Mark L. F. Phillips

(CN4H7)2·Zn3(HPO3)4, a three-dimensional framework zincophosphite: an example of template–template co-operation?

Abstract The hydrothermal synthesis and single crystal structure of (CN 4 H 7 ) 2 ·Zn 3 (HPO 3 ) 4 are reported. This phase is built up from a network of vertex-linked ZnO 4 and HPO 3 building units encapsulating the extra-framework animoguanidinium cations. A new type of three-dimensional network for the inorganic component of the structure arises, which contains polyhedral 4-, 6-, 8-, 12- and 16-rings. There are close (∼3.6 A), side-on, template–template contacts similar to those seen between pairs of guanidinium cations in molecular compounds. Crystal data: (CN 4 H 7 ) 2 ·Zn 3 (HPO 3 ) 4 , M r =666.30, monoclinic, space group P 2 1 / n (No. 14), a =10.2589 (4) A, b =29.5851 (12) A, c =13.7578 (5) A, β =103.303 (1)°, V =4063.6 (5) A 3 , Z =8, T =298 (2) K, R ( F )=0.0399, wR ( F 2 )=0.0792.

(CN3H6)2·Zn(HPO3)2: An open-framework zincophosphite built up from polyhedral 12-rings

The solution-mediated synthesis and single crystal structure of (CN3H6)2·Zn(HPO3)2 are reported. This phase is built up from a three-dimensional framework of vertex-linked ZnO4 and HPO3 building units encapsulating the extra-framework guanidinium cations. The structure is stabilised by template-to-framework hydrogen bonding. The inorganic framework contains polyhedral 12-rings and shows a surprising similarity to those of some known organically-templated zinc phosphates.

Inclusion tuning of nonlinear optical materials: KTP isomorphs

Abstract KTiOPO 4 (KTP) has shown itself to be a premier material for optical second harmonic generation, or SHG. Guest cations ranging in size from Ag + to Cs + can be partially or completely exchanged for K + , altering the structure and changing the reactivity and SHG coefficient of the material. In particular, partial deammoniation of NH 4 TiOPO 4 results in changes in the Ti-O bond lengths and a dramatic reduction in SHG. Many isomorphic derivatives of KTP have been made with 3- and 4-valent transition and main group metals are substituted for Ti, balancing charge by substituting F - and OH - for oxide in the Ti-O chain. Guest and host modification can be used to define nonlinear optic properties over a wide range.

Syntheses and structures of the open-framework phases (CH3NH3)3·Zn4O(AsO4)3 and (CH3NH3)3·Zn4O(PO4)3 related to the M3Zn4O(XO4)3·nH2O family

The solution-mediated syntheses and single crystal structures of the new open-framework phases (CH3NH3)3·Zn4O(AsO4)3 and (CH3NH3)3·Zn4O(PO4)3 are reported. These compounds are built up from vertex-sharing three-dimensional “OZn4” + ZnO4 + AsO4/PO4 tetrahedral frameworks encapsulating methylammonium cations in three-dimensional channel systems. These phases are closely related to the zeolite-like M3Zn4O(XO4)3·nH2O family of phases.

'TEMPLATE COOPERATION' EFFECT LEADING TO 18-RING CAVITIES IN THE OPEN-FRAMEWORK GUANIDINIUM ZINCOPHOSPHATE (CN3H6)3ZN7(H2O)4(PO4)6.H3O

The novel open-framework phase (CN3H6)3Zn7(H2O)4(PO4)6·H3O contains well ordered trios of guanidinium cations cooperating to template 18-ring cavities.

SHG Tuning In The KTP Structure Field

Potassium titanyl phosphate (KTP) has been shown to be a premier material for optical frequency second harmonic generation (SHG). Monovalent cations covering a large size range, e.g. Na+, Ag+, T1+, Rio+, and Cs+, have been used to partially or completely replace K+ in KTiOPO4 or KTiOAsO4, causing subtle structural variations which are frequently accompanied by marked changes in the nonlinear optical properties of these materials. The syntheses of (Na,K)TiOPO4 and (NH4,K)TiOAsO4, both by direct methods and by ion exchange with KTP and KTA are described here, and SHG intensities as a function of composition are presented. In the (Na,K)TiOPO4 phase space, powder SHG intensity initially remains constant with sodium content, then drops by a factor of ten when the KTP isostructure NaTiOPO4 is reached. In the (K,NH4)TiOAs04 system, SHG intensity is reduced by a factor of 5 between 40 and 50 mole percent NH4+. Single crystal X-ray data were collected on the compositions K.5(NH4).5TiOAs04 (KNTA) and NaTiOPO4 (NaTP). In KNTA, refinement reveals little change in the Ti coordination environment, however, unlike K.5(NH4).5Ti0PO4, no selective siting of the potassium and ammonium ions occurs. In NaTP, it is found that one of the Ti-O-Ti bond angles is reduced to 1300, and that one of the sodium atoms has the unusually low coordination number of four. KTixGa1-x0xPO4(F,OH)1-x is isostructural with KTP, with ▵(Ga-0)trans bond length differences of 0.056 and 0.027Å. Preliminary studies of the compositional dependence of SHG in the system KTixGa1-x0xPO4(F,OH)1-x show that SHG drops by 2 orders of magnitude between 50% and 60% Ga substitution.

Hexagonal ammonium zinc ­phosphate, (NH4)ZnPO4, at 10 K

The title compound, (NH(4))ZnPO(4)-HEX, is built up from a three-dimensional network of ZnO(4) and PO(4) tetrahedra [d(av)(Zn-O) = 1.9400 (7) A and d(av)(P-O) = 1.5396 (7) A], fused together via Zn-O-P links [straight theta(av) = 133.47 (4) degrees ]. An undisordered linear Zn-O-P bond occurs (all three atoms lie on a threefold axis). Extra-framework NH(4)(+) cations, which interact with the [ZnPO(4)](-) framework by hydrogen bonds, complete the crystal structure.

Sodium scandium arsenate, Na3Sc2(AsO4)3

Nasicon-type trisodium discandium tris(arsenate), Na3Sc2(AsO4)3, contains a polyhedral network of vertex-sharing octahedral ScO6 and tetrahedral AsO4 units [d(av)(Sc-O) = 2.089 (2) A and d(av)(As-O) = 1.672 (2) A] encapsulating two types of Na+ species. The sodium site occupancies are similar to those of the equivalent species in beta-Na3Sc2(PO4)3.

Sodium zinc hydroxide selenite, NaZn2(OH)(SeO3)2

The title compound, sodium dizinc hydroxide bis-(selenite), NaZn 2 (OH)(SeO 3 ) 2 , contains a dense polyhedral network of octahedral ZnO 6 , pyramidal SeO 3 and tetrahedral NaO 4 units [d av (Zn-O) = 2.120 (2), d av (Se-O) = 1.700(1) and d av (Na-O) = 2.316 (2) A]. It is isostructural with NaCo 2 (OH)(SeO 3 ) 2 .

[CN3H6]2[Zn(CO3)2], the first organically templated open-framework carbonate

[CN3H6]2[Zn(CO3)2], the first organically templated open-framework carbonate has been synthesized hydrothermally and its single crystal structure and some properties have been determined. This phase is built up from a three-dimensional framework of vertex-linked ZnO4 and CO3 building units encapsulating the extra-framework guanidinium cations. Template-to-framework hydrogen bonding appears to play an important role in stabilizing the structure. The zincocarbonate framework shows a surprising similarity to those of known zinc phosphates and phosphites.