Let l be prime number, m 0 an integer prime to l andthe cyclotomic Iwasawa algebra of "tame level m 0 ". Usingétale cohomology one can define a certain perfect complex of Λ-modules ∆ ∞ (see section 1.2 below) and a certain basis L of the invertible In this article we give a proof of Theorem 1.2 for l = 2. This was claimed as Theorem 5.2 in the survey paper [9] but the proof given there, arguing separately for each height one prime q of Λ, is incomplete at primes q which contain l = 2. The argument given in [9][p.95] is an attempt to use only knowledge of the cohomology as well as perfectness of the complex ∆ ∞ q but it turns out that this information is insufficient. Here we shall use the techniques of the paper [6], such as the Coleman homomorphism and Leopoldt's result on the Galois structure of cyclotomic integer rings, to construct the complex ∆ ∞ q more explicitly and thereby verify Theorem 1.2.What is peculiar to the situation l = 2 is not only that Λ is never regular (due to the presence of the complex conjugation) but also that the l-adic L-function L is quite differently defined for even and odd characters. For even characters one interpolates first derivatives of Dirichlet L-functions via cyclotomic units, for odd characters one interpolates the values of these functions via Stickelberger elements. A proof of Theorem 1.2 therefore in some sense involves a "mod 2 congruence" between Stickelberger elements and cyclotomic units. Given the explicit nature of both objects it is perhaps not surprising that this congruence turns out to be an elementary statement which is arrived at, however, only after some rather arduous computations. The statement is the following. Let M ≡ 1 mod 4 be an integer,