BETA SAÚDE
Transition metal cyanate complexes
Texto da Wikipédia (en), licença CC BY-SA. O BETARUBI mostra o verbete inteiro nesta página — a leitura não continua fora do site.
![[Mn(NCO)4]2-](https://upload.wikimedia.org/wikipedia/commons/thumb/e/e5/CSD_CIF_FOFLAP.png/250px-CSD_CIF_FOFLAP.png?utm_source=en.wikipedia.org&utm_campaign=parser&utm_content=thumbnail)
Transition metal cyanate complexes are coordination complexes containing one or more cyanate (NCO−) ligands. Many complexes are known for this venerable ligand.[2]
Structure and bonding
Cyanate is a pseudohalide. As reflected by the pKa's of cyanic acid (3.7) and hydrochloric acid (-5.9), cyanate is more basic than chloride. As a monodentate ligand, cyanate generally binds metals through the nitrogen atom, i.e., M-N=C=O. It is a sigma donor. It is classified as an X ligand in the Covalent bond classification method. In the usual electron counting method, it is a one-electron ligand.
The NCO unit is linear or nearly so in cyanate complexes. The M-N-C angles can be quite bent or nearly linear. The bond distances determined by X-ray crystallography support the description [N=C=O]-.
Examples of homoleptic complexes are the tetrahedral dianions [Mn(NCO)4]2-, [Co(NCO)4]2-, and [Zn(NCO)4]2-.[4]
Preparation
Metal cyanate complexes can be prepared using alkali metal cyanate salts such as sodium cyanate and potassium cyanate.[3]
The complex [Co(NH3)5(NCO)]2+ is prepared from treating the aquo complex [Co(NH3)5(H2O)]3+ with urea.[5]
References
- ↑ Thuyweang, Nittaya; Koh, Lip Lin; Hor, T.S. Andy; Leelasubcharoen, Somying (2014). "Synthesis, characterization, and catalytic activity of heterometallic ion-pair Ni/Mn and Ni/Zn complexes". Journal of Coordination Chemistry. 67 (7): 1219–1235. doi:10.1080/00958972.2014.911850.
- ↑ Hohloch, Stephan; Tambornino, Frank (2025). "Historical and Recent Developments in the Chemistry of Cyanate Congeners". Inorganic Chemistry. 64 (26): 12900–12917. doi:10.1021/acs.inorgchem.5c01041. PMC 12239083. PMID 40498324.
- 1 2 3</sub>py<sub>3</sub>]·2py and ''trans''-(py<sub>2</sub>H)[Mo(NCO)<sub>4</sub>py<sub>2</sub>]"},"journal":{"wt":"Inorganic Chemistry Communications"},"date":{"wt":"2005"},"volume":{"wt":"8"},"issue":{"wt":"4"},"pages":{"wt":"397–400"},"doi":{"wt":"10.1016/j.inoche.2005.01.013"}},"i":0}}]}' id="mwcQ"/>Kitanovski, Nives; Golobič, Amalija; Čeh, Boris (2005). "Syntheses and Crystal Structure of First Octahedral d-Metal Complexes Containing Three and Four Isocyanato Ligands, mer-[Mo(NCO)3py3]·2py and trans-(py2H)[Mo(NCO)4py2]". Inorganic Chemistry Communications. 8 (4): 397–400. doi:10.1016/j.inoche.2005.01.013.
- ↑ Peppel, Tim; Hinz, Alexander; Thiele, Philipp; Geppert-Rybczyńska, Monika; Lehmann, Jochen K.; Köckerling, Martin (2017). "Synthesis, Properties, and Structures of Low-Melting Tetraisocyanatocobaltate(II)-Based Ionic Liquids". European Journal of Inorganic Chemistry (5): 885–893. doi:10.1002/ejic.201601250.
- ↑ Buckingham, D. A.; Francis, D. J.; Sargeson, A. M. (1974). "Hydrolysis and nitrosation of the pentaamine(cyanato-N)cobalt(2+) ion. Evidence for pentaamine(carbamato-N)cobalt(2+) and pentaamine cobalt(3+) intermediates". Inorganic Chemistry. 13 (11): 2630–2639. doi:10.1021/ic50141a019.