(Thio) (meth) acrylate monomers, intermediate compounds for the synthesis of these monomers, polymerizable compositions and polymers obtained, and their optical and ophthalmic uses

Polymerizable composition, comprising at least one monomer of the formula:

• in which Z represents H or CH3 and X represents O or S, and
• when X represents S, Y is a radical of formula:
• where R1 and R2 are chosen from H, alkyl radicals, or alternatively R1 and R2 together form a —(CH2)5— radical and n1 is an integer from 0 to 2 inclusive, and
• when X represents O, Y is the radical (a) defined above or a radical chosen from the radicals of formulae:
• which n2 is an integer equal to 1 or 2, R3 represents H or an alkyl group, R4 represents H, an alkyl group or an aryl group;
• and R5 is a divalent radical chosen from the groups of the following formulae:
• in which:
• A denotes an aryl group, or an alkyl group, R and R″ denote, independently of each other, H, an alkyl group, aryl, or R′ or R″ can be a group
• where Ra is an alkylene group, and Rb is H or CH3, n takes the values 0 or 1 and 0≦m (integer ≦4), and
• and R6 denotes H or a methyl group, and Cy denotes a substituted or unsubstituted aryl ring.