LEWIS-BASE ADDUCTS OF LEAD(II) COMPOUNDS .19. SYNTHETIC AND STRUCTURAL STUDIES OF SOME 1 1 ADDUCTS OF 2,4,6-TRIS (2-PYRIDYL)-1,3,5-TRIAZINEWITH LEAD(II) (PSEUDO-)HALIDES/

Syntheses and room-temperature single-crystal X-ray structure determin ations are recorded for 1:1 adducts of 2,4,6-tris(2-pyridyl)-1,3,5-tri azine ('trz') with lead(II) chloride, bromide, iodide and thiocyanate, the chloride and bromide being methanol monosolvates. [(trz)PbCl2]((i nfinity\infinity)).MeOH is monoclinic, P2/c, a 9.178(2), b 14.833(3), c 7.347(8) Angstrom, beta 93.89(2)degrees, Z = 2 f.u.; R was 0.042 for N-o = 1451 'observed' (I > 3 sigma(I)) reflections; the bromide is re lated, having a derivative triclinic cell, <P(1)over bar>, a 9.259(3), b 15.153(6), c 7.428(2) Angstrom, alpha 90.28(3), beta 94.62(2), gamm a 91.15(3)degrees, Z = 2 f.u.; R was 0.047 for N-o 2729. [(trz)PbI2](( infinity\infinity)), also solvated, is triclinic, <P(1)over bar>, a 15 .266(9), b 8.9448(8), c 8.148(11) Angstrom, alpha 80.60(6), beta 77.05 (7), gamma 83.45(3)degrees, Z = 2; R was 0.032 for N-o 3222. In all th ree compounds an infinite PbX(2)PbX(2)Pb polymer is found with the pla ne of the tridentate trz lying quasi-normal to the polymer axis. Pb-N distances lie between 2.63(1) and 2.803(8) Angstrom; Pb-Cl are 2.848(3 ) and 3.074(3), Pb-Br 2.963(2)-3.257(2) and Pb-I 3.192(3)-3.466(2) Ang strom. The thiocyanate, monoclinic, C2/c, a 16.974(6), b 6.410(2), c 3 9.49(2) Angstrom, beta 96.33(4)degrees, Z = 8, R 0.13 for N-o 2465, is a column of dimeric units stacked up b, successive lead atoms being b ridged by thiocyanate sulfur atoms packed in between them, and quasi-p arallel to a, and by thiocyanates parallel to b which link pairs of le ad atoms in each dimer with the same b coordinate by pairs of bridging nitrogens and bridging sulfurs from the adjacent pair.