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Abstract: The di-N-functionalized macrocycle 2,13-bis(2-phenacyl)-5,16-dimethyl-2,6,13,17-tetraazatricyclo[16.4.0.1.1807.12]docosane (H2L2) bearing two N-CH2COC6H5 groups has been prepared by the reaction of 3,14-dimethyl-2,6,13,17-tetraazatricyclo[16.4.0.07.12]docosane (L1) with phenacyl bromide. Interestingly, H2L2 reacts with Ni2+ ion to form two geometric isomers, trans-[Ni(H2L2)]2+ and cis-[Ni(H2L2)]2+. The axial Ni–O (N-CH2COC6H5 group) bond distance (2.080(2)Å) of trans-[Ni(H2L2)](ClO4)2·2DMSO is shorter than the in-plane Ni–N distances (2.096(2) and 2.100(2)Å). However, the Ni–O distances (2.105(2) and 2.124(2)Å) of cis-[Ni(H2L2)](ClO4)2·H2O are considerably longer than the Ni–N distances (2.053(2)–2.086(2)Å). Each N-CH2COC6H5 group of trans-[Ni(H2L2)]2+ and cis-[Ni(H2L2)]2+ exists as its keto form in the solid state and in various solvents. Two N-CH2COC6H5 groups of trans-[Ni(H2L2)]2+ are readily deprotonated in basic aqueous solutions, producing the enolate form trans-[Ni(L2)]. On the other hand, cis-[Ni(H2L2)]2+ undergoes deprotonation to yield cis-[Ni(HL2)]+, in which one N-CH2COC6H5 group is not deprotonated, under similar conditions. [Copyright &y& Elsevier]

The cis -octahedral complex [NiL 2 ](ClO 4 ) 2 ·H 2 O ( 1 ) (L 2 = C-racemic -1,8-bis( N -2-aminoethyl)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane), bearing two coordinated N -CH 2 CH 2 NH 2 pendant arms, has been prepared by a reaction of the N -CH 2 CN groups of [Ni(L 1 )(CH 3 COO)] + (L 1 = C-racemic -1,8-bis(cyanomethyl)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) with NaBH 4 in acetonitrile. The trigonal bipyramidal complex [Ni(HL 2 )](ClO 4 ) 3 ·H 2 O ( 2 ) (HL 2 = a mono-protonated form of L 2 ), in which the primary amino group of the coordinated N -CH 2 CH 2 NH 2 group occupies one of the three equatorial positions, has also been prepared by the addition of HClO 4 to a methanol solution of 1 . The equatorial Ni–N ( N -CH 2 CH 2 NH 2 group) distance (2.076(2) Å) of 2 is similar to other equatorial Ni–N (macrocyclic ring) distances (2.073(2) and 2.075(2) Å), but is significantly shorter than the Ni–N ( N -CH 2 CH 2 NH 2 groups) distances (2.170(3) and 2.190(3) Å) of 1 . Interestingly, the coordinated N -CH 2 CH 2 NH 2 group of 2 is inert to protonation. [ABSTRACT FROM AUTHOR]

Abstract: Salicylaldehyde reacts with one of the N-CH2CN pendant arms of [CuL1]2+ (L1 =2,13-bis(N-cyanoethyl)-3,14-dimethyl-2,6,13,17-tetraazatricyclo[16.4.0.07.12]docosane) to produce [CuL2]2+ bearing one 1-hydroxy-2-aza-4-oxanaphthalene ring. Interestingly, [CuL2]2+ readily reacts with methanol to yield [CuL3]2+ bearing one 1-methoxy-2-aza-4-oxa-3-naphthyl ring. The heterobicyclic functional pendant arms of [CuL2]2+ and [CuL3]2+ are involved in coordination, and each complex has distorted square-pyramidal coordination geometry. Both [CuL2]2+ and [CuL3]2+ are hydrolyzed to [CuL4]2+ bearing one N-CH2CN and one N-CH2CONH2 pendant arms in basic aqueous solutions, though they are quite stable in acidic aqueous solutions. [Copyright &y& Elsevier]