Organometallic derivatives of penicillin

A semi-synthetic penicillin of the formula:

• ##STR8## wherein:
• L is selected from the group consisting of ##STR9## n being an integer from 0 to 2, and each R.sub.1 and R.sub.2 are the same or different members of the group consisting of hydrogen, alkyl, aryl, alkaryl, aralkyl, alkoxy, --CHO, --COOH, --CH.sub.2 N(CH.sub.3).sub.2, --NH.sub.2, --C.sub.6 H.sub.5, --CH.sub.2 SH, --CH.sub.2 I, --CO--CH.sub.2 Z wherein Z is Cl, Br or I, --MeR.sub.3 wherein Me is Si, Ge or Sn and R is alkyl containing 1 to 3 carbon atoms, or R.sub.1 and R.sub.2 taken together form a cycloalkyl group;
• and M is selected from the group consisting of pi-bonded aromatic organometallic complexes of a transition metal represented by the formulae:
• ##STR10## X and Y being the same of different members of the group consisting of hydrogen, alkyl, aryl, aralkyl, alkaryl, --CHO, --COOH, --CH.sub.2 N(CH.sub.3).sub.2, --NH.sub.2, --C.sub.6 H.sub.5, --CH.sub.2 SH, --CH I or --CO--CH.sub.2 Z wherein Z is Cl, Br or I, --MeR.sub.3 wherein Me is defined as above, or another penicillin nucleus:
• ##STR11## L' represents a methylene linkage or --O--, and m is 0 or 1, or a pharmaceutically acceptable salt thereof.