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                                                                       EXHIBIT F

                      AMENDMENT NO. 1 TO PURCHASE AGREEMENT

         THIS AMENDMENT NO. 1 TO PURCHASE AGREEMENT dated as of May 7, 2001
(this "Amendment") is made and entered into by and among UBS CAPITAL AMERICAS
III, L.P., a Delaware limited partnership ("Americas"), UBS CAPITAL LLC, a
Delaware limited liability company ("UBS Capital" and together with Americas,
the "Purchasers") and IFX CORPORATION, a Delaware corporation (the "Company").

                                    RECITALS

         WHEREAS, Purchasers and the Company are parties to that certain Stock
Purchase Agreement dated as of March 13, 2001 (the "Purchase Agreement"); and

         WHEREAS, the Company and Purchasers desire to amend the Purchase
Agreement as set forth below, which amendment has been approved by the
unanimous consent of the Board of Directors of the Company.

         NOW, THEREFORE, for valuable consideration, the receipt and sufficiency
of which are hereby acknowledged, the parties hereto agree as follows:

         1.       Amendments. The Schedule of Purchasers attached to the
                  Purchase Agreement is hereby deleted in its entirety and
                  replaced with the Schedule of Purchasers attached hereto as
                  Exhibit A.

         2.       Counterparts. This Amendment may be executed in one or more
                  counterparts and all such counterparts shall be deemed an
                  original, shall be construed together and shall constitute one
                  and the same instrument.

         3.       Choice of Law. This Amendment shall be governed by and
                  construed in accordance with the laws of the State of New York
                  without regard to the conflicts of law provisions thereof.

         4.       Defined Terms. Capitalized terms used and not defined herein
                  shall have the meanings ascribed to such terms in the Purchase
                  Agreement.

         5.       Continuance of Purchase Agreement. Except as provided herein,
                  the terms of the Purchase Agreement shall continue in full
                  force and effect.



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        IN WITNESS WHEREOF, the parties hereto have executed and delivered this
Amendment as of the first date written above.


                                      IFX CORPORATION


                                      By:  /s/ Joel Eidelstein
                                           ------------------------------------
                                           Name:  Joel Eidelstein
                                           Title: President


                                      UBS CAPITAL AMERICAS III, L.P.

                                      By:  UBS CAPITAL AMERICAS III, LLC



                                           By:    /s/ Mark O. Lama
                                                  -----------------------------
                                                  Name: Mark O. Lama
                                                  Title: Principal


                                           By:    /s/ Marc A. Unger
                                                  ----------------------
                                                  Name: Marc A. Unger
                                                  Title: Chief Financial Officer

                                      UBS CAPITAL LLC



                                      By:  /s/ Mark O. Lama
                                           ---------------------
                                           Name:  Mark O. Lama
                                           Title: Attorney-in-fact



                                      By:  /s/ Marc A. Unger
                                           ------------------------------------
                                           Name: Marc A. Unger
                                           Title: Attorney-in-fact






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                                    EXHIBIT A

                             SCHEDULE OF PURCHASERS

                                 IFX CORPORATION

                            SERIES B PREFERRED STOCK


             PURCHASER               NUMBER OF SHARES       NUMBER OF SHARES OF
                                   OF CLASS I SERIES B       CLASS II SERIES B
                                     PREFERRED STOCK          PREFERRED STOCK

UBS Capital Americas III, L.P.          3,794,421                 402,928
UBS Capital LLC                           199,706                  21,207





                                    Exh. A-1