Syntheses and X‐Ray Structures of Zinc Amidinate Complexes

Abstract

Reactions of ZnX2 (X = Cl, Br) with equimolar amounts of Li[t‐BuC(NR)2] (R = i‐Pr, Cy) yielded mono‐amidinate complexes [{t‐BuC(NR)2}ZnX]2 (X = Cl, R = i‐Pr 1, Cy 2; X = Br, R = i‐Pr 3, Cy 4), whereas reactions with two equivalents of Li‐amidinate resulted in the formation of the corresponding bis‐amidinate complexes [t‐BuC(NR)2]2Zn (R = i‐Pr 5, Cy 6). 1 ‐ 6 were characterized by elemental analyses, IR, mass and multinuclear NMR spectroscopy (1H, 13C), and single crystal X‐ray analysis (1, 2, 3, 6). In addition, the single crystal X‐ray structure of [t‐BuC(NCy)2]ZnBr·LiBr(OEt2)2 7, which was obtained as a byproduct in low yield from re‐crystallization experiments of 4 in Et2O, is reported.

[tBuC(NiPr)2]2Zn as Starting Reagent for Monoamidinate Zinc Complexes {[tBuC(NiPr)2]ZnX}2

“…Compounds 2 and 3 form centrosymmetric dimers in the solid state with bridging nitrogen atoms and a center of symmetry in the Zn 2 N 2 ring, whereas complex 1 is monomeric in the solid state as it was expected. The structures of 1 and 3 are similar to those previously observed for monoamidinate zinc halides {[ t BuRC(N i Pr) 2 ]ZnX} 2 (X = Cl, Br) and the bisamidinate complex [ t BuC(NCy) 2 ] 2 Zn 12, whereas the structure of {[ t BuC(N i Pr) 2 ]ZnMe} 2 ( 2 ) significantly differs from that reported for {[EtC(N i Pr) 2 ]ZnEt} 2 ( 4 ). Complex 4 forms an eight‐membered [Zn 2 (μ‐NCN) 2 ] heterocycle, which adopts a boat‐type conformation and shows short Zn–N bonds within the ring [1.991(2)–2.014(2) Å] and only weak transannular Zn–N bonds [2.669(1), 2.653(1) Å] 10.…”

“…Only recently, we became interested in zinc amidinate complexes and reported on the reactions of ZnR 2 (R = Me, Et) with isopropyl carbodiimide i PrN=C=N i Pr, which either proceed with formation of the expected amidinate complex {[EtC(N i Pr) 2 ]ZnEt} 2 10 or with formation of novel cluster‐type complexes such as {C[C(N i Pr) 2 ZnMe]} 4 11, Moreover, mono‐ and bisamidinate zinc complexes of the type [ t BuC(NR) 2 ] 2 Zn and [ t BuC(NR) 2 ]ZnX (R = i Pr, Cy, X = Cl, Br) were synthesized by salt elimination reactions 12. In these reactions it became evident that the synthesis of monoamidinate complexes is often complicated because of theformation of the corresponding bisamidinates.…”

Synthesis and Characterization of β‐Diketiminate Zinc Complexes

“…We became only recently interested in zinc complexes containing N,N'-chelating substituents and reported on the synthesis of several zinc amidinate complexes. [12] Herein, we report on the synthesis of -diketiminate zinc complexes of the type LZnX (X = Me 1, Cl 2, Br 3, I 4) containing the sterically demanding MesNacNac ligand.…”

Erste Reaktion von Dizinkocen unter Erhalt der Zn‐Zn‐Bindung

“…Lediglich Carmona et al berichteten über Reaktionen von 1 mit H 2 O, tBuOH, NCXyl (Xyl = 2,6-Me 2 C 6 H 3 ) [1] und anderen Lewis-Basen (NMe 3 , Pyridin, PMe 3 etc. ), [2] Wir interessieren uns seit kurzem für Organozinkverbindungen mit sterisch weniger anspruchsvoll substituierten, N,N'-chelatisierenden Amidinatliganden, [9] aus denen unter anderem Verbindungen mit Zn-Zn-Bindung synthetisiert werden sollen. Parallel dazu untersuchten wir die Reaktivität der Zn-Zn-Bindung und konzentrierten uns dabei auf Dizinkocen [Cp* 2 Zn 2 ] (1), da diese Verbindung wegen der sterischen und elektronischen Flexibilität des Cp*-Liganden am aussichtsreichsten für Folgereaktionen schien.…”