Synthesis, characterization and base hydrolysis of cobalt(III) complexes coordinated by substituted phenylthioether ligands
Lee Roecker![https://orcid.org/0000-0001-8809-4635](/media/client/orcid_16x16.png)
![https://orcid.org/0000-0001-5777-3918](/media/client/orcid_16x16.png)
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Abstract
A synthetic route to the preparation of cobalt(III) complexes coordinated by bidentate phenylthioether ligands is described. Complexes of the type ((2-(X-phenylthio)ethylamine)-N,S)bis(ethylenediamine)cobalt(III) perchlorate, [(en)2Co(S(X-phenyl)CH2CH2NH2)](ClO4)3, where X = 4-methoxy (2a), 4-methyl (2b), 3-methyl (2c), nothing (2d), 3-methoxy (2e), 4-bromo (2f) and 3-bromo (2g) were prepared. The synthetic route involves reaction of trans-dichloridobis(ethylenediamine)cobalt(III) chloride with NH2CH2CH2SC6H4X to produce cis-[(en)2CoCl(NH2CH2CH2SC6H4X)]Cl2 (1a–g). Formation of the Co–S bond, completing the ring closure, is then accomplished by removing the coordinated chlorido by addition of AgClO4 in sulfolane. Complexes were characterized by 1H and 13C NMR spectroscopy, UV-Vis spectroscopy and elemental analysis. In addition, the solid-state structure (X-ray) of the monohydrate of 2d confirms the coordination mode of the ligand. Preliminary kinetic investigations in basic solution show that the Co–S bond is broken resulting in the formation of [(en)2Co(OH)(NH2CH2CH2SC6H4X)]2+. At 15.0°C, a Hammett Plot is linear (r2 = 0.981) with ρ = 2.24 ± 0.13.
Keywords: base hydrolysis, cobalt(III), coordination chemistry, Hammett Plot, reaction mechanisms, SN1CB, thioether, X-ray structure.
References
1 Elder RC, Kennard GJ, Payne MD, Deutsch E. Synthesis and characterization of bis(ethylenediamine)cobalt(III) complexes containing chelated thioether ligands. Crystal structures of [(en)2Co(S(CH3)CH2CH2NH2)][Fe(CN)6] and [(en)2Co(S(CH2C6H5)CH2COO)](SCN)2. Inorg Chem 1978; 17: 1296-1303.
| Crossref | Google Scholar |
2 Roecker L, Dickman MH, Nosco DL, Doedens RJ, Deutsch E. Syntheses and characterization of bis(ethylenediamine)cobalt(III) complexes containing chelated thioether and selenoether ligands. Single-crystal structure analysis of [(1-ethyl-2,5-dioxo-3-pyrrolidinyl 2-aminoethyl thioether)-N,S]bis(ethylenediamine)cobalt(III) perchlorate. Inorg Chem 1983; 22: 2022-2028.
| Crossref | Google Scholar |
3 Roecker L, Lydon JD, Willis AC, Sargeson AM, Deutsch E. Intramolecular quadridentate synthesis: X-ray crystallographic analysis of [(NH2CH2CH2NH2)Co(NH2(CH2)2N=C(NH2)CH2S(CH2)2NH2)](CF3SO3)3.H2O. Aust J Chem 1989; 42: 339-347.
| Crossref | Google Scholar |
4 Roecker L, Deutsch E. Base hydrolysis of bis(ethylenediamine)cobalt(III) complexes containing chelated thioether and selenoether ligands. Observation of dramatic medium effects. Inorg Chem 1985; 24: 16-24.
| Crossref | Google Scholar |
5 Weschler CJ, Deutsch E. Synthesis, characterization, and aquation kinetics of thiolatobis(ethylenediamine)chromium(III) complexes. Inorg Chem 1973; 12: 2682-2690.
| Crossref | Google Scholar |
6 Gahan LR, Hambley TW, Sargeson AM, Snow MR. Encapsulated metal ions: synthesis, structure, and spectra of nitrogen-sulfur ligand atom cages containing cobalt(III) and cobalt(II). Inorg Chem 1982; 21: 2699-2706.
| Crossref | Google Scholar |
7 Jackson WG. Base catalyzed hydrolysis of aminecobalt(III) complexes: from the beginnings to the present. Inorg Rxn Mech 2002; 4: 1-30.
| Crossref | Google Scholar |
8 Hay RW, Cropp PL. Kinetics of base hydrolysis of chloropenta-ammines of the type cis-[Coen2RNH2Cl]2+ in aqueous solution at 25°. J Chem Soc (A) 1969; 42-44.
| Crossref | Google Scholar |
9 Roecker L, Anderson A, Al-Haddad A, Engineer C, Fetty J, Kiaza C, Noinaj N, Coker NL, Krause J, Parkin S. Reaction of 2-pyridylmethylthiourea derivatives with [(en)2Co(OSO2CF3)2]+ induces hypodentate coordination of an ethylenediamine ligand. Aust J Chem 2014; 67: 933-943.
| Crossref | Google Scholar |
10 Roecker L, Aiyegbo A, Al-Haddad A, Fletcher E, Kc R, Hurst J, Lane T, Larsen R, Noinaj N, Teh SL, Wade SK, Parkin S. Synthesis and characterisation of [(en)2Co]3+ complexes coordinated by substituted thiourea ligands. Aust J Chem 2013; 66: 944-951.
| Crossref | Google Scholar |
11 Roecker L. Synthesis and base hydrolysis of a cobalt(III) complex coordinated by a thioether ligand. J Chem Educ 2008; 85: 1562-1564.
| Crossref | Google Scholar |
13 Ishibashi H, Uegaki M, Sakai M, Takeda Y. Base-promoted aminoethylation of thiols with 2-oxazolidinones: a simple synthesis of 2-aminoethyl sulfides. Tetrahedron 2001; 57: 2115-2120.
| Crossref | Google Scholar |
14 Bailar JC. cis- and trans-Dichlorobis(ethylenediamine)cobalt(III) chloride and the resolution of the cis form. Inorg. Synth. 1946; 2: 222-224.
| Crossref | Google Scholar |
16 Parkin S, Moezzi B, Hope H. XABS2: an empirical absorption correction program. J Appl Cryst 1995; 28: 53-56.
| Crossref | Google Scholar |
17 Sheldrick GM. A short history of SHELX. Acta Cryst 2008; A64: 112-122.
| Crossref | Google Scholar |
18 Sheldrick GM. Crystal structure refinement with SHELXL. Acta Cryst 2015; C71: 3-8.
| Crossref | Google Scholar |