in or a cyclic group, optionally comprising a hetero atom or an oxo group, and is an alkylene group having 1 to 20 carbon atoms such as methylene, ethylene, propylene, butylene; the alkyl group represented by W2 is an alkyl group from among the possibilities for groups represented by Y5 and Y6; the alkoxy group represented by W2 is one which comprises 1 to 8 carbon atoms such as a methoxy, ethoxy,