Complexes for transferring nucleic acids into cells

Complex comprising a linear cationic polymer which is soluble or dispersible in water and has hydrophobic substituents, and at least one nucleic acid, wherein the linear catonic polymer comprises a main polymer chain,

• and wherein the polymer has the following formula:
• in which on the acyl group in each individual [CH2—CH2—N] unit
• R1 is hydrogen, methyl or ethyl, and R1 is the same in all occurrences throughout the polymer, and
• R2 is alkyl with 1 to 22 carbon atoms, and R2 is the same in all occurrences throughout the polymer;
• and in which
• R3 and R4 are, independently of one another, hydrogen or alkyl with 1 to 24 carbon atoms, or have a structure dependent on the acid initiator,
• and where
• R5 is a substituent dependent on the termination reaction, and where the average degree of polymerization P=(m+n) is in the range from 45 to 5250, and n=a×P with 0.001<a<0.1, where the units m and n are randomly distributed in the polymer.