Crystal structure of bis-[μ-bis(diphenylphosphino)methane]-(μ-bromo)- isoquinolinebromodicopper(I)-naphthaline — quinoline — acetonitrile, [Cu2(CH2(P(C6H5)2)2)2(i-C9H7N)]Br2 (C10H8) · (C9H7N) · CH3CN