All bonds authorized or issued pursuant to this section under or pursuant to proceedings of the State Bond Commission had or taken prior to July 1, 1974, shall be general obligations of the state and the full faith and credit of the state of Connecticut are pledged for the payment of the principal of and interest on said bonds as the same become due and accordingly, and as part of the contract of the state with the holders of said bonds, appropriation of all amounts necessary for punctual payment of such principal and interest is hereby made, and the Treasurer shall pay such principal and interest as the same become due. All of said bonds and temporary notes in anticipation of the money to be derived from the sale thereof may be sold, executed, issued and delivered, and their proceeds collected, held, invested, applied and used, in all respects as authorized under the provisions of the general statutes in effect on June 30, 1974. Said bonds are made and declared to be (1) legal investments for savings banks and trustees unless otherwise provided in the instrument creating the trust, (2) securities in which all public officers and bodies, all insurance companies and associations and persons carrying on an insurance business, all banks, bankers, trust companies, savings banks and savings associations, including savings and loan associations, building and loan associations, investment companies and persons carrying on a banking or investment business, all administrators, guardians, executors, trustees and other fiduciaries and all persons whatsoever who are or may be authorized to invest in bonds of the state, may properly and legally invest funds including capital in their control or belonging to them, and (3) securities which may be deposited with and shall be received by all public officers and bodies for any purpose for which the deposit of bonds of the state is or may be authorized. All such bonds, their transfer and the income therefrom including any profit on the sale or transfer thereof, shall at all times be exempt from all taxation by the state or under its authority.