High refractive index liquids based on meta-substituted s-alkyl thioethers

A liquid aromatic thioether, satisfying formula A1, A2, A3, or A4:

• wherein X′=Cl, Br, I, or X″, and
• X″=S(CH2CHR1)-Z,
• wherein Z=C(O)G, C(O)A-G, or P(O)(OR2)2,
• wherein G=H, Me, Et, iProp, nProp, or tBut,
• A=O or NH,
• R1=H or Me, and
• R2=Me, Et, nProp, or iProp;
• wherein X′=Cl, Br, I, or X″′, and
• X″′=S(CH2CHR1)-Z′,
• wherein Z′ is as defined above,
• wherein each R1, R3, and R3′ is independently H or Me,
• n=2 or 3, and
• Y=H, Me, Et, iProp, nProp, or tBut;
• wherein X′=I or Br, and
• R4=a C1 to C8 linear or branched alkyl chain, a carbocycle with 5 or 6 C-atoms, or Z″ as defined above, wherein m and n are each independently 1, 2, or 3 and wherein one or two non-neighbouring ring-forming —CH2-moieties of Z″ are replaced by sulfur;
• and
• wherein R4 and R5 are each independently a C1 to C8 linear or branched alkyl chain, a carbocycle with 5 or 6 C-atoms, or Z″ as defined above.