TY - JOUR
T1 - Soluble zintl phases A 14ZnGe16 (A = K, Rb) featuring [(η3-Ge4)Zn(η2-Ge4)] 6- and [Ge4]4- clusters and the isolation of [(MesCu)2(η3,η3-Ge4)] 4-
AU - Stegmaier, Saskia
AU - Waibel, Markus
AU - Henze, Alexander
AU - Jantke, Laura Alice
AU - Karttunen, Antti J.
AU - Fässler, Thomas F.
PY - 2012/9/5
Y1 - 2012/9/5
N2 - The number of Zintl phases containing polyhedral clusters of tetrel elements that are accessible for chemical reactions of the main-group element clusters is rather limited. The synthesis and structural characterization of two novel ternary intermetallic phases A14ZnGe16 (A = K, Rb) are presented, and their chemical reactivity is investigated. The compounds can be rationalized as Zintl phases with 14 alkali metal cations A+ (A = K, Rb), two tetrahedral [Ge4]4- Zintl anions, and one anionic heterometallic [(Ge4)Zn(Ge4)]6- cluster per formula unit. The Zn-Ge cluster comprises two (Ge4) tetrahedra which are linked by a Zn atom, with one (Ge4) tetrahedron coordinating with a triangular face (η3) and the other one with an edge (η2). [(η3-Ge4) Zn(η2-Ge4)]6- is a new isomer of the [(Ge4)Zn(Ge4)]6- anion in Cs 6ZnGe8. The phases dissolve in liquid ammonia and thus represent rare examples of soluble Zintl compounds with deltahedral units of group 14 element atoms. Compounds with tetrahedral [E4]4- species have previously been isolated from solution for E = Si, Sn, and Pb, and the current investigation provides the "missing link" for E = Ge. Reaction of an ammonia solution of K14ZnGe16 with MesCu (Mes = 2,4,6-(CH3)3C6H2) in the presence of [18]-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) yielded crystals of the salt [K([18]-crown-6)]2K2[(MesCu) 2Ge4](NH3)7.5 with the polyanion [(MesCu)2Ge4]4-. This MesCu-stabilized tetrahedral [Ge4]4- cluster also completes the series of [(MesCu)2Si4-xGex]4- clusters, which have previously been isolated from solution for x = 0 and 0.7, as the end member with x = 4. The electronic structures of [(Ge4)Zn(Ge 4)]6- and [(MesCu)2Ge4]4- were investigated in terms of a molecular orbital description and analyses of the electron localization functions. The results are compared with band structure calculations for the A14ZnGe16 phases (A = K, Rb).
AB - The number of Zintl phases containing polyhedral clusters of tetrel elements that are accessible for chemical reactions of the main-group element clusters is rather limited. The synthesis and structural characterization of two novel ternary intermetallic phases A14ZnGe16 (A = K, Rb) are presented, and their chemical reactivity is investigated. The compounds can be rationalized as Zintl phases with 14 alkali metal cations A+ (A = K, Rb), two tetrahedral [Ge4]4- Zintl anions, and one anionic heterometallic [(Ge4)Zn(Ge4)]6- cluster per formula unit. The Zn-Ge cluster comprises two (Ge4) tetrahedra which are linked by a Zn atom, with one (Ge4) tetrahedron coordinating with a triangular face (η3) and the other one with an edge (η2). [(η3-Ge4) Zn(η2-Ge4)]6- is a new isomer of the [(Ge4)Zn(Ge4)]6- anion in Cs 6ZnGe8. The phases dissolve in liquid ammonia and thus represent rare examples of soluble Zintl compounds with deltahedral units of group 14 element atoms. Compounds with tetrahedral [E4]4- species have previously been isolated from solution for E = Si, Sn, and Pb, and the current investigation provides the "missing link" for E = Ge. Reaction of an ammonia solution of K14ZnGe16 with MesCu (Mes = 2,4,6-(CH3)3C6H2) in the presence of [18]-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) yielded crystals of the salt [K([18]-crown-6)]2K2[(MesCu) 2Ge4](NH3)7.5 with the polyanion [(MesCu)2Ge4]4-. This MesCu-stabilized tetrahedral [Ge4]4- cluster also completes the series of [(MesCu)2Si4-xGex]4- clusters, which have previously been isolated from solution for x = 0 and 0.7, as the end member with x = 4. The electronic structures of [(Ge4)Zn(Ge 4)]6- and [(MesCu)2Ge4]4- were investigated in terms of a molecular orbital description and analyses of the electron localization functions. The results are compared with band structure calculations for the A14ZnGe16 phases (A = K, Rb).
UR - http://www.scopus.com/inward/record.url?scp=84961978971&partnerID=8YFLogxK
U2 - 10.1021/ja304251t
DO - 10.1021/ja304251t
M3 - Article
AN - SCOPUS:84961978971
SN - 0002-7863
VL - 134
SP - 14450
EP - 14460
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 35
ER -