ISOLATED VERSUS CONDENSED ANION STRUCTURE .3. THE INFLUENCE OF THE CATIONS 1,3-PROPANEDIAMMONIUM, 1,4-BUTANEDIAMMONIUM, N-PROPYLAMMONIUM, N-BUTYLAMMUNIUM AND N-PENTYLAMMONIUM ON STRUCTURES AND PHASE-TRANSITIONS OF ZNBR42- SALTS - A BR-81 NQR AND X-RAY STRUCTURE-ANALYSIS

The influence of the cations an the condensation of the anions in the salts (A') Zn (II) Br-4 and (A)(2)Zn (II) Br-4 is studied by Br-81 NQR and X-ray crystal structure analysis. (A')Zn(II)Br-4(A'= [H3N(CH2)(3) NH3](2+)) (1) shows a phase transition at 474 K. The phase II of (1) c rystallizes with isolated [ZnB4(4)](2)- tetrahedra:monoclinic P2(1)/n, Z=4, a=1108.4 (5) b=1096.8(2), c=1118.5(6) pm, and beta=117.07(4)degr ees at 296 K. A quarter was observed in the Br-81 NQR spectrum of phas e II: 61.634, 58.062, 56.675, and 53.673 MHz (77 K) 59.193, 57.448, 56 .015 and 52.515 MHz (301 K). (A)(2)ZnBr4(A=[n-H3C(CH2)(2)NH3](+) (2) a nd [n-H3C(CH2)(3)NH3](+) (3)) also show structures with isolated [ZnBr 4](2-)tetrahedra. The compound (2) crystallizes with P2(1)/c, Z=4, a=7 71.8(3), b=1061.9(4), c=2054.2(7) pm, and beta=106.75(1)degrees at 291 K. The compound (3) crystallizes with P2(1)/c, Z=4, a=768.9(4), b=222 9.6(10), c=1071.6(5) pm, and beta=91.70(3)degrees at 295 K. Br-81 NQR and DSC measurements on [H3N(CH2)(4)NH3]ZnBr4 (4), and [n-H3C(CH2)(4)N H3](2)ZnBr, (5) were also performed. The compound (4) shows several ph ase transitions at 349 K and higher temperatures, and a quarter in the Br-81 NQR spectrum could be observed between 77 and 330 K: 65.992, 65 .544, 59.900, and 50.162 MHz (77 K); 63.787, 62.963, 59.928, and 50.36 4 MHz (320 K). The compound (5) shows also a phase transition at 244 K , and a quartet of Br-81 lines could be observed in the NQR spectrum b etween 77 and 244 K: 61.279, 58.933, 57.869, and 56.485 MHz (77 K); 59 .712, 56.936, 57.409, and 54.793 MHz (240 K). The various influences o f the cations, such as size and hydrogen bonds on the condensation of [MX4](2-) (M=Zn, Cd; X=Cl, Br) are discussed.