Treatment of the octachlorodirhenate ion with high-pressure carbon monoxide; preparation and structure of [ cis-Re(CH 3CN) 4(CO) 2] 2 [ReCl 6

Abstract

The reaction of [(n-C 4H 9) 4N] 2[Re 2Cl 8] in acetonitrile with carbon monoxide at 100 atm and ca. 90°C gives several products, the major one being ReCl(CO) 5. One of the minor ones has been identified and characterized by X-ray crystallography as the ionic compound [cis-Re(CH 3CN) 4(CO) 2] 2[ReCl 6]. This compound forms monoclinic crystals in space group P2 1/c with unit cell constants of: a = 13.23(1) Å; b = 10.092(7) Å; c = 13.92(1) Å, β = 112.18(6)°; V = 1721(2) Å 3; Z = 2. The reaction has a distorted octahedral structure with the following distances: ReC (av), 1.877(7) Å; ReN ( trans to CO), 2.134(9) Å and 2.156(10) Å; ReN ( trans to N), 2.052(9) Å and 2.072(9) Å. The [ReCl 6] 2− anion resides on an inversion center and has ReCl distances of 2.367(3) Å, 2.350(3) Å and 2.345(3) Å.