Synthesis of a stable compound with fivefold bonding between two chromium(i) centers

Tailuan Nguyen; Andrew D. Sutton; Marcin Brynda; James C. Fettinger; Gary J. Long; Philip P. Power

doi:10.1126/science.1116789

Synthesis of a stable compound with fivefold bonding between two chromium(i) centers

Tailuan Nguyen, Andrew D. Sutton, Marcin Brynda, James C. Fettinger, Gary J. Long, Philip P. Power

Research output: Contribution to journal › Article › peer-review

473 Scopus citations

Abstract

Although in principle transition metals can form bonds with six shared electron pairs, only quadruply bonded compounds can be isolated as stable species at room temperature. Here we show that the reduction of {Cr(μ-Cl)Ar′}₂ [where Ar′ indicates C ₆H₃-2,6(C₆H₃-2,6-Prⁱ ₂)₂ and Prⁱ indicates isopropyl] with a slight excess of potassium graphite has produced a stable compound with fivefold chromium-chromium (Cr-Cr) bonding. The very air- and moisture-sensitive dark red crystals of Ar′CrCrAr′ were isolated with greater than 40% yield. X-ray diffraction revealed a Cr-Cr bond length of 1.8351(4) angstroms (where the number in parentheses indicates the standard deviation) and a planar transbent core geometry. These data, the structure's temperature-independent paramagnetism, and computational studies support the sharing of five electron pairs in five bonding molecular orbitals between two 3d⁵ chromium(I) ions.

Original language	English
Pages (from-to)	844-847
Number of pages	4
Journal	Science
Volume	310
Issue number	5749
DOIs	https://doi.org/10.1126/science.1116789
State	Published - Nov 4 2005
Externally published	Yes

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title = "Synthesis of a stable compound with fivefold bonding between two chromium(i) centers",

abstract = "Although in principle transition metals can form bonds with six shared electron pairs, only quadruply bonded compounds can be isolated as stable species at room temperature. Here we show that the reduction of {Cr(μ-Cl)Ar′}2 [where Ar′ indicates C 6H3-2,6(C6H3-2,6-Pri 2)2 and Pri indicates isopropyl] with a slight excess of potassium graphite has produced a stable compound with fivefold chromium-chromium (Cr-Cr) bonding. The very air- and moisture-sensitive dark red crystals of Ar′CrCrAr′ were isolated with greater than 40% yield. X-ray diffraction revealed a Cr-Cr bond length of 1.8351(4) angstroms (where the number in parentheses indicates the standard deviation) and a planar transbent core geometry. These data, the structure's temperature-independent paramagnetism, and computational studies support the sharing of five electron pairs in five bonding molecular orbitals between two 3d5 chromium(I) ions.",

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T1 - Synthesis of a stable compound with fivefold bonding between two chromium(i) centers

AU - Nguyen, Tailuan

AU - Sutton, Andrew D.

AU - Brynda, Marcin

AU - Fettinger, James C.

AU - Long, Gary J.

AU - Power, Philip P.

PY - 2005/11/4

Y1 - 2005/11/4

N2 - Although in principle transition metals can form bonds with six shared electron pairs, only quadruply bonded compounds can be isolated as stable species at room temperature. Here we show that the reduction of {Cr(μ-Cl)Ar′}2 [where Ar′ indicates C 6H3-2,6(C6H3-2,6-Pri 2)2 and Pri indicates isopropyl] with a slight excess of potassium graphite has produced a stable compound with fivefold chromium-chromium (Cr-Cr) bonding. The very air- and moisture-sensitive dark red crystals of Ar′CrCrAr′ were isolated with greater than 40% yield. X-ray diffraction revealed a Cr-Cr bond length of 1.8351(4) angstroms (where the number in parentheses indicates the standard deviation) and a planar transbent core geometry. These data, the structure's temperature-independent paramagnetism, and computational studies support the sharing of five electron pairs in five bonding molecular orbitals between two 3d5 chromium(I) ions.

AB - Although in principle transition metals can form bonds with six shared electron pairs, only quadruply bonded compounds can be isolated as stable species at room temperature. Here we show that the reduction of {Cr(μ-Cl)Ar′}2 [where Ar′ indicates C 6H3-2,6(C6H3-2,6-Pri 2)2 and Pri indicates isopropyl] with a slight excess of potassium graphite has produced a stable compound with fivefold chromium-chromium (Cr-Cr) bonding. The very air- and moisture-sensitive dark red crystals of Ar′CrCrAr′ were isolated with greater than 40% yield. X-ray diffraction revealed a Cr-Cr bond length of 1.8351(4) angstroms (where the number in parentheses indicates the standard deviation) and a planar transbent core geometry. These data, the structure's temperature-independent paramagnetism, and computational studies support the sharing of five electron pairs in five bonding molecular orbitals between two 3d5 chromium(I) ions.

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Synthesis of a stable compound with fivefold bonding between two chromium(i) centers

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