One of the most appealing features of[Pd_(2)L_(4)]^(4+)cages is their well-defined cavities,giving binding affinity for specific vips.If seeking to bind larger and more complex vips,an attractive strategy is to le...One of the most appealing features of[Pd_(2)L_(4)]^(4+)cages is their well-defined cavities,giving binding affinity for specific vips.If seeking to bind larger and more complex vips,an attractive strategy is to lengthen the ligand backbone and therefore the inter-palladium(Ⅱ)distance and cavity length.In comparison to large hollow[Pd_(n)L_(2n)]^(2n+)polyhedra,this approach retains a well-ordered cavity environment.We report here a novel ligand,1,3-bis(4-(4-ethynylpyridine)-phenyl)-adamantane,that has a hydrophobic bis(phenyl)adamantane core and forms[Pd_(2)L_(4)]^(4+)cages with a large 19Å inter-palladium(Ⅱ)cavity length.This cage binds long designer anions:naphthalimide sulfonates at≥15Å in length,which consist of two distinct domains:a naphthalimide and a phenyl sulfonate.This binding derives from hydrogen bonding between the endohedral pyridyl protons of the cage and the phenyl sulfonate group,and π-hydrophobic interactions between the adamantane core and the naphthalimide unit.The strength of binding depends on the degree of electron deficiency of the naphthalimide,brought about by the nature of substituents on this moiety,with binding constants for monoanionic vips ranging from 400 to 1800 M^(-1).The host/vip stoichiometry was found to be 1:2,unless the vip possessed a second sulfonate group,and was small enough to fit end-to-end within the cavity,in which case the stoichiometry was 1:1,and resulted in a high binding constant(for DMSO solvent)of 6100 M^(-1).This work demonstrates the subtle interplay and potential between cages and vips that are both large and that both have distinct dual zones able to interact with each other,and offers a pathway to specific and tunable binding of large vips.展开更多
The literature tetradentate acyclic Schiff base ligand HL^(H-OH)(from the 2:1 reaction of pyridine-2-carboxylaldehyde with 1,3-diamino-2-propanol)was alkylated using a range of 1-bromoalkanes varying in length,BrR(R=C...The literature tetradentate acyclic Schiff base ligand HL^(H-OH)(from the 2:1 reaction of pyridine-2-carboxylaldehyde with 1,3-diamino-2-propanol)was alkylated using a range of 1-bromoalkanes varying in length,BrR(R=C_(10)H_(21),C_(16)H_(33),C_(18)H_(37),C_(20)H_(41)and C_(22)H_(45))to yield five new ligands,LH-OR.The synthesis,magnetic and Langmuir characteristics of the corresponding family of six neutral mononuclear Fe(II)complexes,the parent complex[FeII(HLH-OH)(NCBH_(3))_(2)]and the five alkylated ligand derivatives[Fe^(II)(L_(H-OR))(NCBH_(3))_(2)],is detailed.The solution spin crossover temperature,T_(12),can be tuned by two methods:(a)increasing the solvent polarity index(P’)from 5 to 7 increases T_(12)by 172 K,whereas(b)increasing the tail length from C_(10)to C_(22)decreases T_(12)by 115 K.In both cases strong linear correlations are observed,so both of these,choice of solvent(R^(2)=0.99,albeit only for three solvents)and of tail length(R^(2)=0.98,for five complexes),are levers for the predictable tuning of the spin state in advance of synthesis.The compounds with longer tails,C_(18),C_(20)and C_(22),showed a small window of thermal hysteresis(<5 K)in D_(3)-acetonitrile solution.Water solubility hampered the formation of Langmuir films of these complexes.But the use of a 1:1 mixture of stearic acid with[Fe^(II)(LH-OC_(18))(NCBH_(3))_(2)]facilitated the formation of a stable Langmuir film,a monolayer of which was transferred onto a quartz slide:multi-layering was not possible.展开更多
基金the University of Canterbury,the Australian National University,Massey University Albany and the University of Otago for fundingthe MacDiarmid Institute for funding+1 种基金the Royal Society of New Zealand for a Rutherford Postdoctoral Fellowshipthe Australian Research Council for a DECRA Fellowship.
文摘One of the most appealing features of[Pd_(2)L_(4)]^(4+)cages is their well-defined cavities,giving binding affinity for specific vips.If seeking to bind larger and more complex vips,an attractive strategy is to lengthen the ligand backbone and therefore the inter-palladium(Ⅱ)distance and cavity length.In comparison to large hollow[Pd_(n)L_(2n)]^(2n+)polyhedra,this approach retains a well-ordered cavity environment.We report here a novel ligand,1,3-bis(4-(4-ethynylpyridine)-phenyl)-adamantane,that has a hydrophobic bis(phenyl)adamantane core and forms[Pd_(2)L_(4)]^(4+)cages with a large 19Å inter-palladium(Ⅱ)cavity length.This cage binds long designer anions:naphthalimide sulfonates at≥15Å in length,which consist of two distinct domains:a naphthalimide and a phenyl sulfonate.This binding derives from hydrogen bonding between the endohedral pyridyl protons of the cage and the phenyl sulfonate group,and π-hydrophobic interactions between the adamantane core and the naphthalimide unit.The strength of binding depends on the degree of electron deficiency of the naphthalimide,brought about by the nature of substituents on this moiety,with binding constants for monoanionic vips ranging from 400 to 1800 M^(-1).The host/vip stoichiometry was found to be 1:2,unless the vip possessed a second sulfonate group,and was small enough to fit end-to-end within the cavity,in which case the stoichiometry was 1:1,and resulted in a high binding constant(for DMSO solvent)of 6100 M^(-1).This work demonstrates the subtle interplay and potential between cages and vips that are both large and that both have distinct dual zones able to interact with each other,and offers a pathway to specific and tunable binding of large vips.
文摘The literature tetradentate acyclic Schiff base ligand HL^(H-OH)(from the 2:1 reaction of pyridine-2-carboxylaldehyde with 1,3-diamino-2-propanol)was alkylated using a range of 1-bromoalkanes varying in length,BrR(R=C_(10)H_(21),C_(16)H_(33),C_(18)H_(37),C_(20)H_(41)and C_(22)H_(45))to yield five new ligands,LH-OR.The synthesis,magnetic and Langmuir characteristics of the corresponding family of six neutral mononuclear Fe(II)complexes,the parent complex[FeII(HLH-OH)(NCBH_(3))_(2)]and the five alkylated ligand derivatives[Fe^(II)(L_(H-OR))(NCBH_(3))_(2)],is detailed.The solution spin crossover temperature,T_(12),can be tuned by two methods:(a)increasing the solvent polarity index(P’)from 5 to 7 increases T_(12)by 172 K,whereas(b)increasing the tail length from C_(10)to C_(22)decreases T_(12)by 115 K.In both cases strong linear correlations are observed,so both of these,choice of solvent(R^(2)=0.99,albeit only for three solvents)and of tail length(R^(2)=0.98,for five complexes),are levers for the predictable tuning of the spin state in advance of synthesis.The compounds with longer tails,C_(18),C_(20)and C_(22),showed a small window of thermal hysteresis(<5 K)in D_(3)-acetonitrile solution.Water solubility hampered the formation of Langmuir films of these complexes.But the use of a 1:1 mixture of stearic acid with[Fe^(II)(LH-OC_(18))(NCBH_(3))_(2)]facilitated the formation of a stable Langmuir film,a monolayer of which was transferred onto a quartz slide:multi-layering was not possible.
