Donor-funktionalisierte Alkinyle von Titan(IV), Kupfer(I) und Silber(I); Festkörperstrukturen von [Ti](CCCH 2NMe 2) 2 und {[Ti](CC tBu) 2}CuCCCCC 2H 5

Abstract

The preparation of numerous donor-functionalised acetylides with Ti(IV) and/or Group II transition metals is described. The reaction of [Ti]Cl 2 ( 1) {[Ti]=(η 5-C 5H 4SiMe 3) 2Ti} with two equivalents of LiCCR 1 [ 2a: R 1=CMeCH 2; 2b: R 1=C 6H 4CN-4; 2c: R 1=CH 2NMe 2; 2d: R=C 5H 4N-4] affords the bis(alkynyl)titanocenes [Ti](CCR 1) 2 [ 3a: R 1=CMeCH 2; 3b: R 1=C 6H 4CN-4; 3c: R 1=CH 2NMe 2] in good yields. While by treatment of 1 with 2d in a 1:2 molar ratio only non-characterisable products are formed, the use of [Ti](Cl)(CH 2SiMe 3) ( 4) produces [Ti](CH 2SiMe 3)(CCC 5H 4N-4) ( 5) in excellent yields. Monomeric, donor-functionalised copper(I) acetylides of general type {[Ti](CCR 1) 2}CuCCR 3 [R 1= t Bu, 7a: R 3=CCCH 2CH 3; 7b: R 3=CMeCH 2; 7c: R 3=C 6H 4CN-4; R 1=SiMe 3, 7d: R 3=CMeCH 2; 7e: R 3=C 6H 4CN-4] are accessible by (i) the reaction of {[Ti](CC t Bu) 2}CuSC 6H 4CH 2NMe 2-2 ( 6) with equimolar amounts of 2a– 2c or (ii) treatment of the monomeric copper(I) methyl {[Ti](CCR 1) 2}CuCH 3 ( 8a: R 1=SiMe 3, 8b: R 1= t Bu) with HCCR 3 [ 9a: R 3=CCCH 2CH 3, 9b: R 3=CMeCH 2, 9c: R 3=C 6H 4CN-4] in a 1:1 molar ratio. The reaction chemistry of these complexes towards selected transition metal compounds is described. The bis(alkynyl)titanocenes 3a– 3c produce with ML n { 10a: ML n =CuCl; 10b: ML n =CuI; 10c: ML n =[Cu(CH 3CN) 4][PF 6]; 10d: ML n =AgBF 4; 10e: ML n =Ni(CO) 4} the heterobimetallic tweezer complexes {[Ti](CCR 1) 2}ML [R 1=CMeCH 2; 11a: ML=CuCl; R 1=C 6H 4CN-4; 11b: ML=CuCl; 11c: ML=CuI; 11d: ML=Ni(CO); R 1=CH 2NMe 2; 11e: ML=CuPF 6; 11f: ML=AgBF 4]. In complexes 11a– 11f an early and a late transition metal centre [e.g. Ni(0)] are linked via the corresponding R 1CC ligands of the organometallic π-tweezer complexes. For complexes 11e and 11f a dynamic behaviour is observed in solution. The solid state structures of 3c and 7a are reported. Both compounds crystallise in the triclinic space group P 1 ̄ . They exhibit features that are characteristic for this class of complexes: (i) a tetrahedral environment around the Ti(IV) of 3c and 7a, (ii) a lengthening of the CC triple bonds upon η 2-coordination to the transition metal complex fragment CuCCCCC 2H 5, (iii) a trans-deformation of the TiCC t Bu unit, and (iv) a reduction of the bite angle C CCTiC CC for 7a.