TY - JOUR
T1 - Thiapentadienyl-Iridium-Phosphine Chemistry
AU - Bleeke, John R.
AU - Ortwerth, Michael F.
AU - Rohde, Alicia M.
PY - 1995/6
Y1 - 1995/6
N2 - Potassium thiapentadienide (K+C4H5S-) reacts cleanly with ClIr(PMe3)3 in tetrahydrofuran at room temperature to generate ((1,2,5-η)-5-thiapentadienyl)Ir(PMe3)3(1). Treatment of 1 with H+BF4 -OEt2leads to protonation at Cl and production of [((2,3,4,5-η)-5-thiapentadiene)-Ir(PMe3)3]+BF4 -(2), while treatment with CH3O3SCF3results in methylation at sulfur and production of [((1,2,5-η)-5-methyl-5-thiapentadienyl)Ir(PMe3)3]+O3SCF3 - (3). Compound 3 isomerizes to [((l,2,3,4-η)-5-methyl-5-thiapentadiene)Ir(PMe3)3]+O3SCF3 -(4) at room temperature. Upon heating in toluene at reflux, compound 1 slowly converts to the iridathiacyclopentene complex mer-CH2=C—CH=CH—S—Ir(PMe3)3(H) (5), via intramolecular activation of the C—H2bond. Like compound 1, 5 undergoes protonation at C1 when treated with H+BF4 -.OEt2, producing the “iridathiophene” complex, [formula omited] (6), but undergoes methylation at sulfur when treated with CH3O3SCF3, generating [mer-CH2=C-CH=CH-S(CH3)-Ir(PMe3)3(H)]+O3SCF3 -(7). ((l,2,5-η)-5-Thiapentadienyl)Ir(PEt3)3(8), the tris(PEt3) analogue of 1, is produced upon reacting potassium thiapentadienide with ClIr(PEt3)3. Unlike 1, it undergoes intramolecular C—H bond activation upon stirring in tetrahydrofuran at room temperature. Initially, a mixture of the C—H1 bond activation product, mer-CH=CH—CH=CH—S—Ir(PEt3)3(H) (9), and the C-H2 bond activation product, mer-CH2=C—CH=CH—S—Ir(PEt3)3(H) (10), are produced. However, the six-membered ring compound (9) gradually converts to the thermodynamically-preferred five-membered ring compound (10). Like its tris(PMe3) analogue (5), compound 10 reacts with H+BF4 -.OEt2to produce the “iridathiophene” complex, [formula omited] (11), and with CH3O3SCF3to generate the S-methylated compound, [mer-CH2=C-CH=CH-S(CH)3-ir(PEt3)3(H)]+O3SCF3-(12). Excess Cl2 and I2 react with compound 11 exclusively at the metal center to produce the neutral dihalide compounds, [formula omited] (13, X = Cl; 14, X = I). In contrast, excess Br2 reacts with 11 at both the Ir center and C3 of the ring to form the electrophilic aromatic substitution product,[formula omited] (15). Molecular structures of mer-CH2=C—CH=CH-S—Ir(PMe3)3(H) (5) and [formula omited] (15) have been determined by single-crystal X-ray diffraction studies. Crystal structure data for these compounds are as follows: 5, orthorhombic, Pnma, a = 11.935(3) Å, b = 14.251(3) Å, c = 11.908(3) Å, V = 2025.3(7) Å3, Z = 4, R = 0.0206 for 1127 reflections with I > 3σ(I); 15, orthorhombic, Pca21 a = 14.825(4) Å, b = 10.110(2) Å, c = 15.757(4) Å, V =2361.7(10) Å3, Z =4, R = 0.0388 for 3762 reflections with I > 3σ(I).
AB - Potassium thiapentadienide (K+C4H5S-) reacts cleanly with ClIr(PMe3)3 in tetrahydrofuran at room temperature to generate ((1,2,5-η)-5-thiapentadienyl)Ir(PMe3)3(1). Treatment of 1 with H+BF4 -OEt2leads to protonation at Cl and production of [((2,3,4,5-η)-5-thiapentadiene)-Ir(PMe3)3]+BF4 -(2), while treatment with CH3O3SCF3results in methylation at sulfur and production of [((1,2,5-η)-5-methyl-5-thiapentadienyl)Ir(PMe3)3]+O3SCF3 - (3). Compound 3 isomerizes to [((l,2,3,4-η)-5-methyl-5-thiapentadiene)Ir(PMe3)3]+O3SCF3 -(4) at room temperature. Upon heating in toluene at reflux, compound 1 slowly converts to the iridathiacyclopentene complex mer-CH2=C—CH=CH—S—Ir(PMe3)3(H) (5), via intramolecular activation of the C—H2bond. Like compound 1, 5 undergoes protonation at C1 when treated with H+BF4 -.OEt2, producing the “iridathiophene” complex, [formula omited] (6), but undergoes methylation at sulfur when treated with CH3O3SCF3, generating [mer-CH2=C-CH=CH-S(CH3)-Ir(PMe3)3(H)]+O3SCF3 -(7). ((l,2,5-η)-5-Thiapentadienyl)Ir(PEt3)3(8), the tris(PEt3) analogue of 1, is produced upon reacting potassium thiapentadienide with ClIr(PEt3)3. Unlike 1, it undergoes intramolecular C—H bond activation upon stirring in tetrahydrofuran at room temperature. Initially, a mixture of the C—H1 bond activation product, mer-CH=CH—CH=CH—S—Ir(PEt3)3(H) (9), and the C-H2 bond activation product, mer-CH2=C—CH=CH—S—Ir(PEt3)3(H) (10), are produced. However, the six-membered ring compound (9) gradually converts to the thermodynamically-preferred five-membered ring compound (10). Like its tris(PMe3) analogue (5), compound 10 reacts with H+BF4 -.OEt2to produce the “iridathiophene” complex, [formula omited] (11), and with CH3O3SCF3to generate the S-methylated compound, [mer-CH2=C-CH=CH-S(CH)3-ir(PEt3)3(H)]+O3SCF3-(12). Excess Cl2 and I2 react with compound 11 exclusively at the metal center to produce the neutral dihalide compounds, [formula omited] (13, X = Cl; 14, X = I). In contrast, excess Br2 reacts with 11 at both the Ir center and C3 of the ring to form the electrophilic aromatic substitution product,[formula omited] (15). Molecular structures of mer-CH2=C—CH=CH-S—Ir(PMe3)3(H) (5) and [formula omited] (15) have been determined by single-crystal X-ray diffraction studies. Crystal structure data for these compounds are as follows: 5, orthorhombic, Pnma, a = 11.935(3) Å, b = 14.251(3) Å, c = 11.908(3) Å, V = 2025.3(7) Å3, Z = 4, R = 0.0206 for 1127 reflections with I > 3σ(I); 15, orthorhombic, Pca21 a = 14.825(4) Å, b = 10.110(2) Å, c = 15.757(4) Å, V =2361.7(10) Å3, Z =4, R = 0.0388 for 3762 reflections with I > 3σ(I).
UR - https://www.scopus.com/pages/publications/33751156972
U2 - 10.1021/om00006a030
DO - 10.1021/om00006a030
M3 - Article
AN - SCOPUS:33751156972
SN - 0276-7333
VL - 14
SP - 2813
EP - 2826
JO - Organometallics
JF - Organometallics
IS - 6
ER -