Amino acyl cephalosporin derivatives

Antibacterial cephalosporin compounds of the Formula (I): (I) wherein W is a pharmaceutically acceptable salt or a carboxyl-protecting group; n is an integer from 1 to 2; -X- is -X1- where the X1 moieties are the same or different and selected from the group consisting of (D) or (L) Y is -O-; wherein R1 is selected from the group consisting of: R2 is H, -CH2R4, -CHR52 or -CR53, wherein R4 is H, F, Cl, Br, -OH, -CN, -CH(CH3)2, -CH2(OH), or -C 3BOND CH, where Q1, Q2 and Q3 are the same or different and selected from the group consisting of H, F, Cl or Br; R5 is F, Cl or Br; and Z1 is H or an amino protecting group.