54039-38-2Relevant articles and documents
Isolable zirconium(IV) carbonyl complexes. Synthesis and characterization of (C5R5)2Zr(η2-COCH 3)(CO)+ species (R = Me, H)
Guo, Zhaoyu,Swenson, Dale C.,Guram, Anil S.,Jordan, Richard F.
, p. 766 - 773 (2008/10/08)
The synthesis and characterization of the first isolable terminal carbonyl complex of Zr(IV) is described. The reaction of (C5R5)2Zr(CH3)(μ-CH 3)B(C6F5)3 with CO yields the η2-acyl carbonyl complexes [(C5R5)2Zr(η2-COCH 3)(CO)][CH3B(C6F5)3] (2, R = Me; 3, R = H). Complex 2 exists as a 9/1 mixture of O-outside (2a) and O-inside (2b) isomers which differ in the orientation of the η2-acyl ligand. Analogous O-outside (3a) and O-inside (3b) isomers are observed for 3, but the isomer preference is reversed (3a/3b = 1/5). The vCO values for the O-inside isomers 2b (2152 cm-1) and 3b (2176 cm-1) are higher than the free CO value, indicating that the Zr-CO bond is primarily σ-donor in character. The vCO values for the O-outside isomers 2a (2105 cm-1) and 3a (2123 cm-1) are slightly lower than the free CO value, as a result of overlap of a filled Zr-acyl bonding orbital and a CO π* orbital (i.e. σ→π* back-bonding). 2a can be isolated as a thermally stable solid; however, in CH2Cl2 solution both 2 and 3 lose CO under vacuum. 2a has been characterized by single crystal X-ray diffraction: a = 16.951(5) A?, b = 10.642(4) A?, c = 22.217(6) A?, V = 4008(4) A?3, Z = 4 in space group, Pca21. Consistent with the vCO values, the C-O distance (1.13(1) A?) in the nearly linear carbonyl ligand (Zr-C-O angle 175.1(7)°) is not significantly perturbed from that in free CO. The Zr-CCO distance (2.25(1) A?) is consistent with the absence of significant Zr-C π-bonding.
Syntheses, structures, and reactivities of unusual four-membered metallacycles formed in insertion reactions of N=N=O, N=N=NR, and N=N=CR2 with (η5-C5Me5)2Zr(C 2Ph2)
Vaughan, G. Alan,Hillhouse, Gregory L.,Rheingold, Arnold L.
, p. 7994 - 8001 (2007/10/02)
Nitrous oxide reacts with Cp*2Zr(C2Ph2) (1, Cp* = η5-C5Me5) to afford an organometallic product in which N2O has been incorporated without loss of dinitrogen. This adduct, Cp*2Zr{N(O)NCPh=CPh} (2), is isolable yet thermally unstable with respect to loss of dinitrogen at ambient temperature to give the monomeric diphenyloxametallacyclobutene derivative Cp*2Zr(OCPh=CPh) (3). 3 crystallizes from toluene solution in the monoclinic space group P21/n with a = 9.194 (2) A?, b = 19.422 (4) A?, c = 16.642 (4) A?, β = 104.60 (2)°, and Z = 4. The least-squares refinement coverged to R(F) = 0.051 and R(wF) - 0.058 for the 1849 unique data with Fo > 4σ(Fo). Salient metrical parameters of the four-membered oxametallacycle include the following: Zr?C(1), 2.543 (6) A?; Zr-C(2), 2.219 (7) A?, Zr-O, 2.065 (5) A?; C(1)-C(2), 1.348 (12) A?; O-C(1), 1.440 (10) A?. 3 reacts with H2 to give the enolate hydride Cp*2Zr(H)(OCPh=CHPh) (8) and with HCl to give Cp*2ZrCl2 and deoxybenzoin. Substrates with acidic hydrogens (H2O, PhOH, O=CMe2, HC≡CH, HC≡CPh, and HC≡CtBu) react with 3 to give enolate derivatives Cp*2Zr(X)(OCPh=CHPh) (9, X = OH; 10, X = OPh; 11, X = OC(CH2)Me; 12, X = C≡CH; 13, X = C≡CPh; 14, X = C≡CtBu), respectively. In contrast, insertion reactions into the Zr-C bond of 3 are observed for (O=CH2)x, O=CHTol, O=CH(n-Hex), TolN3, Ph2CN2, CO, and tBuN≡C, affording the 5- and 6-membered metallacycles Cp*2Zr(QCPh=CPhCH2O) (15), Cp*2Zr(OCPh=CPhCHTolO) (16), Cp*2Zr{OCPh=CPhCH(n-Hex)O} (17), Cp*2Zr-{OCPh=CPhN(N=NTol)} (18), Cp*2Zr{OCPh=CPhN(N=CPh2)} (19), Cp*2Zr{OCPh=CPhC(=O)} (20), and Cp*2 Zr{OCPh=CPhC(=NtBu)} (21), respectively. p-Tolyl azide and diphenyldiazomethane react with 1 to afford Cp*2Zr{N-(N2-p-C6H4CH 3)CPh=CPh} (4) and Cp*2Zr{N(N=CPh2)CPh=CPh} (5), respectively; these complexes do not cleanly lose N2 on thermolysis. 4 crystallizes from benzene solution in the monoclinic space group P21/c with a = 9.912 (4) A?, b = 30.919 (9) A?, c = 13.583 (5) A?, β = 98.97 (2)°, and Z = 4. The least-squares refinement converged to R(F) = 0.067 and R(wF) = 0.064 for the 2439 unique data with Fo > 3σ(Fo). Important metrical parameters of the planar four-membered azametallacycle include the following: Zr-C(21), 2.285 (8) A?; Zr-N(1), 2.173 (8) A?; C(21)-C(22), 1.373 (16) A?; C(22)-N(1), 1.423 (12) A?; N(1)-N(2), 1.341 (12) A?; N(2)-N(3), 1.305 (12) A?. Water adds accross a Zr-C bond of 1 to give the hydroxy vinyl species Cp*2Zr(OH)(CPh=CHPh) (6), but H2O adds across the Zr-N bond of 5 to yield Cp*2Zr(OH){CPh=CPhNH-(N=CPh2)} (7).
