Synthesis and Structure of a Five-Coordinate Organochromium(III) Thiolate Complex from a Chromium(II) Alkyl Precursor

Abstract

The reaction of the Cr(II) methyl complex, CrMe[N(SiMe2CH2PPh2)2], with diphenyl disulfide (PhSSPh) leads to the formation of the five-coordinate, paramagnetic complex CrMe(SPh)[N(SiMe2CH2PPh2)2] by an overall one-electron oxidation. The complex is unusual in that the phenyl thiolate moiety is terminal and does not engage in bridging to generate a dinuclear system having octahedral Cr(III) centers. The complex was characterized both in solution and in the solid state.

Phenylchromium(III) Chemistry Revisited 100 Years after Franz Hein (Part I)

“…For molecules A and B, τ values of 0.05 and 0.09 were determined. The structure of [{(dme)­Li} 2 CrPh 5 ] ( 5-Li ) represents a rare example of organometallic penta-coordinate chromium­(III) complexes. ,, The Cr1–C bond lengths to the ipso -carbon atoms of the phenyl groups in the square plane are significantly larger than the Cr1–C1 distance to the apical phenyl group. This finding is caused by additional interactions to the lithium atoms.…”

One-electron oxidation of paramagnetic chromium(II) alkyl complexes with alkyl halides: synthesis and structure of five-coordinate chromium(III) complexes

“…The structure reveals a distorted five-coordinate Cr() centre; the complex could be considered as a square-pyramid with the methyl C (31) (µ-Cl) 2 , 34 and is much longer than the 2.054(5) Å found in the related five-coordinate Cr(Me)SPh[N(SiMe 2 CH 2 PPh 2 ) 2 ] complex. 27 The Cr-C bond length in 2 is also longer than the bond in the starting complex CrMe[N(SiMe 19 On the other hand, the Cr-N bond length of 2.009(4) Å in 2 is significantly shorter than in 1 [2.117(3) Å]. This fact, coupled with the observed lengthening of the Si-N bonds in the product 2 [1.712(5) 43 This long bond length in the methyl bromide complex 2 implies that there is little or no π-donation from the bromide to the metal in this complex; short Cr-Br bond lengths of 2.393(4) and 2.375(5) Å in Cp*CrOBr 2 were interpreted as being due to extensive bromide to metal π-donation.…”

“…The recently reported Cr(Me)SPh[N(SiMe 2 CH 2 PPh 2 ) 2 ] complex has a trans-P-Cr-P angle of 166.30(6)Њ and equatorial angles of 150.0(1)Њ, 92.8(2)Њ and 117.2(2)Њ. 27 Steric effects are also important and must be taken into consideration. Of course, the incorporation of different ligands into a complex reduces the symmetry, resulting in the degeneracy of the two d-orbitals in question being removed to a certain extent.…”

Phenylchromium(III) Chemistry Revisited 100 Years after Franz Hein (Part II): From LinCrPh3+n(thf)x (n = 1, 2, 3) to Dimeric Triphenylchromate(II) Complexes

“…The penta-coordinate chromium atom is σ-bound to five phenyl groups, leading to a distorted square pyramid (τ = 0.25). Complex 5-thf-OEt 2 is one of the rather rare examples for mononuclear chromium­(III) organometallics with the coordination number of 5. , The deformation of the square pyramid is caused by the different coordination environments of Li1 and Li2. The Cr1–C1 bond length to the tip of the pyramid is approximately 10 pm smaller than the Cr1–C distances to the ipso-carbon atoms of the square plane.…”

“…NMR (400.1 MHz, in C 6 D 6 ): 2-π: δ 4.08 (12H, s, η 6 -C 6 H 6 ) 65. 3-π: δ 4.18 (1H, t, p-CH, η 6 -Ph), 4 25. (2H, t, m-CH, η 6 -Ph), 4.73 (2H, d, J = 5.2 Hz, o-CH, η 6 -Ph).…”