Tin Scavenging with SiliaMetS Cysteine & TAAcONa
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Organotin compounds are versatile reagents commonly used in organic synthesis. The two main applications are in Stille couplings or in radical reactions. The removal of tin residues can often be an issue due to the well known high toxicity of this metal.
Traditional removal methods for this particular type of impurity are treatment with an aqueous solution of KF, NH4OH or NaOH, or with bases such as DBU. However, the efficiency of these methods can vary and may be inapplicable for particular compounds.
SiliaMetS Cysteine & TAAcONa can be used as an efficient method to remove tin residues from organic mixtures as demonstrated by the exemples below.
Tin Scavenging using SiliaMetS Cysteine (TAAcONa) | ||||||
Reactions | Inital Concentration |
SiliaMetS Cysteine | SiliaMetS TAAcONa | |||
4 eq., 4 h, 22°C [2 treatments] |
8 eq., 4 h, 22°C | 4 eq., 4 h, 22°C [2 treatments] |
8 eq., 4 h, 22°C | 4 eq., 16 h, 22°C | ||
Stille coupling #11 | 3 385 ppm | 99 % | 64 % | 96 % | 62 % | - |
Stille coupling #21 | 981 ppm | 90 % | 66 % | 66 % | 50 % | - |
Radical Reduction | 4 090 ppm | 92 % | 88 % | 90 % | 90 % | 90 % |
1Pd residues were completely removed after only one treatment with SiliaMetS Cysteine. |
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SiliaMetS TAAcONa nec (R69230B)
SiliaMetS TAAcONa or (or SiliaMetS Triaminetetraacetate, sodium salt) is a silica bound metal scavenger for Pd(II), Ni(II) and Cu. It is the supported version of EDTA in its sodium salt form. It is an effective scavenger for metals in higher oxidation state, 2+ or higher. -
SiliaMetS Cysteine (CYS) (R80530B)
SiliaMetS Cysteine (Si-Cys) is the silica bound equivalent of the amino acid Cysteine. It is a versatile metal scavenger for a variety of metals including Pd, Sn, Ru, Pt, Cu, Rh, Cd and Sc under a wide range of conditions and the preferred metal scavenger for tin residues.