TY - JOUR

T1 - Beyond the limits of X-ray powder diffraction

T2 - Description of the nonperiodic subnetworks in aluminophosphate-cloverite by NMR crystallography

AU - Martineau, Charlotte

AU - Bouchevreau, Boris

AU - Tian, Zhijian

AU - Lohmeier, Sven Jare

AU - Behrens, Peter

AU - Taulelle, Francis

PY - 2011/10/11

Y1 - 2011/10/11

N2 - NMR crystallography of the fluorinated aluminophosphate cloverite is presented, with an emphasis on the description of the nonperiodic part of the compound, i.e., the fluorine and organic subnetworks, which are very difficult to access by usual X-ray powder diffraction methods. Multinuclear high-resolution 1D 27Al and 31P NMR support the main cloverite-type topological features previously proposed for aluminum cloverite from powder X-ray diffraction. Spatial proximities are extracted from the 2D 31P-31P and 27Al-31P NMR spectra, allowing a full assignment of the 31P and 27Al resonances to the corresponding phosphorus and aluminum sites in the structure. To go further into the description of the main periodic framework, 13C, 15N, and 1H 1D and 1H-1H and 1H-31P 2D NMR measurements are employed, allowing the characterization and selective locations of the two costructural-directing agents in the pores and channels of the framework. The nonperiodic fluorine subnetwork is described by means of 19F-X (X = 27Al and 31P) 2D NMR experiments. Two kinds of fluorine atoms are distinguished: F- ions trapped in D4R units and F atoms covalently bonded to terminal Al or P atoms and which interrupt the AlPO network. Through the example of aluminum cloverite, we show that, despite the considerable complexity of such systems, an extremely detailed structural model can be obtained, including the simple rules that allow the description of the nonperiodic subnetworks that tailor the structure and properties of a compound, by coupling powder X-ray diffraction and high-resolution NMR data in a generalized crystallography approach.

AB - NMR crystallography of the fluorinated aluminophosphate cloverite is presented, with an emphasis on the description of the nonperiodic part of the compound, i.e., the fluorine and organic subnetworks, which are very difficult to access by usual X-ray powder diffraction methods. Multinuclear high-resolution 1D 27Al and 31P NMR support the main cloverite-type topological features previously proposed for aluminum cloverite from powder X-ray diffraction. Spatial proximities are extracted from the 2D 31P-31P and 27Al-31P NMR spectra, allowing a full assignment of the 31P and 27Al resonances to the corresponding phosphorus and aluminum sites in the structure. To go further into the description of the main periodic framework, 13C, 15N, and 1H 1D and 1H-1H and 1H-31P 2D NMR measurements are employed, allowing the characterization and selective locations of the two costructural-directing agents in the pores and channels of the framework. The nonperiodic fluorine subnetwork is described by means of 19F-X (X = 27Al and 31P) 2D NMR experiments. Two kinds of fluorine atoms are distinguished: F- ions trapped in D4R units and F atoms covalently bonded to terminal Al or P atoms and which interrupt the AlPO network. Through the example of aluminum cloverite, we show that, despite the considerable complexity of such systems, an extremely detailed structural model can be obtained, including the simple rules that allow the description of the nonperiodic subnetworks that tailor the structure and properties of a compound, by coupling powder X-ray diffraction and high-resolution NMR data in a generalized crystallography approach.

KW - 2D correlation

KW - cloverite

KW - fluorinated aluminophosphate

KW - generalized crystallography

KW - high-resolution NMR

KW - NMR crystallography

UR - http://www.scopus.com/inward/record.url?scp=80455132480&partnerID=8YFLogxK

U2 - 10.1021/cm2021033

DO - 10.1021/cm2021033

M3 - Article

AN - SCOPUS:80455132480

VL - 23

SP - 4799

EP - 4809

JO - Chemistry of materials

JF - Chemistry of materials

SN - 0897-4756

IS - 21

ER -