We report on the synthesis of a variety of trigonal imido cobalt complexes [Co(NAryl)L 2 ] À , (L= N-(Dipp)SiMe 3 ), Dipp = 2,6-diisopropylphenyl) with very long CoÀN Aryl bonds of around 1.75 . Their electronic structure was interrogated using a variety of physical and spectroscopic methods such as EPR or X-Ray absorption spectroscopy which leads to their description as highly unusual imidyl cobalt complexes. Computational analyses corroborate these findings and further reveal that the high-spin state is responsible for the imidyl character. Exchange of the Dipp substituent on the imide by the smaller mesityl function (2,4,6-trimethylphenyl) effectuates the unexpected Me 3 Si shift from the ancillary ligand set to the imidyl nitrogen, revealing a highly reactive, nucleophilic character of the imidyl unit.
The impact of 4f
metal ions Ln3+ (Ln = La or Ce) versus
5f metal ions U
n+ (n =
3 or 4) on the compositions and distribution of 5p metal atoms in
the cluster shells of endohedral species [M@Sn14–x
Sb
x
]
q− (M = La, Ce, or U; x = 6–8; q = 3, 4) was studied by means of combined experimental
and quantum chemical investigations. While all known f-block metal
ion-centered endohedral clusters possessed combinations of larger
main group metal atoms so far (Sn/Bi or Pb/Bi), resulting in mixtures
of 13- and 14-atom cages, the 14-atom cages reported herein comprise
exclusively Sn and Sb atoms and therefore are challenged in accommodating
the large 4f and 5f ions. We show that the clusters form in reactions
of (Sn2Sb2)2– anions with
[Ln(C5Me4H)3] or [U(C5Me4H)3Cl], and that salts of [La@Sn6Sb8]3–, [La@Sn7Sb7]4–, [U@Sn8Sb6]4–, and [U@Sn7Sb7]3– can be
isolated from them. The assignment of Sn versus Sb in the encapsulating
cage follows a simple rule. Different central atoms cause only slight
differences in this regard and with respect to distortions of the
cluster shells. The reactions also yielded the salt of the new binary
anion (Sn4Sb4)2– that was
recently predicted by quantum chemical studies.
Multimetallic clusters play a key role as models to doped metals, as candidates to new types of superatomic catalysts and as precursors to new multimetallic solids. Understanding formation pathways is an essential and necessary step forward in the development of cluster synthesis and research, yet remains considerably lacking owing to difficulty in identification of intermediates and the ill-defined nature of common starting materials. Here we show progress in this regard by investigating the reactivity of an intermetallic solid of nominal composition ‘K5Ga2Bi4’ with [W(cod)(CO)4] upon extraction with ethane-1,2-diamine (en) and 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (crypt-222). Several polybismuthide intermediates and by-products were identified along the reaction pathway, ultimately forming the new polybismuthide salt [K(crypt-222)]3[µ:η3-Bi3{W(CO)3}2]∙en∙tol. DFT calculations revealed plausible reaction schemes for the transformations taking place in the reaction mixture providing insight into the complex reactivity of ‘K5Ga2Bi4’ on the basis of in situ generation of Bi22−.
The solid mixture "K 2 GeSb" was shown to comprise single-crystalline K 12 Ge 3.5 Sb 6 (1), a double salt of K 5 [GeSb 3 ] with carbonate-like [GeSb 3 ] 5À anions, and the metallic Zintl phase K 2 Ge 1.5 . Extraction of 1 with ethane-1,2-diamine in the presence of crypt-222 afforded [K(crypt-222)] + salts of several novel binary Zintl anions: (Ge 2 Sb 2 ) 2À (in 2), (Ge 4 Sb 12 ) 4À (in 3), and in the presence of [AuMePPh 3 ] also (Ge 4 Sb 14 ) 4À (in 4). The anion in 2 represents a predicted, yet heretofore missing pseudo-tetrahedral anion. 4 comprises a cluster analogous to (Ge 4 Bi 14 ) 4À and (Ga 2 Bi 16 ) 4À , and thus one of the most Sb-rich binary p-block anions. The unprecedented cluster topology in 3 can be viewed as a defect-version of the one in 4 upon following a "dead end" of cluster growth. The findings indicate that Ge and Sb atoms are at the border of a well-matching and a mismatch elemental combination. We discuss the syntheses, the geometric structures, and the electronic structures of the new compounds.
First explorations of binary Ge/Sb Zintl anions indicated a situation between a “matching” one and one that tends to element segregation owing to a mismatch in atom sizes. Extraction of the ternary solid K12Ge3.5Sb6 allowed access to the so far missing P4‐like anion (Ge2Sb2)2−, as well as to species that show tendencies for spatial separation of Ge and Sb atoms, “incomplete” (Ge4Sb12)4− and “complete” (Ge4Sb14)4−, as confirmed by DFT calculations and described by Stefanie Dehnen et al. in their Research Article (e202207232).
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