Elevated-Temperature Metathesis Syntheses of Structurally novel Alkali-metal Tetrakis(3,5-di-tet-butypyrazolato)lanthanoidate(III) Complexs:Toluene-Corrdinted Dicrete Bimetallic Complexes and Supramolecular Chains

摘要

Sodium and potassium tetrakis(3,5-di-tert-butylpyrazolato)lanthanoidate(II)complexes[M{Ln(tBu_2pz)_4}] have been prepared by reacton of anhydrous lanthanoid trihalides withalkali metal 3,5-di-tert0butylpyrazoltes at 200-3-- deg C,and a 1,2,4,5-tetramethylbenzene flux for M=K.On extractionwithtoluene (or occasionally directly from the reactiontube)the following compelxes were isolated:[Na(phMe}{Ln(tBu_2pz)_4}](1 Ln;1Ln1Tb,1Ho,1Er,1Yb),[K(PhMe){Ln-(tBu_2pz)_4}] (1Ln;1Ln=1Tb,1Hoo,1Er,1Yb),[K(PhMe){Ln-(tBu_2Pz)_4}] 2PhMe(2Ln:2Ln=2La,2Sm,2Tb,2Ho,2Yb,2Lu),[na{Ln-(tBu_2px)_4}]_n(3Ln;3Ln=3La,3Tb,3Ho,3Er,3Yb),[K{Ln)(tBu_2px)_4}]_n (4Ln;4Ln=4La,4Nd,4Sm,4Tb,4Ho,4Er,4Yb,4Lu),wit the last two classes generally being obtained byloss o toluene form 1Ln or 2Ln,and[Na(tBu_2pzH){Ln(tBu_2px)_4}] PhMe(5Ln;5Ln=5Nd,5Er,5Yb).Extracton with1,2-dimethoxethane (DME) after isolation of 2Ho yielded [K(dme){Ho(tBu_2pz)_4}] (6Ho).X-ray crystal structures of 1Ln(=1Tb,1Ho;P2_1/c),2Ln(=2La,2Sm,2Tb,2Yb,2Lu;Pnma),3,4Ln(=3La,3Er,4Sm;P2_1/m),and5Ln(=5Nd,5Er,adn 5Yb;P1) show eachgroup to be isomorphous reradless of the size of the Ln~(3+) ion.All complexescontain eight coordinate {Ln(eta~2-tBu_2pz)_4} units.these are further linked to thealkali metal by bridaging through two (1,2,5Ln)or three(3,4Ln)tBu_2px groups which show striking coordinationversatility.Sodium is coordinated by an eta~4-PhMe,a mu-eta~2:eta~2-tBu_2px,and a mu-eta~4(Na):eta~2(Ln)-tBu_2pz ligand in 1Ln,and by oen eta~1-tbu_2pxH and two mu-eta~3(Na)eta~2(Ln) ligands in 2 Ln.Classes 3,4Ln form polymric chains with the alkali metla bonded by two mu-eta~3(NNC-M):eta~2(Ln)-tB_2px lignads within [MLn(tBu_2px)_4] units whicharejoined together by eta~1(C)-tBu_2px-Na,K linkages.