Unusual Co-Crystallization of both Monomeric and Dimeric Forms of Cu[PhN(py)quin]Cl2

Abstract

The aryl functionalized diquinolyl amine MesN(quin)2 (1) and the pyridyl-quinolyl amine (2,6-iPr2C6H3)N(py)quin (2) have been prepared via palladium catalyzed cross-coupling of substituted anilines with 2-chloroquinoline. The HBF4 acid salts of (2,6-iPr2C6H3)N(quin)2 (3) and MesN(py)quin (4), as well as the copper complex [Cu{PhN(py)quin}Cl2] (5) have been prepared in order to probe the effect that ligand coordination has on its geometry. The molecular structures of each have been determined by X-ray crystallography. The free ligands 1 and 2 crystallize in three-bladed propellar conformations, having smaller degrees of “pitch” between the two heterocycles than either has with the aryl “blade”, allowing for greater heterocycle π-system overlap with the amine lone pair. Acid confinement of similar ligands in 3 and 4 results in forced coplanarity of the two heterocycles, which coordinate the HBF4 proton in an asymmetric fashion. The copper complex 5 crystallizes with both monomeric and dimeric forms present in the asymmetric unit. Crystal data: (1) Space group P21/c, a = 14.058(3), b = 12.202(2), c = 12.831(3) A, β = 104.61(3)°, V = 2129.8(8) A3, Z = 4, R = 0.0596, wR2 = 0.1453. (2) Space group P21/c, a = 22.250(4), b = 8.628(2), c = 23.031(5) A, β = 92.88(3)°, V = 4370(2) A3, Z = 8, R = 0.0514, wR2 = 0.1323. (3) Space group Pbca, a = 13.886(3), b = 18.016(4), c = 21.347(4) A, V = 5340(2) A3, Z = 8, R = 0.0722, wR2 = 0.1635. (4) Space group P21/c, a = 10.629(2), b = 18.489(4), c = 10.907(2) A, β = 92.88(3), V = 2140.6(7) A3, Z = 4, R = 0.0551, wR2 = 0.1531. (5) Space group $${\text P}\bar{1}$$ , a = 9.706(2), b = 11.325(2), c = 17.322(4) A, α = 98.28(3), β = 94.85(3), γ = 91.83(3)°, V = 1875.6(7) A3, Z = 1, R = 0.0481, wR2 = 0.0946. The molecular structures of free ligands MesN(quin)2 and (2,6-iPr2C6H3)N(py)quin, as well as the acid salts [H{(2,6-iPr2C6H3)N(quin)2}]BF4 and [H{MesN(py)quin}]BF4, and the copper complex Cu{PhN(py)quin]Cl2 have been determined. The asymmetric unit of the copper complex contains both monomeric and dimeric forms of the compound.