{μ-6,6′-Dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethanylylidene)]diphenolato-1κ 4O 6 , O 1 , O 1′ , O 6′ ;2κ 4O 1 , N , N ′, O 1′ }(methanol-1κ O )(tetrafluoridoborato-1κ 2F , F ′)