Crystal and molecular structure of the tetrahydrofuran adduct of (vinylgallium)tetracarbonyliron, [(THF)(C2H3)GaFe(CO)4]2: comparison with isoelectronic zinc and germanium dimers

Abstract

An X-ray diffraction study of [(THF)(C2H3)GaFe(CO)4]2 (THF = tetrahydrofuran) reveals a dimeric, planar, four-membered, metal-metal-bonded ring structure analogous to the isoelectronic [(bpy)ZnFe(CO)4]2 and [(C2H5)2GeFe(CO)4]2 structures (bpy = 2,2'-bipyridine). Several distortions are observed in the structure that can be attributed to partial ionic character and the resultant bending of the axial carbonyl ligands over the metal ring. These distortions are intermediate in degree between those observed in the above-mentioned isoelectronic dimers and include a contraction of the M-Fe-M bond angle and a twisting of the idealized Fe(CO)4 tetrahedra to opposite sides of the centrosymmetric dimers. The distortions arise in order to help maintain Oax---Oax nonbonded contacts at no less than ca. 3.04 A. A number of comparisons have been made between the isoelectronic dimers. Other parameters of interest include Ga-Fe = 2.516 (3) Á, Ga-C = 2.069 (5) A, Ga-O = 2.129 (4) A, Fe-C(ax) = 1.775 (4) A, Fe-C(eq) = 1.788 (3) A, /Ga-Fe-Ga = 71.55 (4)°, ZFe-Ga-Fe = 108.45 (4)°, and zCax-Fe-Cax = 156.85 (21)°. The structure has been refined (Mo Ka radiation) to a conventional R index (on F) of 0.036 for 2650 unique reflections having I > 3<r(/). The space group is No. 2 (C}-FT), with a = 8.726

Chromium, Iron and Cobalt Carbonyl Complexes with Gallium Halides: Synthesis and Structures

“…[(CO) 4 [34] [(CO) 4 [8] [Cp(CO) 2 [36] [Cp(CO) 2 FeGaCl 2 (thf)] 231.7(1) 1990 (s), 1995 (s) [37] [Cp(CO) 2 FeGa(R N )(BH 4 )] 237.5 1975 (vs), 1920 (vs) [38] [Fe 2 (CO) 6 {μ-GaSi(SiMe 3 ) 3 } 3 ] 238.18 1964 (s), 1921 (s) [9] [Fe 2 (CO) 6 [40] [{Cp(CO) 2 [30,31] [{Cp(CO) 2 [30,31] [{Cp(CO) 2 [42] [(CO) 4 FeGa(η 1 -C 2 H 3 )(thf)] 2 251.0 - [43] [(CO) 5 CrGaCp*] 240.46 (7) 2052 (s), 982 (s), 1918 (vs), 902 (vs) [8] [(CO) 5 CrGaC 4 H 2 (tBu) 2 P] 239.0(1) 2022 (m), 1936 (sh), 1870 (s) [44] [(CO) 5 CrGaCl(tmeda)] 245.6(1) 2033 (s), 1947 (s), 1900 (vs) [45] [(CO) 5 CrGaCH 3 (tmeda)] 247.9(1) 2013 (vs), 1920 (s), 1844 (vs) [46] [(CO) 5 [45] [(CO) 6 Co 2 (GaCp*) 2 ] 238. 8 2023, 1989, 1953, 1948 [8] [(CO) 6 [12] subhalides with the corresponding metallated silanides.…”

Contents

“…The Al-Al distance is 2.817(1) A and the Al-N-Al angle is 92.5(1)°. [93] There are two red compounds with Fe 2 Ga2 clusters [94,95]. The first one There are three colored compounds containing Fe 2 ln 2 clusters, one of them being deep-red [96], the second one red [8] and the third one yellow [97].…”

Chapter 12. Organometallic chemistry. Part (ii) Main-group elements

“…For example, treatment of isomers (3 1) and (32) of SiloMe16 with AlCl,-MeMgBr in refluxing benzene gave conversion into further isomeric polysilanes believed to have Silo skeletal configurations as in (33) and (34); a number of other similar interconversions were rep~rted.~' Another area of organosilicon chemistry which enjoys success is that concerned with the effects of large degrees of steric hindrance afforded by very bulky methylsilylmethyl groups. Some aspects of this type of chemistry have been reviewed.48 Some of this work is now becoming routine, but of interest in this area are the syntheses of the first stable silyl cyanate [ (Me3Si)3CSiMe2(OCN)],49 the first stable diphosphine (Me3Si)3C-P=P-C(SiMe3)3 (which also has a record low-field l P (31) or Pn.m.r. chemical shift of ca.…”