Synthesis and characterization of the silver maleonitrilediselenolates andsilver maleonitriledthiolates [K([2.2.2]-cryptand)](4)[Ag-4(Se2C2(CN)(2))(4)], [Na([2.2.2]-cryptand)](4)[Ag-4(S2C2(CN)(2))(4)]center dot 0.33MeCN, [NBu4](4)Ag-4(S2C2(CN)(2))(4))], [K([2.2.2]-crytand)](3)[Ag(Se2C2(CN)(2))(2)]center dot 2MeCN, and [Na([2.2.2]-cryptand)](3)[Ag(S2C2(CN)(2))(2)]

Reaction of AgBF4, KNH2, K2Se, Se, and [2.2.2] -cryptand in acetonitrile yi elds [K([2.2.2] -cryptand)](4)[Ag-4(Se2C2(CN)(2))(4)] (1) In the unit cell of 1 there are four [K([2.2.2]-cryptand)](+) units and a tetrahedral Ag4 an ionic core coordinated in mu (1)-Se, mu (2)-Se fashion by each of four mns ligands (mns = maleonitrilediselenolate. [Se2C2(CN)(2)](2-)). Reaction of A gNO3, Na-2(mnt) (mnt = maleonitriledithiolate, [S2C2(CN)(2)](2-)), and [2.2 .2]-cryptand in acetonitrile yields [Na([2.2.2]-cryptand)](4)[Ag-4(mnt)(4)] .0.33MeCN (2). The Ag4 anion of 2 is analogous to that in 1. Reaction of Ag NO3, Na-2(mnt), and [NBu4]Br in acetonitrile yields [NBu4](4)[Ag-4(mnt)(4)] (3). The anion of 3 also comprises an Ag-4 core coordinated by four mnt li gands, but the Ag4 core is diamond-shaped rather than tetrahedral. Reaction of [K([2.2.2] -cryptand)](3)[Ag(mns)(Se-6)] with KNH2 and [2.2.2]-cryptand in acetonitrile yields [K( [2.2.2]-cryptand)](3)[Ag(mns)2]. 2MeCN (4). The anion of 4 comprises an Ag center coordinated by two mns ligands in a tetr ahedral arrangement. Reaction of AgNO3, 2 equiv of Na-2(mnt), and [2.2.2]-c ryptand in acetonitrile yields [Na([2.2.2]cryptand)](3)[Ag(mnt)(2)] (5). Th e anion of 5 is analogous to that of 4. Electronic absorption and infrared spectra of each complex show behavior characteristic of metal-maleonitriled ichalcogenates. Crystal data (153 K): 1. P2/n, Z = 2, a = 18.362(2) Angstro m, b = 16.500(1) Angstrom, c = 19.673(2) Angstrom, beta = 94.67(1)degrees, V = 5941(1) Angstrom (3); 2 P (4) over bar, Z = 4, a = 27.039(4) Angstrom, c = 15.358(3) Angstrom, V= 11229(3) Angstrom (3); 3, P2(1)/c, Z = 6, a 15.6 89(3) Angstrom, b = 51.924(11) Angstrom, c = 17.393(4) Angstrom, beta = 93. 51(1)degrees, V = 14142(5) Angstrom (3); 4, P2(1)/c, Z = 4, a = 13.997(1) A ngstrom, b = 21.866(2) Angstrom, c = 28.281(2) Angstrom, beta = 97.72(1)deg rees, V= 8578(1) Angstrom (3); 5, P2/n, Z = 2, a = 11.547(2) Angstrom, b = 11.766(2) Angstrom, c = 27.774(6) Angstrom, beta = 91.85(3)degrees, V= 3772 (1) Angstrom (3).