Preparation and properties of the halogenoalkyl compounds [(η 5-C 5H 5)(CO) 2(PPh iMe 3− i)Mo{(CH 2) nX}] ( n=3, 4; i=0–3; X=Br, I) and [{η 5-C 5(CH 3) 5}(CO) 3Mo{(CH 2) nX}] ( n=3, 4; X=Br, I) and the crystal structures of [(η 5-C 5H 5)(CO) 3W{(CH 2) 5I}], [(η 5-C 5H 5)(CO) 3W{(CH 2) 3Br}] and [(η 5-C 5H

Abstract

The compounds [Cp(CO) 2(PPh i Me 3− i )Mo{(CH 2) n Br}] (Cp=η 5-C 5H 5, n=3, 4; i=0–3) and [Cp*(CO) 3Mo{(CH 2) n Br}] (Cp*=η 5-C 5(CH 3) 5, n=3, 4) were prepared in medium to high yield by the reaction of the corresponding anion ([Cp(CO) 2(PPh i Me 3− i )Mo] − or [Cp*(CO) 3Mo] −) with Br(CH 2) n Br. The bromoalkyl compounds were subsequently reacted with NaI to give the corresponding iodoalkyl compounds [Cp(CO) 2(PPh i Me 3− i )Mo{(CH 2) n I}] ( n=3, 4; i=0–3) and [Cp*(CO) 3Mo{(CH 2) n I}] ( n=3, 4). The iodoalkyl compounds can also be prepared by the reaction of the corresponding anion and α,ω-diiodoalkane in much lower yields. These compounds have been fully characterised and their properties are discussed. The crystal and molecular structure of [Cp(CO) 2(PPh 3)Mo{(CH 2) 3I}] is reported. The compound forms crystals in the monoclinic space group P2 1/ n, with a Mo–C bond length of 2.40 Å and a C–I bond length of 2.13 Å. The compounds [Cp(CO) 3W{(CH 2) n X}] (X=Br, I; n=3–6) were also prepared in high yield and the crystal structures of [Cp(CO) 3W{(CH 2) 5I}] and [Cp(CO) 3W{(CH 2) 3Br}] are reported. The former compound forms orthorhombic crystals in the space group P2 1 nb and the latter forms triclinic crystals in the space group P 1 ̄ . Both have W–C bond lengths of 2.35 Å. The C–I bond length is 2.12 Å; the C–Br bond length is 1.94 Å.