Zirconium complexes crystal structure

The crystal structure of a mono(cyclopentadienyl)zirconium complex containing a novel Me2Si-linked bis(amidinate) ligand was reported (Scheme 203). In this compound the central Zr atom is octahedrally coordinated with the bis(amidi-nate) acting as a tridentate ligand. ... 

The tendency to form ate complexes observed for yttrium is also seen in the preparation of a novel zirconium alkynyl complex. Reaction of Zr(Por)Cl2 (Por = OEP or TPP) with either two or three equivalents of LiC=CR (R = Ph or SiMe ) gives the trisalkynyl complexes Zr(Por)(C=CR)3Li(TFIF). An X-ray crystal structure of Zr(OEP)(C=CPh)2Li(THF) shows that all three alkynyl ligands are on... 

Figure 7.4. Crystal structure of the 1,1-bimetallic complex of boron and zirconium 22. Adapted by the authors.

Vinylboronates are generally less reactive than vinylzirconocenes towards various electrophiles and hence selective reactions of the latter should be possible. It was found that selective cleavage of the carbon—zirconium bond in 45 by N-halosuccinimides provides (a-haloalkenyl)boronic esters 53 in excellent chemical yields and with complete re-gioselectivity (Scheme 7.17) [54], An X-ray crystal structure determination of 45 confirmed the configuration of the four-coordinate Zr complex, with two cyclopentadienyl rings, Cl, and C(sp2) as the four ligands (Fig. 7.5) [54,126]. 

Diphenyl zirconocene complex 102 is unstable at room temperature and undergoes electrophilic substitution at the alkylated cyclopentadienyl ligand to produce the boratacycle 44 in high yield (Equation 10). The reaction involves loss of 1 equiv of benzene from the central zirconium, and the X-ray crystal structure of 44 (detailed in Section 7.14.3) clearly shows interaction between the zirconium and one of the perfluorophenyl ligands attached at boron <2004CC1020>. 

Complexes of type (90) represent a new class of zirconium hydrocarbyl derivatives in which a strong metal carbene interaction in a pincer hgand structure is formed. The crystal structure of such complexes shows a short metal carbon link common to two fused four-membered rings which are almost coplanar. 

Theopold et al. reported the first structural characterization of a phospho-lide. It was obtained through lithium cleavage of a P-chlorophosphole (prepared in turn by transmetallation of a Fagan-Nugent zirconium complex with PC13) and crystallized from TMEDA-ether as [LiTMEDA(PC4Me4)] 4 (Eq. 10) [8] ... 

A related zirconium complex with a [N2 ]-type of ligation is tetrakis(l,3-diphenyltriazenido)zirconium(lv) 74,85 which is obtained from the amine elimination approach. Thus, treatment of Zr(NMe2)4 with 4equiv. of 1,3-diphenyltriazene in hexanes at ambient temperature affords 74 in 79% yield as a deep red crystalline solid (Equation (6)). This Zr complex is eight coordinate with four 2-l,3-diphenyltriazenido ligands. Complex 74 crystallizes with a distorted dodecahedral geometry about Zr consistent with this solid-state structure, the solution molecular weight measurements indicate a monomeric structure in benzene. 

Zirconium tribenzyl complex 212 incorporating diisopropyltriazacyclonone, a type of mono-anionic, tridentate diamino-amido [/V,iV ,./V] ligand, was obtained via alkane elimination (Scheme 42) alternatively, this complex can also be prepared via either salt metathesis or amine elimination approaches.179 The crystal structure of 212 reveals a monomeric form on heating at 80 °C in benzene solution for 24 h, this complex undergoes elimination of 1 equiv. of toluene, affording complex 213 bearing a dianionic, acyclic, diamido-amino [/V-,iV,./V-] moiety. 

The zwitterionic tris(cyclopentadienyl)zirconocene complex 1213 is obtained by treatment of Cp2ZrCl2 with the lithium, sodium salt of the B(C6F5)3-substituted borato-Gp dianion according to Scheme 286.930 The X-ray crystal structure of this complex reveals that the three 75-cyclopentadienyl ligands are in a nearly trigonal-planar coordination around zirconium with a pronounced Zr-F-G(aryl) coordination perpendicular to it this Zr-F-G(aryl) coordination is persistent in solution based on solution NMR studies. 

---