Formation and Stereochemistry of Octahedral Cationic Hydride-Azavinylidene Osmium(IV) Complexes

Abstract

The complexes [OsHCl 2 (=N=CR 2 )(PiPr 3 ) 2 ] [CR 2 = CMe 2 (1), C a (CH 2 ) 4 C b H 2 (C a -C b ) (3)] react with Ag(CF 3 SO 3 ) in the presence of ligands L [H 2 O, P(OMe) 3 , CO]. The reactions in the presence of water lead to [OsHCl(=N=CR 2 which exist as 1:1 equilibrium mixtures of the isomers 2a/4a (hydride trans to Cl) and 2c/4c (hydride trans to water) in the solid state and in solution. The structure of 2c has been determined by an X-ray diffraction study. The geometry around the metal center can be described as a distorted octahedron with trans phosphane ligands at opposite sites of an ideal coordination plane defined by the other four ligands. The reactions in the presence of P(OMe) 3 afford [OsHCl(=N= CR 2 ){P(OMe) 3 }(PiPr 3 ) 2 ][CF 3 SO 3 ] [CR 2 = CMe 2 (5a), C a (CH 2 ) 4 C b H 2 (C a -C b ) (6a)], with the hydride and chlorine ligands trans disposed. Complexes 5a and 6a can be also ob-

Ortho -CH Activation of Aromatic Ketones, Partially Fluorinated Aromatic Ketones, and Aromatic Imines by a Trihydride-Stannyl-Osmium(IV) Complex

“…The Os−N bond length of 2.094(3) Å and the Os−C(1) bond distance of 2.108(4) Å are typical for Os−N and Os−C(aryl) single bonds, respectively, and are in agreement with the values previously found for the complexes (2.078(18) and 2.080(19) Å, and 2.10(2) and 2.137(19) Å),13a (2.097(3) and 2.069(4) Å),19f (2.106(7) and 2.089(7) Å),13a (2.083(4) and 2.072(4) Å), (2.119(5) and 2.100(7) Å), and fac- Os{ C , N -3-Me[2-(MeC 6 H 4 )NCMe 3 ]C 6 H 3 }(2-MeC 6 H 4 )(CN- t Bu) 3 (2.193(24) and 2.077(20) Å) . The N−C(7) distance of 1.295(5) Å is similar to those observed in imine transition metal complexes, azavinylidene compounds, organic azaallenium cation, and 2-azaallenyl complexes …”

Ortho -CH Activation of Aromatic Ketones, Partially Fluorinated Aromatic Ketones, and Aromatic Imines by a Trihydride-Stannyl-Osmium(IV) Complex

“…The Os−N bond length of 2.094(3) Å and the Os−C(1) bond distance of 2.108(4) Å are typical for Os−N and Os−C(aryl) single bonds, respectively, and are in agreement with the values previously found for the complexes (2.078(18) and 2.080(19) Å, and 2.10(2) and 2.137(19) Å),13a (2.097(3) and 2.069(4) Å),19f (2.106(7) and 2.089(7) Å),13a (2.083(4) and 2.072(4) Å), (2.119(5) and 2.100(7) Å), and fac- Os{ C , N -3-Me[2-(MeC 6 H 4 )NCMe 3 ]C 6 H 3 }(2-MeC 6 H 4 )(CN- t Bu) 3 (2.193(24) and 2.077(20) Å) . The N−C(7) distance of 1.295(5) Å is similar to those observed in imine transition metal complexes, azavinylidene compounds, organic azaallenium cation, and 2-azaallenyl complexes …”

Reduction of Benzonitriles via Osmium–Azavinylidene Intermediates Bearing Nucleophilic and Electrophilic Centers

“…These six-coordinate osmium­(IV) species undergo distortion to destabilize one of the t 2g set orbitals and to stabilize the other two, resulting in them being diamagnetic. Surprisingly, in contrast to 3 , complexes OsHCl 2 (NCC 5 H 10 )­(P i Pr 3 ) 2 , OsCl 3 (NCC 5 H 10 )­(P i Pr 3 ) 2 , and [OsHCl­(NCMe 2 )­(H 2 O)­(P i Pr 3 ) 2 ] + display octahedral structures with angles in the plane perpendicular to the P–Os–P direction closer to the ideal value of 90°, despite the fact that they are also six-coordinated osmium­(IV)–azavinylidene species. The structures of the latter resemble those of the hydride–osmium–carbyne derivatives OsHCl 2 (CR)­(P i Pr 3 ) 2 and [OsH­(CR)­(NCCH 3 ) 2 (P i Pr 3 ) 2 ] 2+ .…”

Diiron-aminocarbyne complexes with amine or imine ligands: C–N coupling between imine and aminocarbyne ligands promoted by tolylacetylide addition to [Fe2{μ-CN(Me)R}(μ-CO)(CO)(NH CPh2)(Cp)2][SO3CF3]

“…Our findings show that the reactions proceed with replacement of the nitrile ligand; thus the observed products are the amine complexes 5b and 7, respectively, obtained in comparable yields with respect to the synthesis (20) 3.098 (14) Å , N(2)Á Á ÁO(10 0 ) 3.001(12) Å . Table 1 Selected bond lengths (Å ) and angles (°) for complex 4a (14) Fe(1)-C (11) 1.729 (12) C(15)-O(15) 1.206(15) Fe(1)-C (12) 1.895 (12) C(12)-N(1) 1.305(15) Fe(2)-C (12) 1.800 (13) N(1)-C(13) 1.48(2) Fe(1)-C(15) 1.938 (14) N(1)-C (14) 1.480 (18) (2) 82.4 (5) Fe(2)-N(2)-C(16) 120.1(9) C(12)-N(1)-C (13) 122.0(13) Fe(1)-C(12)-N(1) 135.9(10) C(12)-N(1)-C (14) 124.7 (13) Fe(2)-C(12)-N(1) 139.1 (10) reported in Scheme 1, and no addition at the coordinated MeCN has been revealed to any extent.…”

“…Support to the above assumptions comes by observing that compound 7, in which the aniline ligand cannot undergo bhydrogen transfer, does not form the hydride complex 14, under the same reaction conditions. Stable azavynilidene complexes can be generated by deprotonation of coordinated imines [12]. However, we have recently reported that the azavinylidene complex [Fe 2 {l-CN(Me)(Xyl)}(l-CO)(CO){NC(C"CTol)Bu t }-(Cp) 2 ] is unstable and undergoes an intramolecular rearrangement, with coupling of the azavinylidene with the aminocarbyne ligands [13].…”

“…Fe(1)-Fe(2) 2.5353(9) C(12)-O(12) 1.144(4) Fe(1)-C (12) 1.741(4) C(13)-C (14) 1.341(4) Fe(1)-C (11) 1.842(4) C(14)-C(22) 1.537(4) Fe(2)-C (11) 2.002(4) C(22)-N(1) 1.503(4) Fe(1)-C (13) 1.898 (3) N(1)-C(35) 1.353(4) Fe(2)-C (13) 1.906 ( of the g 1 :g 2 vinylidene-diaminocarbene [Fe 2 {l-g 1 :g 2 -C@C(Ph)C(Ph) 2 N(H)CN(Me)(Xyl)}(l-CO)(CO)(Cp 2 )]- (16), in lower yields (31%), whereas the corresponding reaction with CH 3 (CH 2 ) 3 C"CLi resulted in a mixture of decomposition products. The formation of 15 is worth some more comments.…”

Ortho -CH Activation of Aromatic Ketones, Partially Fluorinated Aromatic Ketones, and Aromatic Imines by a Trihydride-Stannyl-Osmium(IV) Complex

“…The Os−N bond length of 2.094(3) Å and the Os−C(1) bond distance of 2.108(4) Å are typical for Os−N and Os−C(aryl) single bonds, respectively, and are in agreement with the values previously found for the complexes (2.078(18) and 2.080(19) Å, and 2.10(2) and 2.137(19) Å),13a (2.097(3) and 2.069(4) Å),19f (2.106(7) and 2.089(7) Å),13a (2.083(4) and 2.072(4) Å), (2.119(5) and 2.100(7) Å), and fac- Os{ C , N -3-Me[2-(MeC 6 H 4 )NCMe 3 ]C 6 H 3 }(2-MeC 6 H 4 )(CN- t Bu) 3 (2.193(24) and 2.077(20) Å) . The N−C(7) distance of 1.295(5) Å is similar to those observed in imine transition metal complexes, azavinylidene compounds, organic azaallenium cation, and 2-azaallenyl complexes …”

Reduction of Benzonitriles via Osmium–Azavinylidene Intermediates Bearing Nucleophilic and Electrophilic Centers

“…These six-coordinate osmium­(IV) species undergo distortion to destabilize one of the t 2g set orbitals and to stabilize the other two, resulting in them being diamagnetic. Surprisingly, in contrast to 3 , complexes OsHCl 2 (NCC 5 H 10 )­(P i Pr 3 ) 2 , OsCl 3 (NCC 5 H 10 )­(P i Pr 3 ) 2 , and [OsHCl­(NCMe 2 )­(H 2 O)­(P i Pr 3 ) 2 ] + display octahedral structures with angles in the plane perpendicular to the P–Os–P direction closer to the ideal value of 90°, despite the fact that they are also six-coordinated osmium­(IV)–azavinylidene species. The structures of the latter resemble those of the hydride–osmium–carbyne derivatives OsHCl 2 (CR)­(P i Pr 3 ) 2 and [OsH­(CR)­(NCCH 3 ) 2 (P i Pr 3 ) 2 ] 2+ .…”

Diiron-aminocarbyne complexes with amine or imine ligands: C–N coupling between imine and aminocarbyne ligands promoted by tolylacetylide addition to [Fe2{μ-CN(Me)R}(μ-CO)(CO)(NH CPh2)(Cp)2][SO3CF3]

“…Our findings show that the reactions proceed with replacement of the nitrile ligand; thus the observed products are the amine complexes 5b and 7, respectively, obtained in comparable yields with respect to the synthesis (20) 3.098 (14) Å , N(2)Á Á ÁO(10 0 ) 3.001(12) Å . Table 1 Selected bond lengths (Å ) and angles (°) for complex 4a (14) Fe(1)-C (11) 1.729 (12) C(15)-O(15) 1.206(15) Fe(1)-C (12) 1.895 (12) C(12)-N(1) 1.305(15) Fe(2)-C (12) 1.800 (13) N(1)-C(13) 1.48(2) Fe(1)-C(15) 1.938 (14) N(1)-C (14) 1.480 (18) (2) 82.4 (5) Fe(2)-N(2)-C(16) 120.1(9) C(12)-N(1)-C (13) 122.0(13) Fe(1)-C(12)-N(1) 135.9(10) C(12)-N(1)-C (14) 124.7 (13) Fe(2)-C(12)-N(1) 139.1 (10) reported in Scheme 1, and no addition at the coordinated MeCN has been revealed to any extent.…”

“…Support to the above assumptions comes by observing that compound 7, in which the aniline ligand cannot undergo bhydrogen transfer, does not form the hydride complex 14, under the same reaction conditions. Stable azavynilidene complexes can be generated by deprotonation of coordinated imines [12]. However, we have recently reported that the azavinylidene complex [Fe 2 {l-CN(Me)(Xyl)}(l-CO)(CO){NC(C"CTol)Bu t }-(Cp) 2 ] is unstable and undergoes an intramolecular rearrangement, with coupling of the azavinylidene with the aminocarbyne ligands [13].…”

“…Fe(1)-Fe(2) 2.5353(9) C(12)-O(12) 1.144(4) Fe(1)-C (12) 1.741(4) C(13)-C (14) 1.341(4) Fe(1)-C (11) 1.842(4) C(14)-C(22) 1.537(4) Fe(2)-C (11) 2.002(4) C(22)-N(1) 1.503(4) Fe(1)-C (13) 1.898 (3) N(1)-C(35) 1.353(4) Fe(2)-C (13) 1.906 ( of the g 1 :g 2 vinylidene-diaminocarbene [Fe 2 {l-g 1 :g 2 -C@C(Ph)C(Ph) 2 N(H)CN(Me)(Xyl)}(l-CO)(CO)(Cp 2 )]- (16), in lower yields (31%), whereas the corresponding reaction with CH 3 (CH 2 ) 3 C"CLi resulted in a mixture of decomposition products. The formation of 15 is worth some more comments.…”

Ortho -CH Activation of Aromatic Ketones, Partially Fluorinated Aromatic Ketones, and Aromatic Imines by a Trihydride-Stannyl-Osmium(IV) Complex

“…The Os−N bond length of 2.094(3) Å and the Os−C(1) bond distance of 2.108(4) Å are typical for Os−N and Os−C(aryl) single bonds, respectively, and are in agreement with the values previously found for the complexes (2.078(18) and 2.080(19) Å, and 2.10(2) and 2.137(19) Å),13a (2.097(3) and 2.069(4) Å),19f (2.106(7) and 2.089(7) Å),13a (2.083(4) and 2.072(4) Å), (2.119(5) and 2.100(7) Å), and fac- Os{ C , N -3-Me[2-(MeC 6 H 4 )NCMe 3 ]C 6 H 3 }(2-MeC 6 H 4 )(CN- t Bu) 3 (2.193(24) and 2.077(20) Å) . The N−C(7) distance of 1.295(5) Å is similar to those observed in imine transition metal complexes, azavinylidene compounds, organic azaallenium cation, and 2-azaallenyl complexes …”

Reduction of Benzonitriles via Osmium–Azavinylidene Intermediates Bearing Nucleophilic and Electrophilic Centers

“…These six-coordinate osmium­(IV) species undergo distortion to destabilize one of the t 2g set orbitals and to stabilize the other two, resulting in them being diamagnetic. Surprisingly, in contrast to 3 , complexes OsHCl 2 (NCC 5 H 10 )­(P i Pr 3 ) 2 , OsCl 3 (NCC 5 H 10 )­(P i Pr 3 ) 2 , and [OsHCl­(NCMe 2 )­(H 2 O)­(P i Pr 3 ) 2 ] + display octahedral structures with angles in the plane perpendicular to the P–Os–P direction closer to the ideal value of 90°, despite the fact that they are also six-coordinated osmium­(IV)–azavinylidene species. The structures of the latter resemble those of the hydride–osmium–carbyne derivatives OsHCl 2 (CR)­(P i Pr 3 ) 2 and [OsH­(CR)­(NCCH 3 ) 2 (P i Pr 3 ) 2 ] 2+ .…”

Diiron-aminocarbyne complexes with amine or imine ligands: C–N coupling between imine and aminocarbyne ligands promoted by tolylacetylide addition to [Fe2{μ-CN(Me)R}(μ-CO)(CO)(NH CPh2)(Cp)2][SO3CF3]

“…Our findings show that the reactions proceed with replacement of the nitrile ligand; thus the observed products are the amine complexes 5b and 7, respectively, obtained in comparable yields with respect to the synthesis (20) 3.098 (14) Å , N(2)Á Á ÁO(10 0 ) 3.001(12) Å . Table 1 Selected bond lengths (Å ) and angles (°) for complex 4a (14) Fe(1)-C (11) 1.729 (12) C(15)-O(15) 1.206(15) Fe(1)-C (12) 1.895 (12) C(12)-N(1) 1.305(15) Fe(2)-C (12) 1.800 (13) N(1)-C(13) 1.48(2) Fe(1)-C(15) 1.938 (14) N(1)-C (14) 1.480 (18) (2) 82.4 (5) Fe(2)-N(2)-C(16) 120.1(9) C(12)-N(1)-C (13) 122.0(13) Fe(1)-C(12)-N(1) 135.9(10) C(12)-N(1)-C (14) 124.7 (13) Fe(2)-C(12)-N(1) 139.1 (10) reported in Scheme 1, and no addition at the coordinated MeCN has been revealed to any extent.…”

“…Support to the above assumptions comes by observing that compound 7, in which the aniline ligand cannot undergo bhydrogen transfer, does not form the hydride complex 14, under the same reaction conditions. Stable azavynilidene complexes can be generated by deprotonation of coordinated imines [12]. However, we have recently reported that the azavinylidene complex [Fe 2 {l-CN(Me)(Xyl)}(l-CO)(CO){NC(C"CTol)Bu t }-(Cp) 2 ] is unstable and undergoes an intramolecular rearrangement, with coupling of the azavinylidene with the aminocarbyne ligands [13].…”

“…Fe(1)-Fe(2) 2.5353(9) C(12)-O(12) 1.144(4) Fe(1)-C (12) 1.741(4) C(13)-C (14) 1.341(4) Fe(1)-C (11) 1.842(4) C(14)-C(22) 1.537(4) Fe(2)-C (11) 2.002(4) C(22)-N(1) 1.503(4) Fe(1)-C (13) 1.898 (3) N(1)-C(35) 1.353(4) Fe(2)-C (13) 1.906 ( of the g 1 :g 2 vinylidene-diaminocarbene [Fe 2 {l-g 1 :g 2 -C@C(Ph)C(Ph) 2 N(H)CN(Me)(Xyl)}(l-CO)(CO)(Cp 2 )]- (16), in lower yields (31%), whereas the corresponding reaction with CH 3 (CH 2 ) 3 C"CLi resulted in a mixture of decomposition products. The formation of 15 is worth some more comments.…”