In one aspect, the present invention relates to compounds of Formula (I) and to pharmaceutically acceptable salts thereof, wherein: n is 1 to 4; and R3 in each occurrence is independently selected from —X—R5, —W—R6, —C(O)—N(R3a)—S(O)2—R3b, —C(R3a)═N—R3y, C(R3a)═N—N(R3a)—C(O)—R3b, C(R3a)═N—N(R3a)—C(O)2—R3b, —C(R3a)═N—N(R3y)2, —C(R3a)═N—N(R3a)—C(O)—N(R3y)2, —C(NR3a)2)═N—R3y, —C(N(R3a)2)═N—OR3y, —C(N(R3a)2)═N—C(O)—R3b, —C(N(R3a)2═N—S(0)2—R3b, —C(N(R3a)2)═N—CN, —N═C(R3y)2, —N(R3a)—S(O)2—N(R3y)2, —N(R3a)—N(R3y2, —N(R3a)—C(O)—N(R3y)2, —N(R3a)—C(O)—N(R3a)—S(O)2—R3b, —N(R3a)—C(R3a)═N(R3y), —N(R3a)—C(R3a)═N—OR3y, —N(R3a)—C(R3a)═N—C(O)—R3b, —N(R3a)—C(R3a)═N—S(O)2R—3b, —N(R3a)—C(R3a)═N—CN, —N(R3a)—C(N(R3a)2)═N—R3y, —N(R3a)—C(N(R3a)2)═N—OR3y, —N(R3a)—C(N(R3a)2)═N—C(O)—R3b, —N(R3a)—C(N(R3a)2)—N—S(O)2—R3b, —N(R3a)—C(N(R3a)2)—N—CN, —O—C(O)—R3, and —Si(R3b)3; to methods of using them to treat bacterial infections, and to methods for their preparation.