Hydrogen-Bonded “Zeolite-like” Frameworks and Functional Materials

2009 Spring Symposium

 
Michael Ward
New York Uni­ver­si­ty
Depart­ment of Chem­istry
New York, NY


Abstract — Guest-free guani­dini­um organomono­sul­fonates (GMS) and their inclu­sion com­pounds dis­play a vari­ety of lamel­lar crys­talline archi­tec­tures dis­tin­guished by dif­fer­ent “up-down” pro­jec­tions of the organomono­sul­fonate residues on either side of a two-dimen­sion­al (2D) hydro­gen-bond­ing net­work of com­ple­men­tary guani­dini­um ions (G) and sul­fonate moi­eties (S), the so-called GS sheet. The GS sheets in the inclu­sion com­pounds behave as “mol­e­c­u­lar jaws” in which organomono­sul­fonate groups pro­ject­ing from oppos­ing sheets clamp down on the guest mol­e­cules, form­ing ordered inter­dig­i­tat­ed arrays of the host organ­ic groups and guests. Guest-free and inclu­sion com­pounds dis­play a vari­ety of archi­tec­tures that reveal the struc­tur­al integri­ty of two-dimen­sion­al GS sheet and the unique abil­i­ty of these hosts to con­form to the steric demands of the organ­ic guests. Cer­tain GMS host-guest com­bi­na­tions prompt for­ma­tion of tubu­lar inclu­sion com­pounds in which the GS sheet curls into cylin­ders with reten­tion of the 2D GS net­work. The cylin­ders assem­ble into hexag­o­nal arrays through inter­dig­i­ta­tion of the organosul­fonate residues that project from their out­er sur­faces, crys­tal­liz­ing in high sym­me­try trig­o­nal or hexag­o­nal space groups. This unique exam­ple of net­work cur­va­ture and struc­tur­al iso­merism between lamel­lar and cylin­dri­cal struc­tures, with reten­tion of supramol­e­c­u­lar con­nec­tiv­i­ty, is rem­i­nis­cent of the phase behav­ior observed in sur­fac­tant microstruc­tures and block copoly­mers. The large num­ber of host-guest com­bi­na­tions explored here per­mits group­ing of the inclu­sion com­pound archi­tec­tures accord­ing to the shape of the guests and the rel­a­tive vol­umes of the organomono­sul­fonate groups, enabling more reli­able struc­ture pre­dic­tion for this class of com­pounds than for mol­e­c­u­lar crys­tals in gen­er­al. More recent results that demon­strate the inclu­sion of laser dyes with con­trolled states of aggre­ga­tion, the intro­duc­tion of mol­e­c­u­lar cap­sules, and unusu­al high sym­me­try struc­tures will be described.

Speaker’s Biog­ra­phy — Michael Ward earned his B.A in Chem­istry from William Pater­son Col­lege of New Jer­sey in 1977, and PhD in Chem­istry from Prince­ton Uni­ver­si­ty in 1981. He cur­rent­ly serves as the Sil­ver Pro­fes­sor and Chair, Depart­ment of Chem­istry, Direc­tor of Mol­e­c­u­lar Design Insti­tute and Direc­tor of Mate­ri­als Research Sci­ence and Engi­neer­ing Cen­ter at New York Uni­ver­si­ty, New York City, NY. He is also Edi­tor of Chem­istry of Mate­ri­als. His research inter­ests include syn­the­sis of mol­e­c­u­lar mate­ri­als and crys­tal engi­neer­ing, phys­i­cal and elec­tron­ic prop­er­ties of mol­e­c­u­lar solids, nucle­ation and growth of organ­ic and pro­tein crys­tals, scan­ning probe microscopy and inter­fa­cial phe­nom­e­na.