| Abstrakt: |
The reductive reactivity of a Ln(II) ion with a nontraditional 4fn5d1electron configuration has been investigated by studying reactions of the {GdII(N(SiMe3)2)3]}−anion with a variety of reagents that survey the many reaction pathways available to this ion. The chemistry of both [K(18-c-6)2]+and [K(crypt)]+salts (18-c-6 = 18-crown-6; crypt = 2.2.2-cryptand) was examined to study the effect of the countercation. CS2reacts with the crown salt [K(18-c-6)2][Gd(NR2)3] (1) to generate the bimetallic (CS3)2–complex {[K(18-c-6)](μ3-CS3-κS,κ2S′,S′′)Gd(NR2)2]}2, which contains two trithiocarbonate dianions that bridge Gd(III) centers and a potassium ion coordinated by 18-c-6. In contrast, the only crystalline product isolated from the reaction of CS2with the crypt salt [K(crypt)][Gd(NR2)3] (2) is [K(crypt)]{(R2N)2Gd[SCS(CH2)Si(Me2)N(SiMe3)-κN,κS]}, which has a CS2unit inserted into a cyclometalated amide ligand. Complexes 1and 2reductively couple pyridine to form bridging dipyridyl moieties, (NC5H4-C5H4N)2–, that generate bimetallic complexes differing only in the countercation, {[K(18-c-6)(C5H5N)2]}2{[(R2N)3Gd]2[μ-(NC5H4-C5H4N)2]} and [K(crypt)]2{[(R2N)3Gd]2[μ-(NC5H4-C5H4N)2]}. Complexes 1and 2also show similar reactivity with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) to form the (TEMPO)–complexes [K(18-c-6)][(R2N)3Gd(η1-ONC5H6Me4)] and [K(crypt)][(R2N)3Gd(η1-ONC5H6Me4)], respectively. The first example of a bimetallic coordination complex containing a Bi–Gd bond, [K(crypt)][(R2N)3Gd(BiPh2)], was obtained by treating 2with BiPh3. |
