geoscience.net logo
+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Why [(eta5-C5Me(n)H5-n)2Ti]2(micro2,eta2,eta2-N2) can not add a H2 molecule to the side-on-coordinated N2 while its Zr and Hf analogues can? insights from computational studies


, : Why [(eta5-C5Me(n)H5-n)2Ti]2(micro2,eta2,eta2-N2) can not add a H2 molecule to the side-on-coordinated N2 while its Zr and Hf analogues can? insights from computational studies. Inorganic Chemistry 46(7): 2709-2715

The potential energy surface of the reaction [(eta5-C5MenH5-n)2M]2(micro2,eta2,eta2-N2) + H2 --> [(eta5-C5MenH5-n)2M][(eta5-C5MenH5-n)2MH](micro2,eta2,eta2-NNH) at low-lying singlet and triplet electronic states of the reactants was investigated using density functional methods, for n = 0 and 4, and M = Ti, Zr, and Hf. Ground electronic states of the Ti complexes are found to be triplet states, while that for the corresponding Zr and Hf complexes are singlet states. In their singlet state, all these complexes satisfy known necessary conditions (they have a side-on-coordinated N2 molecule and appropriate frontier orbitals) for successful addition of an H2 molecule to the coordinated N2, and consequently, add of an H2 molecule with a reasonable energy barrier. Hf complexes show slightly higher reactivity than corresponding Zr complexes, and in turn, both are more reactive than their singlet-state Ti counterparts. The calculated trend in reactivity of Zr and Hf complexes is consistent with the latest experimental data (see refs 13 and 16). However, Ti complexes have the ground triplet state that lacks in appropriate frontier orbitals. As a result, H2 addition to the Ti complexes at their triplet ground states requires a larger activation barrier than the singlet state and is endothermic (lacks of driven force for reaction). On the basis of these results, we predict that the [(eta5-C5Me4H)2M]2(micro2,eta2,eta2-N2) and [(eta5-C5H5)2M]2(micro2,eta2,eta2-N2) complexes cannot react with an H2 molecule for M = Ti, while those for M = Zr and Hf can. It was shown that the difference in the B3LYP (hybrid) and PBE (nonhybrid) calculated energy gaps between the lowest closed-shell singlet and triplet states of the present complexes reduces via first- > second- > third-row transition metals; both hybrid and nonhybrid density functionals can be safely used to describe reactivity of the low-lying low-spin and high-spin states of second- and third-row transition metal complexes.

US$19.90

PMID: 17341066

DOI: 10.1021/ic062405b


Other references

Engelbrecht, J.R.; Mirollo, R., 2012: Structure of long-term average frequencies for Kuramoto oscillator systems. We study the long-term average frequency as a function of the natural frequency for Kuramoto oscillators with periodic coefficients. Unlike the case for more general periodically forced oscillators, this function is never a "devil's stai...

Hilgartner M.W., 1977: Psycho social status of patients on home care 6 year follow up. Thrombosis & Haemostasis: 342

Glas, P.S.; Genthner, F.J.; Fisher, W.S., 1995: Extra-embryonic coats of Palaemonetes pugio Morphology and composition. American Zoologist 35(5): 70A

Polikarpov, G.G.; Ivanov, V.N., 1962: Concentration of strontium and yttrium radioactive isotopes in salt water fish roe. Radiobiologiia 2: 207-210

Leisch, F.; Herbinger, W., 1979: One year experience in the public hospital in Linz/Austria. 222 coronary angiographies were performed in a new established laboratory in the medical division of the public hospital in Linz (Austria) from May 1977 to May 1978. Indications, method, complications and results are presented.

Candea V.; Tintoiu I.; Popa A.; Dumitrascu G.; Goleanu V.; Mitrica M., 1990: Aspects of the surgical treatment of nonrheumatic mitral valvulopathies. The present paper analyzed the indications and surgical treatment in 505 patients with lesions of the mitral valve. 350 lesions were of rheumatic nature and 148 with nonrheumatic etiology. 31 patients with infectious endocarditis with mitral local...

Vistnes, K., 1987: Biofeedback--a new type of pain treatment. Sykepleien 74(5): 24-7, 40

Reddy P.K., 1987: Experience with the ileal cecal indiana continent urinary reservoir. Journal of Urology 137(4 PART 2): 205A

Zhu, X.; Mitchell, J.C., 2011: KFC2: a knowledge-based hot spot prediction method based on interface solvation, atomic density, and plasticity features. Hot spots constitute a small fraction of protein-protein interface residues, yet they account for a large fraction of the binding affinity. Based on our previous method (KFC), we present two new methods (KFC2a and KFC2b) that outperform other meth...

Wong, E.K.; Nicolosi, R.J.; Low, P.A.; Herd, J.A.; Hayes, K.C., 1980: Lecithin influence on hyperlipemia in rhesus monkeys. In humans, the ingestion of lecithin can alter plasma cholesterol and triglyceride concentrations by mechanism(s) that remain to be elucidated. To further explore this response to lecithin, hyperlipemic rhesus monkeys were selected from a group of...