities and Ag–P coupling constants in TpAg analogues. For the phosphine complexes 5 – 7 , the 31 P signals appear as two doublets, corresponding to the 107 Ag‐ 31 P and 109 Ag‐ 31 P couplings, and are further split into a fine pattern by 31 P– 19 F interactions (Figures a–c, S8, S12 and S15).…”

Mixed Alkyl‐Perfluoroalkyl Silver Scorpionates: Synthesis, X‐ray Structures and Stabilizing Substituent Effects

“…The calculated 1 J P-¹º⁷AG and ¹ J P-¹º⁹AG values (in 5 for example, 648 and 748 Hz, respectively), are higher than the ones encountered for typical Ag I complexes, but are not uncommon for silver scorpionates . The ⁵ J P‐F coupling was 7–8 Hz.…”

“…In the 1 H spectra, the diagnostic resonances of the boron‐bonded hydrogen appear, as expected,, as a quadrupolar broadend signal stretched over ca. 1 ppm and centered around 5 ppm, confirming the 1 H interaction with the 11 B quadrupole ( I = 3/2) . The 19 F resonances of the CF 3 and C 2 F 5 groups were consistently found at almost same values in all compounds, namely ca.…”

“…Coordination of toluene and phosphine ligands produced minimal shifts (<1 ppm), suggesting that the perfluoroalkyl spin system is not sensitive to electronic changes at the metal site. The 31 P NMR spectroscopic data matched previously reported observations, on signal multiplicities and Ag–P coupling constants in TpAg analogues. For the phosphine complexes 5 – 7 , the 31 P signals appear as two doublets, corresponding to the 107 Ag‐ 31 P and 109 Ag‐ 31 P couplings, and are further split into a fine pattern by 31 P– 19 F interactions (Figures a–c, S8, S12 and S15).…”

Pathway from a Molecular Precursor to Silver Nanoparticles: The Prominent Role of Aggregative Growth

“…The two doublets observed at -80 °C coalesced into a single resonance at -40 °C, and further sharpened at room temperature. Similar coalescence behavior was observed previously for other silver-phosphine complexes, 34,37 and was attributed to a dissociative equilibrium that exchanges bound and free phosphine ligands and therefore collapses the P-Ag J coupling.…”

Tl(I)-, Cu(I)-, and Ag(I) Complexes of the Ditopic 1,3-Phenylene-Bridged Heteroscorpionate Ligand [1,3-C6H4(tBuBpz2)2]2-

“…As in the case of 1Cu , decoalescence is likely due to the deceleration of intramolecular motions, leading to the formation of two rotamers in addition to the two isotopomers. The P−Ag coupling constants of 1Ag ( 1 J ( 31 P− 107 Ag) = 598 Hz, 1 J ( 31 P− 109 Ag) = 690 Hz) are in nice agreement with the values obtained for the related compounds [(pz 2 Bpz 2 )Ag(PPh 3 )] (223 K, CDCl 3 : δ( 31 P) = 16.8, dd, 1 J ( 31 P− 107 Ag) = 622 Hz, 1 J ( 31 P− 109 Ag) = 719 Hz) 15 and [(HBpz 3 )Ag(PPh 3 )] (223 K, CDCl 3 : δ( 31 P) = 17.0, dd, 1 J ( 31 P− 107 Ag) = 607 Hz, 1 J ( 31 P− 109 Ag) = 700 Hz) . In contrast, silver scorpionates bearing two tertiary phosphine ligands were reported to possess significantly smaller coupling constants (e.g., [(H 2 Bpz 2 )Ag(PPh 3 ) 2 ] (223 K, CDCl 3 : average value 1 J ( 31 P− 107/109 Ag) = 387 Hz), which leads to the conclusion that the Ag(I) ions in 1Ag are coordinated to one PPh 3 ligand only.…”

Mixed Alkyl‐Perfluoroalkyl Silver Scorpionates: Synthesis, X‐ray Structures and Stabilizing Substituent Effects

“…The calculated 1 J P-¹º⁷AG and ¹ J P-¹º⁹AG values (in 5 for example, 648 and 748 Hz, respectively), are higher than the ones encountered for typical Ag I complexes, but are not uncommon for silver scorpionates . The ⁵ J P‐F coupling was 7–8 Hz.…”

“…In the 1 H spectra, the diagnostic resonances of the boron‐bonded hydrogen appear, as expected,, as a quadrupolar broadend signal stretched over ca. 1 ppm and centered around 5 ppm, confirming the 1 H interaction with the 11 B quadrupole ( I = 3/2) . The 19 F resonances of the CF 3 and C 2 F 5 groups were consistently found at almost same values in all compounds, namely ca.…”

“…Coordination of toluene and phosphine ligands produced minimal shifts (<1 ppm), suggesting that the perfluoroalkyl spin system is not sensitive to electronic changes at the metal site. The 31 P NMR spectroscopic data matched previously reported observations, on signal multiplicities and Ag–P coupling constants in TpAg analogues. For the phosphine complexes 5 – 7 , the 31 P signals appear as two doublets, corresponding to the 107 Ag‐ 31 P and 109 Ag‐ 31 P couplings, and are further split into a fine pattern by 31 P– 19 F interactions (Figures a–c, S8, S12 and S15).…”

Pathway from a Molecular Precursor to Silver Nanoparticles: The Prominent Role of Aggregative Growth

“…The two doublets observed at -80 °C coalesced into a single resonance at -40 °C, and further sharpened at room temperature. Similar coalescence behavior was observed previously for other silver-phosphine complexes, 34,37 and was attributed to a dissociative equilibrium that exchanges bound and free phosphine ligands and therefore collapses the P-Ag J coupling.…”

Tl(I)-, Cu(I)-, and Ag(I) Complexes of the Ditopic 1,3-Phenylene-Bridged Heteroscorpionate Ligand [1,3-C6H4(tBuBpz2)2]2-

“…As in the case of 1Cu , decoalescence is likely due to the deceleration of intramolecular motions, leading to the formation of two rotamers in addition to the two isotopomers. The P−Ag coupling constants of 1Ag ( 1 J ( 31 P− 107 Ag) = 598 Hz, 1 J ( 31 P− 109 Ag) = 690 Hz) are in nice agreement with the values obtained for the related compounds [(pz 2 Bpz 2 )Ag(PPh 3 )] (223 K, CDCl 3 : δ( 31 P) = 16.8, dd, 1 J ( 31 P− 107 Ag) = 622 Hz, 1 J ( 31 P− 109 Ag) = 719 Hz) 15 and [(HBpz 3 )Ag(PPh 3 )] (223 K, CDCl 3 : δ( 31 P) = 17.0, dd, 1 J ( 31 P− 107 Ag) = 607 Hz, 1 J ( 31 P− 109 Ag) = 700 Hz) . In contrast, silver scorpionates bearing two tertiary phosphine ligands were reported to possess significantly smaller coupling constants (e.g., [(H 2 Bpz 2 )Ag(PPh 3 ) 2 ] (223 K, CDCl 3 : average value 1 J ( 31 P− 107/109 Ag) = 387 Hz), which leads to the conclusion that the Ag(I) ions in 1Ag are coordinated to one PPh 3 ligand only.…”

Mixed Alkyl‐Perfluoroalkyl Silver Scorpionates: Synthesis, X‐ray Structures and Stabilizing Substituent Effects

“…The calculated 1 J P-¹º⁷AG and ¹ J P-¹º⁹AG values (in 5 for example, 648 and 748 Hz, respectively), are higher than the ones encountered for typical Ag I complexes, but are not uncommon for silver scorpionates . The ⁵ J P‐F coupling was 7–8 Hz.…”

“…In the 1 H spectra, the diagnostic resonances of the boron‐bonded hydrogen appear, as expected,, as a quadrupolar broadend signal stretched over ca. 1 ppm and centered around 5 ppm, confirming the 1 H interaction with the 11 B quadrupole ( I = 3/2) . The 19 F resonances of the CF 3 and C 2 F 5 groups were consistently found at almost same values in all compounds, namely ca.…”

“…Coordination of toluene and phosphine ligands produced minimal shifts (<1 ppm), suggesting that the perfluoroalkyl spin system is not sensitive to electronic changes at the metal site. The 31 P NMR spectroscopic data matched previously reported observations, on signal multiplicities and Ag–P coupling constants in TpAg analogues. For the phosphine complexes 5 – 7 , the 31 P signals appear as two doublets, corresponding to the 107 Ag‐ 31 P and 109 Ag‐ 31 P couplings, and are further split into a fine pattern by 31 P– 19 F interactions (Figures a–c, S8, S12 and S15).…”

Pathway from a Molecular Precursor to Silver Nanoparticles: The Prominent Role of Aggregative Growth

“…The two doublets observed at -80 °C coalesced into a single resonance at -40 °C, and further sharpened at room temperature. Similar coalescence behavior was observed previously for other silver-phosphine complexes, 34,37 and was attributed to a dissociative equilibrium that exchanges bound and free phosphine ligands and therefore collapses the P-Ag J coupling.…”

Tl(I)-, Cu(I)-, and Ag(I) Complexes of the Ditopic 1,3-Phenylene-Bridged Heteroscorpionate Ligand [1,3-C6H4(tBuBpz2)2]2-

“…As in the case of 1Cu , decoalescence is likely due to the deceleration of intramolecular motions, leading to the formation of two rotamers in addition to the two isotopomers. The P−Ag coupling constants of 1Ag ( 1 J ( 31 P− 107 Ag) = 598 Hz, 1 J ( 31 P− 109 Ag) = 690 Hz) are in nice agreement with the values obtained for the related compounds [(pz 2 Bpz 2 )Ag(PPh 3 )] (223 K, CDCl 3 : δ( 31 P) = 16.8, dd, 1 J ( 31 P− 107 Ag) = 622 Hz, 1 J ( 31 P− 109 Ag) = 719 Hz) 15 and [(HBpz 3 )Ag(PPh 3 )] (223 K, CDCl 3 : δ( 31 P) = 17.0, dd, 1 J ( 31 P− 107 Ag) = 607 Hz, 1 J ( 31 P− 109 Ag) = 700 Hz) . In contrast, silver scorpionates bearing two tertiary phosphine ligands were reported to possess significantly smaller coupling constants (e.g., [(H 2 Bpz 2 )Ag(PPh 3 ) 2 ] (223 K, CDCl 3 : average value 1 J ( 31 P− 107/109 Ag) = 387 Hz), which leads to the conclusion that the Ag(I) ions in 1Ag are coordinated to one PPh 3 ligand only.…”