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Crystal structures of two unusual, high oxidation state, 16-electron irida-benzenes.

Chase DT, Zakharov LN, Haley MM - Acta Crystallogr E Crystallogr Commun (2015)

Bottom Line: Treatment of carbon-yl(1,2-diphenylpenta-1,3-dien-1-yl-5-yl-idene)bis-(tri-phenyl-phosphane)iridium, [IrCO(-C(Ph)=C(Ph)-CH=CH-CH=)(PPh3)2], with either bromine or iodine produced di-bromido-(1,2-diphenylpenta-1,3-dien-1-yl-5-yl-idene)(tri-phenyl-phosphine)iridium(III), [IrBr2{-C(Ph)=C(Ph)-CH=CH-CH=}(PPh3)], (I), and (1,2-diphenylpenta-1,3-dien-1-yl-5-yl-idene)di-iodido-(tri-phenyl-phosphane)iridium(III), [IrI2{-C(Ph)=C(Ph)-CH=CH-CH=}(PPh3)], (II), respectively, which are two rare examples of 16-electron metalla-benzenes.Structural elucidation of (I) and (II) reveals that these isotypic irida-benzenes are unusual, not only in their electron count, but also in their coordination sphere of the Ir(III) atom where they contain an apparent open coordination site.The coordination geometry of the Ir(III) atom in both structures can be best described as a distorted square pyramid with the P, two Br (or I) and one C atom in the basal plane and another C atom in the apical position.

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Affiliation: Department of Chemistry & Biochemistry and Materials Science Institute, University of Oregon, Eugene, Oregon 97403-1253, USA.

ABSTRACT
Treatment of carbon-yl(1,2-diphenylpenta-1,3-dien-1-yl-5-yl-idene)bis-(tri-phenyl-phosphane)iridium, [IrCO(-C(Ph)=C(Ph)-CH=CH-CH=)(PPh3)2], with either bromine or iodine produced di-bromido-(1,2-diphenylpenta-1,3-dien-1-yl-5-yl-idene)(tri-phenyl-phosphine)iridium(III), [IrBr2{-C(Ph)=C(Ph)-CH=CH-CH=}(PPh3)], (I), and (1,2-diphenylpenta-1,3-dien-1-yl-5-yl-idene)di-iodido-(tri-phenyl-phosphane)iridium(III), [IrI2{-C(Ph)=C(Ph)-CH=CH-CH=}(PPh3)], (II), respectively, which are two rare examples of 16-electron metalla-benzenes. Structural elucidation of (I) and (II) reveals that these isotypic irida-benzenes are unusual, not only in their electron count, but also in their coordination sphere of the Ir(III) atom where they contain an apparent open coordination site. The crystal structures of (I) and (II) confirm that the mol-ecules are complexes containing five-coordinated Ir(III) with only one tri-phenyl-phosphine group bound to the iridium atom, unambiguously proving that the mol-ecules are indeed 16-electron, high-oxidation-state irida-benzenes. The coordination geometry of the Ir(III) atom in both structures can be best described as a distorted square pyramid with the P, two Br (or I) and one C atom in the basal plane and another C atom in the apical position.

No MeSH data available.


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The mol­ecular structure of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.
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fig1: The mol­ecular structure of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.

Mentions: Compounds (I), [IrBr2(C17H13)(C18H15P)], and (II), [IrI2(C17H13)(C18H15P)], are isotypic. The mol­ecular structures of (I) (Fig. 1 ▸) and (II) (Fig. 2 ▸) confirm that IrIII is five-coordinated in these complexes with only one tri­phenyl­phosphine group bound to the iridium atom, unambiguously proving that the mol­ecules are indeed 16-electron, high-oxidation-state irida­benzenes. The coordination geometry of the IrIII atom in both structures can be best described as a distorted square pyramid with the P1, Br1(I1), Br2(I2) and C1 atoms in the basal plane and the C5 atom in the apical position. The Br1(I1), Br2(I2), P1, C1 fragments are planar within 0.17 Å (Br) and 0.21 Å (I) and the Ir atom is out on 0.22 Å (Br) and 0.24 Å (I) from the average planes of this fragment. The C—C bond lengths in the benzene rings in both structures range from 1.360 (15) to 1.402 (16) Å [average 1.387 and 1.382 Å in (I) and (II), respectively], indicative of bond homogenization and electron delocalization. Both Ir—C bond lengths [1.958 (5), 1.903 (5) Å, and 1.963 (11), 1.913 (12) Å, respectively, for Ir—C1 and Ir—C5 in (I) and (II)] are shorter than typical IrI irida­benzenes (2.01–2.05 Å), reflecting the higher IrIII oxidation state (Fernández & Frenking, 2007 ▸).


Crystal structures of two unusual, high oxidation state, 16-electron irida-benzenes.

Chase DT, Zakharov LN, Haley MM - Acta Crystallogr E Crystallogr Commun (2015)

The mol­ecular structure of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4645090&req=5

fig1: The mol­ecular structure of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.
Mentions: Compounds (I), [IrBr2(C17H13)(C18H15P)], and (II), [IrI2(C17H13)(C18H15P)], are isotypic. The mol­ecular structures of (I) (Fig. 1 ▸) and (II) (Fig. 2 ▸) confirm that IrIII is five-coordinated in these complexes with only one tri­phenyl­phosphine group bound to the iridium atom, unambiguously proving that the mol­ecules are indeed 16-electron, high-oxidation-state irida­benzenes. The coordination geometry of the IrIII atom in both structures can be best described as a distorted square pyramid with the P1, Br1(I1), Br2(I2) and C1 atoms in the basal plane and the C5 atom in the apical position. The Br1(I1), Br2(I2), P1, C1 fragments are planar within 0.17 Å (Br) and 0.21 Å (I) and the Ir atom is out on 0.22 Å (Br) and 0.24 Å (I) from the average planes of this fragment. The C—C bond lengths in the benzene rings in both structures range from 1.360 (15) to 1.402 (16) Å [average 1.387 and 1.382 Å in (I) and (II), respectively], indicative of bond homogenization and electron delocalization. Both Ir—C bond lengths [1.958 (5), 1.903 (5) Å, and 1.963 (11), 1.913 (12) Å, respectively, for Ir—C1 and Ir—C5 in (I) and (II)] are shorter than typical IrI irida­benzenes (2.01–2.05 Å), reflecting the higher IrIII oxidation state (Fernández & Frenking, 2007 ▸).

Bottom Line: Treatment of carbon-yl(1,2-diphenylpenta-1,3-dien-1-yl-5-yl-idene)bis-(tri-phenyl-phosphane)iridium, [IrCO(-C(Ph)=C(Ph)-CH=CH-CH=)(PPh3)2], with either bromine or iodine produced di-bromido-(1,2-diphenylpenta-1,3-dien-1-yl-5-yl-idene)(tri-phenyl-phosphine)iridium(III), [IrBr2{-C(Ph)=C(Ph)-CH=CH-CH=}(PPh3)], (I), and (1,2-diphenylpenta-1,3-dien-1-yl-5-yl-idene)di-iodido-(tri-phenyl-phosphane)iridium(III), [IrI2{-C(Ph)=C(Ph)-CH=CH-CH=}(PPh3)], (II), respectively, which are two rare examples of 16-electron metalla-benzenes.Structural elucidation of (I) and (II) reveals that these isotypic irida-benzenes are unusual, not only in their electron count, but also in their coordination sphere of the Ir(III) atom where they contain an apparent open coordination site.The coordination geometry of the Ir(III) atom in both structures can be best described as a distorted square pyramid with the P, two Br (or I) and one C atom in the basal plane and another C atom in the apical position.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry & Biochemistry and Materials Science Institute, University of Oregon, Eugene, Oregon 97403-1253, USA.

ABSTRACT
Treatment of carbon-yl(1,2-diphenylpenta-1,3-dien-1-yl-5-yl-idene)bis-(tri-phenyl-phosphane)iridium, [IrCO(-C(Ph)=C(Ph)-CH=CH-CH=)(PPh3)2], with either bromine or iodine produced di-bromido-(1,2-diphenylpenta-1,3-dien-1-yl-5-yl-idene)(tri-phenyl-phosphine)iridium(III), [IrBr2{-C(Ph)=C(Ph)-CH=CH-CH=}(PPh3)], (I), and (1,2-diphenylpenta-1,3-dien-1-yl-5-yl-idene)di-iodido-(tri-phenyl-phosphane)iridium(III), [IrI2{-C(Ph)=C(Ph)-CH=CH-CH=}(PPh3)], (II), respectively, which are two rare examples of 16-electron metalla-benzenes. Structural elucidation of (I) and (II) reveals that these isotypic irida-benzenes are unusual, not only in their electron count, but also in their coordination sphere of the Ir(III) atom where they contain an apparent open coordination site. The crystal structures of (I) and (II) confirm that the mol-ecules are complexes containing five-coordinated Ir(III) with only one tri-phenyl-phosphine group bound to the iridium atom, unambiguously proving that the mol-ecules are indeed 16-electron, high-oxidation-state irida-benzenes. The coordination geometry of the Ir(III) atom in both structures can be best described as a distorted square pyramid with the P, two Br (or I) and one C atom in the basal plane and another C atom in the apical position.

No MeSH data available.


Related in: MedlinePlus